Melissa Chernick

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Ecologist, procrastinator, water polo-ist, beer snob, underfunded shopoholic, crazy cat lady, undocumented cinephile, and novice blogger extraordinaire.

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  • April 26, 2013
  • 01:53 PM
  • 71 views

The Curious Case of the Earworm (Part 2)

by Melissa Chernick in Science Storiented

In Part 1 of this topic, we explored the reasons why we like certain songs. But what transforms that likable melody into an earworm? Or is likability even a contributing factor? We took the biochemical/neurological route in Part 1, so now we’re gonna go all psychology for this one with a paper published in 2011 in Psychology of Music.Let’s get some terminology out of the way first. We all have internally-directed thought (all that stuff you think to yourself), and we also experience spontaneous cognitions, which are those “common, everyday experiences that occur against a backdrop of deliberate goals-directed mental processes.” Musical imagery is associated with this. Involuntary musical imagery (INMI) is when a piece of music comes unbidden into your mind and repeats outside of your conscious control. It is the “earworm”, “brain worm,” “sticky music,” “cognitive itch,” and/or “stuck song syndrome.” This 2011 study looked to see if there were any patterns in everyday life that lead to an INMI episode, basically what prompts an earworm. The researchers first wanted to catalog known instances of earworms. So they used a radio feature where listeners could contact the presenter/DJ to describe their earworm experiences, and they used an online survey on the radio’s website to collect earworms. This survey allowed people to answer questionnaires and even write descriptions of the songs stuck in their heads. Their results showed eight dominant themes to describe INMI triggering. These themes were then grouped into four abstract categories (listed from most common cause to least):Music exposure – this theme is divided into recent and repeated. Recent exposure is when you hear music and then later have an INMI experience. Repeated exposure is when you hear the music on multiple occasions before an earworm occurs.Memory triggers – this theme relates to INMI episodes that are triggered not when you hear a song but when you remember a song. This can happen through Association in which you might sight a person, situation, word, sound, or rhythm that triggers the earworm. Or it may happen through Recollection, a personal memory that acts as the trigger. It may also be the result of Anticipation, an upcoming event that is connected to a tune.Affective states – this theme is more situational. Your mood, stress level, and emotions can all cause earworms.Law attention states – this theme is abstract in that it relates to circumstances where the demands on your brain are low. These times are usually when you are dreaming or when your mind wanders.This is a psychology study and so delves into involuntary retrieval theory and states of mind. I won’t go in to all of that. I’ll simply say that this study is interesting because it categorizes the cues associated with earworms. A simple but effective exercise. If you are like me, then you probably read most or all of those and thought, “Yep, that’s how it happens with me,” or something similar.A recent study published in Applied Cognitive Psychology, looked into this question of earworms a bit more. These researchers wanted to know what gets stuck and why. This study first uses a survey designed to collect earworm experiences, focusing on the cues that cause them, the nature of re-experiencing the song, and if commonly stuck songs are liked or disliked.This survey found that a person’s connection to the song predicted which songs became earworms (you usually know your earworm well), and it is usually the result of recent exposure (supporting the "music exposure" results of the previous study). It also showed that the song itself was unique to the individual, and that people generally liked the song stuck in their heads but less so the more often it got stuck. That makes sense; the longer that song is in there the more you just go AHH! You know how you repeat only part of the song over and over, usually the chorus? This science says you aren’t alone, this is how it happens with a lot of people. However, if you are a musician or someone who listens to music constantly or for a large part of the day, you are more likely to develop an earworm. When the researchers had people keep an earworm diary, they found similar results.Next, the scientists ran a few lab experiments. The first experiment tried to induce an earworm by having participants evaluate songs, then engage in an unrelated task (solving a maze), and then report any earworms. They found no effects of music type but that song order affected both earworm duration and the likelihood that the earworm would return. The last song you hear is probably the one that will get stuck in your head. The next lab experiment investigated the role of cognitive load (how strained your brain is). They used the method of the first experiment with the exception that they made the tasks harder (Sudoku puzzles of various difficulty levels), making the brain work more (hard puzzle = large cognitive load). They found that the last song became an earworm more often regardless of cognitive load, but it played for a longer time in people with more challenging puzzles. Also, if a person reported the last song as an earworm playing during the puzzle then they were more likely to have the song return later (during a lower cognitive low) as compared to those people who didn’t have the song playing during their puzzle. The last experiment was an extension of the cognitive load experiment, this time using a verbal task (solving anagrams of various difficulties) instead of a puzzle. Here, the researchers found similar results to the second experiment in that song order was important, especially for more difficult tasks. However, the last song was experienced less when completing verbal tasks than nonverbal tasks.Whew. That was a lot of info in a small amount of space. If we sum up Part 1 and 2, what did we learn? Well, when you hear something you like your brain releases dopamine, the feel good, reward stuff. Your brain stores information about the kinds of songs you like and later uses that information to decide if it likes a song if you’ve never heard before. If it decides that you like it then it gives you your reward, making you want to hear that song again. Songs you enjoy are more likely to develop into earworms, particularly if they are the last song you hear, but there are other situational and emotional experiences that can trigger and earworm too (that whole science-is-never-simple thing again).“I’m gonna pop some tags – Only got twenty dollars in my pocket….” ....*sigh*Williamson, V., Jilka, S., Fry, J., Finkel, S., Mullensiefen, D., & Stewart, L. (2011). How do "earworms" start? Classifying the everyday circumstances of Involuntary Musical Imagery Psychology of Music, 40 (3), 259-284 DOI: 10.1177/0305735611418553Hyman, I., Burland, N., Duskin, H., Cook, M., Roy, C., McGrath, J., & Roundhill, R. (2013). Going Gaga: Investigating, Creating, and Manipulating the Song Stuck in My Head Applied Cognitive Psychology, 27 (2), 204-215 DOI: ... Read more »

Williamson, V., Jilka, S., Fry, J., Finkel, S., Mullensiefen, D., & Stewart, L. (2011) How do "earworms" start? Classifying the everyday circumstances of Involuntary Musical Imagery. Psychology of Music, 40(3), 259-284. DOI: 10.1177/0305735611418553  

Hyman, I., Burland, N., Duskin, H., Cook, M., Roy, C., McGrath, J., & Roundhill, R. (2013) Going Gaga: Investigating, Creating, and Manipulating the Song Stuck in My Head. Applied Cognitive Psychology, 27(2), 204-215. DOI: 10.1002/acp.2897  

  • April 19, 2013
  • 03:16 PM
  • 68 views

The Curious Case of the Earworm (Part 1)

by Melissa Chernick in Science Storiented

I have had “Thrift Shop” stuck in my head for what seems like days.Yes, it is always on the radio, and yes, I usually listen to it when it is playing. Don't judge me. But why (*Stella scream* wwhhhhyyyyy!) has it established a permanent residence in my brain? I’m going to use a few studies to make the case that it isn’t my fault; I’m led around by my biochemistry. Basically, I’m blaming it on my neurons.Hmmm…where to start. Let’s try to figure out why we like a song (or music in general) in the first place. A study by Valorie Salimpoor et al. in 2011 suggests that it comes down to the biochemistry of pleasure. We, as humans, as animals, find many things in our lives to be pleasurable. Why is this? Well, our brain tells us so. Pleasure is, in essence, a reward for a good stimulus. In the brain, it is largely mediated by dopamine, which also works to reinforce and motivate these behaviors. Now, most people will agree that music is a pleasurable stimulus, but as an abstract stimulus (one not directly related to survival) is it regulated by the same dopamine pathways? In this 2011 study, subjects were asked to select their own “highly pleasurable music” to play for these tests (since musical preferences are so individualized). Then the researchers used PET scanning to estimate dopamine release. Since there are physiological changes that occur during moments of extreme pleasure, they also used the “chills” or “musical frission” response, an objective phychophysiological measurement of clear and discrete patterns of autonomic nervous system arousal. To tease out the response to the music versus the anticipation of the music, they combined the temporal specificity of functional MRI (through the temporal profile of blood oxygenation level - BOLD) with the neurochemical specificity of the PET scan.Salimpoor's group found that the pleasure experienced when listening to music is associated with dopamine activity, that there was a positive correlation between the intensity of “chills” and dopamine release, and an increased BOLD response. In fact, dopamine levels surge during key passages of favorite music and just in anticipation of it. This release is pivotal for establishing and maintaining the behavior, making listening to music a valued experience.Ok, biochemistry…check. Let’s go bigger: What parts of your brain light up when you hear music you like? Salimpoor et al. has published a new study in the April 2013 edition of Science that looks at neural processes active when this pleasurable musical event is happening. Specifically, they look at the reward value the first time a song is heard. We now know that dopamine is involved in familiar music, so what about previously unheard music? To test this, the researchers recruited people, asked them to share their musical tastes (“indie” and “electronic” were the most popular), and used music excerpts selected from a music-recommendation software to pick a unheard song within that preference. To assess reward value, to see if participants liked a song enough that they wanted to hear it again, they were given the option purchase the music with their own money (I know if I have to use my own money then I make sure I love it). Then the participants underwent fMRI scans while listening to musical excerpts and were asked to provide bids of how much they were willing to spend for each song.The researchers found that the reward value (amount of the bid) was directly related to the region of the brain associated with positive prediction error (the NAcc for you brain folks), or pleasant surprises. Increased functional connectivity with this region was made with the auditory cortices, the region known to play a role in the retrieval of previously stored sound information (STG), and the areas implicated in beat processing (caudate and premotor areas). Additionally, increased connectivity was found in regions associated with emotional processing and value-guided decision-making (VMPFC, OFC, and amygdala), but only when sounds gain reward values. When added to the dopamine findings, the activity in these brain regions suggests that when you hear new music your brain looks at its stored information about sound relationships and makes a decision on whether or not to like it based on previous listening experiences and the expectations of tonal events associated with that type of music. If you like it, then your brain gives you a pleasure reward and you end up using your money to buy the song (or otherwise find ways to hear it again). If you like it better than you expected, you get even more delight.Now we know why we like the song and want to hear it again (and again and again…).In the next post we will go further and explore what turns this likeable song into an earworm. Or is it its likeablity at all? (insert cliffhanger music here…dun dun duuuunnnn…)Salimpoor, V., Benovoy, M., Larcher, K., Dagher, A., & Zatorre, R. (2011). Anatomically distinct dopamine release during anticipation and experience of peak emotion to music Nature Neuroscience, 14 (2), 257-262 DOI: 10.1038/nn.2726Salimpoor, V., van den Bosch, I., Kovacevic, N., McIntosh, A., Dagher, A., & Zatorre, R. (2013). Interactions Between the Nucleus Accumbens and Auditory Cortices Predict Music Reward Value Science, 340 (6129), 216-219 DOI: 10.1126/science.1231059...and an article in ScienceNOW "Why Your Brain Loves That New Song"(image via rockandtheology) ... Read more »

Salimpoor, V., Benovoy, M., Larcher, K., Dagher, A., & Zatorre, R. (2011) Anatomically distinct dopamine release during anticipation and experience of peak emotion to music. Nature Neuroscience, 14(2), 257-262. DOI: 10.1038/nn.2726  

Salimpoor, V., van den Bosch, I., Kovacevic, N., McIntosh, A., Dagher, A., & Zatorre, R. (2013) Interactions Between the Nucleus Accumbens and Auditory Cortices Predict Music Reward Value. Science, 340(6129), 216-219. DOI: 10.1126/science.1231059  

  • April 12, 2013
  • 04:21 PM
  • 67 views

Om Nom Nom: The Links Between Plant Diversity and Herbivory

by Melissa Chernick in Science Storiented

I usually start a post with the reason why a particular article caught my eye. Today, I’m not sure why my eyeballs glommed on to this paper, but they did. As it turns out, they have a pretty good taste in articles. Who knew?An early view paper from the Journal of Ecology looks at how the large herbivores of the African savanna affect the diversity and community structure of plants. More and more studies these days are taking a phylogenetic approach to community ecology questions. That is, they are looking at the evolutionary development and history of a species or taxonomic group to explain the patterns that we currently see. This new study takes this approach in the subtropical woodland biome, or “bushveld,” of the Kruger National Park (KNP) in northeast South Africa. This area is home to 148 mammal species, of which 30 are large herbivores such as elephants, rhinos, and giraffes. The vegetation of this area consists of 1974 species, including 458 species of trees and shrubs. KNP varies from dense thicket, savanna woodlands to forests characterized by tall trees and a closed canopy. These plant communities are under occasional pressure from periodic fire and under constant pressure from large herbivores. This study looks at the impacts of these herbivores on the phylogenetic structure of woody plant assemblages and evaluates the impacts of their removal on plant community composition and structure.The researchers used DNA sequencing to reconstruct the phylogeny of 448 species of trees and shrubs (using Amborella as an outgroup), representing 246 genera, 71 families and 31 orders. ... Let’s pause for a second to say “Wow!” ... Then they calculated divergence times and used speciation models on these data. Next was the community sampling along a north-south transect through KNP. This transect has enclosures situated along it where large herbivores are partly or fully excluded. These enclosures have been established in the park for between 8 and 43 years. Within 15 defined “ecozones,” the researchers surveyed 110 50x50 meter unrestricted herbivory plots and 15 50x50 meter plots in each of the five herbivore exclusion enclosures. Within these plots they recorded all species of trees and shrubs and the number of individuals per species (abundance). Then they evaluated various physical and mechanical plant defense traits (not including chemical defenses), using wood density of quantify plant resistance to physical damage and specific leaf area (SLA) as a proxy for leaf nutrient content.All sorts of indices (MPD, MNTD, SR, Shannon, NRI, NTI) and statistics were used that I’m not going to go into because they will just confuse everyone. But when all the statistics were done, they found a latitudinal gradient in diversity with the highest diversity in the south and extreme north and low diversity in the center (which matches rainfall patterns). In parallel, they found shifts in community phylogenetic structure comparable to these changes in community diversity, indicating that the communities in the center are more highly phylogenetically clustered (composed of more closely related species). Plant diversity in the KNP is strongly spatially structured and this clustering is reflective of generalist browsing, the geomorphology of the area, and the patchy distribution of large herbivores. In plots where herbivory is unrestricted they found significant phylogenetic clustering of plant communities, likely the result of the heavy pressure from the herbivores. They also found that plant defense traits had a weak but significant phylogenetic signal, suggesting that they do not fit well into the simple model they used. When the researchers compared the enclosures to the unrestricted areas they found “that when megaherbivores are excluded, species diversity generally decreases, but changes in phylogenetic diversity [vary] by spatial location.” When large herbivores are excluded, plant community structure is contingent upon the initial community structure. If a community was initially overdispersed then the shift towards a more clustered community would occur by excluding large herbivores and vice versa. Ultimately, they conclude that the exclusion of large herbivores results in impoverished species communities.I think that it is important to mention that these researchers were limited by the study design they had to work with. These enclosures had already been set up by other people. As such, the scientists encountered some issues that they would have been able to control for if they had set up the site themselves. Issues like enclosure age and location. For example, one enclosure was located on a river that periodically floods, altering local plant diversity. Such issues make it difficult for them to predict how specialist vs. generalist herbivores impact community structure and prevents them from drawing strong conclusions about the underlying causes for the patterns they saw.On the upside, their results add valuable knowledge critical for predicting the impacts of overall herbivore decline on African ecosystems and local increases of these animals in protected reserves. This study “shows not only that large herbivores are key to maintaining woody plant diversity, but also that they may impose specific phylogenetic structure on plant communities.” Shifts in this structure have downstream consequences in that phylogenetic diversity can capture genetic and functional diversity, which has been linked to ecosystem productivity. And, ultimately, we want to keep our ecosystems happy and productive, rightKowiyou Yessoufou, T. Jonathan Davies, Olivier Maurin, Maria Kuzmina, Hanno Schaefer, Michelle van der Bank, & Vincent Savolainen (2013). Large herbivores favour species diversity but have mixed impacts on phylogenetic community structure in an African savanna ecosystem Journal of Ecology : 10.1111/1365-2745.12059(image via Animals Time) ... Read more »

Kowiyou Yessoufou, T. Jonathan Davies, Olivier Maurin, Maria Kuzmina, Hanno Schaefer, Michelle van der Bank, & Vincent Savolainen. (2013) Large herbivores favour species diversity but have mixed impacts on phylogenetic community structure in an African savanna ecosystem. Journal of Ecology. info:/10.1111/1365-2745.12059

  • March 29, 2013
  • 07:15 PM
  • 124 views

Getting to the Roots (and Fungi) of Carbon Sequestration

by Melissa Chernick in Science Storiented

This week, I found a paper that I’m calling the best of both worlds. Well, for me at least. This paper combines my past (and lingering) interest in island biogeography with a current interest in climate change and carbon storage.If you have been reading my blog long enough then you already know my love of islands. They are just so darn useful. In the past, I have focused on oceanic islands, but lake islands are also really neat. These types of islands typically form when lower lying land areas fill with water, effectively cutting off higher areas from the mainland and making them into islands. As such, these islands usually already contain forest as opposed to an oceanic island that emerges from the ocean and must be colonized. A new study, published in journal Science, looks at a fire-driven boreal forest chronosequence on forested lake islands in northern Sweden. Such a chronosequence allows the study of soil carbon sequestration over time scales of centuries to millennia.This new study looks at roots and their associated fungi (mycorrhizae) as sources of this stored carbon. I’m not going to spend the space to describe mycorrhize, but will, instead, send you over to my Free Market Fungi post for more information, if you need it. It is known that 16 percent of the global carbon stock is sequestered in soils. To date, most carbon studies of this type focus on aboveground leaf litter as the fundamental determinants of this carbon accumulation. But a large portion of photosynthetically fixed carbon is actually directed belowground to the roots and, subsequently, the mycorrhizae. Now, let’s add fire. It has been shown that when a forest doesn't burn, the soil and ecosystem carbon accumulate unabated, and in a linear fashion. Add this information together and it becomes a big deal when it comes to correctly allocating carbon, calculating the long term sequestration rates, and predicting how forests will respond to climate change and other environmental shifts.The study sites were in two adjacent lakes, Lake Hornavan and Lake Uddjaure, in northern Sweden. The islands in these lakes were formed after the most recent glaciation and come in a variety of sizes. In terms of fire, larger islands burn more frequently because they are larger targets for lightning strikes. As a result, several of the large islands in these lakes have burned in the last century, whereas some of the small islands haven’t burned in at least 5000 years. This lack of fire leads to very thick humus layers (or organic layers towards the top of the soil column) on smaller islands, up to 1 meter thick!The researchers divided islands into three size classes of 10 islands each: large (over 1 ha), medium (0.1-1.0 ha), and small (less than 0.1 ha). They took soil samples from these islands to look at the organic soil profiles and found that large islands accumulated 6.2 kg of C per square meter belowground with a mean time since fire of 585 years, medium islands accumulated 11.2 kg of C per square meter with a mean time since fire of 2180 years, and small islands 22.5 kg of C per square meter with a mean time since fire of 3250 years. Then they looked at the carbon dynamics across this chronosequence by analyzing bomb 14C. This allowed them to determine the age since fixation of soil carbon. Then they fitted a mathematical model to measurements of carbon mass and age distribution across the soil profiles for six of the islands (3 large, 3 small). This model revealed that the distribution of carbon mass and age could only be predicted when they included carbon from roots. This root-derived carbon accumulation was found to be larger on small islands (70 percent, that's a LOT!) than large islands (47 percent). They were able to explain the entire carbon sequestration difference on small islands from these root-derived inputs. The model also showed that small islands store a major proportion of their soil carbon in the deeper soil layers, those over 100 years old. However, below 20 cm depth, the root-derived carbon inputs were shown to be low and to decompose slowly. So the root-derived carbon input into the upper layers probably contributes to the long-term buildup of humus that is seen on these islands. But, as usual, that's not the end of the story.We know that fungi play very important roles in forest ecosystems, both as decomposers and in root-assoicated carbon transport and respiration. So the researchers also profiled the relative abundance of major groups of fungi by depth in the soil profiles. They found that the upper soil layers are dominated by free-living saprotrophs (fungi that obtain their nutrition heterotrophically from non-living organic materials), and greater depths were dominated by mycorrhizal and other root-associated fungi. Their model suggests that these mycorrhizae live at the spots where the largest difference in carbon sequestration between the island size classes exists, which also tends to be the areas of highest root mass. When they ran tests for fungal biomass throughout each soil profile they found greater mycelial (the vegetative part of a fungus, consisting of a mass of branching, threadlike hyphae) production on large islands, but less mycelial necromass (dead stuff) on small islands. This suggests that the large production is counterbalanced by faster decomposition of mycelial remains. “Correspondingly, the 14C model indicated faster decomposition of root-derived [carbon] on large islands, despite inputs being conservatively constrained to be equal across all islands.” I found these conclusions to be interesting because of the amount of soil carbon from roots and mycorrhizal fungi, especially on small islands. And although they saw less carbon accumulation on large islands, these islands have a greater root density and so should have more carbon allocation to roots and the associated fungi. Did you catch the contradiction? Well, in response to increased carbon dioxide, there will be an increase of carbon inputs to the roots which will accelerate the turnover of soil organic matter. This counteracts carbon accumulation and enhances nitrogen cycling through the microbial pools, an effect these researchers observed when they tested the C:N-ratios in the humus of large islands. This is much lower on small islands, possibly because of impared mycorrhizal nitrogen mobilization and the accumulation of nitrogen in fungal remains. This leads to progressive nutrient limitations, then leads to changes plant productivity, leading to changes in community composition, which leads to changes in total belowground carbon allocation, that leads to changes in fungi. Definately starting to grasp the importance of the belowground dirty stuff. There’s a whole lot of carbon down there that we need to start looking at, accounting for, and seeing where it goes. We know that changes in the environment such as climate change, soil fertilization, fire suppression, and forest management make big differences to the aboveground stuff. It only makes sense that the belowground stuff is impacted as well.Clemmensen, K., Bahr, A., Ovaskainen, O., Dahlberg, A., Ekblad, A., Wallander, H., Stenlid, J., Finlay, R., Wardle, D., & Lindahl, B. (2013). Roots and Associated Fungi Drive Long-Term Carbon Sequestration in Boreal Forest Science, 339 (6127), 1615-1618 DOI: 10.1126/science.1231923If you would like some follow-up reading I suggest:Treseder, K. K. (2013-03-29) Fungal Carbon Sequestration. Science, 339(6127), 1528-1529. (DOI: 10.1126/science.1236338)  Also check out the write-up in Nature "Fungi and roots store a surprisingly large share of the world's carbon"... Read more »

Clemmensen, K., Bahr, A., Ovaskainen, O., Dahlberg, A., Ekblad, A., Wallander, H., Stenlid, J., Finlay, R., Wardle, D., & Lindahl, B. (2013) Roots and Associated Fungi Drive Long-Term Carbon Sequestration in Boreal Forest. Science, 339(6127), 1615-1618. DOI: 10.1126/science.1231923  

  • March 22, 2013
  • 05:48 PM
  • 134 views

They're All Alike: The Giant Squid Conundrum

by Melissa Chernick in Science Storiented

I wasn’t going to post on another paper this week but then two things happened: I saw the video of the first giant squid filmed in its natural habitat (those scientists get so excited!), and I saw the study about giant squid diversity. I posted the first above and now we'll take a look at the second.The giant squid (Architeuthis spp.) is one of the largest invertebrates and lives in the deep sea. It was first described as Architeuthis dux in 1857 by Danish naturalist Japetus Steenstrub, but since then, as many as 21 nominal species of Architeuthis have been described. The descriptions of this creature have primarily come from remains found washed up on beaches, found floating on the ocean surface, caught by deep-sea trawling activity, or in the stomachs of sperm whales (Physeter macrocephalus). It wasn’t until 2004 that a live specimen was observed in its natural habitat, and earlier this year that the first video footage was published (although not the in-the-natural-habitat version above). It is estimated that female squid reach a total length of 18m (59ft) and males reach slightly smaller sizes. The giant squid is globally distributed, with the exception of polar regions. They feed primarily on fish and smaller cephalopods. Studies of carbon and nitrogen isotope profiles of the upper beaks suggest ontogenetic diet shift earlier in life (smaller to larger prey items), and carbon isotope composition remains constant in food sources indicating that the squid inhabit relatively small, well-defined and productive areas. The predation of adult squid by sperm whales suggests that squid population size must be large enough to support such a large whale population, although this has never been proven.There are some rather obvious difficulties in studying giant squid using conventional, observational techniques. So other techniques must be utilized. Enter, DNA. Recent advances in DNA sequencing techniques have made it easier, quicker, and more economical to sequence long stretches of DNA. The role of DNA sequencing is becoming more and more important in phylogenetic and population biology studies. It allows you to assess the number of species, examine the amount of genetic variation, and describe population structure.In a new paper in the Proceedings of the Royal Society B: Biological Sciences, researchers collected 43 Architeuthis soft tissue samples from the carcasses of dead animals across their known range. They extracted DNA samples from the specimens to analyze the mitochondrial genomes (mitogenomes) and levels of nucleotide variation. They generated mitogeome datasets using several strategies, depending on the quality of the DNA in each sample. I’m not going to go into their sequencing methods – if you are a molecular biologist then you already know them, and if you aren’t then I’ll just bore you. To look at the population level of the genetic variance, they wanted to compare their samples with the fossil record of coleoid cephalopods. This is challenging considering the extremely limited fossil record for these organisms. So they used four different mutation rates to tentatively estimate a time of expansion and upper and lower bounds for the time of divergence of Achiteuthis from other squid families.They were able to complete 37 complete and 6 partial mitogenome sequences. Remember up at the top of the post where I said “21 nominal species of Architeuthis have been described?” One pretty strong conclusion of this study is that there is only one species of Architeuthis that exists, namely Architeuthis dux (Steenstrub, 1857). The researchers found the haplotype diversity of these giant squid to be high at the mitogenome level, but the level of nucleotide diversity in these sequences was found to be extremely low, with only 181 segregating sites of a 20,331 base pair long sequence. Only the basking shark (Cetorhinus maximus) has a similarly low diversity, which is the result of a recent bottleneck. This diversity for giant squid is much lower than is seen in other squid, 44 times lower than Humboldt squid (Dosidicus gigas) and 7 times lower than the recently restricted population of oval squid (Sepioteuthis lessoniana). The high haplotype to low nucleotide diversity relationship is interesting because it shows that out of a very diverse phyla of animals, the giant squid is the odd one out. Looking at the species across its range, there was no evidence of any phylogeographic structure, which is odd considering the global distribution.So how do you explain the low genetic diversity in comparison to the global distribution (and potentially large population size)? The authors hypothesize that it could be a low rate of mitochondrial DNA evolution, something that has been observed in other marine organisms. But a low mutation rate does not explain why mitogenome duplications maintain near 100 percent identity. The authors suggest that “perhaps the duplicated sequences form stable secondary structures, which are somehow selectively beneficial, thereby causing mutations to be under negative selection,” which would lead to “a decreased rate of divergence in the duplicated regions relative to the rest of the genome, which does not appear to be the case.” Alternatively, it could be a recent selective sweep such as a bottleneck. Bottlenecks are events that greatly reduce the size of a population, usually resulting in a large reduction in the genetic diversity of that group. If this bottleneck were followed by an expansion in the number of individuals in that population then you would see that low diversity spread amongst a large population. Modeling and analysis of data support the latter hypothesis over the former.Unfortunately, genetic data alone can’t provide an answer as to why this might have happened. Whatever event it was, climatic or biological, it would have had to been wide ranging enough to affect a global population. Perhaps it was a sudden inflation of a population that was historically smaller. It is known that cephalopods tend to be subdominant predators, and as such, are affected by the changes in population of predators and competitors. If this small size was due to restraints on predators and/or competition and that restraint were released then you would expect such an inflation in squid numbers. Considering the effect of industrialized whaling in the 1700s to late 1800s, this is a likely explanation, but still too recent to explain it entirely. This change in predators and/or competitors could have been the result of climatic effects such as the last ice age changing. Such changes could have altered the abundance and distribution of competitors such as predatory fish. Or perhaps, rather than a bottleneck, A. dux existed historically as a single, small, geographically isolated population that then expanded globally. This expansion would have had to been in a non-ordered fashion with either nomadic adults or dispersing juveniles and small pelagic paralarvae capable of using currents to travel long distances. But if they can disperse really far then why would they have been restricted historically? The authors hypothesize that a global population existed for a considerable time, and that an average of just one individual exchanged between two populations per generation will be enough to prevent genetic differentiation between them. They believe that the wide ranging dispersal of paralarvae and juveniles on the currents of the upper layers of the oceans could achieve this. These young life stages float along with the currents feeding on zooplankton and such until they reach a sufficiently large size, after which they descend to the closest nutrient-rich deep habitat where they remain until maturation.I think that’s a pretty good explanation. What about you?Winkelmann, I., Campos, P., Strugnell, J., Cherel, Y., Smith, P., Kubodera, T., Allcock, L., Kampmann, M., Schroeder, H., Guerra, A., Norman, M., Finn, J., Ingrao, D., Clarke, M., & Gilbert, M. (2013). Mitochondrial genome diversity and population structure of the giant squid Architeuthis: genetics sheds new light on one of the most enigmatic marine species Proceedings of the Royal Societ... Read more »

Winkelmann, I., Campos, P., Strugnell, J., Cherel, Y., Smith, P., Kubodera, T., Allcock, L., Kampmann, M., Schroeder, H., Guerra, A.... (2013) Mitochondrial genome diversity and population structure of the giant squid Architeuthis: genetics sheds new light on one of the most enigmatic marine species. Proceedings of the Royal Society B: Biological Sciences, 280(1759), 20130273-20130273. DOI: 10.1098/rspb.2013.0273  

  • March 18, 2013
  • 05:39 PM
  • 96 views

Biological Beta Testing: Altitudinal Edition

by Melissa Chernick in Science Storiented

Spatial patterns in biodiversity have always been a popular topic in ecology, and understanding these patterns helps us to address the looming threats to biodiversity.Did you notice how I made the word ‘patterns’ plural? There isn’t a whole separate field of biogeography for nothin’. Biological diversity is difficult (some say impossible) to measure using a single metric. How do you count things? Simply by the number of species? How about rare versus common species? What about species turnover? What geographic scale are you using? How and/or do you define boundaries? Would you like me to keep going or do you get the point?Lately I’ve noticed a surge in the number of studies that look at diversity gradients that occur along latitude and altitude. We visited the topic of latitude and diversity back in October of last year with the “Dinosaurs, Diversity, Distribution, and the LBG” post. Essentially, latitudinal gradients (LBG or LDG) occur when species richness (a simple count of species) is highest in the tropics and declines polewards (warm areas are more hospitable and produce more food). Altitudinal, or elevational, gradients are nearly as ubiquitous as latitudinal gradients, and they have many of the same characteristics. As you go up in elevation (as on a mountain) the temperature gets colder and habitat areas and the communities they support become smaller and more fragmented. Gradients such as these are overall patterns. Now mix them with diversity indices. In 1960, R.H. Whittaker described the terms alpha diversity (α-diversity), beta diversity (β-diversity), and gamma diversity (γ-diversity). Basically, the total species diversity of a geographic area (γ-diversity) is determined by the mean species diversity at the local, within-site or within-habitat scale (α-diversity) and extent of change in community composition between sites (β-diversity). These definitions have been much argued over (see Tuomisto 2010), and we won’t get in to that. We are going to focus on beta diversity (β-diversity), also called species turnover or differentiation diversity. It is a measure of how different sites are from each other and/or how far apart they are on a gradient of species composition. Factors that drive β-diversity are very important, very poorly understood, and very much argued over. Is it dispersal limitation? Habitat specialization? Environmental heterogeneity? The studies published so far seem to lean toward multiple processes operating at various scales. *sigh* Isn’t that always the way? Observational and experimental studies have shown that impacts on β-diversity vary with productivity. So it would make sense to test this in relation to altitudinal and elevational gradients.A new study to be published in Global Ecology and Biogeography looks at how local community processes may create an altitudinal pattern of β-diversity. Their study site was the Shiretoko National Park in north-eastern Hokkaido, the northernmost island of Japan. In addition to being one of the richest temperate ecosystems in the world, the area is characterized by sharp altitudinal changes in forest structure and productivity as a result of strong winds on the western side of the mountains. The researchers chose this western side to measure the diversity of woody plants and mites (Oribatida) in mature stands where they set up seven plots (each containing 10 subplots) at different altitudes. For the woody plants they recorded the number of individuals taller than 0.5 m, measured the girth at breast height (GBH), estimated the total basal area (BA), recorded canopy height (CH) of the stand, measured the diameter and length of all coarse woody debris (CWD), measured understory light, took soil cores to extract the mites, removed roots from the soil samples, measured the thickness and dry mass of the soil surface litter (A0 layer), collected leaf litter, measured water content and pH of the litter, and the carbon-to-nitrogen (CN) ratios of the litter and soil. They then calculated the β-diversity of the two organism groups for each altitude. So as to take into account the dependence of β-diversity on gamma diversity (γ-diversity), they used null modeling. This type of modeling “randomly shuffles individuals among subplots while preserving γ-diversity, the relative abundance of each species per plot and the number of individuals per subplot” which enabled them to estimate how much observed β-diversity differed from expected β-diversity. They also calculated a β-deviation value for each altitude. This is equivalent to a standardized effect size, indicating the magnitude of the deviation from what you would expect of a random (stochastic or by chance) assembly process.First we’ll hit the results for the oribatid mites. These results showed the altitudinal gradient of β-diversity to be less evident than it was for the plants, and β-deviation showed no altitudinal gradient. That said, they found β-deviation to always be greater than expected in all locations for both woody plants and oribatid mites. In woody plants, the magnitude of β-deviation increased with altitude, suggesting that deterministic processes dominate in low-productivity, high-altitude stands, the role of these processes increasing with decreasing productivity in plant communities. The authors conclude that their results support the hypothesis that “the mechanisms underlying community assembly (e.g. niche versus neutral) play an essential role in creating biogeographic patterns of β-diversity.” They found that niche-based processes (species correlate with environmental variables, the conditions in which the species can persist) govern high-altitude stands, particularly when they included the plants growing in lower layers in the analysis. They found similar results when they calculated β-deviation along a stand-structure gradient with basal area, not altitude, particularly when small understory plants were included. This suggests that “given the altitudinal changes in stand structure, the role of understory plants in deterministic assembly becomes more dominant with altitude.” So those little guys really make a difference! Why? Well, considering that light is a precious commodity, low-elevation, structurally well-developed stands have higher competition for available light, especially for those little understory guys. This fierce competition isn’t so fierce in the higher altitude sites where the upper canopy isn't there to usurp all of the light for itself. This favors a greater, more diverse understory in higher elevations. Again, the authors speculate that this greater high altitude diversity is due to fine-scale niche partitioning, which allows more individuals to exist together.Okay, so that is a pretty good explanation for the high altitude communities. Now what is going on at low altitudes? Well, there you have to take the site’s history a little more into account. What made these stands so “structurally developed” and generated this stochasticity? Consider this: The canopy trees of these forests colonized before the understory individuals, negatively affecting understory species by reducing the availability of space and resources. You then see a relative dominance of these big-ole-bully trees (that’s a technical term, you know) and a one-sided competition scenario.Did I scramble your brain and make you hate biogeography yet? Can you see any sort of overall conclusion here? Lemme help you out…β-diversity is dependent on community processes and shaped by local factors within the landscape. The species in a place use what is in a place.Do you agree? Mori, A., Shiono, T., Koide, D., Kitagawa, R., Ota, A., & Mizumachi, E. (2013). Community assembly processes shape an altitudinal gradient of forest biodiversity Global Ecology and Biogeography DOI: 10.1111/geb.12058(image via Japan-Guide.com) ... Read more »

Mori, A., Shiono, T., Koide, D., Kitagawa, R., Ota, A., & Mizumachi, E. (2013) Community assembly processes shape an altitudinal gradient of forest biodiversity. Global Ecology and Biogeography. DOI: 10.1111/geb.12058  

  • February 13, 2013
  • 11:45 AM
  • 201 views

Getting a Date for Valentine's Day: A Scientific Approach (Part 2)

by Melissa Chernick in Science Storiented

Welcome to Part 2 of Getting a Date for Valentine’s Day: A Scientific Approach. This will make sense if you haven’t read Part 1, but to enjoy the full impact of this V-Day themed explosion of scientific knowledge, I suggest you read both. If that cramps your style then here’s a summary: (1) Just Ask, (2) Get Your Foot in the Door, and (3) Gaze Without Being Creepy. Now, let’s move on…4. Make Them LaughHow often do you hear that what people really want is someone with a sense of humor? Yeah, pretty often. There is some evidence that humor is related to sexual attraction, that people with a good sense of humor are preferred as friends and partners. This is especially true when men exhibit a sense of humor or use humor in their social interactions with women. A study published in 2010, again, by Nicholas Guéguen, looks at the sense of humor at the initial stages of a relationship. Does a man’s sense of humor make him more desirable to a woman he approaches to ask out? This study included young women sitting alone in the sidewalk area of different bars. Guéguen had male confederates sit near a woman and, so she could overhear them, start a benign discussion about their summer jobs. After three minutes of this some of the men would switch to a “Humor Condition” where one man in the group would tell three funny jokes while the other men at his table praised his humor. While this script was playing out, the confederates would take note if the woman was laughing or not. After his other confederates left, the joke-teller (or non-joke-teller in the No Humor condition) would then approach the female and say, ““Hello. My name’s Antoine. I noticed you when I arrived here. I just want to say that I think you’re really pretty. I have an appointment now, but I was wondering if you might give me your phone number. I could phone you later, and we could have a drink together someplace to get to know each other.” He would then wait 10 seconds while smiling and gazing Guéguen, N. (2010). Men's sense of humor and women's responses to courtship solicitations: an experimental field study Psychological Reports, 107 (1), 145-156 DOI: 10.2466/pr0.107.1.145-1565. Red is Sexy, Wear Something RedI tend to think of red as an overly commercialized Valentine’s Day ploy. And it is. But, as it turns out, there may also be some actual, scientific validity to the color of love. In nature, red is often a warning color (a prey-on-me-and-die adaptation) but with humans (and some other species, like primates), red may serve as an aphrodisiac, carrying a sex and romance connotation. I’ve come across two studies, one about men the other about women, that help shed some light on this “romantic red” hypothesis. Let’s start with the men. A study published by Andrew Elliot and Daniela Niesta in 2008 investigates this red-sex link for men’s evaluation of women. Their experiment was relatively long, but to boil it down, they asked men to rate photos of women, examining whether or not the presence of red affects attractiveness. The results showed strong support for the “red effect.” Even a brief glimpse of red was shown to enhance men’s attraction to women. Red was found to enhance sexual attraction but not general positivity and characteristics (likeability, kindness, intelligence).Now for the ladies. A study published in 2010, also by Elliot’s group, investigated how red influences how women view men. For women, red has been linked to love and passion, carrying the meaning of sex and romance. Okay, got it, red equals attractive, right? Well…women are complicated creatures, and study upon study has shown that women don’t just take something as simple as attractiveness into account when choosing a partner. They also look for such things as authority, wealth, and status. But research has shown that red is linked to strength, power, high status, and competitive dominance, appearing historically as symbols of these traits. Put together, this means that the color red should enhance women’s attraction to men by increasing their perception of the man’s status and therefore her attraction to him. That is exactly what Elliot et al.’s study tested. Again, I’ll boil down their long experiment: They asked female participants to respond to a photo of a man. These photos were manipulated for color in either the background or on the clothing of the man. The results showed that women who viewed men with red (background or clothing) perceived him to be more attractive and were more sexually attracted to him. Women who viewed a man wearing red also perceived him to have higher status and higher status potential, and women who viewed a man described as high in status perceived him to be more attractive. What did we learn from these studies? That red is a sexy color for both men and women, so try a little red in your wardrobe.Elliot, A., Niesta Kayser, D., Greitemeyer, T., Lichtenfeld, S., Gramzow, R., Maier, M., & Liu, H. (2010). Red, rank, and romance in women viewing men. Journal of Experimental Psychology: General, 139 (3), 399-417 DOI: 10.1037/a0019689 Elliot, A., & Niesta, D. (2008). Romantic red: Red enhances men's attraction to women. Journal of Personality and Social Psychology, 95 (5), 1150-1164 DOI: 10.1037/0022-3514.95.5.11506. Say it With and Near FlowersShow your love, give them dying flower genitalia. Setting aside the fact that a bouquet of flowers is just a bunch of reproductive organs, flowers are used to reflect our emotions and moods, usually in a positive way and especially with women. Given this, a study by (you guessed it!) Nicholas Guéguen in 2011 examines how wome... Read more »

Guéguen, N. (2010) Men's sense of humor and women's responses to courtship solicitations: an experimental field study . Psychological Reports, 107(1), 145-156. DOI: 10.2466/pr0.107.1.145-156  

Elliot, A., Niesta Kayser, D., Greitemeyer, T., Lichtenfeld, S., Gramzow, R., Maier, M., & Liu, H. (2010) Red, rank, and romance in women viewing men. Journal of Experimental Psychology: General, 139(3), 399-417. DOI: 10.1037/a0019689  

Elliot, A., & Niesta, D. (2008) Romantic red: Red enhances men's attraction to women. Journal of Personality and Social Psychology, 95(5), 1150-1164. DOI: 10.1037/0022-3514.95.5.1150  

Guéguen, N. (2011) ‘‘Say it with flowers’’: The effect of flowers on mating attractiveness and behavior. Social Influence, 6(2), 105-112. info:/10.1080/15534510.2011.561556

Guéguen, N. (2012) “Say it … Near the Flower Shop”: Further Evidence of the Effect of Flowers on Mating. The Journal of Social Psychology, 152(5), 529-532. DOI: 10.1080/00224545.2012.683463  

  • February 11, 2013
  • 05:39 PM
  • 214 views

Getting a Date for Valentine’s Day: A Scientific Approach (Part 1)

by Melissa Chernick in Science Storiented

Quite frankly, most years I feel like kicking Valentine’s Day in the truffles. Do I recognize this as a single woman’s reaction to a mushy, lovey, couples' holiday? Sure, but the urge to kick remains. This year, however, I’ve decided to take a more lighthearted, less violent approach. Part of this approach is to recognize, and even revel in, the more ridiculous aspects of commercialism and human relationships. As such, I found a selection of papers that, when put together, loosely instruct on how to get a date for Valentine’s Day (or any day really). As I started writing I realized that it would be just mean to make this a single post. I’d have people unsubscribing and falling asleep (not necessarily in that order) before they got through the second paper. So I’ve divided this “guide” into two parts.1. Just Ask To get a date you must first find someone who is willing to date you. A paper published in the Archives of Sexual Behavior in 2011 by Nicholas Guéguen takes a look at how gender plays a role in receptivity to sexual offers. Guéguen conducted his study in France, gathering male and female university students to act as confederates. These confederates were first rated on their attractiveness using a 9-point attractiveness scale. Then they were asked to approach potential partners of the opposite sex on the street and say “I find you very likeable and attractive.” After this, the confederate asked one of two randomly determined questions: “Will you come to my apartment to have a drink?” or “Would you go to bed with me?” This study found that “men were apparently more eager for sexual activity than women” and that they were more willing to go to an unfamiliar female’s apartment and bed than females were when asked the same questions. You are completely shocked, I can tell. Forty percent of females agreed to go to an unfamiliar male’s apartment, and only one agreed to the sexual offer. These were the same results found in a similar study in the United States, supporting the idea that these reactions aren’t just typical of Americans. The U.S. study, however, did not take attractiveness of the solicitor into account. Guéguen’s experiment found that the more attractive the solicitor the more likely they were to get a positive answer, and that solicitor attractiveness was more important for males than for females. Women were more likely to go for a drink with an attractive man, but that attractiveness had no impact on the sexual offer. The men were more likely to say yes in general and even more likely to say yes to an attractive woman. You’re shocked again I can see. The take home from part 1 of our Valentine’s Day Guide? Perhaps, it is that asking doesn’t hurt. They may say yes, especially if you’re hot.Guéguen, N. (2011). Effects of Solicitor Sex and Attractiveness on Receptivity to Sexual Offers: A Field Study Archives of Sexual Behavior, 40 (5), 915-919 DOI: 10.1007/s10508-011-9750-4 2. Get Your Foot in the Door We can’t argue that the first point/instruction was blunt. Very blunt. So then, let’s refine it a bit. Nicholas Guéguen’s group also published a paper in 2008 about the “foot-in-the-door technique.” In this study, once again conducted in France, male confederates first asked a woman one of two foot-in-the door questions: “Hello, I’m sorry to bother you but would you have a light for my cigarette?” (note: In France, the rate of female smokers is higher so this isn’t a weird question) or “Hello, I’m sorry to bother you but I am looking for the Place de Libération.” If she responded to his question he then said “Thank you very much. Are you busy now? If not, we could have a drink together, if you have some time.” Guéguen found the foot-in-the-door technique to be associated with a greater number of positive responses to the second, courtship-related question. I’ll also point out that the men did not ask the women to go back to a strange apartment and/or jump into bed with them. Probably also a plus. A new, similar study published in 2012 by Dariusz Dolinski, looked at that initial foot-in-the door request, asking if the type of foot to put in that door matters. Dolinski had male and female confederates assigned to three different conditions: no initial request, a typical initial request, or an unusual initial request. The results showed that the “uncommonness of the first, initial request may enhance the effectiveness of the foot-in-the-door technique.” The author suggests that an unusual request requires the respondent to think about why they are complying, looking at themselves and the solicitor more closely. If we put together the blunt, just-ask technique with this second technique then we can conclude that asking is better than not asking and that a unique (and I’ll add: not creepy) lead-in is beneficial in gaining a yes for a date.Gueguen, N. (2008). Foot-in-the-door technique using a courtship request: a field experiment Psychological Reports, 103 (6) DOI: 10.2466/PR0.103.6.529-534 Dolinski, D. (2012). The Nature of the First Small Request as a Decisive Factor in the Effectiveness of the Foot-in-the-Door Technique Applie... Read more »

Guéguen, N. (2011) Effects of Solicitor Sex and Attractiveness on Receptivity to Sexual Offers: A Field Study. Archives of Sexual Behavior, 40(5), 915-919. DOI: 10.1007/s10508-011-9750-4  

Gueguen, N. (2008) Foot-in-the-door technique using a courtship request: a field experiment. Psychological Reports, 103(6), 529. DOI: 10.2466/PR0.103.6.529-534  

Dolinski, D. (2012) The Nature of the First Small Request as a Decisive Factor in the Effectiveness of the Foot-in-the-Door Technique. Applied Psychology, 61(3), 437-453. DOI: 10.1111/j.1464-0597.2011.00477.x  

van Straaten, I., Holland, R., Finkenauer, C., Hollenstein, T., & Engels, R. (2009) Gazing Behavior During Mixed-Sex Interactions: Sex and Attractiveness Effects. Archives of Sexual Behavior, 39(5), 1055-1062. DOI: 10.1007/s10508-009-9482-x  

  • January 28, 2013
  • 04:16 PM
  • 127 views

Dung Beetles and Ball-Rolling: Star Light, Star Bright

by Melissa Chernick in Science Storiented

Lately, it seems that poo is a popular topic in science news sections, and the dung beetle seems to be up front and center. I suppose that, if you are a dung beetle, you've solved all sorts of poo-related problems. If you recall the dung beetles and ball-cooling post from November, you will remember that these insects use their dung balls to help cool off their feet on the blazing hot African sands. But what if you are a beetle that works at night? You can chuck out the hot feet problem and worry about a whole new one: navigation. A new paper published in Current Biology suggests how dung beetles may solve this navigation dilemma.For African ball-rolling dung beetles (Scarabaeus satyrus), the best ball rolling strategy is the straight line. The straighter the path the beetle uses to roll the ball away from the dung pile the less likely it is their ball will be stolen by rival beetles. They spent all that time to pinch and roll the poo together, it is a waste of time and energy if it is stolen. Competition is fierce near the dung heap, so a quick and straight exit strategy is best. Getting that ball to roll straight isn't simply a matter of putting one tarsus in front of another, it usually involves exploiting such celestial features as the sun and the moon to orientate. However, it has been observed that many beetles will still manage to orientate along straight paths on clear moonless nights. So what are they using to help them navigate?To answer this question, a group of researchers set up some beetles in arenas. I know, it already sounds good. On a starlit night, they placed dung beetles with their dung balls in a flattened, leveled, and enclosed circular arena.They first wanted to know how accurately the dung beetles could orientate along straight paths when they were prevented from seeing any celestial cues at all. So they made little hats for them. No kidding. They made little caps from small pieces of cardboard and attached them to the beetles' heads so that their dorsal field of view was obscured but their ventral eyes were unimpeded. Then they let them roll, filming them from above so that the rolling paths could be reconstructed and measured. The sight impeded beetles had path lengths almost 4 times longer than beetles that could see the moonless night sky. Okay, so maybe the beetles are using landmarks, like trees, to help them. To test this, the researchers made another arena that removed all visual cues (including the observer), enclosing it with a circular black cloth wall. Because they removed all observer cues, like the camera, they had to design the arena such that it could tell them when the beetles were at the edge without the researchers filming or looking. So they made the arena wall with a slightly larger diameter than the floor so that there was a gap large enough to allow the beetles reaching the edge to fall from the floor into a trough below, resulting in an audible thump sound. Since ball rolling speed is relative to path straightness (the straighter your path the faster you get to the edge), they just had to time the thumps. Clever. Under a full moon, starry night the beetles took 21.4 seconds to exit the arena and on a moonless, starry night they took a reduced, but not significantly so, 40.1 seconds. The story changes when you put the little beetle hats back on. With the caps they take a significantly longer 124.5 seconds (note: this is not significantly different than an overcast night at 117.4 seconds).Figure 2 from Dacke et al. (2013) showing the effect of stars on dung beetle orientationNow we know that stars are important in getting a dung beetle to roll its ball straight. Good. But we also know that most stars are too dim for tiny beetle eyes to discriminate. It is probably unlikely that the beetles are picking out constellations for their navigating needs. So what orientation information are they extracting from a starry sky? To answer this question, the researchers grabbed their beetle arena and took it to the Johannesburg planetarium, where they could manipulate the sky the beetles were seeing. Again, clever. They performed the experiments under five different conditions: (1) complete starry sky, with more than 4,000 stars and the Milky Way, (2) Milky Way only, (3) dim stars, with the brightest 18 stars excluded, (4) 18 brightest stars only, or (5) total darkness. They found that the beetles took the same amount of time to exit the arena, irrespective of whether they could see the full projection of the starry sky or only the Milky Way. This means that the dung beetles are using the bright band of light produced by the Milky Way. The Milky Way is a bright band because it is made up of stars, and when the Milky Way part of the projection (a diffuse streak of light) is removed you still see a sky where a higher density of stars defines the galaxy's axis. In this case, the beetles were still able to use the star density but it took them somewhat longer to reach the edge of the arena. It is high density of light forming into the streak across the sky that is visible, and therefore usable, to the beetles.There is all sorts of navigating going on in the animal kingdom. Now, it appears that we've found another one. One that may be more widespread than we yet know. We just need to go looking.Dacke, M., Baird, E., Byrne, M., Scholtz, C., & Warrant, E. (2013). Dung Beetles Use the Milky Way for Orientation Current Biology DOI: 10.1016/j.cub.2012.12.034Some press stories on this paper:National Geographic: "Dung Beetles Navigate Via the Milky Way, First Known in Animal Kingdom"ScienceNOW: "Dung Beetles Navigate by the Milky Way"The Naked Scientists: "Dung Beetles Navigate by the Light of the Milky Way"The New Yorker: "Dung Beetles, Dancing to the Milky Way"Wired: "Lowly Dung Beetles Are Insect Astronomers"(dung beetle hat photo credit to Eric Warrant via the NatGeo link above)... Read more »

Dacke, M., Baird, E., Byrne, M., Scholtz, C., & Warrant, E. (2013) Dung Beetles Use the Milky Way for Orientation. Current Biology. DOI: 10.1016/j.cub.2012.12.034  

  • January 17, 2013
  • 01:47 PM
  • 142 views

No Death for Death Panels

by Melissa Chernick in Science Storiented

On Halloween 2009, my costume was a Death Panel. No kidding. And no, I won't show you a picture. As with most political themed costumes, it was funny at the time but was one of those things I thought would melt into the annals of popular culture. I mean, I can't exactly pull that off this year in the way I did then. However, the term "death panel" is one that seems to have perpetuated in the social landscape."Death panel" is a political term that originated in an August 2009 debate about federal health care legislation in the U.S. The former Republican Governor of Alaska, Sarah Palin, used it to describe how the new health care law would lead to the rationing of medical care such that decisions about whether the elderly and special needs children would be "worthy of care" would be decided by a death panel of bureaucrats. Palin took a lot of chaff for this remark and later specified that she was referring to Section 1233 of bill HR 3200 which would have paid physicians to provide voluntary counseling to Medicare patients about living wills, advance directives, and end-of-life care options. Take special note of the words "voluntary" and "counseling" in that statement, the fact-checking portion of the media certainly did, reporting Palin's claim as false. The statement was criticized by the mainstream news media, academics, physicians, Democrats, and some Republicans. However, other prominent and outspoken Republicans took it and ran such that it blew up in ways no one could have predicted. It seems that everyone had an opinion, and public opinion often plays an important roll in the success or failure of many policies, like health care.Public opinion is frequently influenced by misinformation. The media's failure to counter the misinformation about health policy has resulted in a persistence of this misinformation more than two years after the enactment of the Affordable Care Act (ACA), known colloquially as ObamaCare. Unfortunately, it is difficult to overcome "motivated reasoning," people's biases toward their preexisting attitudes and beliefs, which makes them more likely to accept unsupported claims because those claims are consistent with their partisan or ideological views. It certainly doesn't help that the media isn't exactly aggressive about debunking misinformation and even perpetuates it to some degree.A new study, published online in the journal Medical Care, takes a look at how media corrections might reduce misperceptions about death panels and if these corrections would reduce opposition to health care reform. To do this, the researchers recruited from the SurveySpot opt-in panel, validating their sample by comparing control group responses to poll results. Participants were randomly assigned to versions of a realistic article on the Palin claim modeled on the original Associated Press article but attributed to the fictional "Breakingnews.com." One version included corrective information and the other omitted it. This corrective information was a paragraph at the end of the article explaining why "nonpartisan health care experts have concluded that Palin is wrong." They also collected some additional information about the participants that they thought might influence the effect of the correction on their beliefs and opinions. First, they asked the participants to rate their feelings of Sarah Palin on a 0-100 feeling thermometer (a standard measure in the political science world) where higher values equal warmer feelings. Second, they wanted to assess how knowledgeable or sophisticated their participants were as this can affect how someone resists unwelcome information and hold on to certain misconceptions. So they asked the participants to answer a 5-item political knowledge scale, limiting them to 30 seconds per question to limit their ability to look up the answers online (sneaky, sneaky!).The researchers found that corrective information can reduce health policy misinformation for some groups. They found that Palin feelings and knowledge moderated the correction's effect, those who felt more warmly about Palin were more likely to believe in death panels. The results also showed "decreased misperceptions about death panels and increased approval of ACA among low-knowledge respondents who viewed Palin favorably." This suggests that fact-checking may improve understanding of policy controversies in these groups. Alternatively, "the correction backfired among high-knowledge respondents who viewed Palin unfavorably, increasing misperceptions about death panels and strong disapproval of ACA." In this case, the motivated reasoning steps in, it is easier for people to believe things they want to be true and disbelieve things they don't want to be true.  So what does all of this mean? Well, it means that public perception about health care is entrenched, and corrective information alone is not enough to overcome motivated reasoning among the more knowledgeable public.I'm going to end with note to the passionate, the activists (on both sides), and the Internet trolls (who probably won't care regardless): If you've read this far then you also know that I'm not likely to change your opinion of death panels themselves, and I'm not going to try. If you have read this far then you will also have noticed that this post is about a study of public opinion on the matter of death panels rather than death panels themselves (although I describe their origin above and give factual for-your-information links below). As such, if you comment please save us both some time and comment about the study and not about your personal beliefs on whether or not the government wants to kill all of us and our grandmothers. Thanks!Nyhan, B., Reifler, J., & Ubel, P. (2013). The Hazards of Correcting Myths About Health Care Reform Medical Care, 51 (2), 127-132 DOI: 10.1097/MLR.0b013e318279486bMore on the Affordable Care Act (ACA) at HealthCare.gov. You can read the full law, look through key features of the law, learn how it affects you, and find a timeline of what's changing and when.Press release from Duke University's Fuqua School of Business "New Research Shows 'Death Panel' Myth Hard to Correct"Some articles about death panels:U.S. News "The Truth Behind Obamacare's 'Death Panels'"The Daily Beast "The Reality of Death Panels"FactCheck.org's "Palin vs. Obama: Death Panels"PolitiFact's "Lie of the Year: 'Death Panels'" Snopes "Seniors Beware" and "Euthanasia Counseling"(image via HowStuffWorks.com)... Read more »

Nyhan, B., Reifler, J., & Ubel, P. (2013) The Hazards of Correcting Myths About Health Care Reform. Medical Care, 51(2), 127-132. DOI: 10.1097/MLR.0b013e318279486b  

  • January 11, 2013
  • 03:07 PM
  • 143 views

The Silverback Playbook: Changing Climate and Ape Distribution

by Melissa Chernick in Science Storiented

On occasion, I go back to my roots in biogeography and peruse that subset of journals for interesting articles. Admittedly, I now skip over some topics that I used to devour, such as the species-area relationship (the "most general, yet protean pattern" that has recently warranted a special virtual issue). These days, I tend to stop and read articles about distribution patterns, especially as they relate to current problems like climate change.There are an increasing number of studies that show that climate change will affect species distribution patterns and biodiversity patterns in general. Temperatures, rainfall patterns, sea level changes, etc. are likely to cause geographic shifts in the ranges of plants and animals, altering their relationships with the environment and other species. The common methods for predicting these effects are called bioclimatic envelope models. Basically, these models try to determine the "climate envelope," a description of the climate that defines a species' range, and then map the geographic shift of that envelope under climate change. These types of models are useful for predicting distribution patterns, but they do not inform us about the underlying mechanisms that limit species' distribution and how species will change their behavior and/or the kinds of habitats where they can survive. Think about this behavior part a little more in depth, specifically taking brain size into account. It has been shown that large-brained species are better able to cope with seasonal changes in their environments, buffering themselves against modest levels of climate change, and are more resistant to extinction.When you think of large-brained species, which ones come to mind? Probably the primates, specifically the African apes (gorillas and chimpanzees). What do we already know about these species? We know that they live in Africa (the most vulnerable of all continents to the effects of climate change), occur in similar habitats (although they differ somewhat in biogeographical ranges), are highly endangered, have highly restricted ranges, have a slow life history, have a large body mass, and have somewhat similar diets. Knowing this, how do you think climate change will affect them?A study published in the Journal of Biogeography takes a look at how the behavior and distribution of African apes will be affected by climate change. They use a time budget model to investigate how climate warming and behavioral flexibility might affect ape survival. Time budget models are based on individual behavior, how much of an individual animal's time is spent on feeding, resting, traveling and socializing. An animal's time is limited (there is only so much time in a day) and so there is a constraint on the size of a group that can be maintained in a particular habitat which ultimately determines a species' distribution. These types of models can predict distribution as well as the bioclimatic envelope models, as they are based on simple climatological variables, with the added advantage of providing informing us about mechanisms of keeping a species in a particular habitat and evaluating the level of ecological stress in areas where it does occur. They applied this model to data from 20 natural populations of gorillas (Gorilla beringei and Gorilla gorilla) and chimpanzees (Pan troglodytes and Pan paniscus). The model looked at the relationship between climate, group size, body weight, and time budgets. They ran the model to predict ape distribution across Africa under a uniform worst-case climate change scenario, highlighting the importance of individual behavioral requirements for survival. I'm going to save you lengthy descriptions of the model parameters, time budget equations, and model testing. You can thank me later.The study found that gorillas are more restricted by temperature variation than are chimpanzees. This may cause gorillas to suffer more strongly from the effects of global warming. Their larger body mass and smaller group sizes also increase their risk of extinction even with their behavioral flexibility. This doesn't mean that the chimps are unaffected. They found that chimpanzee communities will be significantly reduced even at locations where they are predicted to survive. The model showed that two critical factors may ultimately determine their survival at these locations: minimum viable community size and minimum party size. Although the distribution for both genera is in the downward direction, the two taxa are predicted to respond differently to changes in climate. Chimpanzees are expected to primarily suffer a reduction in community size because they will need to spend an increasing amount of their time moving and resting. And considering that minimum viable community size is one of the two critical factors, chimps will find it difficult to survive in any of their present habitats and may even go extinct. On the other hand, gorillas already live in small groups and when combined with a dramatic reduction in available habitat (again with the moving and resting time), climate change is predicted to have a stronger effect on their biogeography. However, the authors think that the few surviving populations should be able to maintain present-day group sizes, making them locally stable. Even if the changes in climate were not as extreme, the researchers think that their model would still predict that apes will suffer habitat loss simply due to time budgeting problems that may be reinforced by indirect effects (like temperature on leaf quality). Sure, behavioral flexibility may help, particularly with the more socially fluid chimpanzees, but the environment will support only what it can support (especially for hungry, large bodied creatures).It is important to note that this study does not include anthropogenic (human caused) influences. Couple those with the doom-and-gloom predictions that the study already makes and it looks like it's bye-bye time for the big apes. That is a bit of a depressing note to leave the post on. Perhaps the good (or happy?) note to leave on is that studies such as these (that take mechanism into account) can give us better ways to predict and preserve optimal habitats, ultimately finding ways to best conserve these species. After all, that is the goal right?Lehmann, J., Korstjens, A., & Dunbar, R. (2010). Apes in a changing world - the effects of global warming on the behaviour and distribution of African apes Journal of Biogeography, 37 (12), 2217-2231 DOI: 10.1111/j.1365-2699.2010.02373.x(image via earthtimes.org)... Read more »

Lehmann, J., Korstjens, A., & Dunbar, R. (2010) Apes in a changing world - the effects of global warming on the behaviour and distribution of African apes. Journal of Biogeography, 37(12), 2217-2231. DOI: 10.1111/j.1365-2699.2010.02373.x  

  • January 4, 2013
  • 05:22 PM
  • 200 views

Burn Baby Burn: Fire, Forests, and Carbon

by Melissa Chernick in Science Storiented

I know, I know. I've been a bit absent over the last few weeks. I'm going to call laying on the beach in South Florida at Christmas enough of an excuse. That and I was finishing up my Wildland Firefighter course. Yep, I'm now all certified to start and stop forest fires. Should you be afraid? Perhaps. But it got me to thinking about prescribed burning, an area of ecology that I know about but don't regularly keep up with the literature. So I decided to take a look at what has recently been published on the topic and found a nice paper in the journal Forest Ecology and Management about the balance of carbon sequestration and habitat conservation as they relate to fire.Most people tend to think Fire = Bad. In many situations that's true, but in others fire is actually a natural, healthy process. In the past, various federal and state agencies have instituted wildfire suppression policies because they thought it was the best way to preserve the natural state of the land. All it really did was create a massive amount of fuel loading - lots and lots of fuel (dead logs, leaf litter, etc.) around to burn - which created even larger, more destructive fires. Now we know better, and the idea of a more natural fire regime is being used to control fuels and keep the balance of natural habitats.Today's paper takes a look at woodlands, a subset of forests that are composed of low density, short trees  that typically have an open canopy with a ground layer made up of shrubs, grasses, and forbs. They can be economically important for lumber and livestock grazing, but they are also naturally important as significant carbon (C) sinks and as a biologically diverse habitat. Fire is known to be an important process in this ecosystem and is managed such that willdfires are allowed to burn unhindered, landscape level fuel management helps contain fire spread, and prescribed burning reduces fuels. This study investigates the effects of past fires on carbon storage, woody vegetation community composition, and habitat suitability. They do this by utilizing a "chronosequence" approach. This means that they grouped and compared stands of trees at different successional stages following fire events. These stands were located in the woodlands of Balcones Canyonlands National Wildlife Refuge (BCNWR), located northwest of Austin, Texas, USA. The dominant woody vegetation in this area is the evergreen Ashe's juniper (Juniperus ashei), with subdominant species including several oak (Quercus spp.) species and Escarpment Black Cherry (Prunus serotina var. eximia). These woodlands are also inhabited by the golden-cheeked warbler (Dendroica chrysoparia), an endangered bird species they used to assess habitat suitability. The mixed juniper-oak are critical for this warbler as they use the stringy, sloughed bark from the mature Ashe's juniper exclusively for nesting material and requre Lepidopteran (Geometridae) larvae that feed on broadleafed foliage during the spring breeding season.The researchers established 60 plots next to trees that had been used for a previous dendrochronology (tree rings) study. That means that they had the history of the tree from the tree rings, this history including fire scars that could be pinned to exact years. The fires were low-intensity, surface burns that mostly consumed the ground layer, seedlings, and saplings. From this they were able to pick sites with single fire events and then assign their plots into three groups: recent-fire (less than 40 years), old fire (greater than 40 years), and no fire. Then, for each plot, they identified tree species and measured their diameter and heights, collected data on woody debris and leaf litter depths, and collected soil samples for carbon and nitrogen analysis.The authors found significantly different total aboveground biomass C averages for the 60 study plots. Recent-fire showed 5.25 kg m-2, old fire averaged 6.86 kg m-2, and no fire had 9.18 kg m-2 of C. Previous studies have shown that low to moderate intensity fires have less effects on live biomass, stabilize carbon fast afterwards, and primarily affect trees in an age-specific and density-related way. This study found that "the impact of low-intensity fire on C storage increases for sites with higher proportions of biomass in small trees" (greater than 20cm in diameter) as these are more greatly impacted by surface fires. This study's results support that periodic surface fires maintain many forests by favoring fire-tolerant species, such as oaks, and decreasing the density of fire sensitive species, such as juniper. They found that sites with a single fire disturbance had a higher density of oak seedlings than juniper seedlings (though not significantly so), especially in years that had low precipitation in the summer. The densities of mature trees was found to be mainly influenced by differences in topography, herbivory, and historical climate.I would like to say that all of this added up to a good conclusion about habitat suitability for the golden-cheeked warblers but, unfortunately, they found significant differences. Fire reduces mature tree density, which has a negative impact on habitat suitability, but high intensity fire is related to higher oak recruitment (food source for their food source). Managing these woodland for the golden-cheeked warbler may require both mechanical treatment and the use of fire. The critical core breeding habitat for this warbler includes old-growth stands composed of large, mature junipers and about a 40 percent oak species mix. These stands should be protected from intense fire through the mechanical thinning of the understory and the removal of heavy fuels.Overall, the authors conclude that fire management can achieve multiple outcomes on a single site. This means that detailed ecological information about the species composition and population structure of an area are needed in order to assess conditions and projections on restoration.Yao, J., Murray, D., Adhikari, A., & White, J. (2012). Fire in a sub-humid woodland: The balance of carbon sequestration and habitat conservation Forest Ecology and Management, 280, 40-51 DOI: 10.1016/j.foreco.2012.05.042More on wildland fires and prescribed burning:GeoSTAC's Wildland Fires pageUniversity of Florida IFAS Extention's "Benefits of Prescribed Burning"National Interagency Prescribed Fire Training Center(image from Texas Department of Agriculture)... Read more »

Yao, J., Murray, D., Adhikari, A., & White, J. (2012) Fire in a sub-humid woodland: The balance of carbon sequestration and habitat conservation. Forest Ecology and Management, 40-51. DOI: 10.1016/j.foreco.2012.05.042  

  • December 13, 2012
  • 04:52 PM
  • 207 views

Drinking the Clouds

by Melissa Chernick in Science Storiented

I don’t often talk about water movement in plants even though I work in a lab that studies water movement in plants. I should probably ruminate on that but won’t. Instead, I’ll start out by putting a complex problem into the simplest of terms: Plants drink water with their roots. Alright, that’s true but perhaps it is a bit too elementary. I think that, in this case, I need to explain it in more detail so that you can really appreciate why a certain research paper caught my attention.For water to do all the important things it should, it needs to get in and around the plant. This is one of the most basic plant physiology…no, basic biology mechanisms we know. Water diffuses in near the tip of a growing root (you know, the hairy part) and makes its way to the xylem. The xylem is the vascular tissue that conducts water and dissolved nutrients to all parts of the plant. Considering that plants grow up, this water must be moved against gravity. This is where transpiration, root pressure, and capillary action come in. Transpiration (like evaporation, it is the loss of water vapor from parts of a plant, usually the leaves) causes tension and pressure that pulls water up, and root pressure pushes water up when transpiration is low, the soil is moist, and when the roots are absorbing lots of water. Capillary action helps it all as it allows water to flow up the narrow channels of the xylem. The leaves are where the plant usually loses water. Leaves have many, small structures called stomata that function in gas exchange. Guard cells open and close a stoma, and when the carbon dioxide is let in water vapor can be let out. Plants can lose a lot of water through transpiration and have various methods (that I won’t go in to) to try and combat it. Now, this sounds like a lot of info but I’m really just barely scratching the surface (see some links below if you want to know more) of this process. What makes the paper I read today so interesting is that it adds another layer to what we already know about water movement in plants.The authors of a new paper, published online in Ecology Letters, take a look how plants function in cloud forests. These forests are unique and super neat! Tropical montane cloud forests (TMCF) are among Earth’s most rare and endangered ecosystems occupying just 1.4 percent of the world’s tropical forest area. They are like rain forests in that they receive high levels of precipitation. Where they differ is that much of this precipitation comes directly from clouds, through the cloud filtering of the trees. Lateral cloud filtering is a process where clouds blow among the trees and the moisture condenses as it touches the leaves, forming water droplets. This process reduces the vapor pressure deficit (VPD) and photsynthetically active radiation (PAR), decreasing plant water demand and suppressing leaf-level transpiration. When regular, vertical precipitation is limited in the dry season these cloud water droplets can become an important water source. The researchers in this study looked a phenomenon referred to as foliar water uptake (foliar uptake), where this condensed water is taken in through the leaves, and its occurrence in TMCFs.The researchers compared neighboring tropical montane and pre-montane cloud forests along the Pacific slope of the Cordillera de Tilarán mountains near Monteverde, Costa Rica. They characterized the cloud cover using remote sensing and created an environmental characterization of the forest by looking at factors such as humidity, temperature, soil water content, rainfall, and leaf wetness. Then they characterized and compared foliar uptake in situ in both forest types, measuring sap flow on the small branches of woody plants using the heat ratio method. They also measured the capacity for foliar uptake in several woody plant species by collecting leaves, rehydrating them, and measuring them individually in the lab.The researchers found that during the dry season, the pre-montane cloud forests (which are further west and at a lower elevation) are subject to greater rain shadow and less cloud immersion. These forests experienced, on average, a lower number of hours of leaf wetness per day and a shorter duration of each individual leaf wetness event when compared with the tropical montane cloud forests. The higher cloud cover frequency of the TMCF resulted in more, longer leaf wetting events resulting in foliar uptake. They found the prevalence of foliar uptake to be quite high and widespread among species, occurring independently of phylogeny, morphology or growth habit. This foliar uptake also took a significant role in the plants’ water status both in the field and in the lab, resulting in greater water deficit reductions. Furthermore, the results showed that the TMCF plant community demonstrated a higher capacity for foliar uptake than did the pre-montane plant community. This is interesting because foliar uptake benefits the drier, pre-montane forest more and yet these forests are unable to capitalize on them physiologically to the same extent as the TMCF plant communities. This may be a result of the presence or frequency certain leaf traits that facilitate the uptake (cuticle, trichomes, hydathodes) or the ability of water to enter the stomata.As with everything we do now, look at this through your climate change lenses. What are the consequences of climate change in these ecosystems? Tropical mountains are projected to experience high rates of climate change, increasing dry season surface air temperatures 3.8°C and decreasing precipitation by 14 percent. All of this could increase cloud frequency and cloud base height causing a higher water demand in these plants.All in all, this new layer to the water movement mechanisms we all know and love is pretty thought-provoking. I know it set out to shed light on the prevalence and role of foliar uptake, but, with me, it had a greater impact in thinking about its consequences. The effect of drought on plants is a hot topic in the plant physiology world, and this paper is an interesting way to look at it.Goldsmith, G., Matzke, N., & Dawson, T. (2012). The incidence and implications of clouds for cloud forest plant water relations Ecology Letters DOI: 10.1111/ele.12039More on water movement in plants:Bellevue College's "Transport in Plants" notes Univ of Illinois at Chicago's "Transport in Plants" lecture notesScience Mag's "Transpiration: Water Movement in Plants" (Flash player animations that are good)About cloud forests:Community Cloud Forest ConservationCanopy in the CloudsOn this story:Science Daily: "Cloud Forest Trees Drink Water Through Their Leaves"UC Berkeley's "Cloud forest trees drink water through their leaves"(image via Buncee.com) ... Read more »

Goldsmith, G., Matzke, N., & Dawson, T. (2012) The incidence and implications of clouds for cloud forest plant water relations. Ecology Letters. DOI: 10.1111/ele.12039  

  • November 28, 2012
  • 04:50 PM
  • 215 views

The Gift of Regifting

by Melissa Chernick in Science Storiented

Be honest: How bad is it to regift? We've all gotten gifts that are clearly items someone was given and didn't want. A Chia Pet, a fruitcake, or an ugly piece of jewelry. Some things you can just tell. No lie, I once got a set of used cassette tapes. I don't even own a cassette tape player. I considered rethinking a friendship.Most often, people regift things they will not use or gifts they do not like. If you want to stick a name on it, it is a problem researchers refer to as "deadweight loss." This is because the gift recipients would never spend as much money as the giver (especially on an ugly, unusable item like that), and the receiver is left with an item that lingers around in the closet (or wherever) until they can get rid of it (hence, the "deadweight" terminology). How do you shed the deadweight? You pass it on. Maybe the receiver will appreciate it in ways you never did, or at least they will pretend to. And this gets to the heart of today's post: How do people regard regifting? Resourceful and thrifty or rude and distasteful? Does it matter if you are the giver or the receiver? A study published this year in Psychological Science asked just these questions in a series of studies.Study 1: Is it okay to regift gift cards?Participants were asked to imagine that a 50 dollar Amazon gift card had been given as a birthday gift and then regifted to someone else. Then they were asked to assess their feelings as either the giver or the regifter. The researchers found that regifters thought the giver would be more offended if they regifted the card than givers reported that feeling.Study 2: Do you regift or throw away an undesirable present?The first study showed that regifters may be overestimating how offended the givers would be at having their present regifted. But what if that present were just thrown away? Participants were asked to imagine that they had recently given or received a wristwatch as a gift and, depending on the rolls they were assigned (giver or receiver), how would they feel if the watch was either regifted or thrown away? Similar to Study 1, the researchers found that the receivers thought that regifting or throwing a gift away would offend givers more than givers felt they would have been offended. They also found that the recipients found throwing away a gift to be more offensive than regifting it. Givers were less offended if their present was regifted than if it was thrown away.Study 3: In the real world, how do friends really feel about regifting?In this study, the researchers wanted to get a more real world feel. How do real groups of friends feel about regifting? So they asked participants to sign up with two of their friends. One member of this group was assigned the roll of the giver, separated from the group, and asked to choose from three items that were pretested and identified as bad gifts (a magazine for retired people, a DVD about the life of Mandy Moore, and a weight-loss cookbook). The giver then wrapped their gift and gave it to one of their friends. Once the giver had gone back to the waiting room, the receiver (now the regifter) of the bad gift was then asked to rewrap the bad gift. Then, in front of the initial giver, the regifter enters the waiting room with the rewrapped gift and gives it to the final friend. I don't know about you, but this almost sounds mean just reading it. When each was asked about their feelings on this bout of regifting, the regivers again thought the initial giver would be more offended than they were. Givers thought that the regifters were entitled to do what they wished with the gift.Study 4: Is it possible to make receivers more comfortable with regifting?Did you know that there is a National Regifting Day? It's true. In honor of holiday office parties and the “unique” gifts exchanged at them, the creators of Regiftable.com have declared the third Thursday in December as National Regifting Day. The results of Study 3 suggested that interventions that encourage receivers to do what they wish with their gifts may liberate them to regift. The researchers found that study participants were more likely to regift if they were told that it was National Regifting Day than if they were not told. They also found that receivers felt more entitled to do what they wanted with their bad gift if they were told it was National Regifting Day, although they still felt less entitled than givers thought they should.When I stop and think about it, this all makes sense. However, I maintain that giving a bad gift (like used cassette tapes) is still giving a bad gift and that isn't being a good friend or relative. Go back and read the last gift giving post, your friends often don't need something flashy or weird (unless they are that kind of personality). Think about what they want and get it for them. Odds are that they will keep your gift and use it. At least I hope so. And if not, this article suggests that they don't mind if you regift it. I would have been interested to see another choice in Study 2 that included feelings on donating the gift.What about you? What are your thoughts on regifting? Will you be giving away that ugly office gift from last year?Adams, G., Flynn, F., & Norton, M. (2012). The Gifts We Keep on Giving: Documenting and Destigmatizing the Regifting Taboo Psychological Science, 23 (10), 1145-1150 DOI: 10.1177/0956797612439718Some more regifting reading:The New York Times: "Re-Gifting: You Shouldn’t Have. But if You Did, Here’s How to Get Away With It"The Huffington Post: "To Regift or Not to Regift, That Is the Question" and "Regifting Christmas Presents: How To Do It Properly"ABC News: "Re-Gifting: It’s Not Just for the Poor, Frugal or Unashamed Anymore" ... Read more »

Adams, G., Flynn, F., & Norton, M. (2012) The Gifts We Keep on Giving: Documenting and Destigmatizing the Regifting Taboo. Psychological Science, 23(10), 1145-1150. DOI: 10.1177/0956797612439718  

  • November 21, 2012
  • 04:10 PM
  • 240 views

The Psychology of Gift Giving: Unique and Expensive or Ordinary but Useful?

by Melissa Chernick in Science Storiented

The holiday shopping season is almost upon us. Black Friday is but a couple of days away. The annual shopping explosion event when you start thinking how close the year is to being over, how you haven’t even thought about what you are going to buy anyone, and how much money you don’t have to spend. Actually, I tend to be a Cyber Monday kind of shopper, but the same tenets hold true.Gift giving: What do you get someone? Will they like it? What will they give you? Will you like it? Quite frankly, the whole process can be fun but exhausting.Gifts can be tokens of social relationships, ways that we transmit impressions and feelings to one another. If you boil down the above questions, you are really asking about the attractiveness of gifts. A study in 2005 looked at the attractiveness of a gift seen from the perspective of the giver and the recipient. When you are shopping and picking out a gift, you probably go for something that you find attractive and/or you think the receiver will find attractive. Ultimately, you want your gift exchange to be successful. As a giver, that means you try to take the receiver’s perspective into account. As a recipient, that means you realize that any number of gifts could have been chosen for you and the one you received is what the giver thought you would like best. As with so many social psychology papers, this question of gift attractiveness was broken down into a series of studies.Study 1: High-quality and unique or ordinary but useful? Ideally, you want to choose a gift that is both high-quality but also useful to the recipient. But high-quality usually means expensive. If, as a giver, your shopping list doesn’t include expensive then you have to make a trade-off. Usually this means a smaller, high-quality gift or a larger, more ordinary gift. This first type of gift is nice, and often exclusive or unique. The second type of gift is probably something more useful, something the recipient can use. They found that givers preferred to give expensive, exclusive, smaller gifts. On the other hand, receivers preferred less luxurious, more useful gifts. Makes sense I guess. As a giver, you want to give someone something both you and they perceive as nice. As a receiver, you actually have to live with that gift.Study 2: What do you expect of your gifts? Cultural conventions, we all fall into them. In western societies, a gift should be nicely wrapped, come without a price tag, and arrive on time. The gift itself should be neither too cheap nor too expensive (especially as gifts are often reciprocal). Oh, and cash is only accepted under certain circumstances, usually helping someone pay for something specific (house, car, school, etc.). Receivers are expected to act surprised when they open the gift (even if they knew what it is), to be grateful, and to praise the gift (even when they hate it). This study asked people a series of questions: Gift voucher (gift cards) or cash? Opera or movie tickets? How important is it that a gift be a surprise? Or arrive on time? They found that givers prefer gift vouchers to cash and are concerned about timing, showing that gift givers are more serious about social conventions than are recipients. It’s weird really, because they found that gift givers are most concerned with pleasing the receiver even though the givers are abiding by cultural conventions that don’t do that (see Study 1). Receivers accept cash gifts and claim to not really care if the gift arrives late.Study 3: Does self-perception or perceptions of others play into gift giving? Personally, you prefer the ordinary but useful gift, but you think these preferences are not shared by others. So you end up selecting gifts according to the preferences you think are more widespread among others. "Everybody likes expensive wine so I will buy expensive wine as a gift." They found little support for this self versus others perception hypothesis. Rather, people change their preferences in accordance with their rolls as either givers or receivers.Study 4: Why are some conventions more important than others? It is nice to divide these questions up into studies, but in real life, pairwise comparisons aren’t made. When choosing a gift, givers have to choose between two or more simultaneous options and evaluate potential gifts one by one. Receivers don’t know all of the decision-making that the givers went through to pick their gift or what other gifts they could have gotten instead. This study found that when receivers evaluate a gift on its own they tend to agree with the givers’ preferences and prefer more exclusive gifts.So what do we take away from a paper like this? Studies 1 – 3 seem to say “Skip the fancy wine and just buy them the comfy sweater.” I tend to agree. Buy something you know they will both love and use. Look at cultural gift giving conventions and choose to step away and consider your friend or loved one’s interests. Our next topic – Regifiting…you know you shouldn’t but is it really the taboo you think it is?Teigen, K., Olsen, M., & Solås, O. (2005). Giver-receiver asymmetries in gift preferences British Journal of Social Psychology, 44 (1), 125-144 DOI: 10.1348/014466604X23428Read more about gift giving:Scientific American: "The Psychology Behind Gift-Giving and Generosity" NY Times: "A Gift That Gives Right Back? The Giving Itself"(image via MoneyIntention.com)... Read more »

Teigen, K., Olsen, M., & Solås, O. (2005) Giver-receiver asymmetries in gift preferences. British Journal of Social Psychology, 44(1), 125-144. DOI: 10.1348/014466604X23428  

  • November 9, 2012
  • 02:25 PM
  • 208 views

Dung Beetles and Ball-Cooling: The Secret of the Poo

by Melissa Chernick in Science Storiented

You’re a dung beetle. That isn’t an insult, it’s a visualization aid. You are a dung beetle, you live in South Africa, you roll up feces into balls, you push those balls to a storage location, and you use the balls as food or for brooding. Now, as a human visualizing yourself as a dung beetle, consider the environment you are rolling your dung ball across: the sands of the South African desert. Are your feet hot? How do you cool them down?The authors of a new paper in Current Biology asked just these questions. The hot desert sands of South Africa can exceed temperatures of 60°C (140°F). Even for the resident dung beetle (Scarabaeus lamarcki) that’s hot. It is known that many species will seek refuges to cool down in these hot climes. For example, desert ants will spend up to 75 percent of their foraging time cooling down on elevated thermal refuges (like stalks of grass). It would make sense that dung beetles, which work under similar hot conditions, would seek refuges as they roll their poo-balls across the sand. Returning to your imagined-dung-beetle-state, what do you do to cool off?The researchers used infrared thermography and behavioral experiments to see how dung beetles use their dung ball as a mobile thermal refuge onto which they climb to cool down. Jochen Smolka and his colleagues set up two sandy, circular, 3 meter diameter arenas in a natural South African habitat. One of the arenas was shaded in the morning to keep the ground temperature cooler. The other arena was exposed to full sunlight. They found that at the cooler ground temperatures, below 50°C, the beetles roll their dung balls straight across the arena without stopping. On the hotter ground, the beetles were observed to occasionally stop, climb up onto their ball and preen their front legs with their mouth-parts. It is likely that this preening covers the legs in regurgitated liquid, cooling them down by evaporative cooling. After the preening, the beetles perform an orientation dance and continue to roll their balls across the arena.Fig 1. The dung ball as a mobile thermal refuge. (A) With rising soil temperature, beetles climb onto their dung balls more frequently while rolling (B) Temperature of the right front leg (red) and thorax (blue) of a beetle during its first three ball climbs (periods of rolling are grey) (C) Front leg temperature profile averaged over 84 ball climbs from 7 beetles (D) With silicone ‘boots’ on their legs, beetles perform fewer ball climbs. Similarly, beetles climb onto cool balls less often than hot ballsGround temperature also significantly affected the frequency of this ball climbing behavior. At progressively high temperatures, the beetles climbed up on their balls more often, spending almost 70 percent of their time on top of their balls when the ground temperature went above 60°C.So why climb balls? Answer: Ball-cooling. Infrared thermography shows that when the beetles roll their dung balls, the surface temperature of the beetles’ front legs increases by as much as 10°C, but when they climb up on their balls that temperature decreases again. That’s quite a bit, but is it really their hot feet that causes the beetles to ball climb? To this, they applied dental silicone to the beetles’ front legs. Pause: Beetle-booties, fun to say and I’m sure fun to see, and reminds me of the awesomeness that is ants on stilts. They found that these beetle-boots doubled the beetles’ ball rolling time, decreasing their ball climbing by 35 percent. This suggests that the ball climbing behavior is related to ground temperature and the heating up of beetle feet. As it turns out, the poo-balls are acting as thermoregulators in three ways:1. They are portable, elevated platforms that can be used to escape the hot sand.2. They are heat sinks. The moist dung ball undergoes evaporative cooling, keeping it the much cooler temperature of 31.8°C. This is substantially cooler than the beetle and the sand.3. They are sand-coolers. Essentially, they are performing another heat sinking duty, sort of a heat vacuum, if you will. The dung ball draws the heat from the sand so it is cooler for the beetles to walk on.If the poo-balls are actually acting as heat sinks, both during rolling and while the beetle is on it, then warmer balls should be less efficient heat sinks and the beetles should climb on them more often. The researchers tested this by giving beetles cold balls and hot balls. They found that the beetles climbed the hot balls 73 percent more often than the cold balls, supporting the heat sink hypothesis. “Because beetles roll their ball rather than drag it, the ball, preceding the beetle, cools down the sand the beetle is about to step on” by 1.5°C. Put together, these mechanisms allow dung beetles to operate during a time of day when most arthropods, and other animals for that matter, seek a cool shelter. I guess there are a lot more good things about poo than I ever realized. And it appears that dung beetles have uncovered the secret of the poo.Smolka, J., Baird, E., Byrne, M., el Jundi, B., Warrant, E., & Dacke, M. (2012). Dung beetles use their dung ball as a mobile thermal refuge Current Biology, 22 (20) DOI: 10.1016/j.cub.2012.08.057Here are a few news outlets that have picked up the story:From Wired UK "Study: Dung beetles cool their heels atop balls of poo"Discovery News' story "Why Dung Beetles Like to Chill on Poop Balls"LiveScience's "That's Hot! Beetles Dance on Poop Balls to Keep Cool"The Naked Scientists' report "Beetles use dung balls to keep cool"... Read more »

Smolka, J., Baird, E., Byrne, M., el Jundi, B., Warrant, E., & Dacke, M. (2012) Dung beetles use their dung ball as a mobile thermal refuge. Current Biology, 22(20). DOI: 10.1016/j.cub.2012.08.057  

  • October 23, 2012
  • 06:29 PM
  • 211 views

The Rocky Mountain Parnassius Problem

by Melissa Chernick in Science Storiented

Lately, I've been thinking about butterflies. I won't subject you to the interesting, if slightly convoluted, train of thought that led me to today's paper (this post is long enough as it is), but suffice it to say that we are back on the topic of butterflies and climate change. If you remember, back in March I wrote about a paper that explored how a single climate parameter can determine population dynamics in a butterfly species, the Mormon Fritillary (Speyeria mormonia) - An Early Spring Isn't Always a Good Thing. In that case, it was how snow melt time in the first year would affect butterfly fecundity through flower abundance. Along these lines, a preprint in the journal Ecology takes a look at how regional climate, particularly winter and winter extremes, affects annual rates of population change. We know that climate change is causing range shifts in many species. Good examples of this can be seen in high elevation, typically mountainous regions. The idea here is that a warmer climate facilitates growth in areas where a colder climate had previously prevented growth. However, this warming trend is not the only prediction attached to climate change. Variability in climate and weather and the extremes of seasons and events are also expected to have a large impact on ecological processes. This means that not only do species have to respond to general climate warming but also to general and local extremes. Long-lived vertebrate species with overlapping generations may be buffered to this because such these extreme changes act primarily on a single age class or cohort. Short-lived, univoltine (one brood or generation per year) ectothermic species have little to no buffering, meaning the entire population is affected by these extreme events.The authors of this study use long-term (15 year) estimates of population size for 21 subpopulations of the Rocky Mountain Apollo butterfly (Parnassius smintheus Doubleday) in Alberta, Canada. This species is common in the alpine meadows of the Rocky Mountains of North America. They are known to overwinter as pharate larvae inside the egg, hatching in May, feeding on their obligate host plant (Sedum lanceolatum), pupating in late June, emerging as adults in late July, and the females ovipositing on their host plant through August. Although they are common, they tend to occur in relatively small subpopulations, having limited dispersal, which makes them good for metapopulation studies and studies of local changes. The researchers estimated population size in each subpopulation using mark-recapture data. The climate variable they chose was the Pacific Decadal Oscillation (PDO) index, an index shown to have strong correlations with their chosen study site. This index “contrasts the spatial distribution of sea temperatures between the northeastern and northwestern Pacific Ocean after correction for mean global temperature…providing a single integrative measure of climate across western North America through its strong temporal correlation with both temperature and precipitation.” A positive PDO means that warm water is along the coast and are associated with warm, dry years inland. A negative PDO means that cooler water lies along the coast and are associated with cool, wet years. They used both annual PDO as well as seasonal PDO values corresponding to stages of the life-cycle that were of particular interest. Then they ran some models that I won’t go into (I’ve used up a lot of space and I haven’t even gotten to the results yet!).These models showed that “more frequent climate extremes pose important consequences or animal population growth affected by climate.” They found that winter values of the PDO were a strong predictor of annual population growth. The effects of climate in these butterflies was found to be curvilinear wherein both extremes (too warm and too cold) result in population decline. This suggests that the variability and extremes predicted by climate change models will greatly affect the population dynamics of species such as this and that there may be less opportunity for them to adapt to general climate warming as the occurrences of these extremes increases. Additionally, the curvilinear nature of these results suggests some complications in the mechanisms involving range shifts. Their data support range shifts (either poleward or elevational) in that climate warming may sustain a positive population growth, although low latitude and low-elevation range margins might be affected more causing negative growth.Are these results applicable to all species? No. P. smintheus is an alpine species that is naturally subjected to a cold, unpredictable environment, and, as such, they exhibit several behavioral, morphological and physiological adaptations. This means that curvilinear results of the model suggest multiple climate-related factors that need to be teased out (temperature, precipitation, snow cover, snow distribution, etc.) and that the PDO index itself may have a range with extreme values on its edges. Because these are extreme factors rather than just gradual shifts in climate, conservation planning could be more difficult over the long term. The extremes themselves decrease populations and the variability shrinks geographic ranges (depending on event and climate interactions) also causing decreases. Perhaps helping to curtail the effects of the short-term weather extremes may help in the long-term. As yet it is unknown, and, as with most science, needs more investigation.I encourage you to read the entire paper. There are additional ideas and fleshing out of these conclusions that are particularly interesting.Roland, J., & Matter, S. (2012). Variability in winter climate, and winter extremes, reduce population growth of an alpine butterfly Ecology DOI: 10.1890/12-0611.1There are also a couple of articles that have nice interviews with the authors:From EurekAlert! and the University of Alberta: "Climate change isolates Rocky Mountain butterflies"ScienceDaily's article: "Climate Change Isolates Rocky Mountain Butterflies" (image via GeoLocation) ... Read more »

Roland, J., & Matter, S. (2012) Variability in winter climate, and winter extremes, reduce population growth of an alpine butterfly. Ecology. DOI: 10.1890/12-0611.1  

  • October 9, 2012
  • 02:45 PM
  • 294 views

Dinosaurs, Diversity, Distribution, and the LBG

by Melissa Chernick in Science Storiented

For some reason I am in the mood to read a biogeography paper. I didn’t really have a particular topic in mind when I started looking, just a few journals I occasionally peruse. Then I came across a paper about palaeodiversity and the distribution of dinosaurs. I like dinosaurs and I like biogeography. So this must be a win-win. I haven’t visited the idea of dinosaur community structure and distribution since my Dino Eco post back in 2010. That paper concluded that the entire Western Interior of North America may have once been populated by a single dinosaur community with low beta diversity. Today’s paper looks at dinosaur diversity on a global scale. Last month, authors Philip Mannion et al. published a paper in Global Ecology and Biogeography that used the dinosaur fossil record to examine spatial patterns in terrestrial biodiversity.To really get into this paper we’ll have to first explore the latitudinal biodiversity gradient (LBG). The LBG is essentially a biodiversity pattern in which species richness (a simple count of species) is highest in the tropics and declines polewards. It is a well-recognized pattern with causes that are a little less clear and that are still strongly debated. The two strongest hypotheses are that climate is the prime driver that influences biodiversity directly or via increased productivity in the tropics (warm areas are more hospitable and produce more food) or that the global distribution of area where the greater land area supports more species (the more land you have the more species will fit on it). The fossil record offers a deep time perspective that may help figure out the causes of the LBG we see today. The authors of this study chose a group of animals that was widespread, ecologically diverse, well studied, belonged to a long-lived clade, and had a fossil record that was adequate for the application of sampling standardization techniques. This gave them dinosaurs of Mesozoic terrestrial ecosystems for 160 million years, from the Late Triassic to the terminal Cretaceous (230-65.5 Ma).Mannion and his colleagues decided to use genera as the taxonomic unit of analysis for their study as the species scale can be inconsistent in its taxonomic treatment and the family scale tends to have arbitrary content (some families comprise a single genus while others are diverse). They then assembled a comprehensive dataset of Mesozoic dinosaur genera (738), including birds. Using the Paleobiology Database, they compiled stratigraphic ranges and modern geographic coordinates for occurrences, converting modern day coordinates to paleolatitudes using software called PointTracker (uses palaeogographical reconstructions of continental drift to transform present-day coordinates to past ones). They used a number of different methods to account for sampling biases in the fossil record, and they analyzed the data in seven time slices representing epochs and then the entire Jurassic and cretaceous periods as bins.The authors found that dinosaurs did not conform to the modern LBG. Dinosaur diversity was found to be highest at temperate latitudes rather than tropic. This result was consistent across the different time slices suggesting that the pattern was not controlled by climate fluctuations; in fact, it is possible that the Mesozoic climate gradient was much weaker than it is today. Rather, or because of this weakness, the driver of this diversity was likely the result of greater land area in these latitudinal belts. These larger land areas may also have facilitated the gigantism attained by many dinosaur species.Figure 3 Residual dinosaur diversity (thick solid lines) after controlling for numbers of dinosaur-bearing collections (DBCs) and formations (DBFs), plotted against non-marine area (NM area) and palaeogeographical reconstructions (using Mollweide projections) for the Late Triassic (bottom), Jurassic (middle) and Cretaceous (top). From Mannion et al. (2012)Unfortunately, these results suggest modern diversity patterns cannot be extrapolated into deep time. Guess we'll have to look somewhere else. However, it does add support to the hypothesis that land area is the primary control on the terrestrial LBG during times of weakened climatic gradient. And that, on its own, is a really interesting conclusion. The contrary, modern vs. past result also indicates that there may have been some kind of shift that took place during the middle Cenozoic that gave rise to the diversity patterns that we see today. I think I see a future study!Philip D. Mannion, Roger B. J. Benson, Paul Upchurch, Richard J. Butler, Matthew T. Carrano, & Paul M. Barrett7 (2012). A temperate palaeodiversity peak in Mesozoic dinosaurs and evidence for Late Cretaceous geographical partitioning. Global Ecology and Biogeography, 21 (9), 898-908 DOI: 10.1111/j.1466-8238.2011.00735.xAlso, check out this guest post by article author Philip Mannion over at Dave Hone's Archosaur Musings blog: "Guest Post: Dinosaurs and the latitudinal biodiversity gradient" (top image titled Dinosaur Diversity by Elliot Merton III found on Dinosaur Central) ... Read more »

Philip D. Mannion, Roger B. J. Benson, Paul Upchurch, Richard J. Butler, Matthew T. Carrano, & Paul M. Barrett7. (2012) A temperate palaeodiversity peak in Mesozoic dinosaurs and evidence for Late Cretaceous geographical partitioning. Global Ecology and Biogeography, 21(9), 898-908. DOI: 10.1111/j.1466-8238.2011.00735.x  

  • October 2, 2012
  • 04:46 PM
  • 275 views

Hey, I Could Be Your Girlfriend

by Melissa Chernick in Science Storiented

In the immortal words of Avril Lavigne: “Hey hey, you you, I don't like your girlfriend / No way, no way, I think you need a new one / Hey hey, you you, I could be your girlfriend...”Do I need to apologize for subjecting you to that? I almost feel as if I do. But it serves my point, I swear. Let’s say that the song was not titled “Girlfriend,” but instead was called “Mate Poaching.” Admittedly, it doesn’t really have the same ring to it, but that is essentially what she’s talking about.Human mate poaching is when someone tries to attract another person who is already in a relationship. This special form of attraction comes in both the short-term (the casual sexual dalliance) and the long-term (“If they only knew we were soul-mates!”) varieties. You can also look at it from different perspectives, the poacher or the poachee. In the latter, you have what is called mate poaching enticement where the person in the relationship is trying to attract someone new. Regardless of the duration, the interaction involves at least three people in a complex web of emotions, conflict, and sex (usually secretive sex). Put that together and you’ve got one good psychology study and several mediocre movies on your hands. Think about it: Romance, attraction, competition, persuasion, deception, jealousy, betrayal. It’s like the Hollywood checklist. But, being a science blog and this coming from a science paper, we’ll stick to the psychology study part.Now, I’ve done quite a few posts on relationships. Most of these have to do with the attraction of one sex to another. Today we look at the other end of the relationship. A slightly older paper published in the journal Personality and Social Psychology Bulletin delves into mate poaching enticement. How do you attract someone when you have this extra relationship component? Studies have shown that it is the same way you attract someone otherwise. Men tend to like beauty and sex, and women like the resource acquisition and dominance. You’re shocked, I can tell. However, mate poaching has several unique aspects or tactics. For example, targeting the mating rival and manipulating that emotional commitment. It also has costs that range from a blemished reputation to an all-out physical smack-down from the offended party. This paper looks at the former, the tactics, that people use to elicit a poaching attempt on themselves. The researchers do this by separating their study into two studies:Study 1: What tactics do people use to entice other into making a mate poaching attempt? A preliminary study was conducted to identify and name mate poaching enticement tactics so that they could be rated for effectiveness in the main study. In the main study, they gave participants a sheet of paper asking for their sex and containing an instructional set. These instructions explained mate poaching enticement, gave a list of tactics compiled from the preliminary study, and asked the participants to rate the acts on a 7-point scale. They found that already-mated men who were seeking a short-term relationship had the most luck using if the tactics “Enhance Potential Mate” (boost their ego, compliment them, tells them they deserve someone better), “Use Humor”, and “Provide Easy Sexual Access” (offer sex, ask for sex, make a pass). If a man is seeking a long-term relationship then his best tactics are “Enhance Potential Mate,” “Be Generous” (show you are a caring person, be extra polite, help with work or chores), and “Use Humor.” The researchers found that already-mated women seeking a short-term relationship had the best luck when the “Arrange Easy Sexual Access” (appear naked in room or car, turns a friendly date into a romantic one, suggests casual sex only), “Enhance Potential Mate,”, and “Provide Easy Sexual Access” tactics were employed. So, offer sex and thou shalt receive sex? Yep. For women seeking a new long-term partner, the best tactics were to “Develop Emotional Closeness” (confide in them, be good friends, talk about interests), “Mention Looking for Replacement,” and “Be Generous.” Overall, they found that enhancing an ego and being generous worked the best.Study 2: What tactics to men and women use to disguise mate poaching enticement? People tend to use deception tactics to gain access to things that they want. Often these tactics both increase the deceiver’s perceived value while also hiding their intentions from the competition. You can probably see how this is useful in the scope of mate poaching enticement. Again, the researchers conducted a preliminary experiment to identify and name these deceptions and disguise tactics so they could be rated later. As with the previous study, they gave a set of participants an instructional set, asking them to rate on a 7-point scale how effective each tactic would be at hiding from a current partner the fact that someone is trying to attract a new partner. They found that women were seen as more effective when they used the tactics “Keep Things Normal” (don’t change physical look, keep daily routine), “Use Friends” (introduce new partner to a faithful friend, friends help in the cover up, continues to go out with friends), “Lie About Relationships” (future plans, family involvement), "Lie About Self” (lie about past, lie about ending current relationship, keep conversation routine), “Establish Independent Self” (open bank account in own name, separate credit cards), and “Social Isolation” (attend fewer events, don’t discuss new partner, don’t spend much time away from work or home). In contrast, men were more effective when they used the tactics “Decrease Time with Current Partner” (goes out less with current partner, avoid being alone with current partner) and “Use Work Excuse” (work more hours, extra projects, sneak away from work). In terms of social level, when deceiving a community it is best to use the “Distance Friendships” (stop hanging around with mutual friends, don’t tell anyone about new partner, think before speaking in public) tactic, but when deceiving a single person it is best to use “Phone Tactics” (give new partner a fake phone number, buy new cell phone, get separate line). Overall, it was found that the effective acts for men were those that showed others that his current relationship would continue unabated, providing his mate with a close emotional connection. For women to be most successful at deception they must show that they maintain their daily routine. Apparently acting as if nothing is different or even increasing romance and sex with her mate are especially effective in disguising a mate poach. Put simply: blind him with sex.The more I read through this paper the more I felt like I was reading Science’s Guide to Cheating and Getting Away With It. I can’t say that any one thing in this study was particularly surprising. I don’t know if it is because it truly is predictable or if it is because we’ve all heard these excuses before. Hard to tell really. What do you think?David P. Schmitt, & Todd K. Shackelford (2003). Nifty Ways to Leave Your Lover: The Tactics People Use to Entice and Disguise the Process of Human Mate Poaching. Personality and Social Psychology Bulletin, 29 (8), 1018-1035 DOI: 10.1177/0146167203253471... Read more »

David P. Schmitt, & Todd K. Shackelford. (2003) Nifty Ways to Leave Your Lover: The Tactics People Use to Entice and Disguise the Process of Human Mate Poaching. Personality and Social Psychology Bulletin, 29(8), 1018-1035. DOI: 10.1177/0146167203253471  

  • September 19, 2012
  • 04:03 PM
  • 248 views

Snakes, An Origin Story

by Melissa Chernick in Science Storiented

Quite honestly, I should have been reading a plant paper for my upcoming lab meeting. But then I stumbled across a really cool snake paper and, well, that won out. I regret nothing. As with most people, I will most likely read the plant paper right before the meeting anyway.A paper published online today in Biology Letters takes a look at the phylogeny of squamate reptiles (lizards and snakes). This group of reptiles is one of the most diverse and well-known vertebrate groups including approximately 9000 species among 61 families. As with many groups, taxonomists and geneticists are trying to reconcile morphology and molecular analysis. This paper is taking the molecular approach, specifically looking at sister groups and interrelationships of major snake clades and iguanian families. Being a well-studied group, molecular analyses have been conducted in the past. These studies have suggested that squamate molecular phylogeny results differ quite a bit from morphological ones. This study takes one gigantic step forward, increasing the sampling of taxa dramatically and doubling the number of genes studied.The researchers sampled 161 squamate species and 10 outgroup taxa, including mammals (Homo, Mus, Tachyglossus), crocodilians (Alligator, Crocodylus), birds (Dromaius, Gallus), turtles (Chelydra, Podocnemis) and a rhyncocephalian (Sphenodon). Then they sequenced portions of 44 nuclear genes, targeting single-copy genes evolving at appropriate rates. The nucleotide sequences were then translated into amino acids to aid alignment. This alignment consisted of 33,717 base pairs! I’m not going to go into all of the bootstrapping, likelihoods, and Bayesian analyses that were used (even the word Bayesian makes my brain shut down in protest). But suffice it to say that the different analysis techniques that were used yielded similar phylogenies, providing strong support for the relationships found.The results of this molecular analysis were found to be consistent with other, recent, similar studies. However, there were some interesting relationships discovered. The first of these was that dibamid (legless lizards found in tropical forests) and gekkotans (geckos and the limbless Pygopodidae) are together the sister group to all other squamates. They also found strong support for paraphyly of scolecophidian snakes (blind snakes). Scolecophidians have reduced eyes and are specialized burrowers. Considering these traits, the paraphyly of this group suggests that it is the ancestral form, that other snakes may have been burrowers ancestrally. This makes sense if you compare the morphology of snakes to other burrowing species such as limb-reduced lizards. They both have short tails and elongate trunks. Very good for tunneling their way through the earth.Overall, a really interesting study that was huge in its scope. I look forward to more of these kinds of studies in the future.John J. Wiens, Carl R. Hutter, Daniel G. Mulcahy, Brice P. Noonan, Ted M. Townsend, Jack W. Sites Jr., & Tod W. Reeder (2012). Resolving the phylogeny of lizards and snakes (Squamata) with extensive sampling of genes and species Biology Letters, 4 (11) DOI: 10.1098/rsbl.2012.0703If you are a non-scientist and I used too many biology-jargony words for you or you just need a refresher on phylogeny, then I recommend looking through these sites:Fullerton’s Biology 261 course page on Interpreting CladogramsBerkeley’s Understanding Evolution page on reading phylogenetic treesHere is some more information on blind snakes:ScienceBlogs article Scolecophidians: seriously strange serpentsAlso:ScienceShot article: Snakes' Slitherin' Subterranean Kin(images from  Encyclopedia of Life and Neoseeker, respectively)... Read more »

John J. Wiens, Carl R. Hutter, Daniel G. Mulcahy, Brice P. Noonan, Ted M. Townsend, Jack W. Sites Jr., & Tod W. Reeder. (2012) Resolving the phylogeny of lizards and snakes (Squamata) with extensive sampling of genes and species. Biology Letters, 4(11). DOI: 10.1098/rsbl.2012.0703  

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