Ecology / Conservation posts
- August 9, 2011
- 10:30 AM
- 1,747 views
Getting "Mean Girled" in the Baboon World: The Price of Being Sexy.
by Serious Monkey Business in This is Serious Monkey Business
What do female baboons have in common with the Plastics from Mean Girls? A lot of aggression towards attractive female baboons that might pose a threat to their resources--but not in the typical way you might think.... Read more »
Huchard, E., & Cowlishaw, G. (2011) Female-female aggression around mating: an extra cost of sociality in a multimale primate society. Behavioral Ecology. DOI: 10.1093/beheco/arr083
- August 9, 2011
- 09:06 AM
- 1,355 views
Flowers stay open for pollinators, not daylight
by Jeremy Yoder in Denim and Tweed
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A honeybee explores the depths of a dandelion, one of the species used in Fründ et al.'s experiments. Photo by je-sa.If you've ever stopped to admire morning glory flowers opening first thing in the morning, then noticed they've closed by evening, you're at least dimly aware of one of the longest-established ideas in plant biology: that flowers open and close on a reliable daily schedule. Different species are open at different times of day, of course, but each flowering plant has its preferred open period, and it sticks to that schedule during its flowering season.
This idea led Carolus Linneaus, the father of modern biological taxonomy, to propose an Horologium florae, or "floral clock" using plantings of species with known flowering times to mark the hours. You can find his table of proposed species in the online version of Linneaus' 1783 treatise Philosophia Botanica, if you're not averse to Latin. Studies of flowers' daily schedules go back to well before English was the language of international science, and continue to the present day [$a].
Yet no one seems to have spent much time considering how flowers' schedules might respond to the activity of their very reason for being: pollinators. Flowers don't open just to be open in a particular kind of sunlight—they're open to attract animals that can carry pollen to another plant, and maybe leave some, too. If a flower receives enough pollen to make seeds by noon, why would it stay open until two o'clock?
According to some new experimental results, the answer to that question is that they don't [$a].
Jochen Fründ, Carsten F. Dormann, and Teja Tscharntke set out to see whether a selection of European wildflowers adjusted their opening schedules in response to pollination, with two major experiments and a broader-scale observation project. The experiments address whether pollinator activity could change flowers' schedules; the observations help determine how important those changes might be in studies of plant-pollinator interaction.
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A floral clock in Geneva—not quite what Linneaus had in mind. Photo by aranmanoth.In the first experiment, the team planted wildflowers—Crespis capillaris, a close relative of common dandelions—in experimental plots spaced across a field. Plots were either caged or left open to insect visitors, and Fründ et al introduced bees into some of the caged plots. So some plots had a controlled set of pollinators, some had none at all, and some had whatever pollinators were already active in the field.
The team then watched the flowers' daily opening and closing in the experimental plots. (They had a lot of help—a long list of names in the paper's Acknowledgements section ends with "and many others.") Over the same period of time, flowers in the un-caged plots received more insect visitors than flowers in either other treatment, and had mostly closed by midafternoon; flowers in the caged plots with bees introduced received fewer visitors and closed hours later; and flowers in the plots with no pollinators at all stayed open till evening.
So flowers experiencing the same daylight pattern closed earlier if they received more pollinator visits. The team followed up this result by hand-pollinating flowers of C. capillaris and a handful of closely related species growing in the same field, including dandelions—and flowers of three out of four species closed more rapidly when hand pollinated. Dandelions didn't respond to hand pollination, a result the authors explain by noting that dandelions often self-pollinate, and so don't need to wait for animal pollinators.
Finally, the team compiled observations of plant-pollinator interactions from sites similar to their study field located across Germany, and divided them into observations taken before solar noon, when the focal flower species from the experiments above tend to be open, and after solar noon. Which pollinator species visited which flowering plants depended significantly on when the observations were made—to the extent that the apparent importance of C. capillaris and its relatives is entirely different before and after noon.
Of course, these results apply directly to only a handful of species representing a particular group of flowering plants—but it's a group with a lot of widespread and abundant members, and the result is straightforward and striking. Animal-pollinated plants may not behave much like clocks at all. Instead, they're more like the patrons of a singles bar: they show up at about the same time and hang around until they find someone to buy them a drink. That's a dynamic worth keeping in mind for studies of plant-pollinator interaction, since it suggests that the partners a pollinator chooses will depend, at least in part, on whether or not it's out after closing time. ◼
References
Ewusie, J., & Quaye, E. (1977). Diurnal periodicity in some common flowers. New Phytologist, 78 (2), 479-485 DOI: 10.1111/j.1469-8137.1977.tb04854.x
Fründ, J., Dormann, C., & Tscharntke, T. (2011). Linné’s floral clock is slow without pollinators - flower closure and plant-pollinator interaction webs. Ecology Letters DOI: 10.1111/j.1461-0248.2011.01654.x
von Hase, A., Cowling, R., & Ellis, A. (2005). Petal movement in cape wildflowers protects pollen from exposure to moisture Plant Eco... Read more »
Ewusie, J., & Quaye, E. (1977) Diurnal periodicity in some common flowers. New Phytologist, 78(2), 479-485. DOI: 10.1111/j.1469-8137.1977.tb04854.x
Fründ, J., Dormann, C., & Tscharntke, T. (2011) Linné’s floral clock is slow without pollinators - flower closure and plant-pollinator interaction webs. Ecology Letters. DOI: 10.1111/j.1461-0248.2011.01654.x
von Hase, A., Cowling, R., & Ellis, A. (2005) Petal movement in cape wildflowers protects pollen from exposure to moisture. Plant Ecology, 184(1), 75-87. DOI: 10.1007/s11258-005-9053-8
- August 8, 2011
- 12:13 AM
- 847 views
Crop circle hoax and science
by Arunn in nOnoScience (a.k.a. Unruled Notebook)
Crop circles have been popular ever since hoaxes were, and should remain more popular than any of your G+ circles. It is one more (here is another) of those instances — unlike downright crap like Quan-dumb Table or Nano Art — where Art is created out of crafted and conjured up Science. Interestingly, over decades, [...]... Read more »
Haselhoff, E. (2001) Opinions and comments on Levengood WC, Talbott NP (1999) Dispersion of energies in worldwide crop formations. Physiol Plant 105: 615-624. Physiologia Plantarum, 111(1), 123-124. DOI: 10.1034/j.1399-3054.2001.1110116.x
- August 5, 2011
- 01:36 PM
- 754 views
The curious relationship between place names and population density
by Tim De Chant in Per Square Mile
Giving a name to a place is an important act. It says a place has meaning, that it should be remembered. For thousands of years, the way we kept track of place names—or toponyms—was by using our memory. Today, we’re not nearly so limited, and the number of toponyms seems to have exploded. Yet oddly [...]... Read more »
Hunn, E. (1994) Place-Names, Population Density, and the Magic Number 500. Current Anthropology, 35(1), 81. DOI: 10.1086/204245
- August 5, 2011
- 12:35 PM
- 887 views
Homing In For A Blood-thirsty Meal
by Jim Ryan in Wild Mammals
Their stealthy, nocturnal habits and their penchant for feeding on blood have made them Hollywood B movie stars.
...In South America where vampire bats are common, vampires approach their prey on the ground, galloping quickly and quietly as they sneak up on, bite, and drink the blood from sleeping cows, goats and birds.
Vampire bats are the only mammal that survives solely on blood, and they need to drink it pretty much every day to survive.
...Like other bats, they feed only at night, and they have excellent eyesight enhanced by acute hearing and an ability to emit high-pitched sounds that help them navigate. Their teeth lack enamel, which keeps them constantly razor sharp and allows them to delicately tear through the hide of a sleeping animal without waking it. Grooves in their tongue draw up the blood seeping through the open wound through capillary action, and they have anticoagulation chemicals inside their saliva to keep it flowing.
Within minutes of sinking its teeth in an animal’s flesh, an adult vampire bat can drink half its body weight in blood.
...Scientists have known for years that vampire bats seek out the best spots to tear through an animal’s skin with their razor-sharp teeth – where a precise bite will strike a vein and spill forth nourishing blood.
...By investigating wild vampire bats in South America, researchers at the University of California, San Francisco and Instituto Venezolano de Investigaciones Científicas in Caracas, Venezuela have discovered their secret (Gracheva et al., 2011). Its called TRPV1, and it is a sensitive, heat-detecting molecule covering nerve endings on their noses.
“Vampire bats feed on blood, and it’s useful for them to have an infrared detector to be able to find the circulation,” said David Julius, the Morris Herzstein Chair in Molecular Biology & Medicine at UCSF, who led the research.
Similar TRPV1 molecules can be found on pain sensing nerve fibers in human tongue, skin or eyes. They allow people to detect the chemical capsaicin in chili peppers and experience the burning tinge of spicy food.
Described this week in the journal Nature, the discovery highlights how small changes to genes in the genome of a species can contribute to major evolutionary adaptations over time – in this case, allowing the vampire bat to detect infrared heat from their prey, helping them efficiently find and feed on blood.
TRPV1 belongs to a large family of similar molecules common to many types of animals but they differ slightly from animal to animal – both in terms of their DNA and in terms of where they appear in the body.
...Many animals have highly specialized adaptations allowing them to see, feel, hear or taste in special ways. The heat-sensing molecules within vampire bat’s nose is one example.
Researchers have known for years that pits on vampire bats’ noses allow them to detect blood vessels because vessel radiate heat (Figure 2).
...Working with three researchers in South America, Julius’ postdoctoral fellows Elena Gracheva, PhD and Julio Cordero-Morales, PhD, together with UCSF colleagues Nicholas Ingolia, PhD and Jonathan Weissman, PhD, sequenced genes from samples of nose tissue from wild vampire bats in Venezuela, determining that TRPV1 is the molecule responsible for their ability to detect heat.
They also determined that it was not just TRPV1 but an evolutionary genetic variation of it that allows vampire bats to detect low temperature heat. Through a mechanism known as “alternative splicing” a special form of the molecule emerged in the noses of the bats, becoming a sensitive detector for finding the hottest spots.
...This story is adapted from materials provided by the University of California - San Francisco.
...Gracheva, E., Cordero-Morales, J., González-Carcacía, J., Ingolia, N., Manno, C., Aranguren, C., Weissman, J., & Julius, D. ... Ganglion-specific splicing of TRPV1 underlies infrared sensation in vampire bats Nature, 476 (7358), 88-91 DOI: 10.1038/nature10245
... Read more »
Gracheva, E., Cordero-Morales, J., González-Carcacía, J., Ingolia, N., Manno, C., Aranguren, C., Weissman, J., & Julius, D. (2011) Ganglion-specific splicing of TRPV1 underlies infrared sensation in vampire bats. Nature, 476(7358), 88-91. DOI: 10.1038/nature10245
- August 5, 2011
- 10:39 AM
- 1,109 views
The decline and fall of showy bustards
by GrrlScientist in Maniraptora
SUMMARY: The showiest bustards live fast and die young ... Read more »
Preston, B., Jalme, M., Hingrat, Y., Lacroix, F., & Sorci, G. (2011) Sexually extravagant males age more rapidly. Ecology Letters. DOI: 10.1111/j.1461-0248.2011.01668.x
- August 5, 2011
- 10:11 AM
- 1,417 views
The decline and fall of showy bustards
by GrrlScientist in GrrlScientist
Why do we get old and die? Why hasn't natural selection "weeded out" those genes responsible for age-related declines? ... Read more »
Preston, B., Jalme, M., Hingrat, Y., Lacroix, F., & Sorci, G. (2011) Sexually extravagant males age more rapidly. Ecology Letters. DOI: 10.1111/j.1461-0248.2011.01668.x
- August 4, 2011
- 05:51 PM
- 833 views
Dietary change and bioenergy potential
by Paul Spraycar in Agriculture & Land Use Forum
We’ve now reviewed the impacts of dietary choice on greenhouse gas emissions and on the land area required for global agricultural production. Now we turn to dietary trends and the impact on potential bioenergy production.
A new paper in Biomass and Bioenergy assesses the sensitivity of biomass potential to changes in diets, as well as changes in agricultural yields, cropland expansion, and climate change. The study finds a strong influence of global food requirements, especially the feed required for livestock, on global bioenergy potential.
The researchers developed a biomass balance model to estimate the global supply and demand of agricultural biomass, for which bioenergy competes with food production. To model dietary changes, the researchers developed a “fair and frugal” food consumption scenario involving more equitable food distribution and less meat consumption. In this scenario, only 7-10 percent of global calorific energy would come from animal products (vs. 8-32 percent today).
The “fair and frugal” diet would have a substantial impact on bioenergy potential by increasing it by up to 54 percent. (This scenario also assumes relatively high rates of yield growth.) The study therefore confirms that bioenergy potential, because it competes with land and agricultural products used in livestock production, is highly sensitive to changes in diets.
Haberl, H., Erb, K., Krausmann, F., Bondeau, A., Lauk, C., Müller, C., Plutzar, C., & Steinberger, J. (2011). Global bioenergy potentials from agricultural land in 2050: Sensitivity to climate change, diets and yields Biomass and Bioenergy DOI: 10.1016/j.biombioe.2011.04.035... Read more »
Haberl, H., Erb, K., Krausmann, F., Bondeau, A., Lauk, C., Müller, C., Plutzar, C., & Steinberger, J. (2011) Global bioenergy potentials from agricultural land in 2050: Sensitivity to climate change, diets and yields. Biomass and Bioenergy. DOI: 10.1016/j.biombioe.2011.04.035
- August 4, 2011
- 10:00 AM
- 1,093 views
Bacterial Traitors
by Lab Rat in Lab Rat Blog
Aphids are small insects that are a major pest in crop production. Dealing with these aphid pests often involves the use of pesticides, however growing resistance to these pesticides means that many farmers are now looking to use natural predators such as ladybirds or hoverflies to stop aphids destroying crops.... Read more »
Leroy PD, Sabri A, Heuskin S, Thonart P, Lognay G, Verheggen FJ, Francis F, Brostaux Y, Felton GW, & Haubruge E. (2011) Microorganisms from aphid honeydew attract and enhance the efficacy of natural enemies. Nature communications, 348. PMID: 21673669
Wootton L. (2011) Microbial ecology: Bacterial volatiles give the game away. Nature reviews. Microbiology. PMID: 21785449
- August 3, 2011
- 08:00 PM
- 1,114 views
Marine Fungi are Totally Badass
by Holly Bik in Deep Sea News
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That’s right, you heard me—there are mushrooms that live in the sea. OK, well technically a mushroom is a fruiting body of a fungus with a cap, stem and gills, but lets take some dramatic liberties and run with it. A new draft manuscript recently necessitated that I review the literature on marine fungi – . . . → Read More: Marine Fungi are Totally Badass... Read more »
Atalla, MM, Kheiralla, ZH, Hamed, ER, Youssry, AA, & Abeer, AA. (2010) Screening of some marine-derived fungal isolates for lignin degrading enzymes (LDEs) production. Agricultural and Biology Journal of North America, 1(4), 591-599. info:/
Bhadury P, Mohammad BT, & Wright PC. (2006) The current status of natural products from marine fungi and their potential as anti-infective agents. Journal of industrial microbiology , 33(5), 325-37. PMID: 16429315
HOOLEY, P., & WHITEHEAD, M. (2006) The genetics and molecular biology of marine fungi. Mycologist, 20(4), 144-151. DOI: 10.1016/j.mycol.2006.10.002
Jansson, H., & Nordbring-Hertz, B. (1979) Attraction of Nematodes to Living Mycelium of Nematophagous Fungi. Microbiology, 112(1), 89-93. DOI: 10.1099/00221287-112-1-89
Jones, M., Forn, I., Gadelha, C., Egan, M., Bass, D., Massana, R., & Richards, T. (2011) Discovery of novel intermediate forms redefines the fungal tree of life. Nature, 474(7350), 200-203. DOI: 10.1038/nature09984
Sayre RM. (1973) Theratromyxa weberi, An Amoeba Predatory on Plant-Parasitic Nematodes. Journal of nematology, 5(4), 258-64. PMID: 19319347
- August 3, 2011
- 11:55 AM
- 755 views
Dietary choice and land use change
by Paul Spraycar in Agriculture & Land Use Forum
We’ve written before about the strong influence of dietary choice on greenhouse gas emissions. A recent study in Agricultural Systems took a look at the land use effects of different scenarios of meat consumption and livestock productivity. The study concludes that a “faster-yet-feasible” growth in livestock productivity, together with a substitution of pork and poultry for ruminant, reduces global agricultural land use about 20 percent, from 5.4 billion ha to 4.4 billion ha in 2030.
Yields of annual crops are usually considered when we talk about meeting the world’s growing demand for food, but this study looks at some hitherto less investigated options: “1) increasing the efficiency of the entire food chain from ‘field to fork’; 2) changing diets toward food commodities requiring less land; and 3) increasing the yields of pastures.”
The researchers use the physical ALBIO (Agricultural Land Use and Biomass) model to study the effects of food consumption trends, livestock and crop productivity, and efficiency in food industry and trade, among others. To model a change in meat consumption, the researchers substitute 20 percent of per capita beef consumption with the same amount of pork and poultry. One step further, the study also models a minor vegetarian transition in regions with high per capita meat consumption (> 70 kg per capita per year). The magnitude of the changes was constrained to keep the results realistic.
The result of the lower-beef scenario is that global agricultural land use in 2030 would fall from 5.4 billion ha to 4.4. billion ha, “mainly due to substantial decreases in permanent pasture area.”
Even though this transition from ruminant meat to pork and poultry is hypothetical, this trend already is taking place to some degree. Moreover, it’s a trend “that could be boosted by upcoming factors, including increasing prices of agricultural land and feedstuffs, and implementation of stricter environmental and climate policies.” However, the scenario in which there is “a partial substitution of vegetable food for meat cannot be motivated by referring to recent trends.”
Wirsenius, S., Azar, C., & Berndes, G. (2010). How much land is needed for global food production under scenarios of dietary changes and livestock productivity increases in 2030? Agricultural Systems, 103 (9), 621-638 DOI: 10.1016/j.agsy.2010.07.005... Read more »
Wirsenius, S., Azar, C., & Berndes, G. (2010) How much land is needed for global food production under scenarios of dietary changes and livestock productivity increases in 2030?. Agricultural Systems, 103(9), 621-638. DOI: 10.1016/j.agsy.2010.07.005
- August 3, 2011
- 11:53 AM
- 658 views
Indicators for bioenergy
by Paul Spraycar in Agriculture & Land Use Forum
A team of researchers at Oak Ridge National Laboratory provide us this month in Ecological Indicators with a set of indicators that collectively represent how bioenergy systems may affect environmental sustainability. “This suite is intended as a basis or starting point for the selection of indicator suites for particular situations, which may require a subset or expansion of this proposed indicator suite.”
The study seeks to empirically measure environmental effects rather than rely on inferring such effects through assessment of management practices. “Ideally, a comparison between indicator values and baseline conditions should reveal the marginal environmental effects of a bioenergy system.”
The 19 proposed indicators cover six environmental categories:
Greenhouse gases: CO2 equivalent (kg CO2 / GJ)
Productivity: aboveground net primary productivity (g C/m2/yr)
Soil quality: total organic carbon (Mg/ha), total nitrogen (Mg/ha), extractable phosphorus (Mg/ha), bulk density (g/cm3)
Water quality and quantity: nitrate, phosphorus, suspended sediment and herbicide concentrations in streams(mg/L), peak storm flow (L/s), minimum base flow (L/s), consumptive water use (m3/ha/day)
Biodiversity: presence of taxa of special concern (presence), habitat area of taxa of special concern (ha)
Air quality: tropospheric ozone (ppb), carbon monoxide (ppm), total particulate matter (PM2.5 and PM10)
McBride, A., Dale, V., Baskaran, L., Downing, M., Eaton, L., Efroymson, R., Garten, C., Kline, K., Jager, H., Mulholland, P., Parish, E., Schweizer, P., & Storey, J. (2011). Indicators to support environmental sustainability of bioenergy systems Ecological Indicators, 11 (5), 1277-1289 DOI: 10.1016/j.ecolind.2011.01.010... Read more »
McBride, A., Dale, V., Baskaran, L., Downing, M., Eaton, L., Efroymson, R., Garten, C., Kline, K., Jager, H., Mulholland, P.... (2011) Indicators to support environmental sustainability of bioenergy systems. Ecological Indicators, 11(5), 1277-1289. DOI: 10.1016/j.ecolind.2011.01.010
- August 1, 2011
- 03:26 PM
- 343 views
Future sources of biofuels in the U.S.: Residues from agriculture and forestry
by Paul Spraycar in Agriculture & Land Use Forum
Biomass & Bioenergy just published a review of biomass availability for ethanol production as that industry looks beyond corn for the biomass needed to meet the U.S.’s ambitious ethanol mandate. They estimate that agricultural and forestry residues could only provide 5 percent of current U.S. fuel demand, and even that number assumes all available residues are harvested and converted into biofuels.
The study first describes the two primary conversion technologies – bioconversion and thermochemical conversion – and then concludes that “the two technical platforms have the ability to deliver roughly equivalent fuel outputs based on energy content.”
Bioconversion: Lignin, one of the three polymers in agricultural and forestry residues, is “composed of a number of phenolic compounds that may act as an inhibitor to the hydrolysis and fermentation of sugars.” This requires additional steps beyond the much simpler process required with starch. The main step is hydrolysis, typically carried out by enzymes, which breaks down the cellulosic microfibril structure into its carbohydrate components.
Thermochemical conversion combines several processes to generate synthesis gases (H, CO, CO2, et al.) which can then be reacted over a catalyst to produce biofuels including methanol, ethanol and Fischer-Tropsch fuels.
The study describes a few important feedstock characteristics that influence production yields:
The relative difficulty of bioconversion is dependent upon the chemistry of each particular feedstock. Agricultural residues don’t vary much in their lignocellulosic constituents. For wood residues, interspecies variation in basic chemistry is much more significant.
The difficulty of bioconversion increases as one progresses from agricultural residues to hardwood and then to softwood residues.
Hardwood species (e.g., poplar) have more cellulose and less hemicelluloses than softwoods, which means that greater amounts of glucose are available with hardwoods.
Softwoods (e.g., black spruce) have a thicker and more rigid cell wall, composed of a more recalcitrant form of lignin. Thus, softwoods are the most challenging material for bioconversion.
Although bioconversion of agricultural residues has been show to be ‘easiest,’ sugar contents are lower in agricultural residues when compared to forest residues.
In their natural states, both wood and agricultural residues typically contain about 50 percent water (!).
Agricultural residues include corn stover and straw from other cereal crops (wheat, barley, oats, sorghum, rye, and rice). Annual production is estimated to be 103 million tons of dry material (with a range of 45-118 million tons). Including all these cereal crops extends the range of ethanol beyond the major corn-producing regions and into the “geographic band extending from Alberta and Saskatchewan south to Texas.” States with a large existing ethanol industry, including Iowa, Illinois and Nebraska, have a head start in utilizing these lignocellulosic feedstocks.
For forestry residues, the primary areas of production are in the western and southeast states. The potential annual production from forestry residues is estimated to be from 1.7 to 11.3 hm3 per year, representing between 0.2 and 1.6 percent of current U.S. fuel demand.
The buildout of the lignocellulosic-based industry likely will begin in areas that already have a well-established starch-based industry. It was noted that no thermochemical conversion plants have been built to utilize biomass as a feedstock, though these plants typically require a scale 10 times that of a typical ethanol plant.
Although the overall potential of lignocellulosic biofuels from residue feedstocks is limited – estimated to displace a maximum of 5 percent of current U.S. fuel demand – these feedstocks are the cheapest and most readily available, and may therefore provide a bridge toward the development of a large industry utilizing dedicated energy crops.
Mabee, W., McFarlane, P., & Saddler, J. (2011). Biomass availability for lignocellulosic ethanol production Biomass and Bioenergy DOI: 10.1016/j.biombioe.2011.06.026... Read more »
Mabee, W., McFarlane, P., & Saddler, J. (2011) Biomass availability for lignocellulosic ethanol production. Biomass and Bioenergy. DOI: 10.1016/j.biombioe.2011.06.026
- August 1, 2011
- 02:51 PM
- 1,304 views
Superheroes Who Share a Power with Dolphins
by Elizabeth Preston in Inkfish
If only for reasons of terrestrial mobility, you probably shouldn't populate your whole superhero squad with cetaceans. Evil lairs on land would be difficult for you to infiltrate, to say the least. But you'd do well to consider including a dolphin or two in your next hero league. Dolphins were all over science journals last week, displaying powers that could put certain superheroes out of business.WolverineA letter published in Nature's Journal of Investigative Dermatology pointed out that bottle-nosed dolphins have remarkable healing abilities. They have plenty of run-ins with sharks: one survey found that 40% of dolphins had visible shark-bite scars. But all of these wounds had healed without killing the dolphins from blood loss or infection.The author, Michael Zasloff, also cites observations of dolphins healing in captivity. Despite having wounds a foot long and more than an inch deep--reaching all the way through their skin and blubber--these dolphins were as good as new just four weeks later. What's more, they showed no signs of pain while they went about their business.Setting aside the mystery of their apparent lack of discomfort, how do dolphins prevent massive blood loss after having a foot-wide bite taken out of them? It's not clear, especially since their blood actually clots less readily than ours. A further mystery is how they avoid infection. Swimming around in seawater is pretty much the opposite of the advice humans get from their doctors to keep a wound clean and dry.Zasloff speculates that some component of dolphin blubber acts to prevent infection. He suggests a certain molecule called isovaleric acid, which dolphins create within their blubber. It's known that this fatty acid accumulates in the blubber and doesn't get burned up for fuel during times of starvation. The molecule is also known to have antimicrobial powers. Perhaps, Zasloff says, isovaleric acid is released from the blubber after a serious injury and protects the surrounding tissue from infection.Whatever factors give dolphins their healing superpowers, humans would love to go Rogue and borrow a little for ourselves.Iron ManWho needs special healing abilities when you have the brains and resources to build yourself a protective suit? Bottlenose dolphins living in Shark Bay, Western Australia, have come up with a clever way to forage for food. They tear up basket sponges that are unfortunate enough to be living near them, like this one:Then they convert those hapless sponges into protective face-masks:The "spongers" swim along the seafloor and poke around with their sponges until they disturb a fish hiding under the rocks there. Then they ditch the sponge and snag their prey.The seafloor in Shark Bay is littered with shards of shell, rock and coral that could scratch dolphins' skin. So the sponges seem meant to protect dolphins' beaks while they ferret out food. But researchers from Georgetown University wondered why dolphins would bother to go digging for food with their faces when they already possess the power (shared by Daredevil) of echolocation. Since they can hunt effectively with sound, why do these dolphins hunt with sponges?To find out, the researchers gamely attached a sea sponge to a pole and began poking around the seafloor with it, emulating a sponge-hunting dolphin. Whenever a fish popped out of the rubble, they caught it and identified its species. They discovered that the fish species hiding under the rocks were less likely to have the balloon-like organ called a swim bladder. This lack of an airy center, along with their rubbly hideout, makes the fish harder to detect by echolocation.The "sponging" behavior is mostly seen in female dolphins, who teach it to their daughters. Obvious Eline Benes jokes aside, it's a clever solution for reaching a food source the dolphins couldn't otherwise get to. MagnetoAnother way to find food that's well hidden--if your food is a living animal, anyway--is to sense the electrical field around its body. All animals generate faint electrical fields, thanks to the currents running through our nerves and muscles. A group of German researchers has discovered that the Guiana dolphin, a species living off the north and east coasts of South America, is able to perceive these electrical fields.The researchers examined dark pits on the dolphins' snouts that were thought to have no function--they're remnants of the holes whiskers grow out of in some other mammals. Rather than being useless, the researchers found, these pores have evolved into active sensors for electric fields. To test how sensitive the dolphins were to the kinds of electric fields their prey might give off, researchers taught a captive dolphin to hold its beak inside a hoop. When it felt an electric current near its beak, the dolphin was trained to signal the researchers by swimming away from the hoop. (This sounds like a more-fun version of the hearing tests given to kids: If you hear a beep, run!)The dolphin could reliably sense electrical signals like those given off by its prey fish. The researchers think this ability might help supplement the Guiana dolphins' echolocation abilities, since they tend to live in murky waters and hunt for fish that live in mud.Dolphins aren't the only animal with an electric sense. Many fish and some amphibians have also evolved the ability to perceive electrical fields in water. Among mammals, the power had only previously been observed in the echidna and platypus--weird egg-laying mammals that, superhero or not, would have a home on any team of mutants.Zasloff, M. (2011). Observations on the Remarkable (and Mysterious) Wound-Healing Process of the Bottlenose Dolphin Journal of Investigative Dermatology DOI: 10.1038/jid.2011.220Patterson, E., & Mann, J. (2011). The Ecological Conditions That Favor Tool Use and Innovation in Wild Bottlenose Dolphins (Tursiops sp.) PLoS ONE, 6 (7) DOI: 10.1371/journal.pone.0022243... Read more »
Zasloff, M. (2011) Observations on the Remarkable (and Mysterious) Wound-Healing Process of the Bottlenose Dolphin. Journal of Investigative Dermatology. DOI: 10.1038/jid.2011.220
Patterson, E., & Mann, J. (2011) The Ecological Conditions That Favor Tool Use and Innovation in Wild Bottlenose Dolphins (Tursiops sp.). PLoS ONE, 6(7). DOI: 10.1371/journal.pone.0022243
Czech-Damal, N., Liebschner, A., Miersch, L., Klauer, G., Hanke, F., Marshall, C., Dehnhardt, G., & Hanke, W. (2011) Electroreception in the Guiana dolphin (Sotalia guianensis). Proceedings of the Royal Society B: Biological Sciences. DOI: 10.1098/rspb.2011.1127
- August 1, 2011
- 06:52 AM
- 1,102 views
Operation Cat Drop
by bug_girl in Bug Girl's Blog
In the news recently: Operation Rat Drop, where tylenol-laden mice were dropped from planes over Guam. It’s not a bizarre headache remedy; the idea is to try to kill brown tree snakes (a non-native invasive species) when they eat the mice. Acetaminophen kills snakes. Who knew? That reminded me of a similar–but much odder–project: Operation Cat Drop. It’s an [...]... Read more »
O'Shaughnessy, P. (2008) PARACHUTING CATS AND CRUSHED EGGS The Controversy Over the Use of DDT to Control Malaria. American Journal of Public Health, 98(11), 1940-1948. DOI: 10.2105/AJPH.2007.122523
- July 31, 2011
- 12:12 PM
- 1,403 views
101 Uses for Shark Puke Part 2: How Much Do Sharks Eat?
by Chuck in Ya Like Dags?
The last time I wrote about the usefulness of shark puke, I discussed a few of the less obvious uses of diet studies on sharks. As apex predators, sharks can sample a wide variety of potential prey species, and diet studies can provide just as much information on those species as the sharks themselves. That said, the main function and justification for sifting through shark vomit is to figure out what kind of predatory impact the sharks have, which lets us know how these predators fit into the ecosystem and adjust fisheries models accordingly, put protections in if the most important prey are declining, or see if the food web needs any “adjusting” (always a popular topic at fishery advisory council meetings). In order to figure this out, scientists need to figure out just how much food a shark needs, and there are some nifty ways of doing this.... Read more »
Bush, A., & Holland, K. (2002) Food limitation in a nursery area: estimates of daily ration in juvenile scalloped hammerheads, Sphyrna lewini (Griffith and Smith, 1834) in Kane’ohe Bay,O’ahu, Hawai’i. Journal of Experimental Marine Biology and Ecology, 157-178. info:/
Olson, R., & Mullen, A. (1986) Recent developments for making gastric evacuation and daily ration determinations. Environmental Biology of Fishes, 16(1-3), 183-191. DOI: 10.1007/BF00005170
- July 29, 2011
- 12:07 PM
- 1,101 views
Swedes move to the city, but don’t leave the forest behind
by Tim De Chant in Per Square Mile
If there’s one thing that comes to mind when you think of Sweden besides Ikea and meatballs, it’s probably forests. They cover nearly 70 percent of the country. As a result, Swedes have a very close relationship with their forests, though the nature of it has changed in the last few decades. Swedish forests have [...]... Read more »
Axelsson, A. (2001) Retrospective gap analysis in a Swedish boreal forest landscape using historical data. Forest Ecology and Management, 147(2-3), 109-122. DOI: 10.1016/S0378-1127(00)00470-9
Linder, P., & Östlund, L. (1998) Structural changes in three mid-boreal Swedish forest landscapes, 1885–1996. Biological Conservation, 85(1-2), 9-19. DOI: 10.1016/S0006-3207(97)00168-7
Lindhagen, A. (2000) Forest recreation in 1977 and 1997 in Sweden: changes in public preferences and behaviour. Forestry, 73(2), 143-153. DOI: 10.1093/forestry/73.2.143
Kardell, Lars. (1980) Forest mushrooms and berries—an endangered resource?. Ambio, 9(5), 241-247. info:/
- July 29, 2011
- 08:00 AM
- 684 views
Prescribing Gene Flow
by Kevin Zelnio in EvoEcoLab
When ecosystems are sick, who prescribes the cure? Its not as straight-forward as it is in medicine. A doctor diagnoses a problem and prescribes some medication or treatments to ease the pain or kill infectious agents. Sometimes we battle the insurance agents over the necessity of treatments. This is simplified of course. In applied ecology, [...]
... Read more »
Behere, G., Tay, W., Russell, D., Heckel, D., Appleton, B., Kranthi, K., & Batterham, P. (2007) Mitochondrial DNA analysis of field populations of Helicoverpa armigera (Lepidoptera: Noctuidae) and of its relationship to H. zea. BMC Evolutionary Biology, 7(1), 117. DOI: 10.1186/1471-2148-7-117
Sexton JP, Strauss SY, & Rice KJ. (2011) Gene flow increases fitness at the warm edge of a species' range. Proceedings of the National Academy of Sciences of the United States of America, 108(28), 11704-9. PMID: 21709253
- July 28, 2011
- 07:00 AM
- 1,279 views
Book Review: "Elixir" by Brian Fagan
by Matthew Garcia in Hydro-Logic
"Elixir: A History of Water and Humankind" by Brian Fagan, published in 2011 by Bloomsbury Press, New York NY, ISBN 978-1-60819-003-4
... Read more »
Evans, D., Pottier, C., Fletcher, R., Hensley, S., Tapley, I., Milne, A., & Barbetti, M. (2007) A comprehensive archaeological map of the world's largest preindustrial settlement complex at Angkor, Cambodia. Proceedings of the National Academy of Sciences, 104(36), 14277-14282. DOI: 10.1073/pnas.0702525104
- July 27, 2011
- 01:45 PM
- 830 views
Thinking about how we think about landscapes
by Tim De Chant in Per Square Mile
Take a look at the painting above. It’s one of Thomas Cole’s most famous works, commonly known as The Oxbow.¹ It’s got a little something for everyone. A twisted old tree. A menacing thunderstorm. Soaring cumulonimbus clouds. A spot of sunlight. A meandering river. Well manicured farm fields. I could go on and on. Part [...]... Read more »
Kaplan, R., Kaplan, S., & Brown, T. (1989) Environmental Preference: A Comparison of Four Domains of Predictors. Environment and Behavior, 21(5), 509-530. DOI: 10.1177/0013916589215001
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