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  • November 9, 2010
  • 12:23 PM
  • 1,385 views

The Latest On: When Five Hundred Tigers Are Not Enough

by Kelly Grooms in Promega Connections

It is sad but true that the latest news has not been promising for wild tiger populations. In September, an article published in PLoS Biology (1) estimated that the best hope of saving the wild tiger population would be to shift focus to source sites, which are “…at spatially well-defined priority sites, supported by proven best [...]... Read more »

Walston J, Robinson JG, Bennett EL, Breitenmoser U, da Fonseca GA, Goodrich J, Gumal M, Hunter L, Johnson A, Karanth KU.... (2010) Bringing the tiger back from the brink-the six percent solution. PLoS biology, 8(9). PMID: 20856904  

  • November 9, 2010
  • 11:31 AM
  • 20,217 views

Mini frog packs a powerful punch

by GrrlScientist in GrrlScientist

Another tiny-but-deadly poisonous frog has been discovered, this time, in Cuba... Read more »

Ariel Rodriguez, Dennis Poth, Stefan Schulz, & Miguel Vences. (2010) Discovery of skin alkaloids in a miniaturized eleutherodactylid frog from Cuba. Biology Letters. info:/10.1098/rsbl.2010.0844

  • November 9, 2010
  • 11:30 AM
  • 2,126 views

Great diagrams of science: What are they doing to those animals?

by WhySharksMatter in Southern Fried Science

The stereotype of a scientific diagram is a complex, dry, boring graph. While many earn this reputation, a few make can make people do a double-take. Most of these explain research methods involving live animal test subjects. A few of my favorites are shown below.
It is important to note that these images do not show animal [...]... Read more »

Lohmann, K., Lohmann, C., & Putman, N. (2007) Magnetic maps in animals: nature's GPS. Journal of Experimental Biology, 210(21), 3697-3705. DOI: 10.1242/jeb.001313  

Meredith TL, & Kajiura SM. (2010) Olfactory morphology and physiology of elasmobranchs. The Journal of experimental biology, 213(Pt 20), 3449-56. PMID: 20889825  

Mora, C., Davison, M., Martin Wild, J., & Walker, M. (2004) Magnetoreception and its trigeminal mediation in the homing pigeon. Nature, 432(7016), 508-511. DOI: 10.1038/nature03077  

  • November 9, 2010
  • 11:00 AM
  • 1,054 views

It itches! The immune system turns up in the strangest places

by Kevin Bonham in Food Matters

Normally, I would feel woefully unqualified to analyze a Nature Neuroscience paper, but I'm going to do it anyway. How could I pass it up? It features a Toll-like receptor!

Toll-like receptors are typically expressed in immune cells to regulate innate immunity. We found that functional Toll-like receptor 7 (TLR7) was expressed in C-fiber primary sensory neurons and was important for inducing itch (pruritus), but was not necessary for eliciting mechanical, thermal, inflammatory and neuropathic pain in mice.

TLR's are on the front lines of immune defense. They are present on many cells types, especially immune cells, and alert the cell that something foreign is in the area. Evolution has selected them to recognize things that are found on bacteria, viruses and fungi, but not on our own cells. If a cell expresses a TLR, and that TLR binds to its ligand, that usually tells the cell that something is wrong, and an immune response should be triggered.

But a TLR is just a receptor, and there's no reason, in principal, that it couldn't be co-opted for other uses. And that seems to be what these authors found Read the rest of this post... | Read the comments on this post...... Read more »

Liu T, Xu ZZ, Park CK, Berta T, & Ji RR. (2010) Toll-like receptor 7 mediates pruritus. Nature neuroscience. PMID: 21037581  

  • November 9, 2010
  • 09:05 AM
  • 1,668 views

In the depths of a pitcher plant, competitors and predators cancel each other out

by Jeremy Yoder in Denim and Tweed

Species interactions are probably pretty important, in the evolution of life. There are all sorts of studies showing that the fitness and evolutionary history of individual species depends upon interactions with pollinators, symbiotes, food plants, herbivores, parasites, predators, and competitors. Most of these studies focus in on a single interaction—but what living thing interacts with only one other organism? Coevolution, when it happens, happens in a community context.

Adding even a second interaction into the scientific picture can be difficult, but it may also dramatically change the evolutionary outcome, as seen in a new study of evolution in the protozoan communities living in purple pitcher plants. Individually, competitors and predators are significant agents of natural selection—but together, they seem to counterbalance each other [$a].
.flickr-photo { }.flickr-framewide { float: right; text-align: left; margin-left: 15px; margin-bottom: 15px; width:100%;}.flickr-caption { font-size: 0.8em; margin-top: 0px; } The purple pitcher plant, Sarracenia purpurea. Photo by petrichor.Carnivorous pitcher plants grow funnel-shaped leaves that collect water to form a pitfall trap for hapless insects, which provide a source of nitrogen in swampy, nutrient-poor habitats. One species' pitfall is another's ideal habitat, however, and pitchers also play host to diverse micro-communities [PDF] of protozoans, bacteria, and even mosquito larvae. By recreating—and experimentally manipulating—these communities in the laboratory, the new study's author, Casey terHorst, was able to disentangle the individual and combined effects of two different kinds of species interaction within pitcher plant pitfalls.

TerHorst focused on a protozoan species in the genus Colpoda, a widespread single-celled critter found in moist soil and standing water. In pitcher plants, Colpoda makes a living feeding on bacteria that break down insects trapped by the pitfall—and they themselves are prey for the larvae of the mosquito Wyeomyia smithii.

.flickr-photo { }.flickr-frameright { float: right; text-align: left; margin-left: 15px; margin-bottom: 15px; width:40%;}.flickr-caption { font-size: 0.8em; margin-top: 0px; } An example of genus Colpoda, the group of ciliates studied (but probably not the same species). Photo by PROYECTO AGUA** /** WATER PROJECT.To determine the individual and combined effects of competition and predation on Colpoda, terHorst allowed experimental populations of the protozoan to evolve for 20 days (about 60-120 Colpoda generations) with either (1) no competitors or predators, (2) competition from another bacteria-eating protozoan, (3) predation by mosquito larvae, or (4) competition and predation. At the end of the experimental period, he sampled each evolved Colpoda population and measured a number of traits, including the size of Colpoda cells and their speed. Larger Colpoda cells are thought to be better competitors but more vulnerable to predators; faster ones should be better able to evade predation.

Individually, predators and competitors had significant effects on Colpoda evolution. In the presence of mosquito larvae, Colpoda evolved smaller, faster cells than it did alone. Unexpectedly, competitors also caused Colpoda to evolve smaller cells, though not faster ones. TerHorst suggests that this is because competition also favored more rapid reproduction by Colpoda, which meant that individual cells grew less before dividing.

Most interestingly, though, Colpoda evolving in the presence of both predators and competitors looked quite a lot like Colpoda that evolved alone. This is apparently because the mosquito larvae ate both Colpoda and its competitor—the mosquitoes acted to relieve some competitive pressure on Colpoda at the same time they ate fewer Colpoda because they had two prey species to pursue. In fact, the mosquitoes preferred to eat the competitor species, since it tended to hang out in the open while Colpoda hid among the plastic beads lining the base of the artificial habitat.

Thus the indirect effects of the predator offsetting competition, and of the competitor drawing away predation, canceled out the natural selection each imposed on Colpoda individually. Species interactions in a community context, even a simple one like this, are far from straightforward.

References

Buckley, H., Burns, J., Kneitel, J., Walters, E., Munguia, P., & Miller, E. (2004). Small-scale patterns in community structure of Sarracenia purpurea inquilines. Community Ecology, 5 (2), 181-8 DOI: 10.1556/ComEc.5.2004.2.6

terHorst, C. (2010). Evolution in response to direct and indirect ecological effects in pitcher plant inquiline communities. The American Naturalist, 176 (6), 675-85 DOI: 10.1086/657047

... Read more »

  • November 9, 2010
  • 05:30 AM
  • 441 views

Surviving HIV

by Becky in It Takes 30

Untreated, HIV is normally a death sentence.  But not quite always.  A small number of people infected with HIV can survive for decades without symptoms.  They’re called “elite controllers”, and — although the fact that they’re healthy makes them hard to identify with certainty — they’re thought to comprise less than 1% of the infected [...]... Read more »

The International HIV Controllers Study. (2010) The Major Genetic Determinants of HIV-1 Control Affect HLA Class I Peptide Presentation. Science. info:/10.1126/science.1195271

  • November 9, 2010
  • 03:25 AM
  • 755 views

Genes To Brains To Minds To... Murder?

by Neuroskeptic in Neuroskeptic

A group of Italian psychiatrists claim to explain How Neuroscience and Behavioral Genetics Improve Psychiatric Assessment: Report on a Violent Murder Case.The paper presents the horrific case of a 24 year old woman from Switzerland who smothered her newborn son to death immediately after giving birth in her boyfriend's apartment. After her arrest, she claimed to have no memory of the event. She had a history of multiple drug abuse, including heroin, from the age of 13. Forensic psychiatrists were asked to assess her case and try to answer the question of whether "there was substantial evidence that the defendant had an irresistible impulse to commit the crime." The paper doesn't discuss the outcome of the trial, but the authors say that in their opinion she exhibits a pattern of "pathologically impulsivity, antisocial tendencies, lack of planning...causally linked to the crime, thus providing the basis for an insanity defense."But that's not all. In the paper, the authors bring neuroscience and genetics into the case in an attempt to providea more “objective description” of the defendant’s mental disease by providing evidence that the disease has “hard” biological bases. This is particularly important given that psychiatric symptoms may be easily faked as they are mostly based on the defendant’s verbal report.So they scanned her brain, and did DNA tests for 5 genes which have been previously linked to mental illness, impulsivity, or violent behaviour. What happened? Apparently her brain has "reduced gray matter volume in the left prefrontal cortex" - but that was compared to just 6 healthy control women. You really can't do this kind of analysis on a single subject, anyway.As for her genes, well, she had genes. On the famous and much-debated 5HTTLPR polymorphism, for example, her genotype was long/short; while it's true that short is generally considered the "bad" genotype, something like 40% of white people, and an even higher proportion of East Asians, carry it. The situation was similar for the other four genes (STin2 (SCL6A4), rs4680 (COMT), MAOA-uVNTR, DRD4-2/11, for gene geeks).I've previously posted about cases in which a well-defined disorder of the brain led to criminal behaviour. There was the man who became obsessed with child pornography following surgical removal of a tumour in his right temporal lobe. There are the people who show "sociopathic" behaviour following fronto-temporal degeneration.However this woman's brain was basically "normal" at least as far as a basic MRI scan could determine. All the pieces were there. Her genotypes was also normal in that lots of normal people carry the same genes; it's not (as far as we know) that she has a rare genetic mutation like Brunner syndrome in which an important gene is entirely missing. So I don't think neurobiology has much to add to this sad story.*We're willing to excuse perpetrators when there's a straightforward "biological cause" for their criminal behaviour: it's not their fault, they're ill. In all other cases, we assign blame: biology is a valid excuse, but nothing else is.There seems to be a basic difference between the way in which we think about "biological" as opposed to "environmental" causes of behaviour. This is related, I think, to the Seductive Allure of Neuroscience Explanations and our fascination with brain scans that "prove that something is in the brain". But when you start to think about it, it becomes less and less clear that this distinction works.A person's family, social and economic background is the strongest known predictor of criminality. Guys from stable, affluent families rarely mug people; some men from poor, single-parent backgrounds do. But muggers don't choose to be born into that life any more than the child-porn addict chose to have brain cancer.Indeed, the mugger's situation is a more direct cause of his behaviour than a brain tumour. It's not hard to see how a mugger becomes, specifically, a mugger: because they've grown up with role-models who do that; because their friends do it or at least condone it; because it's the easiest way for them to make money.But it's less obvious how brain damage by itself could cause someone to seek child porn. There's no child porn nucleus in the brain. Presumably, what it does is to remove the person's capacity for self-control, so they can't stop themselves from doing it.This fits with the fact that people who show criminal behaviour after brain lesions often start to eat and have (non-criminal) sex uncontrollably as well. But that raises the question of why they want to do it in the first place. Were they, in some sense, a pedophile all along? If so, can we blame them for that?Rigoni D, Pellegrini S, Mariotti V, Cozza A, Mechelli A, Ferrara SD, Pietrini P, & Sartori G (2010). How neuroscience and behavioral genetics improve psychiatric assessment: report on a violent murder case. Frontiers in behavioral neuroscience, 4 PMID: 21031162... Read more »

Rigoni D, Pellegrini S, Mariotti V, Cozza A, Mechelli A, Ferrara SD, Pietrini P, & Sartori G. (2010) How neuroscience and behavioral genetics improve psychiatric assessment: report on a violent murder case. Frontiers in behavioral neuroscience, 160. PMID: 21031162  

  • November 8, 2010
  • 08:47 PM
  • 769 views

Genomic patterns of pleiotropy and the evolution of complexity (Wang et. al 2010)

by Victor Hanson-Smith in Evolution, Development, and Genomics

Posted by Victor Hanson-Smith, Conor O’Brien, and Bryn Gaertner. One of the grand challenges of evo-devo is to understand how mutations of genetic sequences affect concomitant phenotypic traits.  Eighty-one years ago, Fisher (1930) proposed that every mutation may affect every … Continue reading →... Read more »

Wang Z, Liao BY, & Zhang J. (2010) Genomic patterns of pleiotropy and the evolution of complexity. Proceedings of the National Academy of Sciences of the United States of America, 107(42), 18034-9. PMID: 20876104  

  • November 8, 2010
  • 08:41 PM
  • 1,116 views

Caperea alive!

by Darren Naish in Tetrapod Zoology





By now you might be relatively familiar with the bizarre soft tissue and bony anatomy of the peculiar, poorly known Pygmy right whale Caperea marginata [a juvenile Caperea that stranded on New Zealand is shown above; original image by New Zealand Department of Conservation, from Te Papa's Blog]. If you missed the relevant articles you might want to check them out here (on the giant, asymmetrical laryngeal pouch), here (on the vertebrae and ribs) and here (on the skull, ribs and tail). These articles (which were very much thrown together without any planning: they were spin-offs of the [unfinished] pouches, pockets and sacs series) were devoted entirely to the animal's anatomy, and didn't touch on what we know about this weird little whale's ecology and behaviour. Read the rest of this post... | Read the comments on this post...... Read more »

  • November 8, 2010
  • 08:31 PM
  • 1,033 views

Ocean acidification negatively affects coral establishment

by Phil Camill in Global Change: Intersection of Nature and Culture


When CO2 from fossil fuels accumulates in the atmosphere, some of it dissolves into the oceans where it reacts with water to form a weak acid (H2CO3) —carbonic acid— that lowers seawater pH and makes it increasingly difficult for corals and other calcitic organisms to form their calcium carbonate (CaCO3) skeletons.
A new study in the [...]... Read more »

Rebecca Albright, Benjamin Mason, Margaret Miller, and Chris Langdon. (2010) Ocean acidification compromises recruitment success of the threatened Caribbean coral Acropora palmata. Proceedings of the National Academy of Sciences. info:/

  • November 8, 2010
  • 07:27 PM
  • 849 views

Potential genetic basis for why BPA is harmful to animals

by Phil Camill in Global Change: Intersection of Nature and Culture


In a forthcoming article in Proceedings of the National Academy of Sciences, Patric Allard and Monica Colaiácovo use a nemotode (round worm) system to explore how BPA damages genetic processes in animals.
BPA ranks among the highest production volume chemicals with a global annual production scale of ≈4 million metric tons. It is commonly used in [...]... Read more »

Patrick Allard and Monica P. Colaiácovo. (2010) Bisphenol A impairs the double-strand break repair machinery in the germline and causes chromosome abnormalities. Proceedings of the National Academy of Sciences. info:/10.1073/pnas.1010386107

  • November 8, 2010
  • 07:05 PM
  • 472 views

Quantitative Population Impact of Adoption Among California Sea Lions

by Michael Long in Phased

Adoption frequency among California sea lions appears to be between roughly 6% and 17%, and is possibly a major contributor to sea lion populations.... Read more »

  • November 8, 2010
  • 02:52 PM
  • 2,154 views

Autism-Related Gene Spotlight: SLC4A10

by Lindsay in Autist's Corner

I'm doing a series describing genes that have been found to be associated (even weakly, as this one is) with autism. This one is a membrane-spanning transport protein that exchanges sodium and bicarbonate ions for chloride ion; it is primarily expressed in the central nervous system. Mutations in this gene lead to changes in neuronal excitability, which can manifest as seizures.... Read more »

Jacobs, S., Ruusuvuori, E., Sipila, S., Haapanen, A., Damkier, H., Kurth, I., Hentschke, M., Schweizer, M., Rudhard, Y., Laatikainen, L.... (2008) Mice with targeted Slc4a10 gene disruption have small brain ventricles and show reduced neuronal excitability. Proceedings of the National Academy of Sciences, 105(1), 311-316. DOI: 10.1073/pnas.0705487105  

  • November 8, 2010
  • 01:34 PM
  • 2,003 views

Transparent mouse embryos and hematopoietic cell clusters

by Erin Campbell in the Node

I was lucky in graduate school and my postdoctoral research—I was a microscopist working on a transparent organism (C. elegans).  Some microscopists don’t have that luxury, but have developed amazing techniques in order to visualize development in organisms such as mice.  In the November 1 issue of Development, Yokomizo and Dzierzak use a technique that [...]... Read more »

  • November 8, 2010
  • 01:14 PM
  • 995 views

Antibiotics and gut bacteria

by Lab Rat in Lab Rat

All microbiologists end up writing about gut bacteria at some point. It is the way of things. Disease of the Week is currently doing a whole series on it, and a few weeks ago I covered the interaction of the immune system with gut bacteria (here). However a recent paper came out in Microbiology Today concerning the affect of antibiotics on gut bacteria, which is a topic that I both find interesting and have had some actual experience with.I've taken antibiotics a few times, and each time I've found that despite the many positive effects it has (i.e I don't die of septicaemia) being on antibiotics tends to make my stomach fairly unhappy. I usually have a good relationship with my stomach - I feed it regularly with plenty of food and in turn it is generally quite accepting of the fact that I don't always wash my hands as much as I should, and occasionally eat things that might be past their sell-by date, or heated up food that isn't exactly the "piping hot" recommended by the label.Antibiotics however are usually designed to kill off bacteria, and unless the antibiotic in question is very specific that often includes your commensal gut bacteria; the 'friendly' bacteria that yoghurt companies keep mentioning, that hangs around in your gut and prevents other bacteria invading. In the short term this leads too the occasional unhappy stomach but in the long term it can have a more sinister effect, by encouraging antibiotic resistance genes to develop and spread amongst the normal bacteria in your gut.The diagram below shows a stylised (and not to scale) diagram of what happens to your gut bacteria after a dose of antibiotics. The antibiotic resistant bacteria (in purple) are suddenly at an advantage and can proliferate. As time goes by, the other natural bacteria gradually return to your gut (which is not after all the most sterile of environments) but there will be a higher concentration of antibiotic-resistant bacteria around.Diagram taken from the reference (below)It's important to remember that these antibiotic-bacteria are not dangerous in themselves. Unless they move out of the gut for any reason they will remain totally harmless. However they also contain the genes for antibiotic resistance, and if another bacteria manages to survive and get into the gut, they can pass those genes on. As every human carries different gut bacteria, and will take different antibiotics in the course of their lifetime, this study cannot really make any hard and fast rules about what the effect of this might be on any one individual, but it does make the point that many people will be carrying within them a large proportion of bacteria that may have developed a novel form of antibiotic resistance.It's not always terrible, in some cases the antibiotic resistant bacteria are grossly unfit, and are immediately out-competed as soon as the antibiotic goes away. Those that do survive both the antibiotic and the returning bacteria however, can hang around for a long time, and antibiotic resistance was seen in gut bacteria up to four years after antibiotic treatment had finished. And the intestines are such a wonderful environment for bacteria to share DNA in; there are abundant nutrients, everything is all moist and warm and there are a lot of bacteria in very close contact with each other.If you have taken antibiotics it's not worth loosing sleep over, but it's something hospitals are starting to be more and more aware of.---Jernberg C, Löfmark S, Edlund C, & Jansson JK (2010). Long-term impacts of antibiotic exposure on the human intestinal microbiota. Microbiology (Reading, England), 156 (Pt 11), 3216-23 PMID: 20705661... Read more »

Jernberg C, Löfmark S, Edlund C, & Jansson JK. (2010) Long-term impacts of antibiotic exposure on the human intestinal microbiota. Microbiology (Reading, England), 156(Pt 11), 3216-23. PMID: 20705661  

  • November 8, 2010
  • 12:00 PM
  • 1,798 views

Fattening Up Microbial Geological Biomarkers

by Paula Welander in Small Things Considered

by Paula Welander

First Evolved! Last Extinct! This prokaryotic pride motto was coined by my undergraduate advisor (and good friend) Prof. Mark Martin. As a microbiologist, I love this motto for many reasons, but especially because it alludes to one of the underlying principles of my current research. Microbes were indeed the first to evolve and the metabolic inventions of ancient microbes greatly influenced the ancient Earth’s environment and the evolution of life. The interaction between the Earth and microbes has been recorded in sedimentary rocks that are billions of years old.
Accessing this microbial record continues to be one of the challenges of geomicrobiology. One powerful strategy for understanding the microbial signatures in the rock record is the use of “molecular fossils” or biomarkers, organic compounds that are produced by select groups of microorganisms and, amazingly, are preserved in both modern and ancient sediments. Geochemists are able to extract these molecules from very old rocks and, based on their distribution in modern organisms, link specific groups of bacteria to ancient environments.... Read more »

Welander PV, Coleman ML, Sessions AL, Summons RE, & Newman DK. (2010) Identification of a methylase required for 2-methylhopanoid production and implications for the interpretation of sedimentary hopanes. Proceedings of the National Academy of Sciences of the United States of America, 107(19), 8537-42. PMID: 20421508  

  • November 8, 2010
  • 10:46 AM
  • 709 views

A Good Cup of Tea

by Isobel in Promega Connections

If man has no tea in him, he is incapable of understanding truth and beauty. ~Japanese Proverb There is nothing like a good cup of tea. On that there is little dispute. Growing up in Britain, I was introduced to tea at an early age. It was impossible to avoid it. We had tea after [...]... Read more »

van Duynhoven, J., Vaughan, E., M. Jacobs, D., A. Kemperman, R., van Velzen, E., Gross, G., Roger, L., Possemiers, S., Smilde, A., Dore, J.... (2010) Microbes and Health Sackler Colloquium: Metabolic fate of polyphenols in the human superorganism. Proceedings of the National Academy of Sciences. DOI: 10.1073/pnas.1000098107  

  • November 8, 2010
  • 09:59 AM
  • 642 views

Oh, so I guess they just couldn't do the experiment again...

by Alejandro Montenegro-Montero in MolBio Research Highlights

In 20051, the Liu lab described a new central element in the Neurospora circadian clock. They found that an RNA helicase with similarity to the yeast exosome cofactor Dob1p/Mtr4p, associated with FRQ, a core clock component essential for circadian clock function in this fungus (it was termed FRH, for "FRQ-interacting RNA helicase"). Their evidence suggested that FRH played an important role in ... Read more »

  • November 8, 2010
  • 07:23 AM
  • 1,339 views

Gold nanoparticles make plants glow in the dark

by Captain Skellett in A Schooner of Science

Imagine if instead of having sensor lights to illuminate a garden path, you could line it with light-emitting plants. You could stroll along bio-luminescent flower beds, dancing in dappled moonlight and delighting in eerily lit peace, free from the shackles of electricity. It could be possible with sea urchin shaped gold nanoparticles. Seriously, every time [...]... Read more »

  • November 8, 2010
  • 04:21 AM
  • 687 views

The Secret Loves of Trees

by Torah Kachur in Science in Seconds

Falling in love is so romantic, so blissful, so cherished in our lives.  Most people will fall in love more than once, first with the 'wait until we're married' sterilizer, then with the 'jealous defender' and finally you hit an age where want to settle down and find the 'practical answer'.  And then, after imminent divorce you find yourself with some gold digger who just can't wait for you to die and leave him or her everything.

 

That darling of a fairy tale also applies to trees.

 

Trees don't have life partners, lovers, spouses or mistresses, but they do have important partnerships with ants throughout their lives.  This is what evolutionary biologists call mutualism - the cooperation of two species for mutual benefit.  New research conducted by the Pringle group at Stanford University found that lifelong monogamy for plants, just like for humans, is not the best idea.  The common African acacia tree is a bit of a slut as it partners with up to 4 different species of ants through its lifetime.  In fact, the slutty trees that had different ant partners were much better off than those that stayed loyal to only one ant.

 

         

 

Just like humans, young plants were found to partner with the chaste Crematogaster nigriceps species of ant first.  These ants were found mostly on small colonies of trees and also sterilized the trees.  Alas, the virginal ant made the tree wait until they were older and mature enough to consummate their partnership.  So, what's in it for the tree?  While the ant is keeping the tree honest, the acacia tree has time to mature because C. nigriceps aggressively defends the trees from herbivores.  But, like all horny (or thorny) young trees, being sterile sucks and so the tree changes partners to an aggressive non-sterilizer ant - C. mimosae.  Despite constantly being drunk, C. mimosae defends the tree and finally allows it to reproduce. 

 

But the 'jealous defender' stage is only cute for a while.  Depending on the size of the tree colony, some trees then shift to Tetraponera penzigi - the most 'suitable' partner for the tree.  T. penzigi is loyal and treats the tree with respect while tree puts a roof over the ants' head - a match made in heaven.  This phase of the trees life is the "any ant is better than no ant" stage.  The tree is very fecund at this stage producing many progeny, but - like all vanilla relationships - the tree gets bored.

 

Yes, just like humans, the most successful of the species later in life find themselves surrounded by parasitic partners.  In the trees' case, these gold-digging ants are called C. sjostedti.  These ants aren't satisfied with a roof over their heads, instead they allow their beetle buddies to move in and mooch off the tree.  Not surprisingly, these parasites and their beetle friends cause an increase in death rates for trees.  This partnership should not occur in nature because evolution should select against such a negative partnership.  Except, just like Anna Nicole Smith, the ants get one last contribution to the world from their partner - a final spreading of their wealth and seed before they die.  So, the opportunisitc ants actually do benefit the ecosystem and provide an evolutionary purpose, at least in trees.

 

After all of these attempts at love, the poor plant never found the one ant that could complete it.  sigh

 

 

Palmer TM, Doak DF, Stanton ML, Bronstein JL, Kiers ET, Young TP, Goheen JR, & Pringle RM (2010). Synergy of multiple partners, including freeloaders, increases host fitness in a multispecies mutualism. Proceedings of the National Academy of Sciences of the United States of America, 107 (40), 17234-9 PMID: 20855614
... Read more »

Palmer TM, Doak DF, Stanton ML, Bronstein JL, Kiers ET, Young TP, Goheen JR, & Pringle RM. (2010) Synergy of multiple partners, including freeloaders, increases host fitness in a multispecies mutualism. Proceedings of the National Academy of Sciences of the United States of America, 107(40), 17234-9. PMID: 20855614  

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