Ecology / Conservation posts

May 23, 2012
02:09 PM
33 views

Snakes Deceive to Get a Little Snuggle

by Miss Behavior in The Scorpion and the Frog

A lone red-sided garter snake. Photo by Tracy Langkilde.The red-sided garter snake is a small snake species with the largest and most northern distribution of all reptiles in North America. These northern ranges can get quite cold for any animal, let alone a reptile. Like most reptiles, they are ectotherms, meaning they regulate their body temperature largely by exchanging heat with their environment. If an animal gets almost all of its body heat from a cold environment, its body is also going to be cold… So what is a poor red-sided garter snake to do?Red-sided garter snakes that live in the northern end of their range in Manitoba, Canada spend their cold-season (6-8 months of it) hibernating in underground dens called hibernacula. Tens of thousands of snakes may share a winter den and every spring, they emerge to mate and eat and do all the other fun things that snakes do when they’re awake. (If you would like to witness the spectacular sight that is the emergence of the garter snakes, it is occurring this month in the world-famous snake-watching Interlake region of Manitoba).A whole lotta red-sided garter snakes in a spring-mating frenzy. Photo by Tracy Langkilde.When a snake first emerges from its groggy hibernation state its body is cold and movements are sluggish, which puts it at a high risk of predation from animals like crows and weasels. Females are generally at less risk of predation at this time because emergence-time is also sexy-time for this species and females generally find themselves in the middle of a writhing ball of already-warmed-up male suitors (appropriately called a mating ball). For the female, this both increases her body temperature faster (which will allow her to move faster sooner) and provides any would-be predators with many other snakes to choose from.Female red-sided garter snakes produce a male-attracting pheromone (a chemical released by an animal that affects the physiology and/or behavior of other individuals of the same species). Researchers Rocky Parker and Robert Mason at Oregon State University found that the amount of pheromone females produce increases as the females hibernate from fall to spring. This pheromone is a blend of saturated and unsaturated methyl ketones (molecules responsible for many natural odors and flavors) and males are more strongly attracted to the unsaturated components. The chemical composition of the female pheromone also changes from fall to spring, such that female spring pheromones are dominated by these highly attractive unsaturated pheromone components. Presumably, the sexier the pheromone, the more suitors are attracted and the more benefits a recently-emerged female can acquire.It seems that this smell-sexy-and-create-mating-ball strategy is a useful solution for recently-emerged females, but what about recently-emerged males? Parker and Mason collected courting male red-sided garter snakes and brought them into the lab. Then they either implanted them with estrogen (a sex hormone strongly involved in female sexual physiology and behavior) or did not (as a control group). Males with estrogen implants produced more pheromones, had higher ratios of unsaturated pheromone components to saturated pheromone components, and were more attractive to courting males. When the researchers removed the estrogen implants from some of the males, they became less attractive again. So in the lab, estrogen treatment of males makes them produce more female-like pheromones that other courting males respond to. This shows that males are capable of using this smell-sexy-and-create-mating-ball strategy, but do they use it in nature? This graph shows the amount of courtship received by females, "she-males", and "he-males" when either cold or hot. Figure from Shine, Langkilde and Mason's Behavioral Ecology and Sociobiology Paper (2012). Robert Mason at Oregon State University and Rick Shine and Tracy Langkilde at the University of Sydney, Australia collaborated to explore this relationship between temperature and male production of female-like pheromones. It turns out, male red-sided garter snakes in nature can and do produce female-like pheromones when they emerge from their den. Shine, Langkilde and Mason collected some of these males that were being courted by other males (the researchers refer to them as “she-males”). They also collected some males that were courting females (they called them “he-males”) and some females. They then exposed the snakes to different temperatures for 15-minute intervals and tested their attractiveness to other courting males. This graph shows the amount of courtship received by "she-males" when cooled (open circles) and heated (filled circles) for 15-minute intervals. Figure from Shine, Langkilde and Mason's Behavioral Ecology and Sociobiology Paper (2012). The researchers found that females were courted the most, “he-males” the least, and “she-males” were courted an intermediate amount. Interestingly, “she-males” only attracted courtship when they were cold (and their chances of survival could be improved by a mating ball) and their attractiveness shifted with every 15-minute shift in temperatures. How did they do this? 15 minutes is probably not enough time for a hormonal change to alter the pheromone composition enough to change attractiveness so drastically.An important clue comes from the composition of the pheromones themselves. Remember that red-sided garter snake pheromones are a blend of saturated and unsaturated methyl ketones and males are more strongly attracted to pheromones that have a high ratio of unsaturated components to saturated components. Well, saturated and unsaturated fats respond differently to cold: Unsaturated fats (like cooking oil) remain a liquid at cooler temperatures, whereas saturated fats (like margarine) become solid. Solids are less volatile than liquids, which makes them not smell as much. Shine, Langkilde and Mason hypothesize that the ratio of unsaturated to saturated ketones is lower in “she-males” than in females. In the cold, the high amount of saturated components of the “she-male” pheromone is turned off, which raises the ratio of unsaturated to saturated ketones, making them a... Read more »

Shine, R., Langkilde, T., & Mason, R. (2012) Facultative pheromonal mimicry in snakes: “she-males” attract courtship only when it is useful. Behavioral Ecology and Sociobiology, 66(5), 691-695. DOI: 10.1007/s00265-012-1317-4

Parker, M., & Mason, R. (2012) How to make a sexy snake: estrogen activation of female sex pheromone in male red-sided garter snakes. Journal of Experimental Biology, 215(5), 723-730. DOI: 10.1242/jeb.064923

Parker, M., & Mason, R. (2009) Low Temperature Dormancy Affects the Quantity and Quality of the Female Sexual Attractiveness Pheromone in Red-sided Garter Snakes. Journal of Chemical Ecology, 35(10), 1234-1241. DOI: 10.1007/s10886-009-9699-0

May 22, 2012
07:32 AM
53 views

Rattling Nature’s Chains

by gunnardw in The Beast, the Bard and the Bot

To start with a cliché: in nature, everything is connected. Organisms are eaten by each other, waste material (including dead organisms) is used by others, and the impact of animals, plants and other life forms on the environment alters their … Continue reading →... Read more »

McCauley, D., DeSalles, P., Young, H., Dunbar, R., Dirzo, R., Mills, M., & Micheli, F. (2012) From wing to wing: the persistence of long ecological interaction chains in less-disturbed ecosystems. Scientific Reports. DOI: 10.1038/srep00409

May 21, 2012
03:09 PM
62 views

Having a Water Bottle for a Mom Not Ideal

by Elizabeth Preston in Inkfish

In the wild, young rhesus macaques can reasonably expect not to have their mothers replaced by kitchen props. The monkeys depend on their moms to nurse them and tote them through tree branches while they're small, just like other primates. But a laboratory experiment in Maryland took these babies from their mothers and had them raised alone or in groups of their peers. The monkeys' strange infancies had physical and mental effects that lasted into adulthood.

At the National Institute of Child Health and Human Development (part of the National Institutes of Health), rhesus macaques born between 2002 and 2007 were randomly assigned to one of three groups. The lucky first group got to stay with their mothers, who kept their young close by while living in a large cage with other monkeys.

The rest of the young monkeys were taken from their mothers and reared by humans in a nursery for their first five weeks of life. Then, if they were in the second experimental group, they were put into a cage with three other monkeys of the same age. The four peers were left to "raise" each other, Lord of the Flies style.

The final group of monkeys, after being nursed by humans for five weeks, spent two hours a day in these same peer cages. During the remaining 22 hours, they lived alone in a cage with a "surrogate mother." The name is a bit of an insult to primate intelligence, though, since researchers describe this object as "effectively a terry cloth-covered hot water bottle hanging from the top of the cage."

By the end of their first year of life, all the juvenile monkeys had been moved from their experimental cages into one social group. Now the researchers, led by Gabriella Conti at the University of Chicago, began to collect data on the monkeys' health. Over the years of the study, they watched 231 rhesus macaques grow up in this bizarre daycare system. Even though the monkeys all ended up living together, their disparate childhoods left a mark.

The first clear effect was illness. Male monkeys that had been raised by a "surrogate" got sick nearly twice as often as mother-raised or peer-raised monkeys, even though by this time in their lives they all shared the same living conditions. Nearly every surrogate-raised male monkey had an illness at some point during the study.

Female monkeys that had been raised by peers, rather than by a real or fake mother, were more likely to have wounds and bald patches once they were living in the large group. Since these females displayed more aggressive behavior, the researchers think they may have been starting fights with the other monkeys. Their aggression may have goaded other monkeys into biting them and pulling their hair out.

And across all the groups taken away from their mothers—male and female, peer-raised and surrogate-raised—monkeys were more likely to have repetitive habits called stereotypies. In the zoo, a stereotypy such as pacing or swimming in circles suggests that an animal is in distress. In humans, stereotypies can be a symptom of autism. Habits displayed by the rhesus monkeys in this study included "digit sucking (the most frequent behavior), pacing, head tossing, self-grasping, saluting, spinning, rocking, circling, and swinging."

Some of the difference between monkeys raised by their mothers and the rest could be due to breastfeeding, Conti points out. But the increased illness in male monkeys was limited to the surrogate-mom group; the peer-raised monkeys, despite also missing out on breastfeeding, didn't have extra illnesses. And although all motherless monkey groups showed an increase in stereotypy, the effect was greatest in surrogate-raised males. This suggests that even if formula feeding causes some of the health effects seen here, it can't account for all of them.

The not-shocking conclusion is that monkeys need their moms to develop normally. Being raised parentless seems to make them less able to cope with infections or social stressors later in life. It's something to consider for research centers or zoos raising animals without their mothers. Even if the young have been orphaned or abandoned, there may be ways for human keepers to mitigate the damage.

Conti is an economist, though, and she's more interested in another primate: humans. She compares the rhesus research to studies of human children raised without either of their parents. These studies have found mental and physical health effects in children in Romanian orphanages, for example, or Israeli kibbutzim (where kids were raised communally). As smart and independent as we are, we're still primates who need someone to haul us through the tree branches when we're young.

Gabriella Conti, Christopher Hansman, James J. Heckman, Matthew F. X. Novak, Angela Ruggiero, & Stephen J. Suomi (2012). Primate evidence on the late health effects of early-life adversity PNAS : 10.1073/pnas.1205340109

Image: Baby Japanese macaque by Nemo's great uncle/Flickr

... Read more »

Gabriella Conti, Christopher Hansman, James J. Heckman, Matthew F. X. Novak, Angela Ruggiero, & Stephen J. Suomi. (2012) Primate evidence on the late health effects of early-life adversity. PNAS. info:/10.1073/pnas.1205340109

May 20, 2012
10:32 PM
63 views

Phosphorus, detergent, and Canada's Experimental Lakes

by Patrick in Evidence and Error

“I'm angry at the people who decided that phosphate was growing algae. I'm not sure that I believe that.” –Sue Wright, Texas

Sue Wright, quoted above, was upset because in 2010, sixteen American states banned the sale of dishwashing detergent containing high levels of phosphorous, an aquatic pollutant that sometimes causes eutrophication (algal blooms). Unfortunately, phosphorous is a rather effective component of detergent, so phosphorous-free dishwashing detergents did not immediately perform quite as well as their predecessors. This led some consumers (like our pal Sue) to complain to detergent manufacturers, state governments, consumer protection agencies, and the media.

What I like most about Sue’s complaint is that her anger was directed toward “the people who decided that phosphate was growing algae” rather than the policymakers who drafted and enacted the legislation. Her implied logic is exquisite – a factual claim has resulted in legislation that negatively affects some aspect of my life, therefore I don’t believe this factual claim and furthermore am angry at those who made it!

So, who specifically should Sue have directed her anger toward? Which jackass scientist “decided that phosphate was growing algae”?

The answer, unsurprisingly, is that many independent studies (involving various research groups) have demonstrated that phosphorous pollution, under some conditions, will stimulate algal growth and lead to eutrophication (see Schindler 2006 for a review). Here, I will focus on just one of these studies, perhaps the most influential.

My real motivation for discussing this particular paper is the recent announcement that the Canadian Government is discontinuing its operation of the Experimental Lakes Area (ELA), a collection of 58 pristine lakes that for over 40 years have been set aside for long-term ecosystem monitoring and ecosystem-scale experiments (more on the ELA later).

Green sludge

In the 1960s and 70s, many North American rivers and lakes, especially the Great Lakes, were experiencing rapid declines in water quality (see here and here). Industrial and municipal effluents were stimulating the growth of algae and other aquatic plants (termed ‘eutrophication’) leading to unsightly mats of green sludge, oxygen depletion, massive die-offs of fish and other aquatic life, and problems with the taste and odour of municipal drinking water.

The August 1969 issue of Time Magazine describes the then deteriorating state of Lake Erie:

"Each day, Detroit, Cleveland and 120 other municipalities fill Erie with 1.5 billion gallons of inadequately treated wastes, including nitrates and phosphates. These chemicals act as fertilizer for growths of algae that suck oxygen from the lower depths and rise to the surface as odoriferous green scum. Commercial and game fish … have nearly vanished ... Weeds proliferate, turning water frontage into swamp. In short, Lake Erie is in danger of dying by suffocation."

The public, industry, and all levels of government agreed that something had to be done to curb the declining state of North American waterways. However, there was disagreement over the most effective course of regulatory action because at the time, scientists and policymakers were still debating which nutrients were responsible for eutrophication. Was algal growth primarily limited by carbon, nitrogen, or phosphorous?

Schindler 1974

Experiments are the best way to establish causation, but are not always feasible. For example, the best way to test the anthropogenic climate change hypothesis would be to release copious quantities of greenhouse gas into the atmospheres of a random sample of earth-like planets, leave another randomly-chosen bunch of planets untouched, and then compare change in climate across the two groups of planets. Clearly this is not feasible, and clearly we can’t experimentally pollute a bunch of lakes just for the sake of science. Right? Wrong. Well, wrong to the second assertion at least.

The aforementioned Experimental Lakes Area is (was) a wonderful place where scientists could manipulate whole lakes to test hypotheses on the scale of entire ecosystems. In the late 1960s and early 70s, David Schindler – a Canadian limnologist who at the time was director of the ELA – oversaw a number of whole-lake experiments designed to determine which nutrient (out of carbon, nitrogen, and phosphorous) was primarily responsible for eutrophication.

In an initial experiment, Schindler et al. added copious amounts of nitrogen and phosphorous to Lake 227 which naturally had an extremely low concentration of dissolved carbon. If algal growth was primarily limited by carbon (and not nitrogen or phosphorous), then the N P treatment should not stimulate the growth of algae. However, this was not the case. Within weeks of the treatment, Schindler et al. observed that Lake 227 “was transformed into a teeming, green soup” with algal concentrations up to two orders of magnitude higher than nearby untreated lakes. Clearly, low levels of carbon had not been limiting the growth of algae.

In a second experiment, Schindler et al. divided another lake, Lake 226, into two equal halves using a large vinyl curtain that was sealed into the sediment and surrounding bedrock. The team added an equivalent amount of carbon and nitrogen to both halves of the lake, but added phosphorous to only one side. This manipulation resulted in what James Elser at Arizona State University has called “the single most powerful image in the history of limnology”.

Figure 1. Lake 226 following fertilization with carbon, nitrogen, and phosphorous (below divider) versus carbon and nitrogen only (above divider).

Just a few months after the nutrient additions began, the side of the lake receiving C N P was completely covered by a bloom of blue-green algae whereas algae levels on the C N side were essentially unchanged from when the nutrient additions began. It was abundantly clear that phosphorous had been limiting the growth of algae in Lake 226.

In a final experiment, Schindler et al. manipulated a third lake, Lake 304, to test whether, and how quickly, a lake could recover from phosphorous-induced eutrophication. The team measured the concentration of algae in Lake 304 at approximately monthly intervals over the course of five years, between 1969 and 1973. For three of those years, 1971–1973, the lake received additions of carbon and nitrogen, and for two years, 1971–1972, also received phosphorous. The experiment therefore mimicked what might happen if governments took steps to limit the amount of phosphorous entering a polluted water body. The general finding was that summertime algal concentrations increased dramatically in 1971 and 1972 when the lake was being fertilized with C N P, but returned to near baseline levels in 1973 after phosphorous fertilization was discontinued.... Read more »

Schindler, D. (1974) Eutrophication and Recovery in Experimental Lakes: Implications for Lake Management. Science, 184(4139), 897-899. DOI: 10.1126/science.184.4139.897

May 18, 2012
10:55 AM
60 views

The Secret to Success Is Giant-Jawed Snake Babies

by Elizabeth Preston in Inkfish

When coming face-to-face with a wriggling, freshly born pile of poisonous snakes, most of us wouldn't linger for a close look. But it was by looking into these living linguini platters that one biologist found a new answer to an old question: Why does island life make animals such freak shows?

Some big-bodied species shrink when they move from the mainland to an island habitat, a phenomenon that's created pygmy sloths, miniature mammoths, and possibly even a dwarf hominid that's now extinct. Some small-bodied species, meanwhile, grow enormous on islands. This category includes a 3-inch-long earwig, various ungainly and flightless birds, and a giant rat (living on Flores, the same island where the miniature people were, unfortunately for them).

Scientists have explained these fun-house transformations with a lack of resources on an island (keeping animals smaller) or a lack of predators (allowing them to grow bigger). Other factors, such as distance to the mainland or one sex's preference for extreme traits in a mate, could be at work too.

French researcher Fabien Aubret wondered whether scrutinizing the sizes of adult animals was making scientists miss another important variable: the size of babies. A newborn animal that can't find its first meal will quickly exit the gene pool. In snakes, this could be a simple matter of not being able to get one's mouth all the way around one's prey to swallow it.

Aubret studied twelve populations of tiger snakes, some living on mainland Australia or Tasmania and others on nearby islands. Among the island exiles, some groups have grown giant--up to 1.5 meters long, rather than the usual 0.8 or 0.9 meters--while others have shrunk. Most of the island populations were stranded by rising seas six to ten thousand years ago, leaving them with a different selection of prey animals than on the mainland.

Armed with a measuring tape, Aubret asked whether the changes the snakes' bodies have undergone since then can be entirely explained by the need for newborns to get their jaws around a meal. Tiger snake mothers give birth to live young rather than laying eggs, popping out a dozen or more at a time. On the mainland, these snakes and their parents swallow frogs for most of their meals. But on the islands, their prey can range from little lizards to large nesting seabirds.

Aubret captured almost 600 adult snakes from the various populations, measuring their length and weight before releasing all of them except the pregnant females. When the tangles of baby snakes emerged, he monitored the newborns' sizes for six months while feeding them a standard diet. For each study site, he calculated the average weight and circumference of animals on the prey buffet. (Weight because first a snake must subdue the unfortunate gecko or skink, and circumference because the animal must fit down the gullet.)

The size of baby snakes from each site--and the size of their jaws--was closely tied to the weight and circumference of the prey animals available there. Baby snakes from sites with large prey also grew faster.

Aubret says the pressure on newborn snakes to swallow available prey might be the only explanation necessary for the various body sizes tiger snakes have evolved on different islands. Adult body size, though of course it's related to the size of newborns, might be mainly irrelevant.

This gives biologists a new clue to the puzzle of how island life makes animals shrink or grow. While they wrap their heads around that, the tiger snakes will continue to wrap their own heads around any slow-moving animal that fits.

Fabien Aubret (2012). Body-Size Evolution on Islands: Are Adult Size Variations in
Tiger Snakes a Nonadaptive Consequence of Selection on Birth Size? The American Naturalist, 169 (6)

Image: Not actually a tiger snake, by batwrangler/Flickr

... Read more »

Fabien Aubret. (2012) Body-Size Evolution on Islands: Are Adult Size Variations in Tiger Snakes a Nonadaptive Consequence of Selection on Birth Size?. The American Naturalist, 169(6). info:/

May 18, 2012
08:56 AM
45 views

Decay Fungi: Eaters of Forests, Painters of Wood

by Kimberly Gerson in Endless Forms Most Beautiful

Decay fungi are generally disdained, but wood is held in high regard. The meeting of both can create emotional conflict and challenges the viewer to reevaluate their position on functional wood and natural ornamentation processes. – Dr. Sara C. Robinson Gene handed me a small block of maple, maybe an inch across. “This is spalted [...]... Read more »

Rayner, A., & Todd, N. (1977) Intraspecific Antagonism in Natural Populations of Wood-decaying Basidiomycetes. Microbiology, 103(1), 85-90. DOI: 10.1099/00221287-103-1-85

Worrall, J. (2004) Armillaria root disease. The Plant Health Instructor. DOI: 10.1094/PHI-I-2004-0706-01

May 18, 2012
07:56 AM
44 views

Decay Fungi: Eaters of Forests, Painters of Wood

by Kimberly Gerson in Endless Forms Most Beautiful

Decay Fungi: Eaters of Forests, Painters of Wood... Read more »

Rayner, A., & Todd, N. (1977) Intraspecific Antagonism in Natural Populations of Wood-decaying Basidiomycetes. Microbiology, 103(1), 85-90. DOI: 10.1099/00221287-103-1-85

Worrall, J. (2004) Armillaria root disease. The Plant Health Instructor. DOI: 10.1094/PHI-I-2004-0706-01

May 17, 2012
05:46 PM
23 views

Bees and STDs

by bug_girl in Bug Girl's Blog

Solitary bees have parasites too.... Read more »

Miloje KRUNIĆ, Ljubiša STANISAVLJEVIĆ, Mauro PINZAUTI, & Antonio FELICIOLI. (2005) The accompanying fauna of Osmia cornuta and Osmia rufa and effective measures of protection. Bulletin of Insectology, 58(2), 141-152. info:/

May 17, 2012
11:58 AM
59 views

■ Urban trees reveal income inequality

by Tim De Chant in Per Square Mile

Wealthy cities seem to have it all. Expansive, well-manicured parks. Fine dining. Renowned orchestras and theaters. More trees. Wait, trees? I’m afraid so. Research published a few years ago shows a tight relationship between per capita income and forest cover. The study’s authors tallied total forest cover for 210 cities over 100,000 people in the [...]... Read more »

Zhu, P., & Zhang, Y. (2008) Demand for urban forests in United States cities. Landscape and Urban Planning, 84(3-4), 293-300. DOI: 10.1016/j.landurbplan.2007.09.005

May 17, 2012
11:26 AM
52 views

Genomics, Open Access, and China

by Daniel Koboldt in Massgenomics

The associate editor of the journal Genomics has resigned, stating that he can no longer work for a system that puts profit over access to research. In an article in The Guardian, Winston Hide announced his resignation from “system that provides solid profits for the publisher while effectively denying colleagues in developing countries access to [...]... Read more »

Miller RD, Phillips MS, Jo I, Donaldson MA, Studebaker JF, Addleman N, Alfisi SV, Ankener WM, Bhatti HA, Callahan CE.... (2005) High-density single-nucleotide polymorphism maps of the human genome. Genomics, 86(2), 117-26. PMID: 15961272

May 16, 2012
12:33 PM
91 views

Does Social Status Change Brains?

by Miss Behavior in The Scorpion and the Frog

Photo by The Grappling Source Inc. at Wikimedia CommonsBeing subordinated is stressful. The process of one individual lowering the social rank of another often involves physical aggression, aggressive displays, and exclusion. In addition to the obvious possible costs of being subordinated (like getting beat up), subordinated individuals often undergo physiological changes to their hormonal systems and brains. Sounds pretty scary, doesn’t it? But what if some of those changes are beneficial in some ways?Dominance hierarchies are a fact of life across the animal kingdom. In a social group, everyone can’t be dominant (otherwise, life would always be like an episode of Celebrity Apprentice, and what could possibly be more stressful than that?). Living in a social group is more peaceful and nutritive when a clear dominance hierarchy is established. Establishing that hierarchy often involves a relatively short aggressive phase of jostling for position, followed by a longer more stable phase once everyone knows where they fall in the social group. Established dominance hierarchies are not always stable (they can change over time or from moment to moment) and they are not always linear (for example, Ben can be dominant over Chris, who is dominant over David, who is dominant over Ben). But they do generally help reduce conflict and the risk of physical injury overall.Nonetheless, it can be stressful to be on the subordinate end of a dominance hierarchy and these social interactions are known to cause physiological changes. Researchers Christina Sørensen and Göran Nilsson from the University of Oslo, Cliff Summers from the University of South Dakota and Øyvind Øverli from the Norwegian University of Life Sciences investigated some of these physiological differences among isolated, dominant, and subordinate rainbow trout.A photo of a rainbow trout by Ken Hammond at the USDA. Photo at Wikimedia Commons.Like other salmonid fish, rainbow trout are aggressive, territorial and develop social hierarchies as juveniles. Dominant trout tend to initiate most of the aggressive acts, hog food resources, grow larger, and reproduce the most, whereas subordinate trout display less aggression, feeding, growth, and reproduction. The researchers recorded the behavior, feeding and growth rates in three groups of fish: trout housed alone, trout housed with a more subordinate trout, and trout housed with a more dominant trout. The researchers also measured cortisol (a hormone involved in stress responses), serotonin (a neurotransmitter involved in mood, the perception of food availability, and the perception of social rank, among other things) and the development of new neurons (called neurogenesis) in these same fish.This video of two juvenile rainbow trout was taken by Dr. Erik Höglund. Here is Christina Sørensen’s description of the video: “What you see in the film is two juvenile rainbow trout who have been housed on each side of a dividing wall in a small aquarium. The dividing wall has been removed (for the first time) immediately before filming. You will see that the fish initially show interest for each other, followed by a typical display behaviour, where they circle each other. Finally one of the fish will initiate aggression by biting the other. First the aggression is bidirectional, as they fight for dominance, but after a while, one of the fish withdraws from further aggression and shows only submissive behaviour (escaping from the dominant and in the long run trying to hide... and as is described in the paper, depressed feed intake). The video has been cut to show in quick succession these four stages of development of the dominance hierarchy”. The researchers found that as expected, the dominant trout were aggressive when a pair was first placed together, but the aggression subsided after about 3 days. Also as expected, the dominant and isolated trout were bold feeders with low cortisol levels and high growth rates, whereas the subordinate trout did not feed as well, had high cortisol levels and low growth rates. Additionally, the subordinate trout had higher serotonin activity levels and less neurogenesis than the dominant or isolated trout. These results suggest that the subordination experience causes significant changes to trout brain development (Although we can’t rule out the possibility that fish with more serotonin and less neurogenesis are predisposed to be subordinate). In either case, this sounds like bad news for subordinate brains, right? Maybe it is. Or maybe the decrease in neurogenesis just reflects the decrease in overall growth rates (smaller bodies need smaller brains). Or maybe something about the development of these subordinate brains improves the chances that these individuals will survive and reproduce in their subordination. A crayfish raising its claws. Image by Duloup at Wikimedia.Research on dominance in crayfish by Fadi Issa, Joanne Drummond, and Don Edwards at ... Read more »

Sørensen, C., Nilsson, G., Summers, C., & Øverli, �. (2012) Social stress reduces forebrain cell proliferation in rainbow trout (Oncorhynchus mykiss). Behavioural Brain Research, 227(2), 311-318. DOI: 10.1016/j.bbr.2011.01.041

Issa, F., Drummond, J., Cattaert, D., & Edwards, D. (2012) Neural Circuit Reconfiguration by Social Status. Journal of Neuroscience, 32(16), 5638-5645. DOI: 10.1523/JNEUROSCI.5668-11.2012

Yeh, S., Fricke, R., & Edwards, D. (1996) The Effect of Social Experience on Serotonergic Modulation of the Escape Circuit of Crayfish. Science, 271(5247), 366-369. DOI: 10.1126/science.271.5247.366

Issa, F., & Edwards, D. (2006) Ritualized Submission and the Reduction of Aggression in an Invertebrate. Current Biology, 16(22), 2217-2221. DOI: 10.1016/j.cub.2006.08.065

May 15, 2012
09:44 PM
35 views

Spring Bioblitz 2012: The Hunt for Plethodon ainsworthi

by David Steen in Living Alongside Wildlife

The following
article is a guest post by Brian Folt. Brian is a Ph.D. student at Auburn University, where he studies the community
ecology of amphibians and reptiles. He grew up in the Midwest and received a B.S. from Ohio University in 2011. Brian conducted field work in Costa Rica
for his undergraduate thesis and is interested in future tropical ecology work.
Brian is an avid hiker and a... Read more »

Lazell, J. (1998) New Salamander of the Genus Plethodon from Mississippi. Copeia, 1998(4), 967. DOI: 10.2307/1447343

Graham, S., Steen, D., Nelson, K., Durso, A., & Maerz, J. (2010) An Overlooked Hotspot? Rapid Biodiversity Assessment Reveals a Region of Exceptional Herpetofaunal Richness in the Southeastern United States. Southeastern Naturalist, 9(1), 19-34. DOI: 10.1656/058.009.0102

May 14, 2012
08:09 AM
95 views

Map of Life

by gunnardw in The Beast, the Bard and the Bot

A few days ago, the Map of Life went… well… live. It’s an interactive map that aims to… well… map global biodiversity. At present, it’s a beta version, so there are probably some bugs that need fixing. For now, the … Continue reading →... Read more »

Jetz Walter, McPherson Jana M., & Guralnick Robert P. (2012) Integrating biodiversity distribution knowledge: toward a global map of life. Trends in Ecology , 27(3), 159. DOI: 10.1016/j.tree.2011.09.007

May 12, 2012
09:35 AM
97 views

Plastic Seas

by GunnarDW in The Beast, the Bard and the Bot

There is a lot of plastic in the world’s oceans. This is widely known, even though it’s a fairly recent development, tracing back a few decades. Most of this plastic, however, is quite small and, as such, is known by the name microplastic (diameter below 5 mm).

For a while now, it has been known that this is not a good thing (mild understatement). ... Read more »

Goldstein M. C., Rosenberg M., & Cheng L. (2012) Increased oceanic microplastic debris enhances oviposition in an endemic pelagic insect. Biology Letters. DOI: 10.1098/rsbl.2012.0298

May 11, 2012
10:42 AM
112 views

In the Spring, Bat Moms Choose Girls

by Elizabeth Preston in Inkfish

Naturally a mother bat is happy to welcome into the world a bouncing baby whatever, as long as it has all its fingers and toe-claws. But she also wants her little one to have every advantage she can give it. So when spring comes early, big brown bats prefer to keep their female embryos. Unwanted males are reabsorbed into their mothers' bodies as if they never existed.

University of Calgary biologist Robert Barclay learned the bats' secret by spying on three colonies living in the charmingly named city of Medicine Hat, Alberta. The bats roost in the attics of elementary-school buildings. Over the course of 15 years, Barclay snagged the bats in nets at night or plucked them from their roosts among the attic beams to examine them.

Since females return to their birth colony every year to breed, while males disperse, these colonies mainly held mothers and babies. Barclay was able to track which females were pregnant and what kinds of babies they had--and when.

"When" turned out to be the important question. Overall, the Eptesicus fuscus bats gave birth to equal numbers of male and female babies. But certain springs turned out a glut of girl bats, nearly twice as many as boys. By later in the summer, the ratio evened out again.

What was special about these girl-heavy springs, Barclay found, was that the whole colony gave birth earlier than usual. "The entire birth period shifts from year to year, depending on the weather," he wrote in an email. "When it is cold and damp in the spring and there are not many insects for the bats to feed on, the pregnant mother bats drop their body temperature to save energy and wait out the bad weather." This waiting period is called torpor, "a sort of shorter version of hibernation," Barclay says. In addition to lowering the mother's body temperature, it slows the growth of the embryo inside her. It was in the warmest springs, when mothers could end their torpor early, that they favored girls.

Biology says that mothers should skew the sex ratio of their offspring when it will let them pass on their own genes most effectively. A male baby bat won't give his mother any grandchildren until his second year of life, regardless of when he's born. However, "if a mother gives birth to a female baby early enough in the summer for it to be able to grow and put on enough fat for the winter," Barclay says, "that baby will be able to produce her own baby the next summer, as a 1-year-old." Having an extra year's worth of grandchildren is a major evolutionary benefit for a mother bat.

What gives girls a head start on reproduction is the bats' weird way of breeding. Mating happens in the fall and winter, while the bats born that spring and summer are still juveniles--and the young males haven't yet started making sperm. But female bats don't ovulate until the spring. At that point, the male contribution she's stored all winter finally fertilizes her eggs. This means female bats, if they're born early enough, can ovulate and give birth within their first year of life.

Big brown bats have just one baby at a time. But several eggs are fertilized and implant in the mother at once. At some unknown point during gestation, she reabsorbs all but one of those developing embryos into her body. However it happens, evolution has given mother bats the power to choose a female embryo over the others when spring arrives early.

Bats are far from the only species capable of skewing their babies' sex ratios. Other mammal and bird species have been observed giving birth to extra male or female offspring at certain times, depending on their own set of influencing factors. Even humans, it's been suggested, can bias their birth ratios based on life expectancy or parents' wealth or the weather. The mechanisms are mysterious, but evolution will always favor moms whose children produce more grandchildren.

Whatever secrets they're still keeping, the attic bats have taught their young downstairs neighbors a few things about biology. "When we worked in the schools we would give talks to the students about bats, the importance they have in the environment, and how cool it was that they had bats right in their own school," Barclay says. "We frequently had kids come in the evening to watch the bats as they exited to go and feed." One of the hundred-year-old schools is named Elm Street, as in Nightmare on. "A great place to study bats on a dark, moonless night!" Barclay adds.

Even spookier than attic bat colonies is the reminder that our species' whole evolutionary history had a hand in determining whether we were born. We, and the bat babies, should probably thank our moms.

Barclay, R. (2012). Variable Variation: Annual and Seasonal Changes in Offspring Sex Ratio in a Bat PLoS ONE, 7 (5) DOI: 10.1371/journal.pone.0036344

Images: Big brown bat by cotinis/Flickr; school building by Robert Barclay.

... Read more »

Barclay, R. (2012) Variable Variation: Annual and Seasonal Changes in Offspring Sex Ratio in a Bat. PLoS ONE, 7(5). DOI: 10.1371/journal.pone.0036344

May 11, 2012
09:58 AM
121 views

Journal Fire: Bonfire of the Vanity Journals?

by Duncan Hull in O'Really?

When I first heard about Journal Fire, I thought, Great! someone is going to take all the closed-access scientific journals and make a big bonfire of them! At the top of this bonfire is the burning effigy of a wicker man, representing the very worst of the vanity journals.... Read more »

Deans Andrew R., Yoder Matthew J., & Balhoff James P. (2012) Time to change how we describe biodiversity. Trends in Ecology , 27(2), 84. DOI: 10.1016/j.tree.2011.11.007

May 10, 2012
01:46 PM
83 views

■ Farming, circa 2050

by Tim De Chant in Per Square Mile

Farms today look nothing like the farms of 40 years ago. Thanks to market and policy changes along with advances in technology, they’re larger, more mechanized, and more intensive. And while those factors will likely continue to affect farmers, there’s another looming on the horizon—climate change. Agriculture has already seen the effects of a warming [...]... Read more »

Mandryk, M., Reidsma, P., & Ittersum, M. (2012) Scenarios of long-term farm structural change for application in climate change impact assessment. Landscape Ecology, 27(4), 509-527. DOI: 10.1007/s10980-012-9714-7

May 8, 2012
11:44 AM
85 views

Buzz Kill? Bee Populations and Pesticides

by Whitney Campbell in Green Screen

A swarm of studies have recently been released concerning Colony Collapse Disorder (CCD), and considering the serious implications of their findings, it's all of our beeswax. These experiments, including two published in Science1,2 and one forthcoming from the Bulletin of Insectology,3 demonstrate the threat to hive survival stemming from a class of insecticides called neonicotinoids. Individually, I think each study is convincing, but when taken together, the consensus provides overwhelming support as to the harms of neonicotinoids and their possible role in the rash of mysterious bee deaths that gave rise to the term CCD in late 2006.... Read more »

Henry, M., Béguin, M., Requier, F., Rollin, O., Odoux, J.F., Aupinel, P., Aptel, J., Tchamitchian, S., . (2012) A common pesticide decreases foraging success and survival in honey bees. Science, 348-350. PMID: 22461498

Whitehorn, P.R., O'Connor, S., Wackers F.L., . (2012) Neonicotinoid pesticide reduces bumble bee colony growth and queen production. Science, 351-2. PMID: 22461500

May 8, 2012
09:35 AM
97 views

Following a species for twenty years…

by Mauro Mandrioli in The aphid room

Today I was complaining about the loss of some original and unpublished old data obtained by some retired colleagues about aphid reproduction. Unfortunately, it is frequent that original data are lost after retirement, toghether with old papers, photos and so on. This is a true damage since long term studies could become more and more difficult. A [...]... Read more »

Lamb, R., MacKay, P., & Wool, D. (2012) Population stability of a tree-galling aphid, Baizongia pistaciae, at three spatial scales. The Canadian Entomologist, 1-13. DOI: 10.4039/tce.2012.42

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