Constantine Alexander's blog

Meerkats acquire novel behavior using 9 different social and asocial mechanisms

Photograph by Mattias Klum

A novel methodology shows that Wild meerkats engage in nine separate learning processes during foraging, and this method may provide general insight into learning mechanisms for groups of animals and culture development. The full report is published Aug. 8 in the open access journal PLOS ONE.

The researchers, led by William Hoppitt of the University of St. Andrews in the United Kingdom, presented wild meerkats with a novel foraging TASK to investigate the animals' learning mechanisms. They found that the meerkats engaged in a wide variety of social and asocial behaviors to learn to solve the task, and that in general the social factors helped draw the meerkats into the task, while the asocial processes helped them actually solve the task. Based on these results, they propose a model for characterizing social learning mechanisms in the field that may also be more broadly applicable and can be used to investigate the relationship between social learning mechanisms and so-called "behavioral traditions" that together can constitute a culture.

Citation: Hoppitt W, Samson J, Laland KN, Thornton A (2012) Identification of Learning Mechanisms in a Wild Meerkat Population. PLoS ONE 7(8): e42044. doi:10.1371/journal.pone.0042044

Contact: Yael Franco
yfranco@plos.org
415-568-3169
Public Library of Science

 

 

Drivers of marine biodiversity: Tiny, freeloading clams find the key to evolutionary success

Jingchun Li, University of Michigan, trying to find mud shrimps in the mud flat. Hatfield Marine Science Center, Oregon State University

What mechanisms control the generation and maintenance of biological diversity on the planet?

It's a central question in evolutionary biology. For land-dwelling organisms such as insects and the flowers they pollinate, it's clear that interactions between species are one of the main drivers of the evolutionary change that leads to biological diversity.

But the picture is much murkier for ocean dwellers, mainly because the scope of ecological interactions remains poorly characterized for most marine species. In one of the first efforts to examine how species interactions drive diversification of ocean-dwelling organisms, two University of Michigan researchers and an Australian colleague looked at the lifestyle choices within an exceptionally diverse superfamily of tiny clams, the Galeommatoidea.

They found that the fingernail-size-and-smaller clams' propensity to shack up with much larger, burrowing creatures such as sea urchins, shrimp and worms was a key adaptation that led to the evolutionary success of the superfamily, as measured by its "megadiverse" status among marine bivalves. There are about 500 described species of galeommatoidean clams and many more undescribed species.

By becoming the uninvited house guests of their burrowing hosts, these freeloading, thin-shelled clams acquire a safe haven from predators prowling soft-bottomed sediments, where there's nowhere else to hide. Gaining this deep refuge opened up a vast habitat type – soft-bottom marine sediments composed of sand, silt and clay – that would otherwise have remained unavailable to these clams.

Galeommatoidean clams are found worldwide in all the major ocean basins, in both rocky and soft-bottom habitats. Some of the clams live a solitary existence, while others form so-called commensal relationships with larger invertebrate hosts. A commensal relationship is one in which one organism benefits and the other is not harmed.

In a study scheduled for online publication Aug. 8 in the journal PLoS ONE, the U-M-led team performed a statistical analysis of the lifestyle and habitat preferences of 121 galeommatoidean species based on 90 source documents.

The researchers found that all but two of the 57 free-living species were restricted to hard-bottom habitats, typically hidden in rocky or coral-reef crevices. In contrast, 56 of the 60 commensal species were soft-sediment dwellers.

The results show that formation of commensal associations by galeommatoidean clams is robustly correlated with living in sediments. That finding is consistent with the hypothesis that evolution of these commensal relationships was primarily an adaptation to living in soft-bottom habitats.

"What was surprising was the overwhelming evidence that commensalism is associated with the soft-bottomed habitat. You seldom get such clear-cut data in an ecological study," said Jingchun Li, a doctoral student in the U-M Department of Ecology and Evolutionary Biology and first author of the PLoS ONE paper.

Clams and other bivalves have evolved two general anti-predator strategies: armor (think oysters) and avoidance. Since galeommatoidean clams have fragile shells, they must go the avoidance route, and following a larger host into a burrow allows the clams to attain depths of up to 3 feet – hundreds of times their body lengths.

Galeommatoidean clams lack the siphons (often called necks) that other clams use to feed and breathe while remaining safely buried in the sand. Siphons consist of two tubes: Water enters the clam's body through one siphon, flowing into gills that capture oxygen and trap food. The water then flows out of the clam through the other siphon.

The siphon-less galeommatoideans make up for that shortcoming by teaming up with hosts that constantly pump fresh seawater into, through, and then out of their burrows.

"This allows the clams to stay deep and safe, while still having access to water and oxygen and a food supply," Li said. In this way, the hosts act as giant siphon substitutes for the tiny clams.

"Jingchun's finding that the type of sea floor habitat strongly modulates the ecological importance of commensalism in these megadiverse clams gives us a novel insight into how ostensibly irrelevant background physical conditions may shape the evolution of species interactions in marine environments," said study co-author Diarmaid O'Foighil, Li's adviser and the director of the U-M Museum of Zoology.

The second phase of the clam study will test the relative importance of free-living and commensal lifestyles in driving galeommatoidean diversification. Using data from about 300 species, the researchers will construct a phylogenetic tree for the entire superfamily.

The third author of the PLoS ONE paper is Peter Middelfart of the Australian Museum.

The study is supported by a Rackham International Student Fellowship from the University of Michigan, a Molluscan Research Grant from the Malacological Society of Australasia, and a grant from the National Science Foundation.

Contact: Jim Erickson
ericksn@umich.edu
734-647-1842
University of Michigan

 

 

Hyenas that think outside the box solve problems faster

		MSU researchers show that hyenas must think out of the box to solve puzzles. Photo courtesy of MSU Click here for more information.

Innovative problem solving requires trying many different solutions. That's true for humans, and now Michigan State University researchers show that it's true for hyenas, too.

The study, published in the current issue of the Proceedings of the Royal Society B, presented steel puzzle boxes with raw meat inside to wild spotted hyenas in Kenya. To get the meat, the hyenas had to slide open a bolt latch. Even though most of the animals had many opportunities to open the box, only nine out of 62 hyenas succeeded. The successful hyenas tried more solutions, including biting, flipping or pushing the box, than the ones that failed, said MSU zoology graduate student Sarah Benson-Amram.

Another requirement for success was not being afraid to approach new things. The wild hyenas had never seen a steel puzzle box before. And those hyenas that quickly contacted the box when they first saw it were more successful solving the problem than those hyenas that were slower to approach it. Although contacting unknown objects can be quite dangerous for wild animals, this research shows that risk-taking also has some benefits.

Surprisingly, one trait that did not necessarily lead to victory was persistence, said Benson-Amram.

"While those who gave up quickly were more likely to fail, some hyenas that spent more time with the puzzle box appeared to get stuck in a rut and would often try the same solutions over and over again," she said.

Like humans and other primates, hyenas have relatively large brains, said Kay Holekamp, MSU zoologist and co-author of the paper.

"A likely benefit of large brains is the ability to think flexibly about new situations and come up with solutions to novel problems," said Holekamp, co-principal investigator at the BEACON Center for the Study of Evolution in Action.

The research was funded in part by the National Science Foundation.

Michigan State University has been working to advance the common good in uncommon ways for more than 150 years. One of the top research universities in the world, MSU focuses its vast resources on creating solutions to some of the world's most pressing challenges, while providing life-changing opportunities to a diverse and inclusive academic community through more than 200 programs of study in 17 degree-granting colleges.

Contact: Layne Cameron
layne.cameron@cabs.msu.edu
517-353-8819
Michigan State University

 

 

Hibernation altered by climate change takes a toll on Rocky Mountain animal species

Climate change is causing a late wake-up call from hibernation for a species of Rocky Mountain ground squirrel and the effect is deadly

Rocky Mountains

Climate change is causing a late wake-up call from hibernation for a species of Rocky Mountain ground squirrel and the effect is deadly.

A University of Alberta-led international research team examined data on a population of Columbian ground squirrels and found a trend of late spring snow falls has delayed the animals' emergence from hibernation by 10 days over the last 20 years.

U of A Evolutionary Ecologist Jeff Lane explained that Columbian ground squirrels are on a tight schedule; Females mate four days after emerging from hibernation. They give birth 24 days later. The newborns are nursed for 28 days, and then they're on their own.

"Losing just 10 days during their short active period reduces their opportunity to eat enough food so they can survive through the next hibernation period of eight to nine months," said Lane.

Research shows there's little wiggle room in the ground squirrel's life cycle. The period of plant growth, their food supply, is only three to four months long on their home turf, skirting the Rocky Mountains

"Our data shows that over the life of the study, the survival rate of adult females has fallen by 20 per cent and much of this could be due to late emergence from their burrows brought on by late spring snowfalls, "said Lane. " The researchers say the study area's population has gone from one of growth 20 years ago to its current state of just maintaining population stability.

The study area is a 200-metre by 400-metre block in a sub-alpine meadow west of Calgary. Lane says the data was collected through observation and by trapping and releasing all the ground squirrels in the study area to monitor their condition. The study area was set up by U of A biologists in 1992. Lane began his hibernation study five years ago and collaborated with researchers in Scotland, France and the U of A. Lane was the lead researcher on the paper that was published August 8, in the online edition of the journal Nature.

Contact: Brian Murphy
780-492-6041
University of Alberta

 

 

Study finds US among few NATO nations that use animals for military training

More than three-quarters of NATO allies use simulators, other non-animal models

NATO countries shown in green.

A new study published in the August 2012 issue of Military Medicine, the journal of the Association of Military Surgeons of the U.S., reveals that 22 of 28 NATO nations do not use animal laboratories for military medical training.

Researchers from PETA, in collaboration with current and former military medical personnel, surveyed officials in all 28 NATO nations during 2010 and 2011. Twenty-two NATO countries—including Albania, Belgium, Bulgaria, Croatia, the Czech Republic, Estonia, France, Germany, Greece, Hungary, Iceland, Italy, Latvia, Lithuania, Luxembourg, the Netherlands, Portugal, Romania, Slovakia, Slovenia, Spain, and Turkey—confirmed that they do not use animals in military medical training. Officials reported that they use exclusively non-animal methods—such as lifelike human simulators in realistic battlefield scenarios—for various reasons, including legal prohibitions against animal use and the superiority of simulation technology.

Six NATO countries—Canada, Denmark, Norway, Poland, the U.K., and the U.S.—reported using animals in invasive and often deadly procedures.

"The overwhelming majority of NATO allies have moved beyond stabbing and dismembering animals in crude and cruel training exercises," says coauthor of the study and PETA Associate Director Justin Goodman. "Our military's regulations require using non-animal methods whenever they are available—and PETA's report illustrates that modern trauma-training technology is widely available around the world."

Each year, the U.S. military and its contractors shoot, stab, mutilate, and kill more than 10,000 live animals in cruel trauma-training exercises, even though modern simulators that breathe and bleed have been shown to better prepare doctors and medics to treat injured better than animal laboratories.

Reference: Use of Animals by NATO Countries in Military Medical Training Exercises: An International Survey, Authors: Gala, Shalin G.;Goodman, Justin R.;Murphy, Michael P.;Balsam, Marion J.; Source: Military Medicine, Volume 177, Number 8, 2012 , pp. 907-910(4), Publisher: AMSUS - Association of Military Surgeons of the U.S.

Contact: Justin Goodman
JustinG@peta.org
860-882-2492
People for the Ethical Treatment of Animals

 

 

 

Do beavers benefit Scottish wild salmon?

		This is a beaver dam. Credit: University of Southampton

Reintroduced European beavers could have an overall positive impact on wild salmon populations in Scotland, according to a study by the University of Southampton.

Representatives of recreational fisheries interests north and south of the border are concerned that beavers can harm economically important fish stocks due to their dam building activities and potential to block migratory life phases. However, results of a study conducted by scientists at the University of Southampton, funded by Scottish Natural Heritage, indicate that beavers can also have substantial beneficial effects which may outweigh those that are negative.

The study's findings highlight that while the activities of beavers can result in localised and often temporary negative impacts on fish, primarily due to dams impeding their movements and reducing the availability of suitable spawning habitat, these can be at least off-set by the benefits of increased habitat diversity and resulting abundance and productivity of fish, including salmon.

Dr Paul Kemp, a researcher in freshwater fish ecology and fisheries management from the University's International Centre for Ecohydraulics Research, who lesd the study comments that, "the positive findings were more frequently based on quantitative evidence, while discussion of negative impacts was often speculative."

Dr Kemp and his colleagues were surprised that the "weight of evidence" tended to indicate an overall positive effect considering the background of those who participated in the survey. "Most participants were from a fisheries background and whom you might expect would tend to side with the fish, but based on their experience of beaver and fish interactions tended to be positive towards beaver," he says.

Beaver reintroduction has been a contentious issue in Scotland ever since a total of 16 individuals from Norway were released in Argyll in 2009 and 2010 as part of a scientific trial conducted by the Scottish Wildlife Trust, The Royal Zoological Society of Scotland, and the host partners, the Forestry Commission Scotland.

Even more controversy surrounds the establishment of a breeding population of escaped beavers on the River Tay. This has had ramifications south of the border as the Angling Trust has written to Richard Benyon, the UK minister for Fisheries and the Natural Environment, requesting that trapping and destruction of the beavers be urgently undertaken to prevent their spread to England where it is claimed they could damage fisheries.

Researchers carried out a critical view of over 100 sources of peer-reviewed information in which benefits were cited 184 times compared to 119 for the negative effects. Analysis of existing literature indicates that beaver activity can have both positive and negative effects on fish. Negative effects relate to the construction of beaver dams which can temporarily impede the movement of some fish, particularly in narrow rivers and streams, while siltation can cause loss of spawning habitat immediately upstream of dams. But beavers can also have beneficial effects on fish by increasing the variety and area of habitats in streams, and due to the presence of dams and ponds by increasing the abundance of invertebrates, which form the main component of the diet of many stream-dwelling fish, and providing refuge during periods of high or low water flows.

The study, which was published in the leading international fisheries journal Fish and Fisheries, also reports the findings of an expert opinion survey of 49 fisheries managers, scientists, and beaver ecology experts, from Europe and North America, where most of the research has been conducted. More than half (58 per cent) of those who responded believed that the overall impact of beavers on fish populations was positive.

Professor Roger Wheater, the Chair of the Beaver-Salmonid Working Group, says: "I would be very surprised if biodiversity were not increased but our concern continues to be the impact on salmonid spawning areas and the management required to deal with situations where salmonids in any particular system are at risk."

Contact: Glenn Harris
G.Harris@soton.ac.uk
44-023-805-93212
University of Southampton

 

 

 

Diversity keeps grasslands resilient to drought, climate change

For much of the year drought has been plaguing American grasslands. But a recent study found that grasses do not appear to be losing the turf war against climate when it comes to surviving with little precipitation.

The Kansas State University-led study looked at the drought tolerance of 426 species of grass from around the world. The goal was to better understand how grasslands in different parts of the world may respond to the changes in frequency and severity of drought in the future.

Grasslands have several important ecological functions, according to Joseph Craine, research assistant professor of biology and the study's lead author. Grasslands convert and store carbon dioxide, are a food source for grazing animals like cattle and bison, and help cool the surrounding atmosphere.

"The idea is that if you maintain a diverse grassland, you'll have a large number of drought-tolerant species ready to take over critical functions if there is a change in climate or an extended period of drought, like what we've had this year," Craine said. "Yet, we've never known which grasslands have drought-tolerant species in them."

Craine conducted the study with Kansas State University's Troy Ocheltree, research assistant of biology; Jesse Nippert, assistant professor of biology; Gene Towne, biology research associate and Konza Prairie Biological Station fire chief; and Adam Skibbe, information resource specialist for the Division of Biology, as well as with colleagues from the University of Oregon and the Nature Conservancy in Minneapolis, Minn. It is the largest study conducted to quantify how tolerant grass species are to severe drought.

To collect data the team planted 500 species of grass taken from six continents. A majority of seeds were provided by the United States Department of Agriculture, while 52 species were collected from the Konza Prairie in the Flint Hills of Kansas. Grasses were grown on campus in a walk-in growth chamber with high intensity lighting that simulated sunny weather. After six weeks, researchers stopped watering the grass samples and observed at what point each grass stopped being able to take up water.

"In the end they all succumbed to drought," Craine said. "But that was our goal: to stress them all enough to know at what point they give in. What we saw was that some of grass species were about as tough as lettuce, meaning that after a day or two without water they would start to wilt and curl up. Others, however, were able to go for a week or two without water."

When comparing the drought resistance across the sampled species, the team found that drought-resistant grasses are well distributed across the world. As a result, grasslands are more likely to tolerate the increased periods and intensity of drought that are predicted with climate change in the future, Craine said.

"If we still have grasslands that are diverse, the grasslands are going to continue to function relatively well and not change too much," Craine said. "But when we replace our prairies with ones that just have a few species in it, then it's less likely that grasslands will be able to function normally in the future. That affects the animals and other things that depend on grasslands, making it more likely that the whole ecosystem collapses."

Additionally, researchers developed a drought index for the tested species based on the data. The index details each species' tolerance to drought and can help ecologists understand why grasslands around the world are composed of their species. More than 11,000 species of grass exist on Earth.

The benefits of a diverse grassland are evident when the U.S. faced a drought in the 1980s, said Towne, who also collects plant community data.

"After that drought we saw a booming explosion of tall grasses the following year," Towne said. "So it really backs up what the study found: that drought forces the grasslands to adapt to the weather conditions so they can get through that rough period."

Reference: Global diversity of drought tolerance and grassland climate-change resilience. Joseph M. Craine, Troy W. Ocheltree, Jesse B. Nippert, E. Gene Towne, Adam M. Skibbe, Steven W. Kembel & Joseph E. Fargione.

Contact: Joseph Craine
jcraine@k-state.edu
785-532-3062
Kansas State University

 

 

Scientists discover the truth behind Colbert's 'truthiness'

A picture inflates the perceived truth of true and false claims

Stephen Colbert

Trusting research over their guts, scientists in New Zealand and Canada examined the phenomenon Stephen Colbert, comedian and news satirist, calls "truthiness"—the feeling that something is true. In four different experiments they discovered that people believe claims are true, regardless of whether they actually are true, when a decorative photograph appears alongside the claim. The work is published online in the Springer journal, Psychonomic Bulletin & Review.

"We wanted to examine how the kinds of photos people see every day—the ones that decorate newspaper or TV headlines, for example—might produce "truthiness," said lead investigator Eryn J. Newman of Victoria University of Wellington, New Zealand. "We were really surprised by what we found."

In a series of four experiments in both New Zealand and Canada, Newman and colleagues showed people a series of claims such as, "The liquid metal inside a thermometer is magnesium" and asked them to agree or disagree that each claim was true. In some cases, the claim appeared with a decorative photograph that didn't reveal if the claim was actually true—such as a thermometer. Other claims appeared alone. When a decorative photograph appeared with the claim, people were more likely to agree that the claim was true, regardless of whether it was actually true.

Across all the experiments, the findings fit with the idea that photos might help people conjure up images and ideas about the claim more easily than if the claim appeared by itself. "We know that when it's easy for people to bring information to mind, it 'feels' right," said Newman.

The research has important implications for situations in which people encounter decorative photos, such as in the media or in education. "Decorative photos grab people's attention," Newman said. "Our research suggests that these photos might have unintended consequences, leading people to accept information because of their feelings rather than the facts."

Reference: Newman EJ et al (2012). Nonprobative photographs (or words) inflate truthiness. Psychonomic Bulletin & Review; DOI 10.3758/s13423-012-0292-0

Contact: Renate Bayaz
renate.bayaz@springer.com
49-622-148-78531
Springer