The Scent of Love: Decomposition and Male Sex Pheromones

ScienceDaily (Aug. 10, 2012) — Young virgin female hide beetles (Dermestes maculatus) are attracted to cadavers by a combination of cadaver odour and male sex pheromones, finds a new study published in BioMed Central’s open access journal Frontiers in Zoology. Neither cadaver scent, nor male sex pheromones alone, caught the fancy of the fussy females. This predilection ensures that there is both a waiting male and food for her larvae, and optimises the chances of reproductive success.

Dermestes_maculatus. (Credit: Image courtesy of BioMed Central Limited)

 

Decomposition of a vertebrate cadaver is a sequential buffet for many carrion species including insects. Different species have evolved preferences for different stages during decomposition. The first to arrive are blow flies and flesh flies, whose larvae feed on the still moist tissue, followed by clown and rove beetles, who eat the larvae. Adult skin/hide beetles will start to arrive and feed on the remaining skin and ligaments, but will not breed until advanced decay has set in.

By the time the cadaver has been reduced to bones, hair, and dried out skin only the larvae of hide beetles, as well as scarabs and checkered beetles remain. The life cycle and sequence of arrival of these flies and beetles is so predictable that it can be used by forensic scientists to estimate time of death.

A team of researchers, led by Christian von Hoermann from Ulm University, Germany, filled olfactometers with different volatile scents and recorded which scents female hide beetles were attracted to. The scents used were pig cadaver, collected at different stages of decay, male pheromone gland extract, synthetic pheromones, and a control, pentane (an organic solvent which was used to extract the other odours).

The females ignored both the control and synthetic pheromone. In fact they pretty much ignored everything apart from the odour of piglet in the dry remains stage, as long as it was enhanced by male pheromones.

Christian von Hoermann explained, “Although cadaver odour alone is not sufficient to attract two to three week-old virgin female hide beetles, it is enough to attract newly emerged males.” Release of pheromones by these males appears to signal the cadaver as an appropriate site for feeding, mating and egg laying. Evolution seems to have ensured that hide beetle females only respond to a mate (or a food source for their larvae) when the other is also present, so that they can optimise the chances of their offspring’s survival.

 


Story Source:

The above story is reprinted from materials provided byBioMed Central Limited, via AlphaGalileo.


Journal Reference:

  1. Christian von Hoermann, Joachim Ruther and Manfred Ayasse. The attraction of virgin female hide beetles (Dermestes maculatus) to cadavers by a combination of decomposition odour and male sex pheromones.Frontiers in Zoology, 2012 (in press) [link]
Citation:

BioMed Central Limited (2012, August 10). The scent of love: Decomposition and male sex pheromones. ScienceDaily. Retrieved August 15, 2012, from http://www.sciencedaily.com/releases/2012/08/120813203024.htm

How Computation Can Predict Group Conflict: Fighting Among Captive Pigtailed Macaques Provides Clues

ScienceDaily (Aug. 13, 2012) — When conflict breaks out in social groups, individuals make strategic decisions about how to behave based on their understanding of alliances and feuds in the group.

Researchers studied fighting among captive pigtailed macaques for clues about behavior and group conflict. (Credit: iStockphoto/Natthaphong Phanthumchinda)

But it’s been challenging to quantify the underlying trends that dictate how individuals make predictions, given they may only have seen a small number of fights or have limited memory.

In a new study, scientists at the Wisconsin Institute for Discovery (WID) at UW-Madison develop a computational approach to determine whether individuals behave predictably. With data from previous fights, the team looked at how much memory individuals in the group would need to make predictions themselves. The analysis proposes a novel estimate of “cognitive burden,” or the minimal amount of information an organism needs to remember to make a prediction.

The research draws from a concept called “sparse coding,” or the brain’s tendency to use fewer visual details and a small number of neurons to stow an image or scene. Previous studies support the idea that neurons in the brain react to a few large details such as the lines, edges and orientations within images rather than many smaller details.

“So what you get is a model where you have to remember fewer things but you still get very high predictive power — that’s what we’re interested in,” says Bryan Daniels, a WID researcher who led the study. “What is the trade-off? What’s the minimum amount of ‘stuff’ an individual has to remember to make good inferences about future events?”

To find out, Daniels — along with WID co-authors Jessica Flack and David Krakauer — drew comparisons from how brains and computers encode information. The results contribute to ongoing discussions about conflict in biological systems and how cognitive organisms understand their environments.

The study, published in the Aug. 13 edition of theProceedings of the National Academy of Sciences, examined observed bouts of natural fighting in a group of 84 captive pigtailed macaques at the Yerkes National Primate Research Center. By recording individuals’ involvement — or lack thereof — in fights, the group created models that mapped the likelihood any number of individuals would engage in conflict in hypothetical situations.

To confirm the predictive power of the models, the group plugged in other data from the monkey group that was not used to create the models. Then, researchers compared these simulations with what actually happened in the group. One model looked at conflict as combinations of pairs, while another represented fights as sparse combinations of clusters, which proved to be a better tool for predicting fights. From there, by removing information until predictions became worse, Daniels and colleagues calculated the amount of information each individual needed to remember to make the most informed decision whether to fight or flee.

“We know the monkeys are making predictions, but we don’t know how good they are,” says Daniels. “But given this data, we found that the most memory it would take to figure out the regularities is about 1,000 bits of information.”

Sparse coding appears to be a strong candidate for explaining the mechanism at play in the monkey group, but the team points out that it is only one possible way to encode conflict.

Because the statistical modeling and computation frameworks can be applied to different natural datasets, the research has the potential to influence other fields of study, including behavioral science, cognition, computation, game theory and machine learning. Such models might also be useful in studying collective behaviors in other complex systems, ranging from neurons to bird flocks.

Future research will seek to find out how individuals’ knowledge of alliances and feuds fine tunes their own decisions and changes the groups’ collective pattern of conflict.

The research was supported by the National Science Foundation, the John Templeton Foundation through the Santa Fe Institute, and UW-Madison.


Story Source:

The above story is reprinted from materials provided byUniversity of Wisconsin-Madison.


Journal Reference:

  1. Bryan C. Daniels, David C. Krakauer, and Jessica C. Flack. Sparse code of conflict in a primate society.Proceedings of the National Academy of Sciences, 2012; DOI: 10.1073/pnas.1203021109
Citation:

University of Wisconsin-Madison (2012, August 13). How computation can predict group conflict: Fighting among captive pigtailed macaques provides clues. ScienceDaily. Retrieved August 15, 2012, from http://www.sciencedaily.com/releases/2012/08/120813155517.htm

Protective Bacteria in the Infant Gut Have Resourceful Way of Helping Babies Break Down Breast Milk

ScienceDaily (Aug. 13, 2012) — A research team at the University of California, Davis, has found that important and resourceful bacteria in the baby microbiome can ferret out nourishment from a previously unknown source, possibly helping at-risk infants break down components of breast milk.

(Credit: http://www.breastfeeding-problems.com/)


 

Breast milk is amazingly intricate, providing all of the nutrients necessary to sustain and strengthen infants in the first months of life. Moreover, this natural source of nutrition provides protection from infections, allergies and many other illnesses.

Breast milk also promotes the growth of protective bacteria in an infant’s intestine. Because breast milk contains glycans (complex sugars) that infants cannot breakdown, it promotes the growth a specific type of bacteria, called bifidobacteria, that can process these glycans. While it is known that bifidobacteria avail themselves of the free glycans in breast milk, it was not known whether these bacteria could also obtain glycans that were linked to proteins. Such proteins are called glycoproteins, and they are abundant in breast milk.

The research team led by David A. Mills at the UC-Davis investigated the ability of bifidobacteria to remove glycans from milk glycoproteins. Their work was recently published in the journal Molecular & Cellular Proteomics.

Mills’ group found that specific strains of bifidobacteria possessed enzymes capable of removing glycan groups from glycoproteins, enabling them to use these glycans as an additional food source. Surprisingly, one of the enzymes, EndoBI-1, was able to remove any type of N-linked glycan (glycans attached to proteins by the amino acid asparagine). This is unique among enzymes of this type and may provide a growth advantage for bifidobacteria in the infant intestine because the glycoproteins in breast milk have complex glycans attached.

Mills explains that the ability of EndBI-1 to remove a variety of complex N-linked glycans combined with its unusual heat stability make “this potentially a very useful tool in both food processing and proteomics/pharmaceutical research.”

The team’s work suggests that bifidobacteria do not primarily feed on the glycans from milk glycoproteins. However, the study did show that under the proper conditions bidfidobacteria can grow when protein-linked glycans are the only energy source.

“One obvious goal of this research is to find ways to translate the benefits provided by milk and bifidobacteria to at risk populations such as premature infants, malnourished children, among many others,” Mills says.

 


Story Source:

The above story is reprinted from materials provided byUniversity of Illinois College of Agricultural, Consumer and Environmental Sciences. The original article was written by Phyllis Picklesimer.


Journal Reference:

  1. R. S. Chapkin, C. Zhao, I. Ivanov, L. A. Davidson, J. S. Goldsby, J. R. Lupton, R. A. Mathai, M. H. Monaco, D. Rai, W. M. Russell, S. M. Donovan, E. R. Dougherty.Noninvasive stool-based detection of infant gastrointestinal development using gene expression profiles from exfoliated epithelial cellsAJP: Gastrointestinal and Liver Physiology, 2010; 298 (5): G582 DOI: 10.1152/ajpgi.00004.2010
Citation:

University of Illinois College of Agricultural, Consumer and Environmental Sciences (2010, May 13). Why is breast milk best? It’s all in the genes. ScienceDaily. Retrieved August 15, 2012, from http://www.sciencedaily.com/releases/2010/05/100512172342.htm

For Young Birds, Getting Stressed out Can Be a Good Thing

ScienceDaily (Aug. 10, 2012) — Many studies have found that high levels of hormones that are associated with stress are a sign of poor fitness and reduced chance of survival — but recent research on young songbirds found that some elevated hormones can be a good thing, often the difference between life and death.

 

Stress in birds. New research found that stress in small birds such as this Swainson’s thrush can aid their survival. (Credit: Photo courtesy of Oregon State University)

 

The new research concluded that elevated levels of glucocorticoid hormones, which are part of the natural response to stress, were related to the movement, feeding, and anti-predator behaviors of juvenile birds.

The findings were made by researchers at Oregon State University with the Swainson’s thrush as an animal model.

There’s only about a one-in-three chance that juveniles of this bird species will survive, the study found, and it appeared to have more to do with their stress hormones than other factors such as vegetative cover or nesting site.

“In these birds, a little stress and elevated stress hormones were associated with greater survival,” said James Rivers, a researcher with the OSU Department of Forest Ecosystems and Society. “The conventional wisdom is that elevated levels of glucocorticoid hormones are bad for survival, but we found just the opposite.”

“Stress is more complex than we think,” he said.

The hormones associated with stress, which include cortisol in humans, can change the behavior and physiology of animals. If stress is too persistent and the hormone levels remain consistently too high, it appears to impede growth. But especially at vulnerable stages where the task is to keep up with the parents, get enough food to grow, or flee a predator, higher levels of stress hormones appear to improve survival chances.

This was one of the first studies of its type done in small songbirds, researchers said. Some previous research had suggested that increased hormone levels can allocate resources away from normal activities and have long-term health impacts.

The research was published in Functional Ecology, a professional journal. It was supported by the U.S. Department of Agriculture, the National Science Foundation and other agencies.

 


Story Source:

The above story is reprinted from materials provided byOregon State University. 


Journal Reference:

  1. James W. Rivers, Andrea L. Liebl, Jennifer C. Owen, Lynn B. Martin, Matthew G. Betts. Baseline corticosterone is positively related to juvenile survival in a migrant passerine birdFunctional Ecology, 2012; DOI:10.1111/j.1365-2435.2012.02025.x
Citation:

Oregon State University (2012, August 10). For young birds, getting stressed out can be a good thing. ScienceDaily. Retrieved August 15, 2012, from http://www.sciencedaily.com/releases/2012/08/120813092045.htm

Fruity Science Halves Fat in Chocolate

ScienceDaily (Aug. 13, 2012) — It may not make chocolate one of your five a day — but scientists have found a way to replace up to 50 per cent of its fat content with fruit juice.

Dr Stefan Bon has found a way to replace up to 50 per cent of chocolate. (Credit: Image courtesy of University of Warwick)

 

University of Warwick chemists have taken out much of the cocoa butter and milk fats that go into chocolate bars, substituting them with tiny droplets of juice measuring under 30 microns in diameter.

They infused orange and cranberry juice into milk, dark and white chocolate using what is known as a Pickering emulsion.

Crucially, the clever chemistry does not take away the chocolatey ‘mouth-feel’ given by the fatty ingredients.

This is because the new technique maintains the prized Polymorph V content, the substance in the crystal structure of the fat which gives chocolate its glossy appearance, firm and snappy texture but which also allows it to melt smoothly in the mouth.

The final product will taste fruity — but there is the option to use water and a small amount of ascorbic acid (vitamin C) instead of juice to maintain a chocolatey taste.

Dr Stefan Bon from the Department of Chemistry at the University of Warwick was lead author on the study published in the Journal of Materials Chemistry.

He said the research looked at the chemistry behind reducing fat in chocolate, but now it was up to the food industry to use this new technique to develop tasty ways to use it in chocolate.

Dr Bon said: “Everyone loves chocolate — but unfortunately we all know that many chocolate bars are high in fat.

“However it’s the fat that gives chocolate all the indulgent sensations that people crave — the silky smooth texture and the way it melts in the mouth but still has a ‘snap’ to it when you break it with your hand.

“We’ve found a way to maintain all of those things that make chocolate ‘chocolatey’ but with fruit juice instead of fat.

“Our study is just the starting point to healthier chocolate — we’ve established the chemistry behind this new technique but now we’re hoping the food industry will take our method to make tasty, lower-fat chocolate bars.”

The scientists used food-approved ingredients to create a Pickering emulsion, which prevents the small droplets from merging with each other.

Moreover, their chocolate formulations in the molten state showed a yield stress which meant that they could prevent the droplets from sinking to the bottom.

The new process also prevents the unsightly ‘sugar bloom’ which can appear on chocolate which has been stored for too long.

 


Story Source:

The above story is reprinted from materials provided byUniversity of Warwick.


Journal Reference:

  1. Thomas S. Skelhon, Nadia Grossiord, Adam R. Morgan, Stefan A. F. Bon. Quiescent Water-in-Oil Pickering Emulsions as a Route toward Healthier Fruit Juice Infused Chocolate ConfectionaryJournal of Materials Chemistry, 2012; DOI: 10.1039/C2JM34233B
Citation:

University of Warwick (2012, August 13). Fruity science halves fat in chocolate. ScienceDaily. Retrieved August 15, 2012, from http://www.sciencedaily.com/releases/2012/08/120813074015.htm