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Ants leave the nest to die alone

Written by Thomas Hesselberg
Saturday, 13 February 2010
Sick ants leave their nestmates to die alone in order to reduce the risk of spreading their disease to them. Courtesy of Wikimedia Commons. Taken by Fir0002/Flagstaffotos A new study shows that ants that are about to die from illness leave the company of their nest-mates and socially isolate themselves. Since deadly infections can spread quickly among the thousands of individuals in an ant-nest, this behaviour might have evolved to reduce this risk. Ants are highly social insects that live in colonies ranging from thousands to millions of individual ants, all daughters of the single reproductive queen. Although a social life-style gives many advantages including defence, resource utilization and in ant colonies also in the high degree of specialisation, it also results in increased risks from the easy spread of pathogens. One way to reduce this risk is to isolate sick individuals and indeed anecdotes from many different social animals tell of dying animals isolating themselves from their companions shortly before death. However, there is a lack of hard scientific evidence for this. Tag it: ? Be first to comment this article \| Add as favourites (3) \| Quote this article on your site \| Views: 61 \| E-mail
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Endowed Crabs Flaunt it

Saturday, 12 December 2009

Hermit crabs exaggerate their fighting ability with misleading claw displays

Jane Palmer, Ph.D.

Back off. Male hermit crabs display their claws to intimidate and deter attackers. Credit Hans Hillewaert by courtesy of Wikimedia Commons

Well-endowed hermit crabs are not shy about displaying their claws � especially if showing off will mislead potential opponents. When a crab has unusually large claws for its body size, it will spend more time displaying them, says a new study. The research, which suggests such crabs exaggerate their fighting ability to avoid attack, indicates a more subtle form of dishonesty in animal signaling than has been previously recognized.

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We all look alike

Written by Thomas Hesselberg
Sunday, 06 September 2009
Humans do show some height variation among population, here a European with Pygmies at the beginning of the last Century. Scan of Collier's New Encyclopedia, Volume 1 (1921). Courtesy of Wikimedia Commons. We might think that whereas most animals in the same species looks alike, we, humans, show a lot of individual variation. However, new research shows that in fact humans are much similar than we think. The scientists compared variation in length (height) and body mass in various human populations and compared it to animal populations. Surprisingly, they found that humans show some of the lowest levels of variation in height, whereas variation in body was around the average variation found in animals. Tag it: ? Be first to comment this article \| Add as favourites (19) \| Quote this article on your site \| Views: 437 \| E-mail
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Maple seeds stay longer in the air due to their similarity to insect wings

Written by Thomas Hesselberg
Tuesday, 16 June 2009
A maple seed with the heavy nut at the base and the wing shaped seed at the top. Photo courtesy of Wikimedia Commons (by user Kobako). A new study on the aerodynamics of wind dispersed maple seeds show that these seeds descend slower, and thereby disperse wider, by attaching a vortex of air, which generates increased lift. A very similar mechanism is known from insects, where it helps generate the necessary flight forces. Maple, like many other trees, relies on wind to disperse its seeds. To aid the dispersal the maple seeds have evolved a host of morphological adaptations. The heavy nut is at the base of the insect wing shaped seed and this arrangement causes the seed to rotate while falling towards the ground. Tag it: ? Be first to comment this article \| Add as favourites (19) \| Quote this article on your site \| Views: 595 \| E-mail
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Competition and not climate change was responsible for the extinction of Neanderthals

Written by Thomas Hesselberg
Saturday, 03 January 2009
3D reconstruction of a Neanderthal child from a skull found in Gibraltar (from Wikimedia Common, created by Prof. Christoph P.E. Zollikofer from the University of Zurich). A new study published in PLoS ONE shows that the rapid climate change seen in the last glacial period between 60,000 and 30,000 years ago did not contribute to the extinction of the Neanderthals. Instead the Neanderthals were probably out-competed by modern humans. The Neanderthals were humanoids that were shorter and more powerful build than modern humans. Some evidence suggests that they belonged to the same species as modern humans (Homo sapiens), whereas other evidence places them in a separate species (Homo neanderthalensis). Neanderthal remains are found in Europe and Central Asia dating back around 150,000 years. They became extinct around 30,000 years ago. In recent years, the reason for this extinction has been much debated. Tag it: ? Be first to comment this article \| Add as favourites (15) \| Quote this article on your site \| Views: 1618 \| E-mail
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