Evolution

It’s all about smell:
An Olfactory Arms Race in the Animal Kingdom

10 January, 2016 by

Animals use smell to sniff out predators, and to hide from them.

For humans, vision is the dominant sense, and we often overlook the importance of odour (although we’re reminded on those occasions we find ourselves sat next to someone who’s never discovered deodorant, or driving past a particularly pungent farm). But for most animals, it’s all about smell. Two new studies published last month highlight the importance of smell in the lives of animals as different as flies and snakes.

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Stick Insects Sway to Stay Alive

29 October, 2015 by

If you ever owned a pet stick insect as a child, you might have noticed them swaying back and forth at the end of a twig, but until recently, nobody knew what this strange behaviour was for.
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Thanks to Dorothy Floyd for pointing out that we have known anecdotally that this behaviour was likely a form of camouflage for several decades! (see Floyd (1987) Keeping Stick Insects)

Given the chance, parasites evolve to cause less harm

19 October, 2015 by

How do you make a parasite less harmful? It might be as simple as forcing them to stick around.

Amanda Gibson from Indiana University performed experimental evolution with the nematode worm Caenorhabditis elegans and a parasitic bacteria (Serratia marcescens), comparing different scenarios for how the parasite was passed on. Under most circumstances, parasites continued to cause their hosts harm throughout the 20-generation experiment. Only when each strain of parasite was allowed to infect the same host strain, generation after generation, did the parasite evolve to become less harmful.

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Elephant seals are more social than we thought…

15 September, 2015 by

For male elephant seals, the fight to secure a mate can be vicious, even deadly. So they try everything they can to avoid it. This is a pattern biologists see again and again – across the animal kingdom, males have evolved to use signals to assess each other’s prowess and avert costly physical confrontations. In most cases, these signals are honest – they accurately convey an individual’s size, strength or dominance. But new research shows this is not the case for Elephant seals, which have evolved a more sophisticated system.

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Beetles Escape Extinction Because They’re Hard

17 August, 2015 by

The brilliant mathematician and biologist JBS Haldane is famously quoted as once having said, “God had an inordinate fondness for beetles”. He was referring to the fact that nearly half of all insect species known are beetles, but over 50 years after his death, scientists are still gaining new insights into their amazing success. A new study reconstructing the beetle family tree suggests that it is the versatility of beetles that has allowed them to survive even the most testing of times.

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Stink Bugs Provide Sunscreen for their Eggs

10 August, 2015 by

One scientist found his laboratory stink bugs were laying different colour eggs on the black and white squares of a crossword printed on the newspaper lining of their cage. This small observation led him to begin a series of experiments that show how female stink bugs are able to selectively provide sun protection for vulnerable eggs.
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Evolution Shaped these Plants to Resonate with Bats

14 July, 2015 by

A new paper published in Current Biology this month shows how one species of pitcher plant has evolved to attract a species of bat and use it as a source of fertiliser.

The Bornean pitch plant in question (Nepenthes hemsleyana) is part of a mutualistic relationship with the Common woolly bat (Kerivoula hardwickii), in which the pitcher offers the bat a safe place to roost, and in return the bat provides fertiliser in the form of guano (bat poop). Dr Michael Schöner and his team tested the pitcher with a sonar beam and found that it acts as a multidirectional ultrasound reflector. They then experimentally modified the shape of the pitcher, and found that one particular region, known as the orifice, helped bats locate the pitcher.

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Immaculate Conception: Clonal Reproduction in Snakes
(and other animals)

8 May, 2015 by

Reproduction takes two, right? Well, not always. Many arthropods and microscopic animals called rotifers reproduce clonally and although it is relatively rare in vertebrates, clonal reproduction has been confirmed in several species of fish, amphibians, birds and reptiles. Known as parthenogenesis, clonal reproduction in vertebrates can occur when an offspring develops from an unfertilised egg. Parthenogenesis has never been observed to occur naturally in mammals, although it is possible to induce it artificially in the lab.
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