How wily cockroaches trick their predators

November 14th, 2008 - 2:37 pm ICT by IANS  

Washington, Nov 14 (IANS) Do you recall trying to trap a cockroach as a child, only to find that it anticipated your moves and darted away in a jiffy.Now a new study has found how wily cockroaches trick their predators while fleeing from them.

“By using one of a number of possible trajectories, we think that cockroaches may behave with sufficient unpredictability to avoid the possibility that predators will learn their escape strategy,” said Paolo Domenici of CNR-IAMC in Italy.

Cockroaches have been studied for many years as a model for understanding animal escape responses, he said.

While much is known about the neural circuitry underlying their behaviour, it still seemed to Domenici’s team that open questions remained regarding their strategy.

While the insects don’t flee randomly, they nonetheless didn’t seem to do it in an easily predictable manner either.

Researchers searched for some pattern by repeatedly testing cockroaches as they escaped from threats. What they found is that cockroaches select one of a number of preferred trajectories.

Their choice is not completely random because the angle at which the bugs are stimulated to run seems to limit the options.

However, when they are startled from certain directions-head on, for example-cockroaches flee along four primary escape routes at fixed angles from the threat.

The researchers aren’t yet sure exactly how the cockroaches manage this at the neural level, but they suspect they aren’t the only animals that do so.

The findings also raise questions about the evolutionary forces that drive such unpredictable anti-predator behaviour, according to a Cell Press release.

More broadly, the results show that “unpredictable” behavioural patterns in nature can actually be quite structured, Domenici said.

The report was published in the Thursday edition of Current Biology.

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