Moths know how to melt into the background

Douglas Heaven, reporter

Great oak beauty (Hypomecis roboraria) camouflaged against tree bark, in the UK (Image: Stephen Dalton/Minden/Getty)

Many species of moth are experts in camouflage, with the ability to make themselves practically invisible to predators by matching the pattern on their wings with that of their background. But surprisingly little is known about the behaviour surrounding this conjuring trick.

In a first step towards solving the puzzle, researchers at Seoul National University in South Korea placed two species of moth - Jankowskia fuscaria and Hypomecis roboraria - on tree bark and watched what they did. "We let the moths do the job for us," says Changku Kang, one of the researchers.

Rather than remaining where they first landed, the moths tended to walk around, turning their body while repeatedly lifting and lowering their wings until they found a spot where they could blend in (video here).

To test how good the moths were at concealing themselves from predators - or at least beady-eyed humans - the researchers compared photos of the moths taken when they first landed with photos taken when they had settled. Volunteers asked to find the moths in the photos found it much harder when the moths were in their final position.

This finding suggests that evolution of morphological adaptations, such as the moths' colour patterns, needs to be understood alongside the evolution of behaviour that coevolved with the morphology. But how the moths know when they've found the perfect hiding spot remains a mystery, and the team hopes to address this next.

Journal reference: Journal of Evolutionary Biology, DOI: 10.1111/j.1420-9101.2012.02557.x

Source: http://feeds.newscientist.com/c/749/f/10897/s/21f24e0b/l/0L0Snewscientist0N0Cblogs0Cshortsharpscience0C20A120C0A80Cmoths0Eknow0Ehow0Eto0Emelt0Einto0Eth0Bhtml0DDCMP0FOTC0Erss0Gnsref0Fonline0Enews/story01.htm

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