Butterflies and Moths, Do eyespots really ward of predators
The eye spots on the wings of butterflies and moths are intended to be conspicuous to predators, not to resemble the eyes of larger animals, a new study found.
With 150 years of believing that Butterflies and Moths have eye spots to intimidate their predators, Martin Stevens, a behavioral ecologist, has found no proof to backup this age old theory. Now Martin is leading a study into what these eye spots truly do. ]
Martin and his team created artificial paper "Moths" with varying eye spot markings and nailed them to woodland trees. With an additional incentive of meal worm being attached to each moth the woodland birds should have a happy hour at the local watering hole, well, tree. Ideally the local blackbirds, house sparrows and other woodland birds would approach and either be discouraged to eat the worm or happily go ahead and pick it right off the moth.
If eye spots worked by mimicking eyes, the paper insects with circular spots would present a threat and be preyed on last. This was not the case, Martin said " Making the spots appear more eye like by moving the center "pupil" of the eye inward didn't give the paper moths any advantage."
Large bars and squares placed on the waterproof paper wings of the paper moths provided as much protection as circles and the larger the
marking, the less it was preyed upon. Likewise, the more the Insect
spots were on the wing, the less birds attacked them.
Martin and his co workers concluded that the 'visual loudness' of the markings would startle or frighten the predator into avoiding the paper moths.
The well renowned evolutionary ecologist, Tom Sherratt said that;
"It does seem very likely, based on [the new] work, that it's the conspicuousness of the signal that is more of a deterrent than anything to do with it resembling an eye,"
For more information try the following sources:
National Geographic
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