The “squinting bush brown” butterfly squints a little more if it is born in the dry season, and has wider eyes in the wet — at least it does if, like praying mantids, you believe its eyes are on its wings.
Biologists have long known that the wing spots of the Bycyclus anyana, to give it its scientific name, change size depending on the season in which the butterfly is born. But they have not known why. Now a team of scientists from Oregon State University believe they have the answer — and they came to it by constructing nothing less than a butterfly arena of death.
The advantage of having wing spots is that they can confuse predators into attacking the spots rather