彩虹色有助于生物隐藏

This is Scientific American - 60-Second Science. I'm Karen Hopkin. A good disguise keeps you hidden, right?

Well, sometimes the best disguise is actually the most dazzling. Because research reveals that flashy metallic iridescence can visually baffle predators.

Which allows colorful prey to survive another day. Those eye-popping results appear in the journal Scientific Reports.

Shimmering iridescent coloration. . . which changes depending on the angle from which it's viewed. . . is favored by everything from birds to beetles and blossoms to butterflies.

And in our research group we are of course interested in why this vivid metallic coloration is so taxonomically widespread in nature. Karin Kjernsmo of the University of Bristol.

She says that in some cases the showy splashes of light are a sexual strategy. Here I would like to point out that in some species, particularly those that display strong sexual dimorphism,

such as birds of paradise or the pea fowl or even in some butterflies or fishes, the occurrence of iridescence is most likely driven by sexual selection.

For example, in many of these cases it is the males that have these vivid iridescent colors and they use them in mate choice or they use them as a signal to attract mates.

But iridescence also shows up in situations where reproduction is not an issue. . . for example, in caterpillars or chrysalises.

So what we are studying now is whether natural selection imposed by predation could explain the occurrence of iridescence in prey animals. The idea that eye-catching colors could be used as a cover-up isn't a new one.