Science Reuters

Natural selection favors iridescence, beetles are living proof

Iridescence and gloss are usually associated with display, but can they also defend? In new research, scientists at the University of Bristol have tested naïve birds’ willingness to attack glossy and iridescent prey.

Iridescence is known to be an effective form of camouflage, but little is known about the survival benefits it can confer.

To investigate this, University of Bristol’s Dr. Karin Kjernsmo and colleagues measured the attack willingness of naïve chicks presented with real and artificial jewel beetle, and wing cases, all of which were conspicuous on the background against which they were displayed.

The researchers found that iridescence provides initial protection against avian predation by significantly reducing the willingness to attack.

Importantly, they found that the main factor explaining this aversion is iridescence, not multiple colors per se, with surface gloss also having an independent effect.

“Here we have, for the first time, effectively managed to test for each of these two effects on their own, and shown that both iridescence and gloss can protect prey even post-detection, providing yet another adaptive explanation for the evolution and widespread existence of iridescence,” Dr. Kjernsmo said.

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