A new study published today in animal behavior shows for the first time that the brilliant iridescence and sheen found in some animals may have a protective function by functioning as a form of deceptive warning coloration, and that this is the key characteristic of iridescence, its changing colors , which is important for this effect.
This striking form of structural coloration in which the hue and intensity of colors vary with viewing angle, has also evolved independently in everything from birds such as magpies and starlings, to many insects such as rosemary beetles, rosemary beetles and in the damsel.
By examining its biological functions, a team of researchers from CamoLab at the University of Bristol have investigated why this bright metallic coloration has evolved so often in the animal kingdom and what makes this striking form of animal coloration such an anti-predator strategy. efficient. The team had previously found that iridescence can act as a very effective form of camouflage, but whether such striking forms of structural coloration could also protect prey after detection, and if so, what optical properties were important for this effect. , remained unknown until now. .
Lead author Dr Karin Kjernsmo from the School of Biological Sciences at the University of Bristol said: “One of the challenges in studying the functions of such highly reflective structural coloration has been to separate the effects of color variability, the mark of iridescence, the effects of just having multiple colors at the same time, and also separating the shine effects from the iridescent effects.”
They tested if and how iridescence could provide a survival advantage to prey after detection by presenting both iridescent and non-iridescent versions, as well as bright and matte versions of both, to birds that had no previous experience with such prey, then looked at the birds willingness to attack the prey. They found that iridescence significantly reduced birds’ willingness to attack, and that shine also had an independent effect.
“Here we have, for the first time, successfully tested each of these two effects on their own, and shown that iridescence and brilliance can protect prey even after detection, providing yet another adaptive explanation for the evolution and the widespread existence of iridescence,” added Dr. Kjernsmo.
The study was funded by the Biotechnology & Biological Sciences Research Council (BBSRC).
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