Eyespots deter predatory attack

Many butterflies use colouration and patterns to avoid attacks from predators, protecting their most vulnerable parts from those most likely to attack them. New research from Oregon State University, Yale University and four other institutions has revealed that, for one species of butterfly at least, the colour and intensity of their eyespots varies as the season and types of predator change. “Eyespots are conspicuous; they draw your attention and are thought to be used by many animal species to avoid death or attack, by either startling or confusing the predator,” said Katy Prudic, a researcher at OSU. “Many insects have eyespots, which suggests they are an important adaption.” [caption id="attachment_40639" align="alignright" width="200"] During the dry season, this Bycyclus anyana butterfly has small, dull eyespots that make it harder to see and help it avoid the most important predator at that time – birds. Credit: Antonia Monteiro/Oregon State University.[/caption] Bycyclus anyana produces around five generations a year during both wet and dry seasons in its native habitat. Through phenotypic plasticity, the same genes produce two different eyespot patterns in adults. In the warm temperatures of the wet season, adults are adorned with large and bright eyespots, while those in the cooler, drier season have smaller, duller spots. In the wet season, the large eyespots make a colourful target for attack from predators such as they preying mantids. The showy spots led to the mantids attacking the wings, rather than the head or body and although the wings are damaged, the insect survives and can reproduce. Birds are the primary predator in the dry season, and the smaller eyespots make the butterfly more difficult to detect. “Having the right type of eyespot in the right season allowed the butterflies to live long enough to lay eggs and have more offspring in the next generation,” said Prudic. “With the wrong eyespot at the wrong time, they were quickly annihilated.” Prudic and her colleagues took the large eyespots from one butterfly and glued them onto the wings of a butterfly with smaller spots; they found that butterflies with larger eyespots – regardless of what season they were from – survived better and reproduced more than those with tiny eyespots. Eyespots deflect predator attack increasing fitness and promoting the evolution of phenotypic plasticity https://www.youtube.com/watch?v=QQFSahMVuUw https://www.youtube.com/watch?v=cXjglu9g3qg