Paper butterflies uncover function of wing patterns

NUS scientists conducted field experiments using paper models of butterflies to show how particular features of their wing patterns affected predation risk in the wild.

Many butterflies display bull’s-eyes patterns on their wings, called eyespots, that are thought to have one of two functions: deflect the attacks of predators towards the wing margins, or intimidate predators, so they do not dare to strike at all. However, the features that cause these eyespots to serve one function over the other are unclear.

Prof Antónia Monteiro from the Department of Biological Sciences at NUS together with her former honours student, Sebastian HO used hundreds of paper models of a local satyrid butterfly, with an artificially manipulated number of eyespots or eyespot size, to study attack risk by predators in the wild. They found that multiple, but not single, small eyespots resulted in high predation, presumably due to high conspicuousness, whereas single large eyespots (> 6 mm in diameter) resulted in low predation.

They proposed that eyespot patterns on butterfly wings gain an intimidation function when they are larger in size. In collaboration with Prof William PIEL and Master’s student, Sandra SCHACHAT, they showed that large eyespots are relatively rare but have evolved in multiple nymphalid butterfly lineages.

The research team is currently conducting similar experiments to evaluate the significance of the wing patterns displayed by another local butterfly species, the Painted Jezebel.

Figure shows a praying mantis considering whether to attack the wiggly mealworm attached to a paper butterfly with an artificially enlarged single eyespot [Image credit: William Piel].

Reference

Ho S, S Schachat, WH Piel, A Monteiro. “Attack risk for butterflies changes with eyespot number and size”. Royal Society Open Science 3:150614(2016).