Female butterflies are better than their male counterparts at mimicking noxious and unpalatable butterflies, which helps them avoid bird predators, according to a study by scientists of the National Centre for Biological Sciences, Bengaluru, and the National University of Singapore.
They achieve this mimicry by changing their wing coloration and patterns over long evolutionary periods.Visual mimics
In the natural world, mimicry is not entertainment; and for butterflies — one of the most striking visual mimics in nature — this phenomenon of changing colours of their wings to escape from their predators is crucial to their survival.
The study by scientists Shiyu Su, Matthew Lim and Krushnamegh Kunte, recently published in the science journal Evolution , reveals fascinating insights into the evolution of butterfly wing patterns.
“Female butterflies carry heavy loads of eggs, which impairs their escape flight when they are attacked by birds and other predators. Hence, compelled by the necessity of survival, female butterflies are under intense natural selection to be very good mimics. Therefore, it makes sense that females are better mimics than males,” Mr. Krushnamegh Kunte told The Hindu over telephone from London.
Another interesting aspect of the study is that lower (ventral) surfaces of butterfly wings show better mimicry than the upper (dorsal) surfaces.
This is contrary to scientists’ perception that upper wing surfaces are exposed during flight and likely to be more easily spotted by bird predators.
One of the possible reasons for such variation in the change of colours is that birds prey more frequently on resting butterflies when their ventral wing surfaces are exposed to predators.
The study was conducted on 26 different species of butterflies found in the Western Ghats.