Researchers have shown that inedible species of butterfly that mimic each others' colour patterns have also evolved similar flight behaviours to warn predators and avoid being eaten. It is well known that many inedible species of butterfly have evolved near identical colour patterns, which act as warning signals to predators so the butterflies avoid being eaten. these butterflies have not only evolved similar colour patterns, but that they have also evolved similar flight behaviours, which together make a more effective warning signal to predators.

Using high-speed video footage to record the flight of wild butterflies in South America, researchers at the University of York measured the wing beat frequency and wing angles of 351 butterflies, representing 38 species each belonging to one of 10 distinct colour pattern mimicry groups. Using this dataset they investigated how the flight patterns of butterflies are related to factors such as habitat, wing shape, temperature and which colour pattern mimicry group the butterfly belongs to see which elements most heavily affected flight behaviour. Although the species habitat and wing shape were expected to have the greatest influence on flight behaviour, the researchers found that in fact the biggest determinant of flight behaviour was the colour pattern mimicry group a butterfly belonged to.

The researchers plan to Sharing flight behaviour across multiple species seems to reinforce this 'don't eat me' message. It is fascinating that this behaviour has evolved between distant relatives over a long period of time, but they can also see flight behaviour diverging between differently patterned populations within a species over a relatively short period of time too. The extent of flight mimicry in this group of butterflies is amazing. It is a great example of how evolution shapes behaviour, with selection from predators driving subtle changes which enhance the survival of individuals. The challenge and interest now is to identify the genes causing these changes, which will tell us how such behavioural mimicry evolves.