Mimetic resemblance in the butterfly mimicry rings of North-East India

Abstract

Aposematism is a major defensive strategy that deters prey by displaying warning colourations indicating its toxicity. Mimicry is one such example which utilises this concept. Mimicry helps prey survive by resembling the unpalatable or toxic model. This study aims to investigate the extent of mimetic resemblance in the butterfly mimicry rings found in the North Eastern part of the Indian subcontinent. We analysed the mimetic resemblance by comparing the spectral reflectance of colours on the wings of the model and mimic using relative discriminability (Dmimic). Relative discriminability had a low value for all the pairs, indicating a great extent of resemblance. The ventral side had a stronger resemblance compared to the dorsal side, but not significantly different across most pairs. This might suggest that the selective pressure acting on both sides is comparable. There were no significant differences in the Dmimic values between the two avian visual model systems (UVS and VS), implying that mimicry is similar across both predator vision types. This evolution of broad-spectrum resemblance might provide adaptive benefits to the prey, saving them from the diverse avian predator community. It was also observed that the mimics resembled the female models more closely in a monomorphic model system. This study sheds light on our understanding of factors affecting the evolution of mimicry and its extent in the older mimetic communities of North-East India.