Influence of seasonal fluctuations on eyespot variation in Ypthima asterope Klug and Y. inica Hewitson (Nymphalidae, Satyrinae)

Abstract

The eyespots of certain brown butterflies vary in response to seasonal changes. The present study mainly focuses on the variation in eyespot patterns of two Ypthima species (Y. Asterope and Y. inica) under the influence of seasonal fluctuations. Morphologically similar, both species differ in number, size, and the ocelli (eyespot) arrangements present on both forewings and hindwings, indicating how the species vary from each other, with seasonal forms mostly noticeable in the wet season and reduced or absent in the dry season. Seasonal monitoring showed Y. asterope had limited activity in winter, while Y. inica showed more abundance, had a wider range of seasonal presence, and was more resilient overall. A correlation study for both species revealed that their abundance decreased as temperatures increased, but their numbers rose with higher air pressure, while relative humidity had no significant effect.