Tropical butterflies use thermal buffering and thermal tolerance as alternative strategies to cope with temperature increase

Abstract

Climate change poses a severe threat to many taxa, with increased mean temperatures and frequency of extreme weather events predicted. Insects respond to non-optimal temperatures using behaviours or local microclimates to thermoregulate (thermal buffering ability), or through physiological tolerance. We studied the thermal buffering ability and thermal tolerance of a community of 54 butterfly species in Panama. Thermal buffering ability and tolerance were influenced by family, size, and colour, with Pieridae, large, and dark butterflies having the strongest thermal buffering ability, and with Hesperiidae, small, and dark butterflies tolerating the highest temperatures. We identified an interaction between thermal buffering ability and physiological tolerance, where species with stronger thermal buffering abilities had lower thermal tolerance, and vice versa. This interaction implies that most species will be vulnerable to climate change to an extent, considering that species appear to adapt to one strategy at the expense of the other.