Sexual selection drives maladaptive learning under climate warming

Abstract

Current predictions for the effects of the climate crisis on biodiversity loss have so far ignored the effects of learning ability and sexual selection. Using the African butterfly Bicyclus anynana, which shows strong phenotypic plasticity in response to temperature, we show that learning produces a maladaptive mate preference under climate warming. We modelled climate warming and found that as temperature becomes an unreliable cue at the onset of the dry season, adult butterflies displayed the wet season rather than the dry season form. Female learning further suppressed their innate, adaptive sexual preference for dry season males. Instead, females learned to prefer a phenotype transiently present during the seasonal transition. Female fertility and longevity were also affected by learning, reducing female fitness following climate warming. Our results emphasize the importance of sexual selection, learning, and their fitness consequences for understanding (mal)adaptation of natural populations to climate warming.