Fitness implications of simulated climate change in three species of copper butterflies (Lepidoptera: Lycaenidae)

Abstract

Ongoing climate change and especially the associated heat waves may pose a major challenge to biodiversity conservation. Although many ectotherms in temperate zones may benefit from current climate change, others will suffer. However, the specific biological features determining the response of a given species to climate change have remained largely unknown. In the present study, conducted in three copper butterfly species that likely differ in their vulnerability to climate change, we tested the responses to simulated heat waves using ecologically realistic diurnal temperature cycles. Surprisingly, we found little support for our hypothesis that the most vulnerable species will suffer most from simulated climate change. Although species differed significantly in their responses to treatments, such variation appears to be largely ruled by selection pressures associated with the specific developmental pathway. In general, simulated heat waves had little effect on fitness components including fat content and immune function. Consequently, all three species appear to be capable of dealing with projected changes during their larval and pupal development. Whether this also applies to other developmental stages, more extreme stress or indirect effects climate change remains to be seen. Identifying the critical factors determining the vulnerability of a species to climate change will remain an important task for future research.