Landscape heterogeneity affects developmental and dispersal-related traits of a butterfly in agricultural landscapes.

The loss and fragmentation of natural habitats due to the intensification of agricultural land use have detrimental impacts on the biodiversity of arthropods. The reduction of natural habitats results in a decreased availability of essential resources, which may select for rapid development and phenotypes enhancing dispersal ability. We here compared replicated populations of the butterfly Coenonympha pamphilus in field-caught females and their laboratory-reared offspring across two landscape types: highly fragmented and intensified "modern" and less fragmented "traditional" agricultural landscapes. We also examined the effects of food stress and landscape parameters representing compositional and configurational landscape heterogeneity on intraspecific trait variation at different spatial scales. The differences between the two landscape types in butterfly traits were nonsignificant throughout, but both field-caught females and their offspring exhibited various responses to the measured landscape parameters. In particular, landscapes with (1) high heterogeneity of habitat patches (i.e., relatively smaller grassland patches with high boundary length), (2) higher proportion of non-crop habitats (i.e., grassland, forests, and woodland), and (3) lower proportion of crop fields seemed to select for phenotypes enhancing dispersal ability. Flight propensity of male offspring was increased under food stress, indicating plastic responses to resource scarcity. In conclusion, our findings suggest that the compositional and configurational landscape heterogeneity, namely parameters indicative of agricultural intensification, select for enhanced dispersal in C. pamphilus. As higher investment in dispersal often comes at a cost to reproduction, such trait shifts may reduce population viability, which may have important implications for insect declines in agricultural landscapes.