Abstracts (first author)
Evolution on the move: adaptation to use a widespread host associated with responses to climate change in the UK butterfly Aricia agestis
A species’ geographical ranges typically consists of many populations differently adapted to local ecological conditions, such as the availability of particular hosts or prey. Specialization on localized resources could prevent species from colonizing new sites where the same resources are not available, limiting their capacity to track climatic changes. Consistent with this, we observe that rapid evolution of host preference as well as morphology related to increased dispersal has been associated with recent range expansion of the Brown Argus butterfly, Aricia agestis. While butterflies in long-established parts of their range exhibit local adaptation, usually showing increased preference for laying their eggs on the locally most abundant host plants, butterflies in recently-colonized areas show a consistent preference for a host plant species (Geranium molle) that is geographically widespread in the region of expansion, despite being locally rare. Reciprocal transplant experiments support these data, and show that recent colonists have lost local adaptations present in the established part of the range. Our data suggest that future anthropogenic warming can be expected to bring about a major restructuring of patterns of local adaptation, and may limit the potential for popuations to continue to evolve in the future.