Speaker
Description
Butterfly migration is an enchanting yet complex natural phenomenon. However, to date, detailed knowledge about its genetic basis is limited to a few model organisms. The painted lady butterfly, Vanessa cardui, stands out for its remarkably long-distance migrations and virtually cosmopolitan distribution and has become an emerging model species for research on migratory behavior. Here we focused on two aspects of migration in the painted lady. Using stable isotopes, we identified two distinct migratory phenotypes - short-distance migrants flying from temperate Europe to the Mediterranean, and long-distance migrants crossing the Sahara to reach West Africa (> 4,000 km). We found no significant genetic differentiation between these groups, indicating that individual differences in migration distance reflects a plastic response to environmental conditions. To get insight into the genetic basis of the response to environmental cues, we quantified gene expression and chromatin accessibility differences between experimental cohorts exposed to different conditions associated with migration-reproduction trade-offs. Our results revealed significant changes in gene expression and regulatory element activity of pathways predominantly associated with metabolism, immunity and reproduction. We identified ecdysone esterase, juvenile hormone, ARC1 and Geminin as key candidates involved in the trade-off between migration and reproduction. Our results provide novel insights into the genomic underpinnings of migratory behavior in butterflies and how long-distance migration can affect population structure in insects in general.
