SD17: Comparing thermal reaction norms of two buckeye butterfly populations

Countless species of Lepidoptera are expected to face changes in geographic range and temperature
tolerance due to rising global temperatures. Wide-range generalist species of insects can be studied to
provide comparisons between populations of the same species in vastly different locations, and can assist
in predicting future range and population trends. In a 2023 laboratory experiment, we studied the
development and life history traits of two populations of Common Buckeye butterflies (Junonia coenia).
Adults were collected from the wild in North Carolina and California, and their offspring were reared
from hatching to eclosion across five temperature treatments. Our findings suggest that the California
population developed faster, grew larger as larvae and pupae, and survived better than their North
Carolina counterparts. Follow-up experiments will take place in the Fall of 2024 to evaluate additional
temperature treatments. This work will help identify higher and lower temperature limits for multiple
populations of a wide-ranging generalist, and increase our understanding for regional adaptations of insect
populations.