Meeting Abstract

64.7  Monday, Jan. 6 09:30  Thermal stress and heat tolerance in Rocky Mountain butterflies MACLEAN, HJ*; HIGGINS, JK; BUCKLEY , LB; KINGSOLVER, JG; University of North Carolina, Chapel Hill ; University of North Carolina, Chapel Hill ; University of Washington, Seattle ; University of North Carolina, Chapel Hill hmaclean@live.unc.edu

Short-term exposure to high temperatures can reduce activity and survival in many ectothermic organisms. Populations and species of Colias butterflies in the Rocky Mountains exhibit local adaptations in morphology , which enable them to achieve the body temperatures needed for flight activity along elevational gradients. We conducted lab and field experiments to compare behavior and tolerance to high temperatures between adults from high-elevation C. meadii (3.5km) and two populations of lower-elevation C. eriphyle (1.5 km and 2.2 km).Common-garden experiments at the low elevation field site showed that high-elevation C. meadii had significantly greater heat-avoidance behavior and higher mortality than lower-elevation C. eriphyle in sunny, hot conditions. We then quantified thermal stress tolerance as survival following a one hour exposure to a constant temperature ranging from 25 to 47C. Surprisingly, the high elevation species (C. meadii) had greater survival at higher temperatures relative to the low elevation species ( C. eriphyle). This suggests the importance of coping with acute thermal stress events associated with high radiation at high altitudes and highlights the importance of considering both acute and chronic thermal stress when examining responses to climate change.