Consequences of heat hardening on a field fitness component in Drosophila depend on environmental temperature

Abstract

Heat hardening increases thermal resistance to more extreme temperatures in the laboratory. However, heat hardening also has negative consequences, and the net benefit of hardening has not been evaluated in the field. We tested short-term heat hardening effects on the likelihood of Drosophila melanogaster to be caught at different temperatures at baits in field sites without natural resources. We predicted that hardened flies should be more frequently caught at the baits at high but not low temperatures. Under cool conditions, flies hardened at 36°C, and to a lesser extent at 34°C, were less frequently caught at baits than nonhardened flies a few hours after release, indicating a negative ef..