Behavioural response to combined insecticide and temperature stress in natural populations of Drosophila melanogaster

Insecticide resistance evolves extremely rapidly, providing an illuminating model for the study of adaptation. With climate change reshaping species distribution, pest and disease vector control needs rethinking to include the effects of environmental variation and insect stress physiology. Here we assessed how both long term adaptation of populations to temperature and immediate temperature variation affects the genetic architecture of DDT insecticide response in Drosophila melanogaster. Mortality assays and behavioral assays based on continuous activity monitoring were used to assess the interaction between DDT and temperature on three field-derived populations from climate extremes (Raleigh for warm temperate, Tasmania for cold oceanic and Queensland for hot tropical). The Raleigh population showed the highest mortality to DDT whereas the Queensland population, epicentre for derived alleles of the resistance gene Cyp6g1, showed the lowest. Interaction between insecticide and temperat...