Rapid adaptation to high temperatures in Chironomus riparius

Effects of seasonal or daily temperature variation on fitness and physiology of ectothermic organisms and their ways to cope with such variations have been widely studied. However, the way multivoltines organisms cope with temperature variations from a generation to another is still not well understood and complex to identify. The aim of this study is to investigate whether the multivoltine midge Chironomus riparius Meigen (1803) responds mainly via acclimation as predicted by current theories, or if rapid genetic adaptation is involved. To investigate this issue, a common garden approach has been applied. A mix of larvae from five European populations was raised in the laboratory at three different pre-exposure temperatures (PET): 14, 20, 26°C. After three and five generations respectively, larvae were exposed to three treatment temperatures (TT) 14, 20, 26°C, mortality was monitored for the first 48h and after emergence. After three generations significant mortality rate differences d...