The selective environment: genetic adaptation of the midge Chironomus riparius to metal pollution

The aim of the present study was to provide conclusive evidence for either genetic adaptation or phenotypic plasticity of the midge Chironomus riparius in response to metal pollution. To this purpose the genetic structure and copper sensitivity of C. riparius populations from metal-polluted and reference sites was compared. Microsatellite analysis demonstrated that populations from metal-polluted sites were genetically different from the population of a nearby reference site. In addition, midges from a metal-polluted site were less sensitive to copper than the laboratory culture. By combining the population genetic structure of C. riparius and copper sensitivity of the F1 larvae we concluded that metal tolerance in C. riparius is most likely due to genetic adaptation.