Short and long-term effects of imidacloprid on the burrowing behaviour of two earthworm species

Adverse effects of agrochemicals on earthworms’ burrowing behaviour can have crucial impacts on the entire ecosystem. In the present study, we have therefore assessed short- and long-term effects on burrowing behaviour in the earthworm species Aporrectodea caliginosa and Lumbricus terrestris after exposure to a range of imidacloprid concentrations (0.2–4 mg kg-1 dry weight (DW)) for different exposure times (1, 7, 14 d). Short-term effects on the burrowing behaviour of A. caliginosa were already detected at the lowest test concentration (0.2 mg kg-1 DW), whereas such effects in L. terrestris were not observed until exposure to concentrations 10 times higher (2 mg kg-1 DW). Since many of the observed effects occurred at imidacloprid concentrations relevant to natural conditions and since reduced activities of earthworms in soils can have crucial impacts on the ecosystem level, our results are of environmental concern.

Nils Dittbrenner, Isabelle Moser, Rita Triebskorn, Yvan Capowiez
Chemosphere 84 (2011) 1349–1355