Toxicity of imidacloprid for nontarget arthropods in a laboratory experiment

Abstract

The use of systemic neonicotinoid insecticides disrupts the ecological balance in agrocenoses and is detrimental to no n target invertebrates. Therefore, in a laboratory experiment, we evaluated the sensitivity of 50 nontarget species of invert e brates to imidacloprid. No sensitivity to this insecticide was shown by Cylindroiulus truncorum , Formica rufa , Geophilus carpophagus , and Pterostichus niger (the LС 50 values were in the range of 10 to 166 mg/m 2 ). A moderate sensitivity was exhibited by Lithobius forficatus , Megaphyllum sp., Forficula auricularia , Labia minor , Porcellio laevis , Notiophilus pal u stris , Harpalus rufipes , H. latus , Amara nitida , Ophonus rufibarbis , Ponera coarctata , Lasius fuliginosus , L. niger , L. flavus , Rhyparochromus phoeniceus , Lygus pratensis , Oxythyrea funesta , and Teuchestes fossor (LС 50 measuring 1 to 10 mg/m 2 ). Imidacloprid-sensitive species were found to be Carabus convexus , C. granulatus , C. hortensis , Nebria brevicollis , Tach y porus hypnorum , Tachinus signatus , Drusilla canaliculata , Philonthus coprophilus , Ph. decorus , Ph. niti dus , Ph. cognatus , Silpha carinata , Phosphuga atrata , Aphodius foetens , Hister fenestus , Chortippus sp., Graphosoma itali cum , Coreus marg i natus , Pyrrhocoris apterus , and Myrmica ruginodis (LС 50 ranging 0.1 to 1 mg/m 2 ). A hypersensitivity to the studied insect i cide was registered for Ph. carbonarius , Xantholinus tricolor , and Oxytelus sculptus (LС 50 accounting for 0.03 to 0.08 mg/m 2 ). The values of median lethal concentration for some nontarget arthropods could vary by over 5 ,000 times. We o b served no relationship between trophic specialization of the species and sensitivity to imidacloprid. The larger the invert e brate’s body, the less sensitivity to the insecticide it exhibited.