Insecticides affect more than just so-called pests. Other living beings that are exposed to the chemicals are also harmed. This is confirmed by a current study by researchers at the Leibnitz Institute for the Analysis of Biodiversity Change (LIB), the University of Duisburg-Essen and the Technical University of Kaiserslautern-Landau. The scientists examined the development of three species of aquatic invertebrates from larva to adult under the influence of the insecticide chlorantraniliprole.
For their experiment, the research team took water from the Hessian Bach Bieber, which they kept in a closed water circuit in the laboratory. There they exposed larvae of the large mayfly (Ephemera danica), the caddisfly (Lepidostoma basale) and the common amphipod (Gammarus pulex) to various insecticide concentrations. Using RNA sequencing, they decoded the organisms’ genetic response.
To their surprise, the researchers found significantly changed gene activity in the two insect species. The pesticide activated and inhibited various genes that control the development of the flies from the larval stage to the adult. The impact of the insecticide on the amphipod larvae was comparatively small.
The adults of the aquatic insects studied provide an important source of food for birds and other animals. “Changes in the development cycle of the larvae can therefore not only influence life in the rivers, but also food webs in adjacent meadows, forests and fields,” explains the first author of the study, Marie Brasseur from LIB. “In this respect, pesticide contamination can have consequences across ecosystems.” The findings are particularly worrying because chlorantraniliprole is often used by farmers against plant-damaging butterfly larvae.