TY - JOUR

T1 - Terrestrial adult stages of freshwater insects are sensitive to insecticides

AU - Bruus, Marianne

AU - Rasmussen, Jes Jessen

AU - Strandberg, Morten Tune

AU - Strandberg, Beate

AU - Sørensen, Peter Borgen

AU - Larsen, Søren Erik

AU - Kjær, Christian

AU - Lorenz, Stefan

AU - Wiberg-Larsen, Peter

PY - 2020/1

Y1 - 2020/1

N2 - Terrestrial adult stages of freshwater insects may be exposed to pesticides by wind drift, over-spray, contact or feeding. However, studies addressing insecticide effects on freshwater invertebrates focus primarily on the impact of pesticides reaching the streams and potentially harming the aquatic juvenile stages. This is also reflected in the current risk assessment procedures, which do not include testing of adult freshwater insects. In order to assess the potential impact of insecticides on adult stages of freshwater insects, we exposed six common species to the insecticides Karate (lambda-cyhalothrin) and Confidor (imidacloprid). Dose-response relations were established, and LD 50 estimates were compared to those of the honey bee, Apis mellifera L. (Hymenoptera: Apidae), which is the standard terrestrial test insect when pesticides are evaluated prior to commercial release. Generally, the tested species were more sensitive to the studied insecticides than the honey bee. In order to examine whether the sensitivity of adult stages of freshwater insects corresponds with the sensitivity of the juvenile stages of the same species, the ranking of the two life stages with respect to the toxicity of Karate was compared, revealing some correspondence, but also some dissimilarities. Our results strongly indicate that terrestrial adult stages of aquatic insects are not adequately protected by current risk assessment procedures.

AB - Terrestrial adult stages of freshwater insects may be exposed to pesticides by wind drift, over-spray, contact or feeding. However, studies addressing insecticide effects on freshwater invertebrates focus primarily on the impact of pesticides reaching the streams and potentially harming the aquatic juvenile stages. This is also reflected in the current risk assessment procedures, which do not include testing of adult freshwater insects. In order to assess the potential impact of insecticides on adult stages of freshwater insects, we exposed six common species to the insecticides Karate (lambda-cyhalothrin) and Confidor (imidacloprid). Dose-response relations were established, and LD 50 estimates were compared to those of the honey bee, Apis mellifera L. (Hymenoptera: Apidae), which is the standard terrestrial test insect when pesticides are evaluated prior to commercial release. Generally, the tested species were more sensitive to the studied insecticides than the honey bee. In order to examine whether the sensitivity of adult stages of freshwater insects corresponds with the sensitivity of the juvenile stages of the same species, the ranking of the two life stages with respect to the toxicity of Karate was compared, revealing some correspondence, but also some dissimilarities. Our results strongly indicate that terrestrial adult stages of aquatic insects are not adequately protected by current risk assessment procedures.

KW - Dose-response

KW - Insecticides

KW - Relative sensitivity

KW - Risk assessment

KW - Terrestrial adult freshwater insects

U2 - 10.1016/j.chemosphere.2019.124799

DO - 10.1016/j.chemosphere.2019.124799

M3 - Journal article

C2 - 31518926

VL - 239

JO - Chemosphere

JF - Chemosphere

SN - 0045-6535

M1 - 124799

ER -