Evaluation of Imidacloprid Genotoxicity in Chrysoperla Externa Eggs (Neuroptera: Chrysopidae) Through Comet Assay

FERNÁNDEZ ACEVEDO, VICTORIA; RODRÍGUEZ GIL, SERGIO; SEOANE ANALIA; GRACIELA MINARDI; SCHNEIDER, MARCELA I.

CHEMOSPHERE

PERGAMON-ELSEVIER SCIENCE LTD

Lugar: Amsterdam; Año: 2024

0045-6535

The comet assay allows the analysis of DNA damage caused by different genotoxins. This assay has recently gained interest because of its ease of studying the interactions of xenobiotics with different organisms.Chrysoperla externa (Hagen, 1861) is a species of great economic relevance because it is a predator of major agricultural pests during its larval stage. Neonicotinoids are the most important chemical class of insecticides introduced into markets. A previous imidacloprid toxicity assessment on C. externa showed that this neonicotinoid insecticide reduced the egg viability. The objective of this study was to analyze the genotoxicity of imidacloprid on the biological control agent C. externa at DNA level using the comet assay as an ecotoxicological biomarker. This technic was used for the first time for this organism under laboratory insecticide exposition. For the bioassays, the commercial product formulated Confidor OD® (imidacloprid 20% a.i., LS, Bayer CropScience) was used in two concentrations. The selected eggs were dipped in a Confidor OD® solutions for 15 s. Controls were treated with solvent alone. A comet assay protocol was develop for this species at first time. Variables evaluated in Comet assay were as follow: damage index, % DNA damage and tail length. All statistical analyses were performed using R software. The damage index did not show any significant differences between the different concentrations evaluated, but differences were observed for the tail length, because at higher concentrations of imidacloprid, smaller DNA fragments. The DNA of the cells from treated eggs analyzed at 48 h and 96 h of development showed the same % DNA damage; that is, they had no recovery capacity. Applications of imidacloprid on C. externa eggs produce irreparable breaks at the DNA level. The technique adjusted for C. externa can be used in other beneficial insects to study pesticide genotoxicity using the comet assay.