LAUSR

The aim of the present study was to evaluate the effects of the neonicotinoid insecticide imidacloprid (commercial formulation) on juveniles of the spider Misumenops maculissparsus (Keyserling, 1891). We first analyzed whether spiders recognized the presence of the insecticide on surfaces and in drinking water (in the form of droplets). Next, we investigated if the insecticide generated histologic, physiologic, and/or biochemical alterations. We observed that spiders do not detect the insecticide on a surface (e.g., paper) or in the form of droplets. After the imidacloprid ingestion by droplet intake, most spiders exhibited a paralysis that reverted after 48 h. Consequently, we observed histopathologic damage (i.e., pigment accumulation, necrosis, and cuticle detachment), and an increased catalase (CAT) activity and total‐protein concentration in the individuals treated. The activities of glutathione‐S‐transferase, glutathione peroxidase, glutathione reductase, and superoxide dismutase, however, did not undergo significant variations. The results obtained emphasize the need to consider different classes of biomarkers, such as CAT and other proteins, to identify and evaluate the histologic, biologic, and biochemical effects of imidacloprid, one of the most widely used insecticides. Environ Toxicol Chem 2022;41:2152–2161. © 2022 SETAC