Exposure to the insecticide, imidacloprid, impairs predator-recognition learning in damselfly larvae

Thiamethoxam Exposure Impairs Oocyte Maturation via Induction of Lipid Metabolism and Mitochondrial Dysfunctions in Porcine

Neonicotinoid insecticides (NEOs) are the most widely used pesticides in modern agriculture, and there are residues in the environment and food. Thiamethoxam (TMX) has been proven to destroy the ovarian homeostasis of mice in vivo and reduce the development of porcine oocytes in vitro. However, whether TMX can interfere with porcine oocyte maturation and its potential mechanism remains unknown. This study indicated that TMX affects the expansion of cumulus cells, destroys the balance of lipid metabolism, and damages mitochondrial function. TMX treatment decreased the expression of genes related to cumulus cell expansion, lipid synthesis and mitochondrial synthesis. Collectively, results confirm that TMX exposure can damage oocyte maturation and produce reproductive toxicity by inducing lipid metabolism and mitochondrial dysfunction in porcine.

Sub-lethal effects of the insecticide, imidacloprid, on the responses of damselfly larvae to chemosensory cues indicating predation risk

Insecticides, including the widely used neonicotinoids, can affect both pest and non-target species. In addition to lethal effects, these insecticides at sub-lethal levels may cause disruption to sensory perception and processing leading to behavioural impairments. In this laboratory experiment, we investigated the effects of a 10-day exposure to the neonicotinoid insecticide, imidacloprid, on the behaviour of larvae of the damselfly, Lestes congener. In tests of baseline activity, imidacloprid concentrations of 1.0 and 10.0 μg/L caused significant reductions in foraging behaviour. Moreover, in response to chemical cues that indicate a potential risk to the larvae, imidacloprid caused the loss of an appropriate antipredator response (reduced foraging) depending on the concentration and duration of exposure. Imidacloprid at 0.1 μg/L caused the loss of responses toward the odour of a beetle (Dytiscus spp.) predator after 10 days of exposure, whereas 1.0 μg/L caused lost responses toward both the predator odour and injured conspecific cues (i.e., alarm cues) and after only 2 days of exposure. However, at 10.0 μg/L, larvae responded appropriately to both cues throughout the duration of the study, suggesting compensatory responses to imidacloprid at higher concentrations. Hence, the lack of appropriate responses at 1.0 μg/L likely resulted from a cognitive impairment rather than chemical alteration of these important chemosensory cues. In the natural environment, such effects will likely cause decreased survivorship in predator encounters. Hence, imidacloprid exposure, even at low concentrations, could have adverse consequences for chemosensory ecology of this damselfly species.