Fipronil affects cockroach behavior and olfactory memory.

Fipronil (FPL), an insecticide belonging to the class of phenylpyrazoles, is associated with the widespread mortality of pollinator insects worldwide. Based on studies carried out on residual concentrations of FPL commonly found in the environment, in this work, we evaluated the sublethal effects of FPL on behavior and other neurophysiological parameters using the cockroach Nauphoeta cinerea as a biological model. Sublethal doses of FPL (0.1-0.001 µg/g) increased the time spent grooming and caused dose-dependent inhibition of exploratory activity, partial neuromuscular blockade in vivo, and irreversible negative cardiac chronotropism. FPL also disrupted learning and olfactory memory formation at all doses tested. These results provide the first evidence that short-term exposure to sublethal concentrations of FPL can significantly disrupt insect behavior and physiology, including olfactory memory. These findings have implications for current pesticide risk assessment and could be potentially useful in establishing a correlation with pesticide effects in other insects, such as honey bees.