Impacts of a 96-h imidacloprid challenge on ghost shrimp (Palaemonetes paludosus) survival and exploratory behavior.

Aquatic invertebrates are widely recognized as indicators of environmental health because their physiology and survival are closely linked to water quality. Among these organisms, freshwater shrimp contribute to nutrient cycling as detritivores and serve as an important prey base for fish and other aquatic species. Despite their ecological importance, freshwater invertebrates face increasing exposure to agricultural contaminants, particularly neonicotinoid pesticides. Imidacloprid, one of the most applied insecticides worldwide, frequently enters aquatic systems through runoff; however, its sublethal effects on non-target freshwater invertebrates remain poorly resolved. Behavioral impairments that precede mortality may carry significant ecological consequences yet are often overlooked in toxicity assessments. This study investigated whether imidacloprid exposure influences survival and exploratory behavior in freshwater ghost shrimp (Palaemon paludosus) over a 96-hour period. Shrimp were exposed to a range of imidacloprid concentrations under controlled laboratory conditions, and both mortality and locomotor activity were quantified. Preliminary results indicate that higher concentrations were associated with reduced survival and marked declines in movement and exploration. These patterns suggest neurological or physiological impairment even when individuals remained alive. Reduced exploratory behavior could translate to diminished foraging success, impaired predator avoidance, and lowered fitness in natural environments. Together, these findings demonstrate that ghost shrimp are highly sensitive to imidacloprid exposure and highlight the importance of incorporating behavioral endpoints into ecotoxicological evaluations. By showing that environmentally relevant concentrations can alter shrimp behavior, this study provides evidence that pesticide contamination may disrupt freshwater food webs in ways not captured by mortality metrics alone.