Contaminant class reconfigures the effect of predators on prey: A meta-analytic synthesis of aquatic invertebrate responses across pollution scenarios.

Predation risk and chemical contamination are pervasive stressors in aquatic ecosystems; however, their interactive effects remain insufficiently understood. This meta-analysis synthesizes evidence from 41 independent studies across four scenarios: unpolluted, organic pollution, inorganic pollution, and mixed pollution. Under unpolluted conditions, we show that predation pressure consistently suppresses physiological performance in aquatic invertebrates while eliciting adaptive behavioral responses. Notably, the type of pollutant fundamentally reshapes this response pattern. Organic pollutants attenuate physiological responses and impair behavioral decision-making through energy trade-offs and neurotoxic effects. In contrast, inorganic pollutants enhance morphological defenses while concurrently weakening other physiological and behavioral responses. Mixed pollutants amplify biochemical costs and reduce behavioral effectiveness of predation avoidance, though the underlying mechanisms remain poorly understood. The analysis of the response differences among various invertebrate groups revealed that their responses to predation pressure reflected their unique life history strategies. Taken together, our findings demonstrate that pollutants do not merely add to predation stress; rather, they fundamentally reconfigure how organisms allocate resources among survival, growth, and reproduction. These insights carry important implications for predicting ecosystem responses under intensifying anthropogenic stress.