Microplastics Alter Predator Preferences of Prey through Associative Learning

Abstract

Microplastics (MPs) are pervasive environmental pollutants that pose significant threats to wildlife health and ecological interactions. While the toxicological impacts of MPs are increasingly recognized, their influence on animal behavior─particularly feeding preferences─remains underexplored. In this study, we investigated whether animals can discriminate between MP-contaminated (“dirty”) and uncontaminated (“clean”) food sources and whether such preferences can be shaped by experience. Using the model nematode Caenorhabditis elegans, we found that individuals preferentially consumed clean bacterial prey over MP-contaminated prey via olfactory cues mediated by the odr-10 gene. Strikingly, prolonged multigenerational exposure to MP-contaminated prey led to a reversal of this preference: the progeny of exposed worms developed a learned attraction to dirty food, a phenomenon absent in associative learning-deficient mutants (lrn-1). Soil microcosm experiments confirmed that MP contamination influenced predator foraging behavior with nematodes migrating toward cleaner prey patches. Our findings reveal that microplastic pollution can reprogram predator feeding preferences through associative learning and transgenerational inheritance, with broad implications for trophic dynamics and the ecological impact of plastic contamination.