Interactions of insects with micro- and nanoplastics: A review

Despite the rapid spread of plastic pollution, and particularly micro- and nanoplastic pollution, a comprehensive systematic review of microplastic distribution and toxicology in terrestrial and aquatic insects has yet to be conducted. This leaves a significant gap in contrast to the well-documented impacts on marine and vertebrate lineages. In light of the current context, the present review synthesises 114 studies that investigated the occurrence, abundance, ecotoxicological effects, and biodegradation potential of plastic particles across major insect orders. Field evidence demonstrates widespread contamination, particularly in freshwater taxa, with fibres and common polymers such as polyester, polyethylene, and polypropylene dominating. Microplastic concentrations ranged from as low as 0.21 items/ind. (Trichoptera) to nearly 500 items/ind. in dipteran species. Laboratory studies reveal diverse sublethal effects on development, physiology, immunity, behaviour, and gut microbiota, with Diptera and Lepidoptera showing marked sensitivity, while some coleopteran larvae exhibit the capacity to fragment and biodegrade specific polymers. Despite increasing research efforts, major gaps persist regarding environmentally realistic exposures, trophic transfer, long-term and multigenerational effects, and population-level consequences. Integrating ecotoxicology, ecology, and environmental chemistry is crucial for understanding the ecological significance of insect-microplastic interactions and their broader implications for ecosystem functioning.