Insects at the crossroads of microplastics pollution: Mechanistic insights, ecological risks, and research frontiers

Insects are foundational to ecosystem stability, biodiversity, and essential services such as pollination and nutrient cycling. However, global declines in insect biomass highlight the urgent need to characterize emerging ecological stressors. Microplastics (MPs), a pollutant of global concern, have recently been recognized as potential disruptors of terrestrial ecosystems, yet their interactions with insect biology remain poorly resolved. Using a PRISMA-based systematic review, the present study provides the first integrative synthesis of insect-MP dynamics, emphasizing exposure pathways, toxicological mechanisms, and ecological implications. Evidence indicates that MPs not only infiltrate insect habitats through pervasive anthropogenic inputs but are also actively processed by insects, which fragment macroplastics into secondary MPs, which are representing an overlooked amplification pathway of plastic pollution. Accumulation of MPs within insect tissues is increasingly associated with oxidative stress, inflammation, and disruptions in digestion, neural function, and reproduction. Furthermore, MPs serve as vectors for co-contaminants, amplifying composite toxicological risks. By consolidating mechanistic and empirical findings, the present review identifies critical data gaps and proposes directions for developing predictive models and risk assessment frameworks tailored to terrestrial invertebrates. Recognizing insects as both receptors and transformers of MPs reframes current paradigms of pollution fate and effect, advancing the scientific basis for assessing emerging stressors in terrestrial ecosystems.