Insect Interactions with Microplastics Under Different Ecosystems

Microplastic pollution (<5 mm in size) is undoubtedly considered a massive threat to living organisms across the globe in almost all ecosystems, i.e., aquatic and terrestrial ecosystems. These microplastic particles are transferred across food chains and food webs through inhalation or ingestion by organisms. Various persistent organic pollutants and metals are known to absorb on microplastic surfaces. Insects, being the most abundant life form on the earth, are major drivers of ecosystem services. Their immense contribution to ecosystem stability, sustainability, and resilience has been acclaimed in the literature. Plastic pollution and insect interactions have been reported consistently in the last two decades globally from both aquatic and terrestrial ecosystems. Many insect groups chew and ingest plastic films including PP, PE, and PVC. Plodia interpunctella and Tenebrio molitor larvae are known to ingest and degrade polyethylene and Styrofoam, respectively. Insect pollinators transport microplastic particles to flowers, hence interfering with the pollination process. Termites and ants are known to transport microplastics in the soil. These microplastics are being ingested by insects, and vertebrate predators of insects transfer the toxic chemicals to higher trophic levels. Microplastics affect biota adversely by disturbing metabolism, reducing survival by impairing growth and development, and declining reproduction potential. This may affect endocrinal activity by interfering with hormones. Many plastic fragments can mimic hormones, which can potentially disrupt the ecological roles of many insects. In terrestrial ecosystems, microplastics can potentially interfere with the natural biocontrol of insect pests by hormonal dysregulation in the predator species, i.e., ladybird beetles, prolonging the duration of larval instars. Polyvinylchloride microplastics have been reported to negatively affect the emergence, weight, and development of Chironomus riparius. The exposure to microplastics also alters various behaviors, i.e., oviposition and foraging behavior in different species of insects.