Combined exposure to microplastics and heat changes behavior, colony development, and social networks in pollinators (Bombus terrestris)

Abstract Pollinators play a critical role in terrestrial ecosystems and for food security, but their populations are declining from multiple stressors including pollution and climate change. The effects of plastic pollution alone or in interaction with climate change remain largely unexplored. Here, we use computer-vision monitoring to investigate microplastic exposure effects on pollinators at individual, colony and network level in combination with heating to simulate climate warming. In a one-generation trial with 30 bumblebee ( Bombus terrestris ) colonies, we kept colonies under optimal (25 °C) or heated condition (30°C), and fed them with pollen and sucrose solution containing no, low, or high polyethylene concentrations (respectively 0, 10, or 100 mg/L 30μm beads). We find individual and combined effects of microplastic exposure and heat stress on bumblebees across levels, including stimulating individual activity, altering labor division, impairing colony development, and influencing social interactions. These findings show that plastic pollution under a changing climate has significant implications for pollinator behavior and colony development. Future research urgently needs to target the interactions of plastic pollution with other pollinator decline stressors and assess the potential implications for food security.