Pesticides but not microplastics affect pollination in rape seed production in China

Abstract Humanity depends on agriculture for food, fiber and energy provisioning, but input-intensive agricultural production is impacting ecosystem services such as pollination. Pollution effects from neonicotinoid insecticides on pollinators receive much attention, but nothing is known on the synergistic effects with emerging plastic contaminants and the mitigation potential of agricultural diversification. Here, we conduct the first full-factorial mesocosm study to understand two-generation effects of diversified floral resources (diversification treatment), and neonicotinoid and microplastic pollution (pollution treatments) on Osmia cornifrons bees in 72 mesocosms. In a three-year experiment, we found that diversification can mitigate negative neonicotinoid effects. We did not find any individual or synergistic effects of realistic exposure levels of microplastic on reproductive performance of solitary bees. None of our treatments detectably affected rapeseed yield. Diversified flower resources in Chinese agricultural landscapes to mitigate pesticide pollution effects on pollinators is an important policy argument for pollinator protection with downstream implications for food security.