Changing honey bee overwintering dynamics under warmer autumns and winters create new risks for pollination services.

Abstract Pollinators are critical for food and nutritional security and face multiple stresses including climate change. Climate change research has mostly overlooked managed pollinators (honey bees) – in spite of them playing an outsized role in providing pollination services for agriculture – and focused on feral pollinator species range shifts and altered plant-pollinator interactions that affect forage availability. Impacts of warmer autumn temperatures have also received limited focus, even though they can have subtle but important effects on plants and animals. We highlight that warmer autumns and winters in higher latitudes result in expanded geographic areas with conditions conducive for late-season honey bee flight. Utilizing honey bee colony population dynamics model simulations, we demonstrate that this late-season flight alters the overwintering colony age structure, skews the population towards older bees, leading to greater risks of colony failure. Management interventions such as overwintering colonies in cold storage facilities will likely become a critical tool to reduce honey bee colony losses. There are critical gaps in our current understanding of winter management strategies to improve the survival of overwintering colonies, and it is imperative that we bridge this gap to sustain honey bees and the beekeeping industry and ensure food and nutritional security.