A University of Regensburg study in the Swiss mountains shows that warmer winters and increased winter rainfall are causing new bumblebee queens to emerge prematurely from hibernation, draining their energy before flowers bloom. Published in the Journal of Animal Ecology, the research warns that temperature and precipitation together reduce queens' chances of founding healthy colonies. Because bumblebees are vital pollinators linked to about one-third of global food production, disrupted winter rhythms could have wider ecological and agricultural impacts. Researchers recommend planting flower-rich, native habitats and creating continuous urban and roadside floral corridors to help queens survive.
Warmer Winters Are Waking Bumblebee Queens Early — Threatening Pollination and Food Security
A University of Regensburg study in the Swiss mountains shows that warmer winters and increased winter rainfall are causing new bumblebee queens to emerge prematurely from hibernation, draining their energy before flowers bloom. Published in the Journal of Animal Ecology, the research warns that temperature and precipitation together reduce queens' chances of founding healthy colonies. Because bumblebees are vital pollinators linked to about one-third of global food production, disrupted winter rhythms could have wider ecological and agricultural impacts. Researchers recommend planting flower-rich, native habitats and creating continuous urban and roadside floral corridors to help queens survive.
07:02 AM, 11/12/2025Environment
Warmer winters are disrupting bumblebee queens' natural rhythms
Warmer winters — not just hotter summers — are an increasingly visible consequence of climate change, and new research shows they may harm key pollinators. A team from the University of Regensburg studied newly produced bumblebee queens in the Swiss mountains and found that rising winter temperatures can trigger premature emergence from hibernation.
These queens normally remain dormant until spring, conserving energy until flowers become available. If they wake early because winters are warmer, they can exhaust their stored energy at a time when floral resources are scarce. That reduces their chances of successfully founding and provisioning a colony.
The study, published in the Journal of Animal Ecology, also found that increased winter rainfall and more frequent extreme weather events further worsen the problem by reducing foraging opportunities during these false starts.
"It is worrying," said co-author Dr. Ruth Archer. "Our results show that various climatic factors — especially temperature and precipitation — in combination significantly impair the living conditions of bumblebee queens."
Protecting bumblebees' winter dormancy matters because these insects are vital pollinators. Bumblebees contribute to the pollination of many crops and wild plants and are linked to roughly one-third of the food people eat, according to the U.S. Department of Agriculture. Disruptions to their seasonal rhythms can ripple through ecosystems and agriculture, affecting biodiversity and food production.
Practical steps to help
The researchers recommend simple, scalable actions to support queens through vulnerable periods: planting flower-rich gardens that bloom early and late in the season; creating continuous flowering corridors in urban and roadside green spaces; prioritizing native plant species; reducing pesticide use; and preserving sheltered, undisturbed nesting sites.
"If we ensure that bumblebees find sufficient flowers during crucial phases of their development, we can protect them from the worst effects of climate change," said co-author Professor Lena Wilfert.
Community efforts — from backyard gardeners to city planners — can make a measurable difference. Small changes in planting and habitat management can help buffer bumblebee queens against climate-driven mismatches between their life cycles and the availability of food.