More frequent heatwaves mean bees are unable to thermoregulate their hives – further endangering a species already in decline

Bumblebee nests may be overheating, killing off broods and placing one of the Earth’s critical pollinators in decline as temperatures rise, new research has found.

Around the world, many species of Bombus, or bumblebee, have suffered population declines due to global heating, the research said. Bumblebee colonies are known for their ability to thermoregulate: in hot conditions, worker bees gather to beat their wings and fan the hive, cooling it down. But as the climate crisis pushes average temperatures up and generates heatwaves, bumblebees will struggle to keep their homes habitable.

Most bumblebee broods would not survive at temperatures above 36C, the paper, published in Frontiers in Bee Science, concluded. The research team reviewed 180 years of literature, and found that for all bumblebee species studied the optimum temperature range for incubating nests was between 28C and 32C.

Peter Kevan, the lead author of the study, told the Guardian: “If [bumblebees] can’t keep temperatures below what is probably a lethal limit of about 35C, when the brood may die, that could explain why we are losing so many bumblebees around the world, especially in North America and Europe.”