Male honeybees, also known as drones, are the most susceptible, said Alison McAfee, a postdoctoral research fellow at the University of British Columbia.

Alison McAfee is a postdoctoral research fellow with the University of British Columbia, studying how heat affects honeybees and their fertility. (Leslie Kennah/Michael Smith Lab)

She said her research has found half of drones die from heat stress after being exposed to temperatures of 42 C for six hours. While outdoor temperatures have so far not exceeded 35 C in Calgary, according to Environment and Climate Change Canada, McAfee said temperatures inside the hive can be much warmer.

In the short-term, intense heat affects how bees behave and produce honey, McAfee said.

Normally, honeybees focus their efforts on foraging for nectar and pollen to support their colony, but when temperatures heat up, they have to divert their efforts to cooling off.

“Some of those foragers then need to change tactics and actually forage for water instead,” said McAfee. “They’re still foraging, but they’re not pollinating when they’re foraging for water.”