HOT BUZZ: Heat waves lead to unhappy ending for bees

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Last summer’s sweltering weather heat wave in British Columbia had male honeybees ejaculating themselves to death.

Emily Huxter, a rural beekeeper in Armstrong, noticed dozens of dead drones on the ground.

It was a bit of a phenomenon, so she emailed photos of her discovery to bee health expert Dr. Alison McAfee and was shocked by what was found.

“When drones die from shock, they spontaneously ejaculate,” McAfee, a postdoctoral fellow at UBC’s Michael Smith Laboratories, told Phys.org.

According to McAfee, other beekeepers also witnessed what Huxter came across, which is cause for concern for the survival of colonies.

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McAfee reviewed the photos from Huxter and realized how big an issue changes in the environment can be for drones, whether it’s exposure to pesticides, cold or, in this case, heat.

Bee researchers have studied heat stress and bee health before but the inside of a colony is thermoregulated, a stable environment that maintains a temperature of around 35C.

The bees Huxter stumbled upon were able to cope with warm weather but the heat wave was simply too much.

“We know that after six hours at 42 degrees, half of drones will die of heat stress,” said McAfee. “The more sensitive ones start to perish at two or three hours. That’s a temperature they shouldn’t normally experience, but we were seeing drones getting stressed to the point of death.”

The bees’ endings aren’t happy. When male workers die, they start convulsing, which causes their endophallus — a sexual organ the size of their own abdomen — to burst out of their bodies.

“It’s pretty extreme,” said McAfee.

As a result, many beekeepers saw half their “small starter colonies die off during the first heat wave,” she explained. “That’s a massive die-off and tells me we need to find better ways of protecting bees.”

McAfee and Huxter are working on finding “better ways of protecting bees” and have designed experiments to test insulate hives and protect the drones from future heat waves.

McAfee believes drones may be even better indicators of environmental changes than queen bees.

“Drones have the advantage that they are very sensitive and easy to see,” she explained. “If drones are dying, it’s much easier to study them than to take a queen from a colony to perform tests. It’s also more conducive to citizen science efforts.”