If you’ve ever seen a dead bee lying on its back, with something white oozing out from its stomach, chances are it was a male bee and it had a rather embarrassing death.
When male bees die in extreme outdoor temperatures, their last act before dying is to ejaculate part of its abdomen, according to a new study from the University of British Columbia, Canada.
This is an instinctive and automatic behavior of male bees, said Dr Alison McAfee and postdoctoral fellow Michael Smith from the University of British Columbia. These bees really did”ejaculate to death“.
The behavior of male bees was first noticed by scientists in the summer of 2021. In the midst of that year’s heat wave, Armstrong’s honey beekeeper Emily Huxter emailed Dr. McAfee to tell her story. about dozens of her bees suddenly dying.
Attached were photos of their corpses scattered on the ground, with white matter on their bellies as if they had just exploded popcorn.
Dr McAfee then contacted a network of honey producers and beekeepers across British Columbia to ask if this was happening elsewhere. Turns out, it’s more common than she thought.
Normally, the inside of a honey bee hive is a stable environment maintained at around 35 degrees Celsius. The bees in British Columbia have probably weathered the first half of summer. But a heat wave eventually pushed them forward.”doomsday“.
“We know that it takes only six hours for the temperature to reach 42 degrees Celsius, half of the male bees will die from heat stress. The bees that are more sensitive to heat will even begin to die after two or three hours. It’s a temperature they shouldn’t be exposed to, but we’ve seen male bees suffer from heat stress to death there.“, said Dr. McAfee.
The younger the bee colonies, the larger the dead population. There are newly formed beehives that have died out to half of the male population.
Normally, researchers like Dr. McAfee don’t pay much attention to male bee deaths. They only care about queens if they die in the colony because each colony has only 1 queen bee.
But if the male bees die in mass, as during the heat waves in British Columbia, things get serious.
Dr McAfee said a decrease in the population of male bees in the colony means that the colony will be less genetically diverse. This can cause the immunity and disease resistance of the bees to decline, but vice versa, it accelerates gene degradation.
During the heatwave that Dr. McAfee monitored, she found that only 40% of queens’ matings were successful, compared with 75-80% in cooler weather.
It is not clear whether the male bees’ ejaculate before death is a last-ditch attempt to fulfill their responsibilities and show their loyalty to the queen. But Dr McAfee, says the behavior is quite extreme. These male bees have ejaculated to the point of popping their genitals out of their abdomens, making their corpses look like popcorn.
To prevent heat stroke and save the lives of male bees, Dr McAfee and beekeeper Emily Huxter at Armstrong tested several strategies. The goal is to cool the hive.
“In the wild, bees often find water to bring back to the hive, and then they use their propellers to blow steam inside to help cool down and cool by evaporation, just like when we sweat.Huxter said.
So she and Dr. McAfee set up cooling stations by diluting sugar syrup and placing them near the hive, so that the male bees carry liquid water back to the hive.
By experimenting with placing thermometers in the hive and monitoring them every 10 minutes, the researchers found that their syrup-cooling stations actually helped the hive lower by 1.1 degrees Celsius.