Scientists Discover How Bees Keep Their Cool Even in the Heat

It's hot outside and for some insects, it's essential to keep cool. This is especially true of honeybees, which are highly sensitive to temperature when they're developing. Now, researchers have found exactly how honeybees manage to keep their cool.

Previous research has shown that worker bees can actually control the thermostat essential to the hive's survival. Young bees develop within wax cells, and for healthy development the young bees must be maintained between 89.6 degrees Fahrenheit and 95 degrees Fahrenheit. In contrast, adults can withstand temperatures as high as 122 degrees.

That's where the workers come in. Scientists have found that worker bees create heat by contracting their thoracic muscles, similar to shivering in mammals. When it's hot, the bees fan the comb, spread fluid to induce evaporative cooling or absorb heat by pressing themselves against the brood nest well. Yet scientists have long wondered how the bees got rid of the heat after they absorbed it.

The researchers collected data on seven active honeybee hives that were framed by clear Plexiglas walls. Each colony consisted of 1,000 to 2,500 bees. The scientists used a theater light to raise the internal temperature of the hives by 15 minutes and then used temperature probes to record internal temperature.

It turns out that immediately following the heating, the bees pressed their bodies against the heated surfaces near broods. Then, the bees moved to previously cooler areas of the hive in order to release the excess heat.

"Moving heat from hot to cool areas is reminiscent of the bioheat transfer via the cardiovascular system of mammals," said Philip Starks, one of the researchers, in a news release.

The findings reveal a bit more about how honeybees manage to keep cool. This, in turn, could be important for understanding the conditions under which hives can thrive.

The findings are published in the journal Naturwissenschaften.