Asian honeybees have an impressive array of tactics to protect their hives: hypnotic shimmering waves to warn off predatory hornets; protective balls to roast intruders alive with their body heat; and of course the once in a lifetime use of a stinger.
Add another weapon to the bee’s arsenal: wings. Scientists in Japan have learned that Asian guard honeybees use their wings to swat pesky ants for the next week. A slow-motion video published alongside a study in the journal Ecology last week shows what happens when ants try to sneak through a hive entrance: The guard bee moves toward the ant like a tennis player making a bad backhand, then hits with an ant’s wing flaps so hard that it flips through the air as it falls to the ground.
Wing flapping appears to be a low-energy way for Asian honeybees to get petty thieves to pack in, researchers say — while Japanese ants don’t often kill honeybees, they can drain the nest’s food reserves and devour the bees’ protein-rich eggs.
To see how the strategy worked, a team of researchers from Japan’s National Environmental Research Institute trained slow-motion cameras on guard bees as they encountered different types of ants invading their hive.
The replications revealed that the bees’ wing beats caused the smaller ant species to float about half the time. When the wing beat doesn’t connect, the ants will occasionally try to bite the guard bee, but usually “just freeze,” said Kiyohito Morii, a study author and behavioral ecologist at the Japanese institute. The flapping of the wings may be too fast for the ant to even feel it, added Yoshiko Sakamoto, another study author and a senior researcher at the same institution.
Larger ants present more of a challenge, but honey bee keepers occasionally get a lick. About one in 10 wing beats successfully dislodged Japanese wood ants, which are about the same size as bees and significantly more agile than smaller ants.
Wing flapping appears to require less effort than other, more energy-intensive bee jitsu movements, such as wing flapping, in which the bee flaps its wings to blow away the ant without touching it, the researchers say. This matters because fending off a flood of invading ants can become a grueling game of Whac-a-Mole as the ants wear down the bees’ defenses in large numbers.
Wing-beating is only an option, they add, because the ants in Japan are not well-suited for mandible-to-mandible combat — direct contact with the ants is not dangerous to the bees. But it is likely to be less successful against more aggressive invasive species like the large ant that it is known to kill and consume healthy worker bees.
Asian honey bees, a species distinct from those found in Europe and North America, are important crop pollinators. One benefit of the research is that studying their defense techniques can help scientists understand how they will stand up to invasive species and other emerging threats.
“People always pay attention to how bees survive and thrive,” said Heather Mattilla, a professor at Wellesley College who studies the behavior of Asian bees and was not involved in the study. “We need to figure out how we can help them because they do so much for us.”
But why do European bees not seem to know how to flap their wings? “Asian bees have evolved in an area of the world where they are under some of the worst insect predation pressure on the planet,” says Dr Mattila.
That means they had to get… creative.
In 2020, Dr. Mattila and her team discovered that Asian honey bee hives sometimes build a dirt fence around the entrance of their nests with animal feces. Researchers believe that the smell of this perimeter of feces may repel attacks on their nests by predatory insects, such as so-called killer hornets.
Dr. Morii says they saw the Asian honey bees in their research using a variation of this defensive tactic—but this time, instead of animal feces, they used the body parts of other, as-yet-unidentified insects as a horribly unwanted bedding.
“Asian honey bees are extremely resourceful, and after hundreds of years we are still discovering new ways in which they protect themselves,” said Dr Mattila. “You just can’t count them.”
