Watch bees defend their nest by slapping ants with their wings

With a flick of the wing, Japanese honeybees slap away ants that try to infiltrate their hive.

Ants often invade honeybee nests, seeking to steal honey, prey on eggs or kill worker bees. In defence, bees have been known to fan their wings to blow ants away. Now, researchers have documented making contact with their wings and physically batting ants out of the hive, a behaviour that hasn’t been studied before.

Footage from a high-speed camera shows that guard bees, positioned near a nest’s entrance, tilt their bodies towards approaching ants and flutter their wings while pivoting away. A successful hit sends the ant flying.

Many beekeepers seem unaware of this strategy, says Yoshiko Sakamoto. “I myself did not notice this behavior during my approximately 10 years of beekeeping experience,” she says.

Sakamoto, Yugo Seko and Kiyohito Morii, all at the National Institute for Environmental Studies in Tsukuba, Japan, introduced three local species of ants to the entrance of two Japanese honeybee (Apis cerana japonica) colonies and filmed hundreds of showdowns between the insects.

In most of these interactions, the bees smacked at ants with their wings. But the defence didn’t always work. For Japanese queenless ants (Pristomyrmex punctatus) and Japanese pavement ants (Tetramorium tsushimae), about half to one-third of attempts flung ants away. Wing-slapping was far less successful against Japanese wood ants (Formica japonica), a larger and faster species.

Ants vary in their level of menace to bees: some species bite or kill workers, while others are less of a threat. Bees may have evolved to favour the fanning defence to avoid making contact with the more dangerous ants, but wing-slapping may be a more efficient option against other species, the researchers suggest.

They hope to investigate this idea by mapping bee responses against ant aggression. The team also plans to study how bees’ interactions with ants change over time and whether they improve at wing-slapping with more experience. “These defensive behaviours still hold many mysteries,” says Morii.