untitled design

Bees sound alert to defend against killer wasp attack

When a herd of giant wasps attacks a bee hive, the kill is brutal and swift.

The group descends en masse after a scout identifies the target hive, killing the defending adult bees, occupying their nest and harvesting the bees’ brood to feed their own young. Wasps can decimate a hive within hours.

But bees are not entirely defenseless against the killer wasps, native to Asia, but which first appeared in the United States in 2019.

Insects have their own survival strategies, including a unique and frenzied warning signal that encourages defensive movements, documented by scientists for the first time.

“I feel a strong reaction when I hear the alert because it’s clear that the bees are agitated,” said Heather Mattila, a professor in the biological sciences department at Wellesley College, who was part of the team that identified the sound.

She described the signal, known as “anti-predator alert”, as harsh and noisy, with different durations and tones similar to the screams and panic calls used by mammals such as primates and meerkats when they are afraid.

“They have different durations, but bees emit many of them over and over, longer. They change the tone a lot too, and irregularly, which makes them stand out.”

She said the sound seems to be used by Asian bees (Apis cerana) only when giant wasps attacked the colonies studied by the team. The research was published in the Royal Society Open Science magazine this Tuesday (9).

“Our study showed that bees wouldn’t make the sound if there were no wasps. It was done very rarely in response to smaller wasps, a little more often if the bees smelled giant wasps, and they did it much more when a giant wasp was directly outside their nest,” said Mattila.

“We haven’t tested all the predatory scenarios Asian bees can encounter, but this is good evidence that a true wasp attack is needed to trigger this response.”

The signal is used to trigger some of the defense mechanisms that bees have in their arsenal. This includes strategies such as using manure at your colony’s entrances to repel and confuse wasps and swarming to neutralize the enemy.

The latter wraps hundreds of bees around a wasp in seconds, squeezing it and restricting its ability to breathe. Bees raise their body temperature to a level lethal to wasps, Mattila explained.

“They act like an overheated collective boa constrictor,” she said.

The giant Asian wasp was first seen in the US in Washington state in 2019. How it arrived from native Asia is unclear – but it is possible that it arrived with international ships. Three wasp nests were found in Washington state in 2021.

Unlike Asian bees, western bees (Apis mellifera) have not developed any strategy to ward off giant wasps.

“American bees do not have the historical experience of developing defenses against giant wasps. We don’t expect the same sounds that Asian bees make, and they don’t execute many of the other important strategies either,” Mattila said.

Reference: CNN Brasil

You may also like

Get the latest

Stay Informed: Get the Latest Updates and Insights

 

Most popular