I scream. You shout. The bees also scream

Bees do not cry with their mouths but with their bodies. When giant hornets approach and threaten their colony, Asian bees raise their abdomen in the air and run, vibrating their wings. The noise may sound strangely like a human scream.

In an article published Wednesday in the newspaper Royal Society Open Science, the researchers describe the Asian bee’s unique acoustic signal, called the anti-predator pipe. Researchers colloquially call it a “bee cry”.

“It’s like a scream,” said Hongmei Li-Byarlay, an entomologist at Central State University in Ohio, who was not involved in the new research. Li-Byarlay added that his colleagues who observed the sounds compared the noise to “crying”.

Bees make this noise because their nests are threatened by Vespa soror hornet, which hunts in packs and can dispatch a hive in a few hours.

Heather Mattila, a behavioral ecologist at Wellesley College in Massachusetts and author of the study, first heard the cry of bees in Vietnam in 2013. She was studying how Asian bees coat animal feces around their nests to keep them away. V. soror and Vespa mandarinia, better known as the murderous hornet. The behavior showed the bees’ highly evolved social organization, said Lien Thi Phuong Nguyen, wasp researcher at the Vietnam Academy of Science and Technology in Hanoi and author of the new article.

Mattila noticed that the beehives exploded loudly when V. soror the hornets approached. When she planted a recorder at the entrance to a beehive lined with hornets, she heard a cacophony of noise.

Although she recognizes certain sounds bees are known to make – hissing, beeping, and piping – Mattila, who has studied European bees for 24 years, had never heard anything as loud and frantic as that -this.

Researchers placed recorders inside the beehives and video cameras outside the entrances to record the soundscapes of the bees. The buzzes and sounds of hornet helicopters often drowned the bees, so they also recorded hives reacting to glossy paper with hornet pheromones.

Mattila brought the recordings back to the United States, where Hannah Kernen, now a research technician at the University of Louisiana at Lafayette, helped analyze the recordings.

As Kernen and Mattila pored over nearly 30 hours of bee noise, which contained around 25,000 instances of acoustic signaling, they were convinced they were listening to a new sound: a piercing alarm signal that shared traits with animal calls, including unpredictable frequencies and loud volumes. .

A still image from the video provided by Heather Matilla shows Vespa hornets threatening a bee hive. (Heather Mattila via The New York Times)

For months, researchers compared the video recordings inside the hive to those outside the entrance to see if they could isolate a moment when the new sound could be heard for the first time in the rooms. two videos and pinned to a single bee.

Mattila listened to these recordings for hours at night.

“I was having chills and was starting to worry about them, even though the recordings are from years ago and the bees have been dead a long time ago,” she said. “There is something very human and recognizable in the sounds. “

One day after 2:30 a.m., a sleepless Mattila finally saw a video that captured a cry and the bee behind: a restless worker bee approaching a hornet-scented paper. She lifted her abdomen and exposed her Nasonov gland, a thin white band on its back end that can release pheromones.

The researchers listened to the audio inside the hive from the same period and looked at spectrograms, visualizations of sound frequencies, which showed similar sounds occurring inside and outside the hive. This confirmed that the bees crying outside the hive made the same noises as the bees crying inside the hive.

“It was a eureka moment, and I only had a few,” Mattila said.

The researchers suggest that the noise from the anti-predator pipe works as an alarm signal, as the call production peaked when V. soror hornets hovered outside the entrance to the colony. The data are correlative, so the exact function of the cry is still unknown.

This article originally appeared in The New York Times.