When Murder Hornets Attack, Bees Start Heartbreaking 'Shrieks' to Warn The Colony

Bees are capable of doing much more than buzzing. A new study found that Asian honeybees (Apis Cerana) can react to a deadly'murder hornet' by using a variety of warning signals.
These signals are so complex that researchers have compared them with the alarm shrieks and fear screams of birds and primates.

Some bee sounds, also known as "antipredator pipes", have not been recorded before in this species. They seem to only occur when a particularly dangerous predator is present.

The Asian hornet, V. velutina, and the especially large hornet V. soror fit the bill. These predators, closely related to the recently discovered'murderhornets' in North America, often attack bee colonies and may even kill the entire colony.

The colony can't lose if a scouting or just its scent is detected close to the hive.

Researchers discovered that the presence of predatory beets was detected by worker bees at the entrance to the hive. They strung together their antipredator pipes into "longer, more insistent messages, analogous in how individual clangs on a bell contributes to a sustained fire alarm."

Technically speaking, these alarm bells can be described as vibroacoustic signals. They are short pulses of vibration and sound frequencies that are produced by the wings and thorax of a honeybee.

Even when there's no threat, Asian honeybees will 'buzz' even when there's not one. They may be 'hissing together or head-butting each other with vibrational pulses, although we don't know what they mean.

The current research, which collected nearly 30,000 recordings of honeybee signals, shows that when a murderhornet appears, the usual hissing, head-butting, and head-butting increase seven-fold.

Gleichzeitig, worker bees start making antipredatory pipe, which is more harsh and irregular in frequency.

Video footage shows the bees making this antipredatory signal, which is shown by them raising their abdomens and buzzing their wings while racing "frantically".

Sometimes, worker bees may react to the signals by spreading animal dung around the hive to repel predators, or trying to form a ball with other bees around scouting beets to heat it to death.

Although it's not clear if antipredatory pipes contain messages about these defensive actions, the large number of recordings suggests that bee pipes serve as a "rallying cry for collective defense".

The authors state that these sophisticated defenses require prompt predator detection and rapid activation of a defending force.

Because they can be transmitted quickly within nests between senders, receivers and senders, vibroacoustic signal likely plays an important role in organizing these replies."

Researchers found that smaller hornet species, which hunt alone, caused less chaos in honeybee colonies than a swarming of huge murder hornets. The anti-predatory pipes were also initiated less often. This call could be a special one for murder hornets.

Gard Otis, a behavioral ecologist at the University of Guelph, Canada says that this research "shows how complex signals produced Asian hivebees can be."

"We feel that we have only scratched the surface of their communication. There is so much more to learn.

Royal Society Open Science published the study.