Yellow-legged hornets (Vespa velutina) generally hover outside the hive and select off returning forager bees. When threatened by yellow-legged hornets, the bees gave off more hisses and stop signals. The bees produced less of these signals than when huge hornets were present. The bees collected at the hive entryway and performed group shaking displays at yellow-legged hornets but not for giant hornets.
” Our research study shows how astonishingly complicated signals produced by Asian hive bees can be,” stated Otis.
Asian hive bees (Apis cerana) offer particular “calls” in reaction to huge hornets, their worst predator. Credit: University of Guelph
Study is the first to reveal that invertebrates use varying signals in response to various species of predators.
Like triggering alarms in a beehive, Asian honeybees use complex signals to alert nest mates about huge hornet attacks, according to a new study co-led by University of Guelph scientists.
The study reveals that honeybees respond and acknowledge to various kinds of hornets using a number of signals, a sort of alert system that is much better known amongst social mammals and birds, said Dr. Gard Otis, professor emeritus in the School of Environmental Sciences within U of Gs Ontario Agricultural College.
The study in Royal Society Open Science by a team of North American and Vietnamese researchers reveals that Asian hive bees (Apis cerana) offer specific “calls” in response to giant hornets, their worst predator.
The two primary hornet predators of honeybees in Vietnam, where Otis has run long-time fieldwork, have really different bee-hunting techniques.
Yellow-legged hornets (Vespa velutina) typically hover outside the hive and choose off returning forager bees. Giant hornets (Vespa soror in Vietnam) present a greater hazard. After discovering a colony of bees or other social wasps, they recruit their nestmates to massacre a number of the adults. The hornets then occupy the nest and harvest the pupae and grubs to feed their own developing larvae.
The researchers discovered that bees use a number of noises to rapidly spread an alarm message throughout the nest about nearby hornet predators.
Dr. Gard Otis, teacher emeritus in the University of Guelphs School of Environmental Sciences, helped discover how intricate signals produced by Asian hive bees can be. Credit: University of Guelph
” We stumbled into these sounds by mishap,” stated Otis, who was studying another element of Asian bees with a research group consisting of Dr. Heather Mattila, a U of G grad who is now a professor at Wellesley College in Massachusetts.
During fieldwork, they heard abnormally loud noises coming from a hive that had actually simply been gone to by a huge hornet. “I actually might not think what I was hearing,” stated Otis.” I could hear the bees from a meter away.”
From recordings taken inside hives during hornet sees, the group spotted different noises. However they required a method to digitally make and separate sense of the noises.
Using a computer program established for identifying bird hire recordings, Wellesley trainee Hannah Kernen aimed to separate individual bee signals. She and Mattila, in addition to other Wellesley trainees, eventually isolated more than 29,000 bee signals from the recordings.
” The process itself was quite tough sometimes,” stated Kernen. “For each recording, we had to mark out specific signals by hand, and we reviewed recordings several times to verify them.”
” These signals are striking and have acoustic homes that are developed to get the attention of nest members, much like the noises that are shared amongst alarmed groups of birds and mammals,” stated Mattila. “For human observers eavesdropping on the bees, their sounds convey a sense of seriousness that feels somewhat universal.”
This is the very first time that invertebrates have been shown to use differing signals in response to different types of predators. Earlier research revealed that social mammals, including vervet monkeys, ground squirrels and marmots, and some birds release distinct calls to various kinds of predators.
Honeybees communicate extensively through vibrations transmitted in their combs within the nest. Much less typically, they interact through air-borne noises. It is uncertain how bees transmitted “vibroacoustic signals” to their nestmates in this study.
Asian hive bees were already understood to produce numerous vibroacoustic signals, including “hisses” and “stop signals.” The team discovered that both signals are produced regularly in reaction to hornets.
When giant hornets were outside the hive, nevertheless, the bees likewise produced previously unrecognized signals with abrupt shifts in frequency– called “antipredator pipelines” by the scientists. Antipredator pipelines share qualities of alarm squeals, fear screams, and panic calls of birds, primates, and meerkats.
The scientists captured video of a number of bees making antipredator signals as they ran over the fronts of hives, rapidly vibrating their wings and exposing a gland as they piped. Those habits recommend that antipredator pipers were likewise notifying their nestmates with numerous types of signals, stated Otis.
When threatened by yellow-legged hornets, the bees released more hisses and stop signals. The bees produced fewer of these signals than when huge hornets were present. The bees collected at the hive entryway and carried out group shaking screens at yellow-legged hornets but not for huge hornets.
” Our research study demonstrates how incredibly complex signals produced by Asian hive bees can be,” stated Otis. “We feel like we have actually just grazed the surface of understanding their interactions. Theres a lot more to be gathered.”
For more on this research study, see Hear a giant and see “Murder” Hornet Attack on a Beehive.
Recommendation: “Giant hornet (Vespa soror) attacks set off mad antipredator signalling in honey bee (Apis 2 cerana) nests” by Heather R. Mattila, Hannah G. Kernen, Gard W. Otis, Lien T. P. Nguyen, Hanh D. Pham, Olivia M. Knight and Ngoc T. Phan, 9 November 2021, Royal Society Open Science.DOI: 10.1098/ rsos.211215.
This research study was funded by the National Geographic Society Committee for Research and Exploration.