Honeybees in East Asia are regularly subjected to giant hornet attacks, which range from individual attacks on lone bees or entire swarms entering hives, beheading bees, and then feasting slowly on the larvae that remain. As such, various protection mechanisms against them have been developed by the bees under attack.
For example, Japanese honeybees retaliate by creating hot “bee-balls”, in which they surround isolated hornets and quiver their muscles. The heat generated by this collective movement is enough to fry the hornet in question.
Recently, however, the actions of Vietnamese honeybees have sparked surprise from the scientific community. In an unprecedented move, these honeybees are resorting to “tools” to counter hornet attacks, the tool being animal dung. These honeybees coat their hives with chicken and cow dung to stave off giant hornet – Vespa soror – attacks.
Heather Matilla, an entomologist at Wellesley College, Massachusetts, and co-author of the study that shed light on this fascinating development, says it is the first recorded usage of a tool by honeybees to prevent attacks. However, what exactly about dung-coated hives wards off giant hornets is not clear yet. Suggestions include the smell itself makes hornets want to avoid it, as well as the thought of biting through a dung-coated hive – which is the usual way employed by hornets to create openings wide enough to enter hives.
Another possible deterrent can be the feces acting as a camouflage, suggests Lars Chittka, who studies bee behavior and perception at QMU, London. Since hives usually smell sweet and of honey, a dung-coated hive could not possibly be the same.The implications of honeybees employing tools to deter hornets are huge. Vesper mandarinia, commonly known as murder hornet, has been doing rounds in the news since late 2019 after arriving on the Pacific Northwest. If hornets can indeed be chased off by animal feces and similar tools, it will open pathways for researchers to prevent V. mandarinia from establishing itself in the US. This will be a much-needed development as, unlike their Asian counterparts, American bees do not have any methods of staving off hornet attacks.
Understanding this development is also necessary to understand the possible hygiene and health related side-effects dung-coated hives pose.
The study was published in December in the journal PLOS ONE.