Honey bees (Apis cerana) use animal feces as a tool to defend colonies against group attack by giant hornets (Vespa soror) (2020) Mattila et al., PLoS One. https://doi.org/10.1371/journal.pone.0242668
Honey bees are one of the most familiar sights in the natural world. Even for those who know nothing about insects, many will be well acquainted with those small, black and yellow striped bugs that fly from flower to flower. Most people also know that bees live in hives, but what you may not know is that these hives make honey bees the target for many predators and opportunistic parasites. A large group of animals living together in one spot is like an all you can eat buffet for a wide variety of species that have evolved to exploit just such a collection of resources. One of the bee’s most notorious enemies is the giant hornet, an insect that has become rather famous in my home country due to its recent invasion. These large, well-armored predators not only pick off bees one-by-one, but groups of them can slaughter an entire hive of bees within a matter of hours.
The fun thing about evolution though is that when you have enemies evolve to exploit a hive, the hive has to evolve its own defenses against the enemies, otherwise they go extinct. Honey bees are known to gather into a “heat ball” (see Did You Know), but they have also been seen smearing plant matter around their nest entrances, possibly as a way of confusing the chemical-sensing ability of the giant hornets. Though researchers have seen unknown material smeared on the entrance of hives, beekeepers have reported that this material was in fact animal feces that the bees had collected. Today’s authors wanted to study if these honey bee (Apis cerana) were in fact using animal feces as one of their defenses against a formidable, but under-studied giant hornet predator, Vespa soror.Read more