Heather Mattila stood in the middle of a chicken coop at the rural Ba Trai Commune 60 miles west of Hanoi, Vietnam, watching to see if the Asian honey bees (Apis cerana) she was researching would indeed forage for animal feces, as a local beekeeper had previously mentioned to a member of her research team.
Seven years later, Mattila, associate professor of biological sciences at Wellesley, and an international team of researchers are now the first scientists to document that honey bees forage for animal dung and then use it as a tool—a chemical weapon of sorts—to defend their hives from giant hornet (Vespa soror) attacks.
“Not only have we documented the first example of tool use by honey bees in nature,” Mattila said, “but the act of foraging for feces itself is another documented first for honey bees.” Honey bees routinely forage for materials produced by plants (such as nectar, pollen, and resin), but have not been known previously to collect solid materials from any other source. They occasionally collect fluids from animal waste, which can provide them with needed salts, but this is the first time they have been seen collecting solid pieces of dung, carrying it home with their mouthparts, and applying it to the entrance of their nests (called “fecal spotting”).
“We documented that hornets were less likely to land on entrances or chew their way into hives when there were more fecal spots around entrances,” Mattila said of their findings, which were recently published in the journal PLOS ONE, and covered in The New York Times and The Guardian. “While further research is needed to determine exactly what properties of animal feces repel the hornets, the barrier the bees create is an effective defense against their attacks.”