Quirks & Quarks

Bees defend themselves from 'murder' hornets with animal poop

Honey bees in Vietnam paste animal poop around entrances to their hives as a tool to repel the predatory Asian giant hornet

Honey bees in Vietnam use dung as a repellent to defend against carnivorous giant hornets

This Asian honey bee has a mouthful of animal poop it is intending to use as a defence tool against the Asian giant hornet (Submitted by Heather Matilla)

Insects using animal dung as an insect repellent is an interesting phenomenon, but it also could be the first documented example of tool use by honey bees. 

The observations that led to this latest  scientific study began with a beekeeper in Vietnam who noticed his honey bees collecting water buffalo dung from the fields, returning to the colony, and pasting it around entrances to their hive. The beekeeper correctly assumed it had something to do with protecting the hive from the Asian giant hornet.

Asian giant hornets attacking a honey bee hive (Submitted by Gard Otis)

Scientists made aware of this, including Canadian researcher Heather Matilla, an associate professor of biological sciences at Wellesley College in Massachusetts,wanted to learn more.

The attack: hornets vs bees

Asian giant hornets are a similar species to the so-called 'murder hornets' recently identified on the west coast of North America. They attack honey bee hives, kill the bees then take them back to their own colonies to feed their workers. Bees are often forced to abandon their colonies when the hornets attack. 

When this happens, the hornets take over the hive, and remove the larvae to feed their offspring. But the hornets are less likely to attack at all if the honey bees surround the entrance to their colony with animal dung.

Heather Matilla stands in the middle of a chicken coop at the rural Ba Trai Commune west of Hanoi, Vietnam. She is watching to see if the honey bees will forage on chicken poop (Submitted by Heather Matilla)

The poop defence

Researchers aren't entirely sure what the dung does to discourage the predatory wasps. Matilla thinks it could simply be that hornets find dung unpleasant both in smell and texture. She also suggests that there might be plant toxins from semi-digested plants in the dung that are repellent.

Another possibility is that the dung is masking the smell of the bees, which the hornets target in order to find them. One more mystery is why and how the bees are not repelled by the dung themselves.

Asian honey bees using poop to defend their colony against Asian giant hornets. Heather Matilla, Wellesley College

 

 

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