Grooming bees help boost colony immunity

A honeybee grooms one of its nestmates. Photo by Rita Cervo/University of Florence
A honeybee grooms one of its nestmates. Photo by Rita Cervo/University of Florence

June 2 (UPI) -- New research suggests designated bee groomers, or allogroomers, are essential to the health of their colony.

Varroa mites and other ectoparasites, parasites that reside on the outside of a host's body, are a major threat to the health of honeybees and their colonies all over the world.


Fortunately, bees have allogroomers to keep them clean.

Allogroomers are worker bees that help remove bits of debris, including parasites and pathogens, from their peers. It's a dangerous job, but new research suggests allogroomers are equipped with especially powerful immune systems.

"Here, we found worker bees that specialize in allogrooming are highly connected within their colonies, and have developed stronger immune systems," Alessandro Cini, researcher at the University College London, said in a news release. "We suspect that if more bees engaged in these allogrooming behaviors that ward off parasites, the colony as a whole could have greater immunity."

For the study, scientists monitored the activity of workers in western honeybee hives. The western honeybee is the world's most common honeybee. Researchers identified and tested the immune systems of allogroomers and non-grooming workers.

Tests showed the hemolymph of bees that regularly groomed their peers was better able to clear pathogens. Hemolymph is like blood for insects.


"By identifying a striking difference in the immune systems of the allogrooming bees, which are involved in tasks important to colony-wide immunity from pathogens, we have found a link between individual and social immunity," said researcher Rita Cervo, scientist at the University of Florence.

The new research -- published Tuesday in the journal Scientific Reports -- suggests efforts to encourage allogrooming behavior inside hives could help protect bees from parasites like the Varroa mite.

By tracking the movements and interactions of grooming bees, researchers determined that allogroomers are the most socially connected bees in the colony.

But their specialty is relatively weak, as allogroomers spend equal amounts of time on other tasks. The research suggests not all bees are hyper-specialized, and that some amount of physiological plasticity is innate in worker bees.

Scientists aren't yet sure why some workers engage in grooming behavior and others don't, nor can researchers say how allogroomers know when their peers need cleaning. Per usual, more research is necessary.

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