In the World of Bees, It Pays to Be Tidy

For honey bees, good hygiene can mean the difference between life and death.

Agricultural Research Service scientists have discovered that honey bees genetically resistant to minute, parasitic mites are almost obsessive when it comes to grooming themselves. These busy bees use their legs to brush off tracheal mites that could otherwise invade their airways and choke them.

Bee researchers Robert Danka and Jose Villa at the agency’s Honey Bee Breeding, Genetics and Physiology Research Unit at Baton Rouge, La., wanted to see how this grooming behavior varies from bee to bee--specifically, how resistant bees’ hygiene habits differ from those of susceptible bees.

To gauge this, Danka and Villa placed tracheal mites directly onto individual bees from each of the two groups. Because the mites are so tiny, the scientists rigged a miniature brush to transfer them: an eyelash mounted to a small, three-inch stick.

Grooming is an important line of defense for honey bees since tracheal mites are most vulnerable when they’re crawling around on the insect, outside of its airways.

After transferring the mites, the researchers watched to see how long it took for the bees to brush them off.

Their findings? Resistant bees groomed more than susceptible bees. They also groomed more often on whichever side of their bodies the mites were placed, suggesting that resistant bees could simply be more sensitive to the parasites’ presence.

But when counting the number of mites actually knocked off by the bees within just a few minutes, the researchers found that the resistant bees’ persistent grooming didn’t always lead to a significant number of mites removed.

The scientists emphasize that their study was just a brief look into young bees’ grooming habits. In a real colony, honey bees are continuously challenged by tracheal mites throughout their lives, so more aggressive grooming would seem to pay off over time.

Read more about this research in the December issue of Agricultural Research magazine.

ARS is theU.S. Department of Agriculture’s chief scientific research agency.