How Can Bees Tell Friend From Foe?
AILSA CHANG, HOST:
In the late summer to early autumn, leaves fall, flowers wilt, and it becomes harder for bees to harvest nectar, which they use to make honey. So some turn to thievery.
CASSONDRA VERNIER: Bees will go to other colonies and go into the colony and steal honey.
ARI SHAPIRO, HOST:
That's Cassondra Vernier of the University of Illinois. She says honey robbing can be pretty devastating. Once a bee finds a colony packed with honey, it goes back to its own colony, tells its friends where it found the sweets, and then...
VERNIER: Large numbers of bees will go to that other colony and will basically rip it apart.
CHANG: But honey bees do have a defense against that sort of thing - guard bees, sort of like bouncers for the hive who inspect intruders and bite or attack them if they do not belong.
SHAPIRO: So how do the guards know friend from foe? Well, one way is through what you might call a bee's BO, as in body odor.
CHANG: Specifically, pheromones in the form of waxy compounds on the surface of each bee. Until recently, that unique chemical signature was thought to be influenced by a colony's shared genetics.
VERNIER: However, people were finding that you could basically take bees from one colony, put them into a different colony when they're babies, and they'll just be accepted.
SHAPIRO: Now, Vernier and her colleagues have found that the bees' pheromones are influenced in part by the menagerie of microbes that live inside them, rather than their genes, which would explain how transplanted baby bees could fit in.
CHANG: You see, bees pick up their microbes through food and contact with other bees. And those microbes, in turn, influence the makeup of those waxy compounds that create a bee's unique BO. The details are in the journal Science Advances.
SHAPIRO: So bees gain this form of communication from their inhabitants. But what's in it for the microbes?
VERNIER: It would limit the other bees coming into the colony and basically bringing different microbes.
SHAPIRO: Meaning less competition for microbes that already live in the hive.
CHANG: Microbes' relationships with their hosts are still barely understood, and Vernier says this research points to their importance in other species as well, like humans.
VERNIER: The role that microbes play in human physiology and functioning is astounding. Specifically, there have been studies that show that the microbiome plays roles in depression, anxiety, social behaviors, including the way that humans interact with one another.
SHAPIRO: And, of course, we can't forget the role microbes play in our own human scent. Transcript provided by NPR, Copyright NPR.