Bees 'Shout' Instead of 'Whisper' to Avoid Eavesdroppers

Deterring outside competition is an important part of survival in the animal kingdom. In fact, some species have developed "whispers" in order to communicate the location of a prized food source to nestmates while keeping it hidden from outside competitors. Now, though, researchers have found that some species of bees in Brazil do the exact opposite; they "shout" when it comes to their food-recruitment signals.

"Our study provides a new way of looking at how eavesdroppers affect the evolution of animal communication signals," said Elinor Lichtenberg, one of the researchers, in a news release. "Until now, it was thought that eavesdroppers select against conspicuous signals, for example by more easily finding and eating prey that sings loudly. But our results show that eavesdroppers can help select for the same conspicuous signals that are easiest for intended recipients to detect and understand."

When it comes to bees, a network of signals and cues shapes pollination and informs the insects where and when food is available. The researchers focused on species of stingless bees for this particular study. These bees recruit nestmates to food sources with chemically distinct pheromones. What was interesting, though, was that the researchers found that species that find desirable sites actually "shout out" the location of these sites with the pheromones. Other species, in turn, will avoid these sites in order to keep from being attacked from rival bees.

In fact, eavesdropping on rival bees may be more of an effort than it's worth. An effective eavesdropper would have to gather enough nestmates in order to take over a food source; finding another source of food would be a far more effective use of time and energy.

"Such strategies affect not only the individuals directly involved, but also broader ecological interactions between the food-gatherers and their food," said Lichtenberg. "This is particularly important for animals such as the bees I studied, because their movements determine plant pollination."

The findings are published in the journal Current Biology.