Imagine you're a bee and you just located a prime nectar source. You want to alert your hivemates, but not attract competitors. What should you do?
Some bees devise a special "whisper" to discretely let bees in their colony know about a food source, but others, new research has shown, "shout" it out loud with a message along the lines of, "This is good nectar and it's all ours or -- watch out!"
In the case of bees, the insects aren't actually shouting, but signalling to each other and outside bees using information-rich pheromone trails.
"It tells nestmates where to find good food and hints at a larger occupying force," explained Elinor Lichtenberg in a press release. Lichtenberg, a postdoctoral researcher at Washington State University, focused on species of singless Brazilian bees for her paper in the journal Current Biology.
The finding, she says, demonstrates how eavesdropping competitors can alter the evolution of animal signals -- even in unexpected ways.
"Our study provides a new way of looking at how eavesdroppers affect the evolution of animal communication signals," she said. "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."
The hunt for good nectar can become fiercely competitive between some bee colonies, requiring bee species to develop critical communication strategies.
Among the Brazilian bees analyzed for the research, the bee species Trigona hyalinata is known to spy on species of Trigona spinipes bees to detect good foraging spots. But invading the other bees' nectar source can come at a price.
If individuals can recruit enough of their colony mates, then honing in on Trigona spinipes' source can be a good bet. But if they only manage to rally a small group of their colony mates to a competitor’s source, they're likely to lose out to the other bees, or, worse, die fighting for it.
By sending out bold signals claiming a nectar source, species of Trigona spinipes hope to deter their eavesdropping competitors from even trying to invade their source.
"In this stingless bee system, with aggressive colonies jockeying for limited resources, more conspicuous food-recruitment signals indicate a higher likelihood that a resource will be harder to wrest away," said James Nieh, a professor of biology at UC San Diego who oversaw the research.
Photo: A Trigona spinipes bee. Credit: Wikimedia Commons