Wasps literally drum up interest in food. They bang their abdomens against the walls of their nests, and it now seems this informs other wasps that food is available. It is the first time that wasps have been shown to communicate in this way.
Several species of wasp are known to perform “gastral drumming”. From time to time, they rapidly pummel their abdomens against their nest walls in a series of short bursts.
The scientists who first reported this behaviour in the 1960s thought it may have been a way for wasps to communicate that they were hungry. Observational studies suggested that, if a colony was starved of food, the wasps would drum more, as if in anguish. In response to drumming, other wasps started moving more, foraging more, and performing trophallaxis: regurgitating food to share with their nestmates.
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However, the idea that gastral drumming communicates hunger was never tested empirically. Meanwhile, other researchers suggested the wasps might be telling their nestmates about useful sources of food. This “recruitment” behaviour is common in social animals, such as and .
Talkative wasps
at the City University of New York and his colleagues have put the two ideas to the test.
They housed six colonies of German yellowjacket wasps () in artificial nests in the lab, with controlled access to the outside world. Then they varied the amount of food available, and tracked how much drumming the wasps did.
To test the effect of starvation, the wasps were allowed to freely forage for a day, but on the second day they were shut in and only given water. On the third day, the exit was opened again. In other shorter trials, colonies were given sucrose solution and behaviours were measured before, during and after additional food was provided.
Drumming declined in the starvation tests, suggesting it was not a signal of hunger. However, the wasps drummed more when sucrose was offered, and levels of drumming consistently returned to a baseline level after starvation periods had ended. This suggests that the wasps were drumming to alert each other to the presence of food.
Insect chatter
There may be a lot more to the drumming than it seems. Famously, honeybees perform an ingenious “waggle-dance” to tell each other about food sources. The angle of the dance points the way to the food, its length reveals the food’s distance from the hive, and the number of runs in each dance .
Just like honeybees, many wasps are highly social – so might the drumming be their version of the waggle dance?
There are some tentative hints. “It’s amazing how bouts might only include a couple of drums in one instance, and in others it can last for several minutes,” says Taylor. “The thought here is that it might contain more information about the resource.”
It’s an exciting possibility, says at Iowa State University in Ames. “If so, this behaviour would stand as one of the most complex known recruitment signals in animal societies, akin to the waggle dance of honey bees.”
It’s also possible that wasps might send negative feedback signals, for instance , says at the University of Sheffield, UK. Such signals have been seen in honeybees and ants, and “enable really sophisticated collective behaviour”.
Toth adds that the existence of such signalling should change our perception of wasps. “These creatures, despite their interesting biology and ecological importance, have been much maligned and misunderstood alongside their much more popular bee cousins,” she says.
The Science of Nature
