A society’s success can hinge on its head honcho. That’s true even for insects under the rule of a queen.
One way to judge the success of social insects such as paper wasps is by the size of their colonies, with bigger typically meaning better. Polistes metricus paper wasp queens with bold personalities and big bodies tend to produce larger colonies than their smaller, shyer counterparts, a new study finds. These queenly characteristics can help to predict a colony’s success, even a month before there’s even a colony to speak of, says Colin Wright, a behavioral ecologist at Penn State.
Colony-founding P. metricus paper wasp queens blaze their own trails. These females often strike out alone, build their own nests and raise their young. Once they’ve reared a brood, they defend the nest from invaders while policing workers’ behavior and preventing workers from reproducing.
In May 2016, Wright and colleagues collected 40 paper wasp queens and their nests, within a couple of weeks of the females founding the nests. The researchers gave the insects a “personality” test by poking them in the face, up to 50 times, to see if the wasps would stay put or fly away.
“Some queens, you can prod them up to a hundred times, and they’ll stand their ground,” Wright says. Less tenacious queens would fly away after one or two jabs.
The researchers also measured the queens’ heads to estimate body size, and then returned the wasps to their nests and the nests to the field. To track colony growth, the team monitored the populations of 27 colonies led by queens that didn’t abandon their nests over several months.
Queens had two pathways to success. Having either a bigger head or bolder behavior tended to mean that a queen’s colony had more members than those colonies whose leaders lacked those qualities, researchers report online August 8 in Behavioral Ecology and Sociobiology.
Larger queens may have physical advantages that allow them to lay more eggs or to forage or work on their nests for longer each day than their smaller counterparts, the authors suggest. Being big or bold, or both, may help queens be better fighters. A 2009 study by evolutionary biologist Elizabeth Tibbetts of the University of Michigan, a coauthor on the new paper, suggested that larger queens are less likely to have their nests usurped by a rival.
“The queen herself can have this legacy effect on the traits of the colony,” says Amy Toth, a social insect biologist at Iowa State University in Ames, who was not involved with the work. “It’s super clear with [these wasps], because you start with a single individual, and she creates a city essentially.” Populated by a queen’s descendants, that city is an extension of the queen’s genes and characteristics.