ITHACA, N.Y. - Just as humans are challenged from the social isolation caused by the coronavirus pandemic, a new study finds that a solitary lifestyle has profound effects on the brains of a social insect: paper wasps.
Paper wasps recognize the brightly colored faces of other paper wasps, an ability they lose when reared in isolation. The wasps' ability to remember faces is similar to primates and humans, but unlike other social insects.
The study revealed that when adult wasps are housed in solitude, visual areas of their brains - especially those involved with identifying nuanced color patterns and shapes - are smaller and less developed than their peers who lived with other wasps.
"To my knowledge, this is the first empirical study to propose a candidate brain region in an insect that is involved with individual identity processing," said first author Christopher Jernigan, a postdoctoral researcher in the lab of Michael Sheehan, assistant professor of neurobiology and behavior at Cornell University.
Paper wasps, native to the eastern United States, live in smaller colonies (up to a few hundred individuals) than honeybees (tens of thousands). Unlike honeybees, whose hives have a single queen, paper wasps can have multiple queens. When starting nests each spring, these future queens can form small groups that collaborate on labor. Still, colonies have social hierarchies and competition. The dominant queen monopolizes egg-laying and subordinate queens do most of the work. Subordinates may leave the nest to join another or start their own colony if they feel the arrangement isn't fair.
"There's tension of balancing conflicts among the cooperating queens, and that seems to be the thing that has favored individuals to recognize each other, to know who's who, how work is being divided up, whether they are getting their fair share," Sheehan said. "It seems to help manage conflicts."
This study tests the effects of maturation and social experience on the wasps' brain development, with a focus on regions involved in visual and olfactory processing, as paper wasps also sense individuals through smells and chemical communication.
The paper, "Age and Social Experience Induced Plasticity Across Brain Regions of the Paper Wasp Polistes fuscatus," published April 14 in the journal Biology Letters.
For additional information, see this Cornell Chronicle story.