Paper wasps can recognize each others’ faces, researchers report. This ability is separate from the wasps’ more general capacity to distinguish shapes and patterns, and it seems to be a specialized skill that evolves independently in various lineages of social animals, including humans.
Paper wasps, or Polistes fuscatus, are often known for their delicate, honeycomb-like nests. They live in colonies with multiple queens, so the offspring of each queen work together. Michael Sheehan and Elizabeth Tibbetts of the University of Michigan hypothesized that these wasps would be able to learn to identify images of faces faster and more accurately than other types of images.
The researchers also predicted that a closely related species, Polistes metricus, whose nests have just a single queen, would not have this particular facility for face learning.
Sheehan and Tibbetts trained both types of wasps to discriminate between two images, using a T-shaped maze whose entire floor was electrified, except for a safety zone in one arm of the maze. One of the two images—sometimes a wasp face, sometimes another image—was consistently placed in the safety zone, though the location of the safety zone itself varied from one trial to another.
The paper wasps learned to identify the “safe” faces faster than other images associated with the safety zone, and they did so faster than P. metricus. The authors note that wasps and mammals have dramatically different eyes and neural structures, but both groups have independently evolved the ability to recognize the faces of other individuals in their species.
The research appears in the 2 December issue of Science.
Read the abstract for “Specialized Face Learning Is Associated with Individual Recognition in Paper Wasps,” by Michael J. Sheehan and Elizabeth A. Tibbetts.
Listen to a related Science Podcast about the research.