In a series of studies over more than 20 years, University of Michigan evolutionary biologist Elizabeth Tibbetts and her colleagues have demonstrated that paper wasps, despite their tiny brains, have an impressive capacity to learn, remember and make social distinctions about others.
The researchers showed that paper wasps recognize individuals of their species by variations in their facial markings and that they behave more aggressively toward wasps with unfamiliar markings.
They established that paper wasps have surprisingly long memories and base their actions on what they remember of previous social interactions with other wasps. And they provided the first evidence of transitive inference—a behavior that resembles logical reasoning—in a nonvertebrate animal, the lowly paper wasp.
Now, Tibbetts and her students are reporting the first evidence that paper wasps can form abstract concepts. Strikingly, the wasps were also able to transfer what they learned through visual training into a different sensory modality: the sense of smell.
The study used laboratory tasks to test whether paper wasps (Polistes fuscatus) could learn and apply one of the most basic abstract concepts: the idea of sameness and difference.
The wasps were trained to distinguish between pairs of visual or olfactory stimuli (two colored bits of paper, two photos of wasp faces, or two chemical odors) that were either identical or different. One pair of stimuli was associated with a mild but unpleasant electrical shock, the other was not.
Then the stinging insects were exposed to novel pairs of stimuli (either identical or different) and tested on their ability to avoid an electric shock by selecting the “correct” pair—the one associated with safety.
The previously trained wasps made the correct choice more than 80% of the time, according to the researchers. The team’s findings were published online July 20 in the journal Proceedings of the Royal Society B.
“Our findings show the wasps learned the general concept of sameness and difference and applied it to new samples and new types of stimuli,” said Tibbetts, a professor in the U-M Department of Ecology and Evolutionary Biology.
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