It may seem like a wasp’s only concern is getting at your can of pop, but a new study published out of the University of Michigan suggests that they may be smarter than we think. Elizabeth Tibbetts, the associate chair for research and ethics at the University of Michigan’s biology department and the lead researcher on the study, says paper wasps exhibit transitive inference.
“Transitive inference is using what you know to make inferences about what you don’t know,” she says. So, if wasp A is stronger than wasp B and wasp B beats up wasp C, then wasp A can assume it is also stronger than wasp C.
Transitive inference was once thought to be a highly logical cognitive function exclusively found in humans. But researchers have discovered that primates, birds, fish, and now wasps also utilize this function. “From what people have studied in other species, transitive inference is often important for figuring out dominance relationships because it helps you make guesses about how strong you are relative to other individuals without actually fighting them,” Tibbetts says.
Tibbetts and her colleagues tested the wasps in her laboratory, presenting them with pairs of colours. One colour was associated with a mild shock while the other wasn’t. The wasps quickly learned which colours dispersed a shock and which didn’t, using the information to choose which colour to engage with.
A similar test was run on honey bees, but the insect did not exhibit transitive function. This is what motivated Tibbetts to run the test on wasps. “It has long been considered something that’s a relatively cognitively complex task,” she says. “Since honey bees couldn’t do it, I thought wasps might be able to do it because wasps have very different social behaviours than honey bees.”
While wasps exhibit many of the same characteristics as honey bees: flying, stinging, pollinating, even brain size—approximately the size of a grain of rice, Tibbetts says—wasps’ social interactions are governed by dominant relationships. Honey bee colonies are run by a single queen bee, while paper wasp colonies have multiple reproductive females. These females compete for dominance within the colony. A higher ranking in the hierarchy determines a greater share in reproduction, work, and food.
Tibbetts credits wasps’ ability to use transitive inference to evolution. “I think it has to do with how evolution shapes their brain,” she says. “Evolution shapes your brain over a long period of time, so animals are really good at doing what they need to do and not so good at doing other things.” It’s a form of natural selection designed to help them survive.
Moving forward, Tibbetts plans on studying how wasps use transitive inference in the wild to manage social relationships. “When we tested transitive inference, we did it in a lab. It was a specific experiment,” she says. “Now we want to know how it translates to nature.” Specifically, she wants to see whether wasps “watch each other fight and then [use] transitive inference to know whether they’re going to win or lose against a rival.”