The Northern paper wasp (Polistes fuscatus) is a common and widely distributed species throughout central and eastern North America. While males have indiscriminate thin pale faces and curly antennae, each female contains a unique arrangement of facial markings that play a role in maintaining a social hierarchy. Paper wasps establish dominance hierarchies through aggressive interactions, and via individual recognition of facial patterns, wasps create a social memory of previous associations. This enables them to identify foreign wasps and remember aggressive vs. non-aggressive interactions with nestmates to reduce the energy expenditure of frequent agonistic behaviors. Surprisingly, Polistes fuscatus is able to recall individual wasps after more than a week of separation, even when maintaining interactions with ten other individuals. Through experimental manipulation, it was found that wasps with altered facial patterns initially received heightened aggression, followed by a waning of aggressive interactions over time as familiarity with the novel markings increased.
The capability of transitive inference has also been demonstrated in some species of Polistes. In a study, wasps were trained to discriminate between five elements in a paired series, and when presented with novel pairings, wasps could logically infer relationships by evaluating differences hierarchically. Through having logical reasoning and robust social memory, paper wasps are countering the notion that miniaturized nervous systems prevent the evolution of higher cognitive processes.
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