It is no secret that wasps are aggressive insects. But, in a recently unveiled secret, scientists discovered that a specific species of wasp, paper wasps, are fully capable of carefully calculating that very same aggression towards direct rivals.
In their June 2020 report from the journal Current Biology entitled “Wasps Use Social Eavesdropping to Learn about Individual Rivals,” Elizabeth A. Tibbetts, Ellery Wong, and Sarah Bonello establish that paper wasps, also known as Polistes fuscatus, rely upon observation of other paper wasps in order to make nuanced, and crucial, social decisions.
The Ecology and Evolutionary Biology researchers from the University of Michigan at Ann Arbor reveal in their report that paper wasps, specifically regarding the identification of direct rivals of the same species, use “social eavesdropping” in order to scrutinize the threat of each individual observed. Social eavesdropping is just the same as if one were to go “people-watching” in a crowded train station: you observe the interactions between a daughter returning from school and her mother, a father bringing a new puppy to his awaiting family, or two friends embarking on a long commute back. Just like the paper wasps, we remember the looks of faces and the languages of bodies.
However, the paper wasps studied by Tibbetts, Wong, and Bonello were not so excited to see each other. They were made to face-off, one-on-one, and the winner of the meeting faced a former onlooker in one experiment. In the other, the winner faced a wasp who had not watched its fight.
The method designed by the three researchers pitted P. fuscatus against one another in direct confrontations, which allowed for the scientists to observe expressed aggressive behavior from both subjects as well as determine the outcome — the winner — of the meeting. In order to establish that social eavesdropping is the prevailing method by which paper wasps learn of rivals and their relative aggressiveness, Tibbetts, Wong, and Bonello conducted two different experiments: one wherein social eavesdropping was possible, and the other wherein the phenomenon was not possible (see Diagram 1). The design of this experiment allowed the researchers to eliminate other possible reasons — specifically “priming,” or observation of a confrontation without committing results to memory, and “rival fighting experience,” or reliance on prior results independent of the rival — by which paper wasps were perhaps able to express, and regulate, aggressive behavior.
Tibbetts, in her previous research on P. fuscatus, established that these wasps are able to familiarize themselves with individuals of the same species through facial recognition. By extension of Tibbetts’ diligent work establishing complex activity in interactions between paper wasps, the authors of this report, through their conclusions, make it clear that brain size does not directly correlate with behavioral capability: “This study adds to a growing body of evidence that the miniature nervous systems of insects do not limit sophisticated behaviors.”
The authors of the report point out that many animals with spines are capable of the “cognitively challenging” feat of remembering individuals within the same species, and in turn their levels of aggression, but that it is not as common in those animals without spines. Paper wasps buck this trend, because they “learn about individual [rivals] via observation, make deductions about fighting ability based on these observations, remember those deductions, and use the information when they encounter the particular individual again.” For an insect of small stature, the proof of this ability begs thinkers to wonder about all of the decisions an individual paper wasp may make in its lifetime.
A fine analogy to make against this sophisticated behavior of P. fuscatus is the function of professional mixed martial arts. In one given instance, a fighter is on a two- or three-win streak and is pitted against a top-ranking fighter. The “hot” fighter may be confident in his abilities, because he is on a win-streak, but through observation of the top-ranking fighter — whether it be on film or in person — the hot fighter is fully aware of the top-ranking fighter’s capabilities, strengths, and repeated moves. Therefore he is careful in the matchup.
In a second instance, the very same fighter is on the very same win-streak, and is poised to go against the very same top-ranking fighter. However, he is so confident in his abilities, and his win-streak, that he does not care for the reputation of the top-ranking fighter. Most readers can deduce the outcome of the second instance, just as paper wasps can infer the likelihood of success against a direct rival solely through observation.
