Insect Study: Dishonesty Cannot Get Away With Paper Wasps

A new study reveals that paper wasps that send dishonest signals are penalized.

The study was published online in the Proceedings of the National Academy of Sciences on July 4, 2016. It was authored by Elizabeth Tibbetts, an evolutionary biologist from the University of Michigan and other colleagues, according to Science Daily.

Tibbets asked, "Why don't animals cheat by signaling that they are strong when they are actually weak?" She further explained that in their study, they found that inaccurate signaling produces a cascade of costly social and physiological effects. They propose that interactions between behavioral and physiological costs of dishonesty could play a significant role in maintaining honest communication over evolutionary time.

Paper wasps are also referred to as umbrella wasps because of the unique design of their nests. They are about 0.7 to 1.0 inch (1.8 to 2.5 cm) long. They collect fibers from dead wood and plant stems, which they mix with saliva. They use this to construct water-resistant nests, which are made of gray or brown papery material.

In regards to their behavior, paper wasps only attack if they or their nests are threatened. Paper wasps have this distinct feature. They have patchy black facial patterns that signal their fighting ability. The more irregular black spots on their faces, the more fights they win. These wasps are avoided by their rivals, compared with wasps with fewer irregular black spots. These facial signals signify that wimpy wasps don't waste time--fighting strong rivals they would unlikely beat.

In the study, the researchers set up attacks between pairs of female Polistes dominulus paper wasps to examine how signals contained in wasp facial patterns influence social interactions and hormone levels. They collected paper wasp queens from different locations in Ann Arbor in the spring nest-founding period. This is a time of intense conflict between queens competing to build nests.

Each female wasp was paired with the same size rival. They have two-hour videotaped fights in a small Plexiglas box. One wasp in each pair remained unchanged and the other wasp, which is the bluffer, was painted so its facial patterns signal erroneously high fighting ability. The aggression in the attacks was scored based on the quantity of bites, mounts, grapples and stings observed.

The researchers analyzed their juvenile hormone levels after the attacks. Juvenile hormone is an invertebrate hormone that has strong functional parallels to androgens, which are the male sex hormones in vertebrates. In the world of paper wasps, higher levels of Juvenile hormone are linked to aggression, dominance and increased fertility.

The results of the study showed that paper wasps signaling erroneously high fighting ability received more aggression than control wasps. Likewise, the receiving aggression lessened their JH levels immediately after the bouts. On the other hand, wasps that combated the bluffers have their JH levels increased.

The results surprised Tibbetts. She then said that one of the interesting things about the study is that it shows that cheating influences the physiology of cheaters and individuals who interact with the cheaters.