Eavesdropping and the audience effect in fighting fruit flies reveal feedback between social information use and production

Abstract

AbstractSocial information use and production occur simultaneously during social learning events; however, these two processes are often studied independently. We propose that social information use and production represent a feedback loop: eavesdroppers influence the behaviors of those being observed, which then alters the eavesdroppers’ social decisions. Here, we used Drosophila melanogaster to investigate the relationship between social information use and production in an aggressive context. We quantified aggressive behavior between two males being observed by either a male, female, or no one. We then measured variation in social information use by allowing the eavesdroppers to interact directly with the observed males and compared their behavior to individuals who did not observe the aggressive encounter. Male eavesdroppers caused the observed males to decrease their aggressive behaviors, thus altering their social information production. Male eavesdroppers were then less likely to attack observed contest winners than males without social information. Female eavesdroppers did not elicit any change in the aggression of the two males, and female eavesdroppers did not use social information to inform their mating decisions. Overall, we found support for the feedback loop in males, but not females: information was exchanged bi-directionally during eavesdropping events, resulting in the modification of behavior by all parties.