Behaviour 2019
Eavesdropper Pressure on Mating Signals: The Importance of Neighbors and Neighborhood
Paula/A Trillo1, Christopher/S Benson2, Michael/S Caldwell1, Tiffany/L Lam1, Oliver/H Pickering1, David/M Logue2. 1Gettysburg College, Gettysburg, Pennsylvania, United States; 2University of Lethbridge, Lethbridge, Alberta, Canada

Males of species with similar breeding requirements often display from mixed-species aggregations. While studies have explored how signaling conspecific neighbors mediate predation and parasitism risk suffered by a focal individual, less is known about how signaling heterospecific neighbors shape these risks. Our studies using two species of neotropical frogs: túngara frogs, Engystomops pustulosus, and hourglass treefrogs, Dendropsophus ebraccatus, demonstrate a mechanism by which interactions between heterospecific signalers can substantially influence the attraction of eavesdropping parasites (blood-sucking flies of the Corethrella genus), thereby altering parasitism pressure on their neighbors. We find that the species identity of, call variants produced by, and density of signaling túngara neighbors can each strongly affect these risks for hourglass treefrogs. As a companion to our experimental studies, we have developed a simple model, illustrating how the relative attractiveness of neighbors can alter eavesdropper risks faced by signalers. This work indicates that neighbors may play an important role in the attraction of eavesdropping parasites to heterospecific signalers.