Behaviour 2019
Damage influences contest outcomes
Zachary Emberts1, Ummat Somjee2, John J Wiens1. 1University of Arizona, Tucson, AZ, United States; 2Smithsonian Tropical Research Institute, Balbo, , Panama

In many animal species, individuals engage in fights with conspecifics over access to limited resources (e.g. mates, food, or shelter). During these fights, injuries can occur. Most theory assumes that such damage has an important role in determining the contest winner. However, no study has experimentally tested whether injury itself actually influences fighting success. In this study, we investigated whether inhibiting damage by enhancing an individual’s armor influences fighting behavior and success in the giant mesquite bug, Thasus neocalifornicus (Insecta: Hemiptera: Coreidae). We found that experimentally manipulated individuals (i.e. those prevented from being injured) were 1.6 times more likely to win a fight when compared to the control. These results demonstrate that damage can influence fighting success, experimentally supporting a fundamental assumption of most theoretical fighting models.