Pure Self‐Assessment of Size During Male–Male Contests in the Parasitoid WaspNasonia vitripennis

Abstract

AbstractDuring contest competition, a competitor may persist in a given contest based on information regarding its own fighting ability (resource‐holding potential,RHP), or that of its opponent. Although a number of models formalize the ways in which competitors are hypothesized to useRHP‐related information to determine their persistence in contests, we focused on pure self‐assessment and mutual assessment models in this study. According to pure self‐assessment models, a competitor uses only information regarding its ownRHPto determine its persistence in a contest. In contrast, according to mutual assessment models, persistence is based on information regarding a competitor'sRHPrelative to that of its opponent and therefore requires assessment between competitors. In this study, using size as a proxy forRHP, we tested whether the parasitoid waspNasonia vitripennisutilizes pure self‐assessment or mutual assessment during pairwise, male–male contests. When we examined competitors of varied sizes, we found that the losing male's size was positively related to contest duration, but the winning male's size was uncorrelated with contest duration. When we examined contests in which competitors were size‐matched, we found that the mean size of paired competitors was positively related to contest duration. These results suggest that maleN. vitripennisengage in pure self‐assessment during contests.