The relative importance of RHP and resource quality in contests with ownership asymmetries

Ownership asymmetries lead to owners (residents) having substantial contest advantages over intruders, and this may overwhelm the fighting advantage of large body size. Why such an ownership advantage occurs, however, is not clear and requires further investigation. Here, we use a jumping spider, Phidippus clarus, to examine the role of ownership asymmetries and resource quality in determining contest outcomes and assessment strategies of both intruders and residents. Resident male P. clarus cohabit with and defend virgin females where reproductive potential increases with body size. Here, we show that ownership plays a significant role in contest outcomes, despite the previously demonstrated importance of body size when males encounter each other in the absence of a female. Owners have a substantial advantage over intruders with residency being more important than body size in determining contest outcomes. Intruders gave up more quickly when owners were larger, suggesting that owners follow a partial mutual assessment strategy. In contrast, contests won by intruders were "wars of attrition" where owners fought until resources were depleted as they were governed by the resource holding potential of the resident (loser). Finally, female size (reproductive potential) did not alter contest outcomes; however, it did affect how quickly contests were escalated. We highlight the importance of understanding the life history and reproductive biology along with the behavior and ecology of the species under study to truly understand the traits associated with fitness in contests. Copyright 2011, Oxford University Press.