Meeting Abstract
Competition for resources can result in physical contests which are energetically costly and potentially injurious. Organisms with a strategy to assess when costs of a contest have outweighed the benefit of a resource can minimize overall costs that could negatively impact fitness. Males and females of a species incur different types of fitness costs due to reproductive differences, and evidence suggests that these differences can influence contest behavior and persistence. Longer contests equate to greater energy expenditure and risk of injury which could be more costly to female opponents. Consequently, male and female differences in assessment strategies present an ecologically relevant exploration of the context dependence of assessment. Using crayfish as a model organism, we have found that male and female crayfish likely differ in the information used to determine contest persistence and intensity. We first explored the assessment strategy in place for same-sex and mixed-sex dyads and found that mixed-sex contests differed from same-sex contests. While both male and female same-sex contests showed strong evidence for a self-assessment strategy, mixed-sex opponents had no obvious strategy in place. Subsequent trials limited the availability of a chemical signal during mixed-sex contests and revealed varied impacts for males and females. While contest outcome was simply a function of size, contest duration was dependent on both opponent size and the accessibility of chemical information. We suggest that chemical information is equally important for male and female crayfish in contest assessment but the information contained in or conveyed by the signal likely differs.
