Meeting Abstract
Animals participate in agonistic interactions to secure or maintain necessary resources. Crayfish fight vigorously when introduced, with aggressive behaviors decreasing in frequency and duration as the population stabilizes. This results in dominant and subordinate relationships between individuals; interactions between different sized crayfish cause the large animal to become dominant, while the small animal becomes subordinate. However, populations of crayfish are complex and are difficult to assess. Mutual- and self-assessment are ways animals evaluate conspecifics within a population. Theoretical models by Mesterton-Gibbons and Heap (2013) proposed that assessment and aggression within populations differ in relation to varying resource value. This study attempts to empirically address one piece of this puzzle, the influence of population structure on aggression. Populations of crayfish (4 large, 4 small, 3 small vs. 1 large, 2 small vs. 2 large, 1 small vs. 3 large) are provided with 4 identical shelters and are recorded for 24-hour trials for fight duration and outcome. Preliminary fight duration data suggests populations with primarily large animals (4 large, 3 large vs. 1 small) fight longer as compared to populations with equal or a greater number of small animals (2 large vs. 2 small, 1 large vs. 3 small). Additionally, numbers of fights are found to be greater in populations with all large animals. This data suggests populations consisting of larger crayfish increases the overall aggression of the population. This study, along with future studies involving differing resources, will provide empirical evidence to better understand how resources and assessment strategies collectively influence the intricacies of population structure.
