Summary: Callander et al. (2012)

 Fighting success in most males is determined by physical strength and the value of the resource over which males fight. Callander et al. (2012) looked at the how much fiddler crabs Uca annulipes valued a territory/burrow as a resource during the breeding season. During the mating season, burrows were deemed more valuable, as males escalated fights to maintain a territory for breeding and mating. In the non-breeding season, however, males did not fight as hard, even though burrows are still considered a valuable resource for access to food. Interestingly, although males with regenerated claws are weaker competitors than males with undamaged appendages, damaged males fought extra hard to avoid evictions during the breeding season and escalated fights more to maintain the resource. Callander et al. (2012) suggest that weaker males should fight harder when the resource is required for breeding.