Meeting Abstract
Animals that form social groups do so for a number of reasons including avoidance of predators, increased efficacy at finding or guarding food or resources, or for greater success at acquiring mates. While each of these explanations of grouping are associated with fitness gains, there are also potential costs associated with grouping depending on the size of the group, the quality of the territory, or competition in the environment. The dusky damselfish, Stegastes adustus, is a reef fish found in the Caribbean where it defends a territory on which it “farms” algae turf. These fish protect their territory and turf from heterospecific intruders who move through the reef and attempt to graze on the algae. Some, but not all damselfish territories are occupied by more than one fish who appear to share in territory defense and maintenance duties. We investigated variation in damselfish territory size and quality in Akumal Bay, QR, Mexico to determine i. whether larger groups hold higher quality territories, ii. whether the relative size of group member’s influences territory defense, and iii. whether being a part of a group reduces the workload for dominant fish. We found that groups of fish occupied larger territories which contained more rock shelters and algal cover than solitary fish. We also found that the largest fish in groups performed the majority of territory defense behaviors. The amount of defense performed by the largest fish in groups was not significantly different from that performed by solitary fish. Taken together, these results suggest that while grouping may impart benefits on individuals in that they can maintain larger and higher quality territories, individuals do not face a reduced workload by forming a group.
