Influences of individual phenotypic traits on the habitat preferences of the sand fiddler crab, Uca pugilator

Recognizing which phenotypic traits are predictors for habitat choice can have important implications for understanding population dynamics. This study determined whether body size, sex, activity level, or origin habitat affected the preference of the fiddler crab, Uca pugilator, in selecting either a marsh or open mudflat, two habitats differing in risk level and food availability. Combining field and laboratory experiments, this study indicated a significant difference in body size and activity level of crabs between habitats. Further investigation of phenotypic dependency on habitat preference resulted in interactions between origin habitat and carapace width and activity level. When split by origin habitat, habitat preference for the open mudflat was predicted by body size for crabs originating from the open mudflat and by activity level for the crabs originating from the Spartina marsh. These results suggest that, for U. pugilator, body size plays a large role in the preference for exposed habitat.