The Effect of Sediment Temperature on the Burrowing Behavior of Male Fiddler Crabs, Uca pugilator

Uca pugilator, the sand-fiddler crab, is commonly found in marshes and mud flats in South Carolina. When the tide has recessed, fiddler crabs spend their time on the surface of the marsh or in their burrows. Burrows are an important factor of a crab\u27s life as burrows provide shelter from adverse environmental conditions and predators, as well as a location for mating and egg maturation. Burrowing is also an effective way for fiddler crabs to thermoregulate. Fiddler crabs experience a variety of temperatures on a daily, seasonal, and an annual basis. Temperatures in the salt marsh exceed 40°C during the summer months and approach 0°C during the winter. Uca pugilator are most active in temperatures between 18-25°C and activity is inhibited between 11-12°C (Powers and Cole 1976). The objective of my thesis was to examine the effect temperature had on burrowing behavior. I exposed male crabs to substrates that ranged in temperatures from 0-2, 8-10, 18-20, 28-30 and 38-40°C. I measured how long it took the crabs to burrow beneath the substrate. The ANOVA of the five temperature ranges 0-2°C, 8-10°C, 18-20°C, 28-30°C, and 38-40°C indicates that there is a significant difference between burrow times and temperature (F=5.23, d.f.=4, P\u3c.01). A Tukey test indicated that burrowing times of crabs in the 0-2°C group were significantly different from burrowing times of crabs in the 38-40°C group (