A laboratory study of spatial organization in the crab Ebalia tuberosa (Pennant) (Crustacea : Decapoda : Leucosiidae)

In the laboratory, the spatial distribution of Ebalia tuberosa on a homogeneous substratum over a 20 day period was mainly random and was not affected by the initial distribution pattern. Population density and population sex-structure similarly had no effect. At low population densities no sexual difference in home range area was found but at high density male home range area was significantly larger than female home range area. There was little overlap in home range between individuals at low population densities but as density increased so did male-male overlap. Female-female and male-female overlap first increased and then decreased. Crowding suppressed female activity. At high population densities, females, and to a lesser extent, males, appeared to restrict their movements to a small area from which they probably excluded other individuals. At all population densities tested, the majority of individuals tended to move for short distances only and very infrequently. The crabs tended to remain in one spot for long periods especially in the case of females which, at high population densities, became very sedentary.peer-reviewe