Resource utilization and competition among the five Hawaiian species of Trapezia (Crustacea, Brachyura)

Abstract

Crabs of the genus Trapezia and their hosts, the reef corals Pocillopora spp., were collected at 2 sites on the island of Oahu, Hawaii. At one site, Kahe Point, all 5 Hawaiian species of Trapezia were common, while at Kaneohe Bay, the other site, only T. intermedia and T. digitalis were abundant. More than 90% of corals at both sites were inhabited by at least 1 species of Trapezia . Crabs usually occurred as heterosexual pairs, with a single pair of a given species per coral head. Up to 5 species were found to co-occur on single coral colonies. T. intermedia is abundant on coral colonies of all sizes, but the other species of Trapezia are largely restricted to colonies larger than 2000 to 4000 cm super(3), probably as a result of their aggressive exclusion from small colonies by T. intermedia).