The habits and populations of terrestrial crabs (Brachyura: Gecarcinucoidea and Grapsoidea) in the Gunung Mulu National Park, Sarawak

Four species of terrestrial crabs, Perbrinckia loxophthalma (De Man), Thelphasula granosa Holthuis, T. baramensis (De Man) and Geosesarma gracillimum (De Man) were caught in pitfall traps in forested alluvial plains in the Gunung Mulu National Park, Sarawak. The density of a monospecific population of Perbrinckia near a river bank was 0.32/m2. The air-dry biomass of this species on two plots was estimated at o.6og/m2 and o.82g/m2. Fore-guts of 11 specimens of Perbrinckia were found to contain vegetable and mineral matter and insect remains. It is suggested that crabs may contribute significantly to litter comminution and removal from alluvial forest, where other groups of soil invertebrates are poorly represented.