Cessation of hole-digging by the crab Helograpsus haswellianus: A resource-conserving adaptation

Cases where the mud crab Helograpsus haswellianus (Whitelegge) have dug too many holes and collapsed the mud surface are not observed in the field. Experiments have shown that there is a specific density of holes above which the mud collapses. H. haswellianus at different densities in closed cages do not dig holes over this density. Instead, two or more individuals occupy existing holes on a short-term basis. The significance of this behaviour is discussed.