Physiological Tolerances and Behaviour Responses of Five Species of Haustoriidae (Amphipoda: Crustacea) to Five Environmental Factors

Abstract

Five species of haustoriid amphipods from Cape Cod, Massachusetts, differed in their tolerances to high temperature, desiccation, low salinity, and low oxygen concentration and in preferences for different sediment sizes. Two intertidal species, Haustorius canadensis Bousfield and Neohaustorius biarticulatus Bousfield, survived longer in air at 100% relative humidity and were more resistant to high water temperature than three species that are basically subtidal, Acanthohaustorius millsi Bousfield, Parahaustorius longimerus Bousfield, and Protohaustorius deichmannae Bousfield. All five species preferred sediments of a particular size range, the intertidal species selecting coarser sediments than the subtidal species. The sediment preference shown by the intertidal species could be changed by altering the organic conditions of the sediment by either drying or igniting the sediment. Acanthohaustorius millsi was the species most tolerant to low oxygen concentration and H. canadensis had the lowest oxygen consumption rate of the five species.The ecological significance of these findings is discussed in relation to the distribution of the five species on Cape Cod.