Distribution and behaviour of the amphipod, Talorchestia capensis (Crustacea; Talitridae)

Abstract

Distribution of the amphipod, Talorchestia capensis (Crustacea; Talitridae) has been studied in a dune-beach system. The majority of amphipods occurred in dune slacks with fewer on the beach. No zonation of size classes existed, both juveniles and adults occurring throughout the slack. Amphipods were concentrated in the top soil layers, where temperature fluctuations were highest and per cent moisture lowest. However, gravid females preferred slightly deeper soil layers. Studies during a spring and a neap tide indicated that the animals have a Circadian rhythm with a nocturnal activity phase, and a weak tidal rhythm, but no lunar orientation mechanism.