Rhythmic Behaviour of the Intertidal Amphipod Bathyporeia Pelagica
Several authors have studied the rhythmic behaviour of amphipods, including Papi (1955) who demonstrated an endogenous solar time sense in Talitrus saltator which was used for navigation. Talitrids were also investigated by Featherston & Maclntyre (1957) who suggested that changes in light intensity triggered the nocturnal foraging activity. Enright (1961, 1962, 1963) tested the effects of pressure, temperature, light intensity, absence of sand and shaking on rhythmic behaviour of the intertidal and in-faunal amphipod Synchelidium. The activity rhythm of Corophium volutator has been reported by Morgan (1965) in which a peak occurred on the early ebb. Various rocky shore Peracarida including species of Gammarus also perform vertical migrations into the surf at night (Jansson & Källander, 1968); the inhibiting effect of light was proven by experiments with controlled illumination.