Tidal and Diurnal Rhythms of Locomotory Activity in Carcinus Maenas (l.)

Since the early observations of tidal rhythms in Convoluta (Gamble & Keeble, 1903, 1904) and in Actinia (Bohn, 1906) much experimental work on rhythms of behaviour in intertidal animals has been concerned with such phenomena as oxygen uptake and colour changes. Gompel (1937) demonstrated tidal rhythms of oxygen consumption in Patella, MytUus and Hatiotis and similar rhythms have been shown more convincingly in several other organisms by F. A. Brown and his co-workers. Superimposed tidal and diurnal rhythms of oxygen consumption are described in Littorina littorea and Urosalpinx cinereus (Sandeen, Stephens & Brown, 1954), and in Uca pugnax and U. pugilator (Brown, Bennett & Webb, 1954), and similar rhythms of colour change occur in U. pugnax (Brown, Fingerman, Sandeen & Webb, 1953) and CaUinectes sapidus (Fingerman, 1955). Along similar lines, Rao (1954) has described persistent tidal rhythmicity in the rate of water propulsion by MytUus. Many physiological rhythms of this kind have been reported but, as has been noted by Bennett, Shriner & Brown (1957) several are apparent only after statistical analysis of extensive data. Despite the fact that it is often more simple to obtain a continuous record of the movement of an animal than of its oxygen uptake there are few published examples of rhythms of locomotory activity in marine animals. Recent demonstrations of tidal rhythms of this nature in Nassa obsoleta (Stephens, Sandeen & Webb, 1953) and Uca pugnax (Bennet et al. 1957) are notable. The present paper describes spontaneous tidal and diurnal rhythms of locomotory activity in Cardnus maenas (L.)