Vb. Meyer-rochow et Pj. Brown, Possible natural circaseptan rhythm in the beach beetle Chaerodes trachyscelides White, ACT NEUROB, 58(4), 1998, pp. 287-290
Activity rhythms in groups of captive beach beetles (Chaerodes trachyscelid
es White) have been recorded in an actograph over a period of 29 days. Unde
r constant illumination and when no sand was provided for the beetles to bu
rrow in abnormal behaviour occurred. With sand and in constant darkness a s
trictly nocturnal activity period with apparently circaseptan components su
perimposed was observed. The beetles in their natural habitat are confined
to the debris zone where they feed on washed up seaweed and this debris zon
e moves up and down depending on the heights of the tides. Circaseptan elem
ents in the beetles' activity may act as adaptations to the weekly alternat
ions between spring- and neap-tides.