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Circadian activity rhythms in the crayfish Paranephrops zealandicus (Crustacea)
Author(s) -
Quilter C. G.,
Williams B. G.
Publication year - 1977
Publication title -
journal of zoology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.915
H-Index - 96
eISSN - 1469-7998
pISSN - 0952-8369
DOI - 10.1111/j.1469-7998.1977.tb04170.x
Subject(s) - circadian rhythm , biology , period (music) , rhythm , diel vertical migration , crayfish , crustacean , infradian rhythm , darkness , chronobiology , seasonality , zoology , ecology , ultradian rhythm , endocrinology , medicine , botany , physics , acoustics
The diel activity rhythm shown by Paranephrops is usually unimodal with most activity occurring at night. In constant darkness, locomotor activity is expressed for up to 60 days as a free‐running circadian rhythm. The period varies from 18 to 38 hours following a seasonal cycle (summer mean period 24 hours, winter mean 30 hours). No adaptive significance can be attached to either seasonal or individual variations in period and it is suggested that such variations are a consequence of the way in which the clock mechanism operates, the period being linked to the overall activity level following Aschoff's ( 1960 ) “Circadian Rule”. Activity levels will inevitably vary individually and seasonally.