Towards a characterization of the locomotor activity rhythm of the supralittoral isopod Tylos europaeus.
Freshly collected samples of Tylos europaeus from Korba beach (northeast of Tunisia) were housed in an environmental cabinet at controlled temperature (18°C ± .5°C) and photoperiod. Locomotor activity was recorded under two photoperiodic regimens by infrared actography every 20 min by multichannel data loggers. One regimen simulated the natural light-dark cycle on the day of collection, whereas the second imposed a state of continuous darkness on all individuals. Under entraining conditions, the animals displayed rhythmic activity, in phase with the period of darkness, whereas in continuous darkness these isopods exhibited a strong endogenous rhythm with circadian and semidiurnal components at mean periods of τ (h:min) = 25:09 ± 01:02 h and τ = 12:32 ± 00:26 h, respectively. Under free-running conditions, this endogenous rhythm showed significant intraspecific variability.
Unité de recherche Biologie Animale et Systématique Evolutive, Faculté des Sciences de Tunis, Campus Universitaire de Tunis El Manar I, Tunis, Tunisie. bohli.dhouha@gmail.com
Dhouha
D
Bohli-Abderrazak
Amel
A
Ayari
Elfed
E
Morgan
Karima
K
Nasri-Ammar
D000818:Animals; D001683:Biological Clocks / Q000502:physiology; D002940:Circadian Rhythm / Q000502:physiology*; D003624:Darkness; D033321:Isopoda / Q000502:physiology*; D008027:Light; D009043:Motor Activity / Q000502:physiology*; D017440:Photoperiod; D014416:Tunisia