title: Tidal, daily, and lunar-day activity cycles in the marine polychaete Nereis virens.
abstract: The burrow emergence activity of the wild caught ragworm Nereis virens Sars associated with food prospecting was investigated under various photoperiodic (LD) and simulated tidal cycles (STC) using a laboratory based actograph. Just over half (57%) of the animals under LD with STC displayed significant tidal (approximately 12.4 h) and/or lunar-day (approximately 24.8 h) activity patterns. Under constant light (LL) plus a STC, 25% of all animals were tidal, while one animal responded with a circadian (24.2 h) activity rhythm suggestive of cross-modal entrainment where the environmental stimulus of one period entrains rhythmic behavior of a different period. All peaks of activity under a STC, apart from that of the individual cross-modal entrainment case, coincided with the period of tank flooding. Under only LD without a STC, 49% of the animals showed nocturnal (approximately 24 h) activity. When animals were maintained under free-running LL conditions, 15% displayed significant rhythmicity with circatidal and circadian/circalunidian periodicities. Although activity cycles in N. virens at the population level are robust, at the individual level they are particularly labile, suggesting complex biological clock-control with multiple clock output pathways.
authors.affiliation: The Scottish Association for Marine Science, Dunstaffnage Marine Laboratory, Oban, UK. kim.last@sams.ac.uk
authors.forename: Kim S
authors.initials: KS
authors.lastname: Last
authors.forename: Thierry
authors.initials: T
authors.lastname: Bailhache
authors.forename: Cas
authors.initials: C
authors.lastname: Kramer
authors.forename: Charalambos P
authors.initials: CP
authors.lastname: Kyriacou
authors.forename: Ezio
authors.initials: E
authors.lastname: Rosato
authors.forename: Peter J W
authors.initials: PJ
authors.lastname: Olive
mesh_terms: D000818:Animals; D001522:Behavior, Animal / Q000502:physiology*; D001683:Biological Clocks / Q000502:physiology*; D002940:Circadian Rhythm / Q000502:physiology*; D016081:Moon; D017440:Photoperiod; D011077:Polychaeta / Q000502:physiology*; D055871:Tidal Waves