title: Phase-shifting the light-dark cycle influences food-anticipatory activity in golden shiners.
abstract: This study provides evidence that a circadian light-entrainable oscillator is at least partially involved in the timing of food-anticipatory activity (FAA) in a fish, the golden shiner, Notemigonus crysoleucas. Shoals of four golden shiners were fed for 11-20 days at a fixed daily time (either early night, midnight, late night, early day, midday, or late day). Most (78%) shoals developed peaks of FAA during that period of time. Food was then withheld for 7 days, and the light-dark (LD) cycle was either advanced or delayed by 6 h on the first of those days. The activity waveform of most (53-58%) shoals shifted along with the LD cycle, as indicated by significant correlation coefficients between pre- and postshift waveforms plotted relative to LD. Nonsignificant correlations were linked to low activity levels rather than to persistence of the activity peak at the old clock time. Activity shifts were gradual, taking 2-4 days, which indicates that the underlying mechanism is circadian rather than hourglass.
authors.affiliation: Département de biologie, Université de Moncton, NB, E1A 3E9, Moncton, Canada.
authors.forename: M
authors.initials: M
authors.lastname: Lague
authors.forename: S G
authors.initials: SG
authors.lastname: Reebs
mesh_terms: D000818:Animals; D002940:Circadian Rhythm / Q000502:physiology*; D003463:Cues; D003530:Cyprinidae / Q000502:physiology*; D005247:Feeding Behavior / Q000523:psychology*; D008960:Models, Psychological; D009043:Motor Activity / Q000502:physiology; D017440:Photoperiod