TIME-DEPENDENT EFFECTS OF DAILY THERMOPERIODS, FEEDING, AND DISTURBANCES ON SCALE ALLOGRAFT SURVIVAL IN THE GULF KILLIFISH, FUNDULUS-GRANDIS

The length of time required to reject scale allografts was examined in groups of male gulf killifish (Fundulus grandis) treated daily with e ither 4-h thermoperiods (daily intervals of 30 degrees C during a 20 d egrees C continuum), single meal feedings, or net-chasing disturbances at one of six different times after the onset of daily photoperiods ( LD 12:12 or LD 14:10). Scale allograft survival varied by 30-60% in ea ch timed stimulus experiment as a function of the time of day when the stimulus was provided. The phase relationship between two circadian n euroendocrine oscillations, previously proposed to regulate physiologi c and behavioral conditions in gulf killifish, may have important infl uences on the immune system as well. The phase of one oscillation is t hought to be set by the daily photoperiod, and the other is preferenti ally set by the nonphotic daily stimulus. (C) 1995 Wiley-Liss, Inc.