Pulses of darkness shift the phase of a circadian rhythm in an insectivorous bat

Abstract

The circadian rhythm of a tropical insectivorous bat, Taphozous melanopogon, free-runs in dim light and responds to dark breaks of a few hours' duration with 'advances' and 'delays' as a function of the phase experiencing the "black out". Similarly phase shifts also follow perturbations by light breaks. The time course and the wave form of the phase response curves obtained from experiments using pulsed light and pulsed darkness are mirror images of each other.