On the photosensitivity of the circadian time-sense in Drosophila pseudoobscura

摘要: Abstract In populations of the fruitfly Drosophila pseudoobscura reared at constant temperature, first under continuous light, and then transferred to darkness, pupal eclosion occurs in bursts 24-hr intervals. A brief pulse light resets phase this circadian rhythm by up ± 12hr, depending on its energy when it is given. The graphed dependence resembles a lattice helicoidal surfaces. new finding here detailed that rhythm's susceptibility resetting pulses 10 2 4 ergs/cm deviates systematically from strict periodism observed with more energetic stimuli: clock oscillation becomes sensitive phase-resetting longer has been kept dark. three days sensitivity increases than tenfold. This recovery process can be retarded exposure 7 erg/cm . These observations are compatible (i) linear kinetic model involving bleachable pigment which very slowly regenerates or (ii) any diversity models non-periodic—e.g. damped—circadian oscillation. either case, saturation response stimulus energies below cannot attributed quantitative removal pigment.