Reciprocal behaviour associated with altered homeostasis and photosensitivity of Drosophila clock mutants.

The circadian oscillators of genetically short-period and long-period Drosophila exhibit reciprocal behaviour in four distinct ways: (1) with respect to the dependence of period on temperature, (2) in the change of period during constant darkness after ten days of constant light, (3) in the change of period during the second ten days of darkness as compared with the period during the first ten days, and (4) in the period change resulting from exposure to low-intensity constant light. The homeostatic control of the dependence of period length on temperature is impaired in the mutants as compared with wild-type files. The normal Drosophila pacemaker may comprise two mutually coupled oscillators, whereas the mutants may represent a reduction in activity of one or the other constituent oscillator.

The amplitude of circadian oscillations: temperature dependence, latitudinal clines, and the photoperiodic time measurement.

This paper develops several propositions concerning the lability of the amplitude of Drosophila circadian pacemakers. The first is that the amplitude of the pacemaker's motion, unlike its period, is markedly temperature-dependent. The second is that latitudinal variation in pacemaker amplitude (higher in the north) is responsible for two very different sets of observations on Drosophila circadian systems at successively higher latitudes.

Reciprocal behaviour associated with altered homeostasis and photosensitivity of Drosophila clock mutants.

The circadian oscillators of genetically short-period and long-period Drosophila exhibit reciprocal behaviour in four distinct ways: (1) with respect to the dependence of period on temperature, (2) in the change of period during constant darkness after ten days of constant light, (3) in the change of period during the second ten days of darkness as compared with the period during the first ten days, and (4) in the period change resulting from exposure to low-intensity constant light. The homeostatic control of the dependence of period length on temperature is impaired in the mutants as compared with wild-type flies. The normal Drosophila pacemaker may comprise two mutually coupled oscillators, whereas the mutants may represent a reduction in activity of one or the other constituent oscillator.

Latitudinal clines in the properties of a circadian pacemaker.

The circadian rhythm of eclosion activity and its pacemaker were analyzed in a series of latitudinal races of Drosophila auraria ranging from 34.2 degrees to 42.9 degrees N in Japan.