Kinetics in metabolic control of time measurement in photoperiodism

Abstract

The period length of the locomotor activity rhythm of Drosophila melanogaster wild form is under conditions of continuous weak red light 23.38 h, whereas die eye mutants Ly3 with a 23.71 h mean period and JK 84 with 23.14 h differ significantly. This might be due to a changed perception of light and not the result of a change in the circadian pacemaker by the mutation.

The mutant sine oculis exhibits a normal activity rhythm if the complex eyes are not completely reduced. If this is the case, the activity pattern is either less rhythmic, composed of several rhythms with different periods or truely arrhythmic depending on the individual fly.

Since the mutation in sine oculis affects in addition to the complex eye the distal part of die medulla and the lamina of the optic lobe, it is suggested that the circadian pacemakers for the locomotor activity rhythm is localized in these parts.