Biological Clocks and Their Interactions in Insects

摘要

The research described falls into four sections: (a) Histological investigations into the activity of the neurosecretory cells in the cockroach suboesophageal ganglion show that no clear changes ocur in the stainable secretory material in these cells to parallel the animal's circadian locomotor activity cycle. The nuclei of some of these cells showed a possible circadian cycle of change in volume. (b) A method of bioassaying pharmacologically active extracts of cockroach tissues was set up. After initial trials it was considered that the necessary further development of the apparatus was not warranted. (c) Operations on the nervous system of cockroaches confirmed that the clock mechanism controlling the activity cycle could function without direct nervous connection between the sub-oeosophageal ganglion and the corpora cardiaca. (d) The rate of development of Drosophila pupae is affected by factors following a circadian rhythm. The form of the rhythm is determined by both light-on and light-off signals, but the timing of the rhythm is determined by the two signals acting independently of each other. The circadian rhythm of eclosion of Drosophila cultures is shown to be the result of the summation of different individual rhythms of development at earlier stages. (Author)