Neurosecretion and water balance in the male desert locust (Schistocerca gregaria)

Abstract

Cautery of the cerebral neurosecretory cells in the immature male desert locust results in a retention of water and a consequent dilution of the haemolymph. If such cauterized locusts are given an excess water load this is lost far more slowly than in control animals; further, water is lost at a much slower rate in water loaded decapitated males than in decapitated males given a water load containing neurosecretory material (extract of corpora cardiaca).The histology of the neurosecretory system of the adult male desert locust is in all respects similar to that of the female. In the mature male most of the cerebral neurosecretory cells are histologically “full”, and injection of distilled water into such locusts results in a significant decrease in the number of “full” cells, indicating a release of neurosecretory material. Injection of 10% sodium chloride does not result in any such change.Allatectomy of males results in an accumulation of neurosecretory material in both the cerebral neurosecretory cells and corpora cardiaca. Injection of distilled water into these locusts results in a significant decrease in the number of “full” cells and injection of 10% sodium chloride does not result in any change.These results are consistent with the idea that the cerebral neurosecretory system produces a diuretic factor. However, as yet, no observations have been made of the effects of neurosecretion on the Malpighian tubules and so the possibility that the neurosecretory system is not directly related to the general mechanism of water balance remains open.