The relationships between the brain, corpora allata, and oöcyte growth in the Central American locust, Schistocerca sp.—I. The cerebral neurosecretory system, the corpora allata, and oöcyte growth

Abstract

In the adult female Central American locust, only slight changes occur in the amounts of stainable material in the neurosecretory system as the insect matures. However, the corpora allata undergo striking changes in volume and appearance during the course of maturation. Material from the median neurosecretory cells cannot be seen in the nerves which innervate the corpora allata, but lateral cell neurosecretion, which differs in histochemical properties from that of the median cells, can be detected in the nerves. Extirpation of the cerebral neurosecretory cells prevents oögenesis, but this operation also inhibits the activation of the corpora allata, which are essential for oöcyte growth. While oöcyte development is completely prevented by allatectomy, implanted corpora allata will not restore maturation. If immature corpora allata are implanted they do not become active, and if mature glands are used they rapidly lose their activity. In order to become and remain active, corpora allata must retain intact connexions with the central nervous system.