The influence of feeding upon the activity of the neuroendocrine system during oocyte growth in Tenebrio molitor

Abstract

In Tenebrio molitor the production of midgut proteases is dependent upon the activity of the neurosecretory cells and not upon the activities of the corpora allata or the ovaries. The secretory activity of the neurosecretory cells can thus be judged on the basis of protease production as well as oocyte production. Neurosecretory cells devoid of stainable material can have very different secretory activities. Inactive neurosecretory cells may be full of, or devoid of, stainable material. In crowded virgins, the stimuli from feeding, irrespective of diet, result in some protease and some oocyte production. Little oocyte or protease production occurs in starved virgin females; in these females the stimuli from crowding alone have no effect upon oocyte and protease production. The neuroendocrine system is activated during the imaginal moult and the continued production and release of neurosecretion and corpus allatum hormone occurs only if the females are fed. The secretory activity of the corpora allata is not related to the size of the glands. Results from experiments in which the diet is varied, and from others involving section of the nervi corporis cardiaci I (NCCI) show that gland size is controlled by humoral factors and via the NCCI, whereas release of hormone is controlled via the NCCI.