Neurosecretory system of the adult flesh-fly Sarcophaga ruficornis F. (Diptera: Sarcophagidae)

Abstract

The histomorphology of neurosecretory cells and the retrocerebral endocrine glands of immature and mature female flesh-fly, Sarcophaga ruficornis F. have been described using the PF-staining technique in bulk and sectioned material. In the brain of S. ruficornis are found six groups of neurosecretory cells: two medial (MNC), two lateral (LNC) and two posterior (PNC). While the MNC and LNC groups consist of A- and B-cells, the PNC groups have only the B-cells. The medial groups contain about 26 A-cells and each lateral group consists of three cells: one A-cell and two B-cells. The posterior group has three B-cells. The immature fly shows a poor amount of PF-stainable material, which repletes as the fly ages. A newly-emerged fly reveals either very poor quantity of NSM or its complete absence. The corpus cardiacum (CC)-corpus allatum (CA) complex lies in front of the cardia in the anterior part of the prothorax. The CC is triangular in form and lies ventral to the aorta. In live immature flies it appears dull white and in mature flies bright silvery white. The CA is oval or elongated in shape and is situated on the dorsal side of the aorta. The CC and CA of immature individuals, occasionally show an accumulation of green material whereas the glands of mature individuals exhibit PF-stainable material of cerebral origin. In addition, CC of mature flies elaborates its own material. The corpus allatum is small in the newly-emerged flies but it increases appreciably in mature flies. From the CC a number of nerves arise and supply NSM to CA, oesophagus, crop duct and cardia. The aorta contains a fair amount of NSM in mature flies. The NSM is partly stored and released from CC and partly from the aorta.