The histology of the first batch of eggs and their associated tissues in the ovariole of Dysdercus fasciatus signoret (heteroptera: Pyrrhocoridae) as seen with the light microscope.

Abstract

In the telotrophic ovarioles of Dysdercus fasciatus, mononucleate, binucleate and multinucleate trophocytes are seen in the germarium. Cellular breakdown of the multinucleate cells is seen in the posterior part of this tissue. The nutritive cords, which are continuous with the trophic core at the one end and the oocytes of the vitellarium at the other, contain material of fibrous appearance which continues into the trophic core. The ovariole is enclosed in two sheaths throughout its length. Prefollicular tissue in the germarium appears to give rise to the follicle cells. Mitosis is common in this zone. Oocytes are at first surrounded by a multilayered epithelium. This is later reduced progressively to one layer. This one layered follicular epithelium is at first columnar but then changes to cuboidal mononucleate, cuboidal binucleate and finally to a squamous binucleate condition This epithelium thus seems to accommodate the increased volume of the oocyte by growth and a change of shape. The oocyte grows fastest at those times when it is surrounded by cuboidal and squamous epithelial cells.