Mature gonadal histology and gametogenesis of the tortoise beetle Aspidimorpha sanctaecrucis (Fabricius, 1792) (coleoptera: Cassidinae: Chrysomelidae): Histological observation

Abstract

© 2020, Prince of Songkla University. All rights reserved. The gonadal structure of insects has been well reported but there is a lack of such information from tortoise beetles that are an economically important insect. In this study, the gonadal structure and differentiating stage of gametogenesis of tortoise beetles Aspidomorpha sanctaecrucis are examined using the histological technique. At the level of light microscopy, our results revealed that the A. sanctaecrucis male reproductive system has a pair of testicular structures that consist of six seminiferous tubules. All zones contained various stages of spermatogenesis and could be divided into five stages depending on the shape and histological organization, particularly chromatin organization, which was divided into spermatogonia, primary spermatocytes with 8 sub-steps (leptotene, zygotene, pachytene, diplotene, diakinesis, metaphase, anaphase, and telophase), secondary spermatocytes, spermatids (two sub-steps), and spermatozoa. A pair of ovaries was observed in the female A. sanctaecrucis. Each ovary is considered to be a meroistic ovariole that exists with nurse cells. The differentiating oogenic stages including previtellogenic and vitellogenic stages were observed. Our study provides baseline data that will be useful for future work involved in the ultrastructure and physiology of the reproductive tissue in tortoise beetles, especially the differential characterizations of the seminiferous tubule and ovarian type in beetles.