Ovary Structure and Oogenesis of Trypophloeus klimeschi (Coleoptera: Curculionidae: Scolytinae)

Jing Gao,Hui Chen,Jiaxing Wang

doi:10.3390/insects12121099

Abstract

Simple SummaryColeoptera is the largest animal taxon, with many species being agricultural and forest pests. The phylogeny of these species has aroused great interest among scientists. The characteristics of ovariole structure and ultrastructure are useful for phylogenetic work, especially with the improvement of micro technology in recent years. The types of ovarioles are varied. Usually, each family conforms to one type or another. However, in this study, we report on the ovaries of Trypophloeus klimeschi (Coleoptera: Curculionidae: Scolytinae), and find a different ovariole type from that of other known species of Curculionidae. We describe the features of the female reproductive system, ovary and oogenesis of T. klimeschi and also compare these features with those found in other Curculionidae. This study provides novel information on the reproductive biology of the Curculionidae.The female reproductive system, ovary structure and ultrastructure of Trypophloeus klimeschi (Coleoptera: Curculionidae: Scolytinae) were investigated using light microscopy, scanning electron microscopy, and transmission electron microscopy. Its female reproductive system is comprised of two ovaries (each ovary has two ovarioles), lateral oviducts, common oviduct, spermathecal sac, spermathecal pump, two accessory glands and bursa copulatrix. Well-developed endoplasmic reticulum can be clearly seen in the secretory cells of spermathecal sac. This species has telotrophic meroistic ovarioles that are comprised of terminal filament, tropharium, vitellarium and pedicel. The terminal filaments are simple; each is comprised of cellular peritoneal sheath. The presence of several clusters of nurse cells in the tropharium is indicative that its ovarioles conform to the transition stage. This indicates that there are at least two different types (transition stage and secondary stage) of ovarioles in Curculionidae.

Highlights

Coleoptera is by far the largest animal taxon
The female reproductive system of T. klimeschi is comprised of two ovaries, two lateral oviducts, a common oviduct, a spermathecal sac, a spermathecal pump, two accessory glands (Figure 1A) and a bursa copulatrix (Figure 1B)
Each ovariole is embraced by the peritoneal sheath and acellular basal lamina (Figures 4E and 5B)

Summary

Introduction

Coleoptera is by far the largest animal taxon It includes so many species associated with human production and living. The phylogeny of this order of insects has aroused great interest among scientists [1,2]. The female reproductive system is a traditional characteristic of internal organs [9,10,11,12,13,14,15,16,17,18]. With the improvement of micro technology in recent years, the research of female reproductive system is moving into more microscopic areas, like the structure and development of ovarioles [19,20,21]

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