Structural and ultrastructural characters of the reproductive tract in females of the mint leaf beetle Chrysolina herbacea (Duftschmid 1825) (Coleoptera: Chrysomelidae)

Abstract

In this study, Chrysolina herbacea female reproductive system, differentiating stages of vitellogenesis, the egg chorion are examined with light and scanning electron microscopies. C. herbacea is chosen for this study because it is considered to be one of the most harmful insects that destroy mint plants, and it is an agricultural pest. Female reproductive system consists of a pair of ovaries, a pair of lateral oviducts, a common oviduct, spermathecae and a genital chamber. The ovary has 18 meroistic telotrophic ovariole. Each ovariole is divided into four regions: terminal filament, germarium, vitellarium and pedicel. Terminal filament is a long tubular structure. Germarium contains trophocytes (nurse cells), young oocytes and prefollicular cells. Vitellarium consists differentiating oogenic stages including developmental periods of previtellogenesis, vitellogenesis and choriogenesis. The ovarioles open into lateral oviduct by pedicel. The single spermatheca is located near the base of the common oviduct. Spermathecae consist of spermathecae reservoir for sperm storage and a short spermathecae duct. C. herbacea eggs are yellow and elongated. The structure of female reproductive system, the egg chorion and larva of C. herbacea are important to understand the outbreak of this insect pest and to biological control this harmful species.