Reproductive system: male

Abstract

Introduction Insects vary greatly in their reproductive anatomy, behavior and physiology. This chapter provides a general overview of the male reproductive system, including the mechanisms of copulation and insemination. It describes in Section 12.1 the basic elements of the internal anatomy, which include the testes that produce sperm, the vas deferens and seminal vesicles for their storage prior to ejaculation and the accessory glands that manufacture seminal fluids that mix with sperm to form the ejaculate and, in species in which insemination is indirect, the spermatophore in which the ejaculate is housed when passed to the female. Section 12.2 provides a detailed overview of the ultrastructure of insect spermatozoa and the processes of spermatogenesis. Section 12.3 describes the various means by which insemination is accomplished, covering a description of the male external genitalia, copulation and the transfer of sperm to the female reproductive tract. Finally, Section 12.4 discusses the various effects of mating on female nutrition and physiology that are brought about by accessory gland products that are transferred to females as part of the ejaculate. Anatomy of the internal reproductive organs The male reproductive organs typically consist of a pair of testes connecting with paired seminal vesicles and a median ejaculatory duct (Fig. 12.1). In most insects there are also a number of accessory glands which open into the vasa deferentia or the ejaculatory duct.