Chapter 13 - Accessory Reproductive Glands

Abstract

Accessory sex glands (ASG) in Crustacea show diversity in morphology and their location with respect to gonadal ducts. The primary function of ASG is its role in gamete transport and protection during their transit to the site of fertilization. In the males, such functions are taken over by the vas deferens, which secretes copious quantities of seminal substances, and produces spermatophores. In addition, seminal secretions enable sperm maturation and capacitation. Nevertheless, discrete male ASG have been reported in several brachyuran crabs. Their secretions contain cathepsin-like proteases that aid in the digestion of spermatophore envelopes within the spermatheca. Male accessory secretions also modify female reproductive behavior and activate spermatozoa in spermatheca before fertilization. In stomatopods, male ASG secretions are absorbed into the hemolymph and then passed on to the ovary for incorporation as yolk protein. In the females, the presence of seminal receptacle or spermatheca is the only ASG in the brachyuran crabs. However, several of the nonmalacostracan forms possess different female ASG. Examples are shell glands, ovisac glands, tegumental glands, and cement glands. They secrete egg shell envelopes and help in the attachment of egg masses to the pleopods.