![]() In some species, even noxious chemicals are transferred and incorporated into developing eggs to protect them from predators and pathogens ]. Moreover, antimicrobial agents in the secretions ensure that the female reproductive tract is a hospitable environment during sperm transfer and storage. The few substances that have been identified have marked effects on the reproductive success of males and females: seminal fluid proteins and peptides can decrease female receptivity, increase egg production, facilitate sperm storage, and are necessary for sperm transfer and success in sperm competition. ![]() The seminal fluid of Drosophila melanogaster contains over 80 proteins and peptides. In this group of spiders sperm should be produced throughout a male's lifetime.ĭuring mating, males not only transfer sperm, but also seminal fluid. In our focal species, Pholcus phalangioides, adult males are especially long-lived, with life-spans of up to a year. For spiders, both evolutionary scenarios are conceivable: in sexually cannibalistic spiders, males load each of their copulatory organs, the pedipalps, only once and cease to produce sperm after the final molt, which seems to be a consequence of the high incidence of monogamy that is forced upon the male by female cannibalistic attacks PM personal observation], whereas in most spider species, males can expect more than one mating. On the other hand, in species with a short reproductive time window or in species that show a considerable drop in female receptivity after a single mating, a male is expected to allocate all resources into sperm production for a single mating. Long-lived species in which males can expect several matings probably continue to produce sperm throughout their lifetime. When and for how long males produce sperm very likely depends on the mating system of the species in question. Possible functions of the various types of secretion in the seminal fluid and previously investigated female secretions are discussed in the light of sexual selection. This study reveals that spermatogenesis begins weeks before maturity and takes place continuously in the long-lived males of P. We could identify a dense matrix of secretion consisting of mucosubstances and at least three types of secretion droplets, likely consisting of proteinaceous substances. The lumina of the vasa deferentia are narrow and filled with spermatozoa and secretions. The latter are produced by the somatic cells that bear microvilli and contain many vesicles. In adult males, the wide lumina of the testes are packed with spermatozoa and secretions. The wide, proximal portion of the vasa deferentia is filled with secretion and a large number of spermatozoa, and the narrow distal part also contains secretion. In male stages approximately two weeks prior to the final molt, the lumina of the testes are wider and filled with a dense secretion. phalangioides are typical cleistospermia with individual secretion sheaths. Their vasa deferentia possess proximally a very voluminous lumen containing dense seminal fluid and few spermatozoa, whereas the distal part is seemingly devoid of contents. Testes already display all stages of spermatogenesis in subadult males (about four weeks before the final molt). In order to shed light on these aspects of the reproductive biology of spiders, we investigated the male genital system of the common cellar spider Pholcus phalangioides, with special emphasis on its development and seminal secretions. Likewise, it is unclear whether sperm are produced throughout male adulthood or only once in a lifetime, as is whether seminal secretions contain factors capable of manipulating female behavior. For example, it is unknown whether spermatozoa exist prior to-, or only after the final molt. In spiders, very little is known about the male genital system, its development and seminal secretions. Most arthropods pass through several molting stages (instars) before reaching sexual maturity.
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