Sperm Storage, Internal Fertilization, and Embryonic Dispersal in Vent and Seep Tubeworms (Polychaeta: Siboglinidae: Vestimentifera)

Abstract

Vestimentiferan tubeworms are ecologically important members of deep-sea chemosynthetic communities, including hydrothermal vents and cold seeps. Some are community dominants and others are primary colonists of new vent sites; they include some of the longest living and fastest growing marine invertebrates. Their mechanisms of propagation, dispersal, and genetic exchange have been widely discussed. Direct sperm transfer from males to females has been documented in one species, Ridgeia piscesae, but others are known to discharge what are apparently primary oocytes. Brooding of embryos has never been observed in any vestimentiferan. These observations have led to the supposition that fertilization might be external in most species. Here we report sperm storage at the posterior end of the oviduct in five species, including tubeworms from both vents and seeps. We show experimentally that most eggs are inseminated internally, that fertilization rate is typically lower than 100%, that meiosis is completed after eggs are released from the female, and that the dispersal phase includes the entire embryonic period.

Spatial and temporal dynamics of reproduction and settlement in the Pompeii worm Alvinella pompejana (Polychaeta: Alvinellidae)

“…Because some of these characteristics are shared between most hydrothermal polychaetes (Zal et al 1994, Copley et al 2003, Hilario et al 2005, we propose that they represent a recent adaptive convergence to vent patchiness and instability, in order to minimise the extinction risk for the species.…”

“…They all showed peculiar adaptive convergence on reproductive mode and larval development. Indeed, most of them display continuous oogenesis (McHugh 1989, Copley et al 2003, Pradillon et al 2005, organs for oocyte storage with spermathecae and thus internal fertilisation of oocytes (Zal et al 1994, Jollivet et al 2000, Hilario et al 2005. These species are also characterised by a high fecundity relative to their body size and produce mature oocytes of great size consistent with the hypothesis of lecithotrophic or direct development (McHugh & Tunnicliffe 1994, Zal et al 1995, Jollivet et al 2000.…”

A place for nourishment or a slaughterhouse? Elucidating the role of spermathecae in the terrestrial annelid Hormogaster elisae (Clitellata: Opisthopora: Hormogastridae)

“…Female sperm storage has been observed in many different animal groups, both vertebrates Holt and Lloyd 2010) and invertebrates, such as Insecta (e.g., Hellriegel and Bernasconi 2000), Mollusca (e.g., Beese et al 2009), and Annelida (e.g., Hilario et al 2005;Jamieson 2006), including Opisthopora (e.g., Jamieson 1981;Edwards and Bohlen 1996), but further studies are needed to completely understand this peculiar reproductive strategy. Sperm storage in the female body allows the spermatozoa to be used for fertilization some time after mating, which is particularly useful for Opisthopora living in the soil, because in this cryptic milieu, favorable conditions are discontinuous in time and space.…”

Spatial and temporal population genetics at deep-sea hydrothermal vents along the East Pacific Rise and Galapagos Rift

“…Eggs are small, yolky, lipid-rich (Cary et al 1989), and near-neutrally buoyant . Sperm released into the water column are then stored in ovarian spermatheca, and imperfect (< 100%) fertilization occurs internally before oocyte release (Hilário et al 2005). Riftia embryos presumably undergo initial development at depth, as it has been demonstrated that they require ambient pressure in order to progress to the larval stage ).…”

“…Sperm released into the water column are then stored in ovarian spermatheca, and imperfect (< 100%) fertilization occurs internally prior to oocyte release (Hilário et al 2005). Riftia embryos develop at depth ).…”