The larvae of
Bathymodiolus thermophilus drift with the currents and are planktotrophic, feeding on
phytoplankton and small
zooplankton. This method of feeding is likely to give them good dispersal capabilities and it has been shown by
DNA analysis that there is a high rate of
gene flow between populations round different vents. The
Bathymodiolus species represents one of the most well-known fauna to colonize hydrothermal vents and cold seeps. In particular,
B. thermophilus has been extensively studied due to their chemosynthetic symbioses and their crucial roles in ecosystem productivity. In early stages of development, deep-sea mussels appear to follow similar growth processes of
gametogenesis in comparison to shallow-water
mytilidae. It has been observed that Bathymodiolins produce small oocytes which may predict high fecundity levels for this species. While there are limited studies regarding fecundity of
B. thermophilus, one way to improve understanding of both fecundity as well as spawning patterns would to observe a spawning event with use of yearly sampling. Adult stages of the bathymodioline species have received the most attention, especially when studying the bacterial symbionts that are fundamental to the mussels nutritional needs. When reaching maturity, adults form close aggregations along seeps and vents. The mantle of
B. thermophilus serves two physiological roles, one being the accumulation of somatic reserves, and the other being the development of the gonads. Gonads likely originate from germinal stem cells that appear in germinal stem-cell clumps around the dorsal region, between the mantle and the gill of the animal. In larger adult specimens, gonads can extend along the mantle epithelium.
Gametogenesis occurs in small saclike cavity in a matrix of connective tissue supplied with seminal cells. In males,
sertoli cells deliver nutrients to the developing gametes, where follicle cells perform the analogous role in female mussels. == Symbiosis and feeding ==