Reproduction and Larval Biology
S. luhuanus is a dioecious species (sexes separate), with males and females becoming distinct from each other after about 20 months of age (Catterall and Poiner, 1983). Fertilisation is internal and via copulation, where the male inserts his penis under the lip of the females shell (Catterall and Poiner, 1983). Males and females aggregate in dense mating aggregations (refer to Local distribution and habitat page), and copulating pairs and trios (two males with one female) are evident (Catterall and Poiner, 1983; Wiedemeyer, 1998).
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Figure 1: A male and female engaged in mating activity. The male mounts the female and inserts his penis underneath the lip of the females shell to copulate. |
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After reproduction occurs, females lay large (5-25m long), tubular, gelatinous egg masses, which are very adhesive and can attach to sand and/or hard substrates (Wiedemeyer, 1998). These egg masses contain hundreds of thousands of eggs, but larval survival is very low (Wiedemeyer, 1998).
Weidemeyer (1998) found that on average, eggs take 92 hours to develop into swimming veliger larvae. He also found that the approximate pelagic larval duration of S. luhuanus individuals was 16.5 - 17.4 days. The eggs of S. luhuanus develop faster than most other strombid gastropods (less than 4 days as opposed to 5-7 days) (Wiedemeyer, 1998).
Major problems for larvae are parasitism (by protozoans) and predation (by copepods) (Wiedemeyer, 1998).
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