BIOTIC Species Information for Aphrodita aculeata
|Researched by||Lizzie Tyler||Data supplied by||University of Sheffield|
|Refereed by||This information is not refereed.|
|Reproductive Season||winter - spring||Reproductive Location||Water column|
|Reproductive frequency||Annual episodic||Regeneration potential||No|
|Life span||6-10 years||Age at reproductive maturity||1-2 years|
|Generation time||Insufficient information||Fecundity|
|Egg/propagule size||Fertilization type||External|
|Reproduction Preferences Additional Information||Little information on the reproduction and development of this species was found.
Aphrodita aculeata is dioecious, i.e. has separate sexes. In females, the ova (eggs), and in males the sperm, develop from the peritoneal sheath of the blood vessels (except the major dorsal and ventral vessels and branches close to the intestine) (Fordham, 1925). The ova and sperm are released into the body cavity (coelum) where the sperm complete their development. Mature females can be identified by 'cream coloured' eggs visible through the thin walls of the parapodia. In mature males the coelum is filled with a milky fluid, i.e. sperm (Fordham, 1925). No spermatophore was observed, although sperm may be arranged in groups of up to four (Fordham, 1925). Presumably large numbers of eggs and sperm are released although no estimate of fecundity was found.
Sperm and ova are shed through the nephridia (the annelid excretory organs) and their nephridiopores on the dorsal surface (Fordham, 1925). Mature males and females were observed at Plymouth in October, when males were seen to spawn, although mature specimens were also collected in March (Fordham, 1925). Fordham (1925) also reported mature individuals in May and spawning in June (location unknown), and mature females in the Naples area in September. Individuals were observed spawning off Rame, Plymouth in November 1923 and mature females were collected in the Plymouth area in September 1930 (MBA, 1957). Thorson (1946) reports spawning in the Naples area in January and February, in aquaria in Naples in March, and mature females in the St Andrews area in May. Overall, Thorson (1946) suggested that spawning occurred in winter and spring.
Larval development is probably but not necessarily similar to related species of Aphroditidae such as Hermonia hystrix and to a lesser degree to members of the Polynoidae such as Harmothoe lunulata (as imbricata). Larval development is lecithotrophic in the Aphroditidae so far studied i.e. Hermonia hystrix (Rouse & Pleijel, 2001). The larva is probably a ciliated, free-swimming trochophore, which develops into a juvenile composed of only a few segments on settlement. The larvae of Hermonia hystrix has a long pelagic phase (von Draschke, 1885 cited in Thorson, 1946). However, although Aphrodite aculeata were very common in the Øresund and, therefore, their larvae were expected to be common in the plankton, none were found in a four year period (Thorson, 1946). Therefore, Thorson (1946) suggested that the larvae of Aphrodite aculeata either had a very short pelagic phase or non-pelagic development. However, no information on the larval development of this species was found.
|Reproduction References||Fordham, 1925, Thorson, 1946, Schroeder, 1989, Rouse & Pleijel, 2001, MBA, 1957, Schroeder & Hermans, 1975, Julie Bremner, unpub data,|