BIOTIC

BIOTIC Species Information for Styela spp.

Researched by

Sean Lindsley-Leake

Data supplied by

MarLIN

Refereed by

This information is not refereed

Reproduction/Life History

Reproductive type

Permanent hermaphrodite

Developmental mechanism

Lecithotrophic

Reproductive Season

April to November

Reproductive Location

Water column

Reproductive frequency

Annual episodic

Regeneration potential

Yes

Life span

1-2 years

Age at reproductive maturity

<1 year

Generation time

<1 year

Fecundity

20000

Egg/propagule size

150 µm

Fertilization type

External

Larvae/Juveniles
Larval/Juvenile dispersal potential	10-100m	Larval settlement period	Following day
Duration of larval stage	<1 day

Reproduction Preferences Additional Information

Although it is hermaphroditic, Styela is ordinarily self-sterile. Eggs and sperm are shed between 4 and 7 P.M., and fertilization takes place when the ripe gametes from two different individuals are mixed. The mature unfertilized egg is approximately 150 microns in diameter, and has a tough membrane, the chorion, to which a few follicle cells adhere at the outer surface. Between the chorion and the egg surface, there are small, spherical inner follicle cells ("nurse cells"), which contain yellow granules. The peripheral layer of the egg is clear and contains minute yellow granules, and the central part of the egg consists of grey yolk platelets. The germinal vesicle is large and clear, and is excentrically placed, near the animal pole; it ruptures and maturation begins at about the time when the eggs are discharged. The maturation spindle remains at the metaphase of the first division until the sperm enters.

Reproduction References

Berrill, 1929, Bourque et al., 2007, Millar, 1970,