Biology

Reproduction and lifecycle

Agalma elegans has never been bred in a laboratory, because it is too fragile to keep in captivity.

Each animal produces male and female organs, the gonophores, and these mature at different times to prevent self-fertilisation. Eggs or sperm are released by different individuals, and fertilisation takes place externally in sea water.

One cormidium of the siphosome of Agalma elegans

One cormidium of the siphosome of Agalma elegans, showing the gastrozooid with a tentacle bearing many tentilla, palpons, bracts, and male and female reproductive organs. © Keith Hiscock (MBA, Plymouth)

The fertilised egg grows into a small siphonula larva which at first develops:

  • a single swimming bell 
  • 1 mouth with a tentacle

Gradually, as growth proceeds:

  • more swimming bells are added from a budding (or growth) zone at the anterior end, just behind the float
  • more cormidia are added from a second more posterior budding zone just behind the swimming bells

Finally, the animal matures and the lifecycle begins again. 

The length of time taken to complete the lifecycle is unknown.