Female alitta virens produce a pheromone attracting and signalling the males to shed sperm which in turn stimulates females to shed eggs, this behavior is known as swarming which is how the worms reproduce. Gametes are spawned through the metanephridia or body wall rupturing (termed as "epitoky", wherein a pelagic, reproductive individual, "epitoke", is formed from a benthic, nonreproductive individual, "atoke").

After fertilization, most eggs become planktonic(organisms that float or drift in water); although some are retained in the worm tubes or burrowed in jelly masses attached to the tubes (egg brooders). The eggs then develop into trocophore larva, which later metamorph into juvenile stage (body lengthened), and later develop into adults.

(Ruppert, E.E., R.S. Fox and R.D. Barnes, 2004)