Mating behavior of a brooding Antarctic asteroid, Neosmilaster georgianus

Summary

Spawning behavior and male-female superposition of Neosmilaster georgianus, a common brooding asteroid, were observed both in the field and the laboratory at Palmer Station, Antarctica, during the austral spring of 1991. Pseudocopulation is preceded by exploration, contact, and mounting of a female by individual or multiple males. Male pre-mating activity in the field was initiated by the spawning of a nearby conspecific female. However, in laboratory experiments a similar pattern of activity was triggered by the presence of spawning conspecific males or male sea urchins, indicating the presumed inductive signal lacks specificity. Pseudocopulation in this species may ensure maximal fertilization and enhance reproductive success. This is the first reported instance of aggregative spawning in an Antarctic echinoderm. Moreover, pseudocopulation is a rare phenomenon among echinoderms worldwide and N. georgianus is only the third asteroid described to utilize this fertilization strategy.

Key words:

• Asteroid
• spawning behavior
• brooding
• Antarctica
• Neosmilaster georgianus