Sea-spider  (Nymphon gracile)

Biology

This sea-spider feeds on a variety of animals, such as small marine worms, sea-anemones and whelk egg-capsules (2). Individuals migrate to the sublittoral zone during the winter breeding season.

The sexes are separate, and males and females cling together during fertilisation. The eggs are released from openings at the base of the female's legs, and are fertilised externally (2). The male carries the eggs around on the special egg-carrying appendages. The larvae are similar in appearance to the adults, and undergo a series of moults before reaching the adult stage after five months. The average life-span is thought to be around one year (2).