Is individual recognition involved in the maintenance of pair bonds in Ophryotrocha diadema (Dorvilleidae Polychaeta)?

Ophryotrocha diadema is a simultaneous hermaphroditic worm whose peculiar m ating system involves forming pairs within which partners exchange eggs rep eatedly in a kind of serial monogamy. To test whether direct recognition of the former partner exists in this species we checked whether two familiar partners, after a short separation, spawned again without engaging in a new courtship. In contrast, non-familiar partners were expected to invest a lo nger time in courtship before spawning again. Results indicate that no dire ct individual recognition of a former mate exists and that only indirect cu es are used to identify former partners.