Conditioned water affects pair formation behaviour in the marine polychaete Neanthes (Nereis) acuminata.

Assessing cues from conspecifics is paramount during mate choice decisions. Neanthes acuminata is a marine polychaete with a unique life cycle: pair formation, female death following reproduction, male parental care and male ability to mate again after egg care. Males completing such egg care are 'experienced'. Females have been shown to prefer experienced males over all others, including aggressively dominant males. As the female dies following reproduction, the reproductive success of her offspring depends upon successful parental care by the male. It is therefore vital that the female makes a good mate choice decision. This paper shows that the use of conditioned water from males caring for eggs and newly experienced males caused the female to alter her choice to a previously undesired male. However, conditioned water from males, which had reproduced but were isolated for 2 weeks, did not have the same effect on pairing behaviour. This indicates that the smell of experience is short lived.

Experience matters: females use smell to select experienced males for paternal care.

Mate choice and mating preferences often rely on the information content of signals exchanged between potential partners. In species where a female's reproduction is the terminal event in life it is to be expected that females choose high quality males and assess males using some honest indicator of male quality. The Nereidid polychaete, Neanthes acuminata, exhibits monogamous pairing and the release of eggs by females terminates her life and larval success relies entirely on a male's ability to provide paternal care. As such females should have developed reliable, condition-dependent criteria to choose mates to guarantee survival and care for offspring. We show that females actively chose males experienced in fatherhood over others. In the absence of experienced males dominance, as evident from male-male fights, is utilized for mate selection. The preference for experienced males is not affected by previous social interactions between the individuals. We show that the choice of the partner is based on chemical signals demonstrating a 'scent of experience' to females providing evidence for the role of chemical signals in sexual selection for paternal care adding to our understanding of the mechanisms regulating condition-dependent mate choice.