Sexual Interference and Sexual Defense in the Smooth Newt, Triturus vulgaris (Amphibia, Urodela, Salamandridae)


Department of Biology, The Open University, Walton Hall, Milton Keynes MK7 6AA, England.

Abstract and Summary

  • 1When a male smooth newt encounters a ♀ who is already engaged in courtship, he may mimic her behaviour during the spermatophore deposition and transfer stages of the courtship. He thereby usurps the courting ♂ and may inseminate the ♀ himself. Such sexual interference depresses the short-term, and perhaps long-term, mating success of the courting ♂.
  • 2In the presence of a potential rival, the courting ♂ alters certain aspects of his sexual behaviour. He displays more intensely to the ♀ and attempts to draw her away from the rival by increasing the duration of his display. He may also “check” that it is the ♀, and not the rival, who will elicit the deposition of a spermatophore from him. These changes in the behaviour of the courting ♂ are interpreted as defense against sexual interference.
  • 3Female smooth newts may be multiply inseminated as a consequence of sexual interference; this may result in sperm competition. However, ♀♀ seem to find competitive interactions between ♂ ♂ “aversive”.
  • 4Sexual interference by ♀-mimicry and associated defensive behaviour patterns are common in the urodele amphibians. Interference can be thought of as a “side-payment” conditional mating strategy.