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

Authors


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.

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