This study investigates spermatophore production and sperm utilisation in the smooth newt Triturus v. vulgaris. Chapter one outlines the natural history of the species and describes the physiology of reproduction and the sexual behaviour of male and female smooth newts. Chapter two describes the general methodology.
Chapter three investigates the relationship between sperm accessory materials and spermatophore production. Spermatophore base height was correlated with male body size. The size of the glands that secrete the spermatophores was best predicted by body size, crest height and time post deposition.
Chapter four determines the gametic strategies exhibited by males. Males may be optimising their spermatophore output by depositing spermatophores of similar size and sperm content, but production may be limited by the availability of sperm and sperm accessory materials.
Chapter five examines the relationship between male body size and seasonal spermatophore production. Spermatophore production was correlated with body size, although crest height was the best predictor.
Chapter six investigates sperm utilisation in females. Female smooth newts may require courtship as well as insemination to induce ovulation and they may need to remate during the season in order to lay a full clutch.
Chapter seven investigates sperm utilisation due to polyspermy. Between 1 and 20 sperm may enter the ovum, although some ova were found to contain much higher numbers.
Chapter eight discusses the results from the preceding chapters. Male reproductive success may be limited by spermatophore production and by females' utilisation of sperm. Female reproductive success is related to an individual's fecundity, but this study has shown that it may be also partly determined by the number of mates obtained and the timing of insemination. Mating patterns in smooth newts may be influenced by females' requirements for sperm as well as by males' seeking multiple mates to enhance their reproductive success
