Multiple insemination increases reproductive success of female Montandon'snewt (Triturus montandoni, Caudata, Salamandridae)

The adaptive significance of multiple matings for females is a matter of mu ch controversy. In insects, supplying the female's sperm reserves with port ions of fresh spermatozoa may be the main function of multiple matings. Thi s simple explanation may also be applied to other animals which produce lar ge numbers of eggs over prolonged periods of time. We tested the fertility insurance hypothesis in Montandon's newt (Triturus montandoni, Amphibia, Sa lamandridae). T. montandoni females are inseminated internally by spermatop hores they have picked up, and subsequently lay eggs fertilized by spermato zoa released from the spermatheca. We compared the reproductive success of singly and multiply inseminated females of Montandon's newt in the laborato ry. Multiply inseminated females laid more eggs and had a lower percentage of non-developing eggs than females who mated only once. Our data suggest t hat remating increases the reproductive success of multiply inseminated fem ales by replenishing sperm reserves in the spermatheca or by supplying fema les with fresh portions of spermatozoa with high fertilizing capacity.