Male Discrimination of Larger, More Fecund Females in the Smooth Newt, Triturus vulgaris

Abstract

ABSTRACr. -Theory predicts that if males invest nothing in their offspring except genes, they should maximize their reproductive success by fertilizing as many eggs as possible. Male smooth newts (Triturus vulgaris) have a limited capacity for multiple mating (which would result in a high fertilization rate) due to limitations in sperm and spermatophore supply. It is demonstrated that the fecundity of female newts varies with body size; large females both contain and lay more eggs than smaller females. Using proximity to restrained females as an indicator of discrimination and mate choice, males preferred visual cues associated with large females. Using a Y-maze olfactometer device, data were obtained which suggest that males preferred the odor of large females. These results support the hypothesis that male T. vulgaris prefer larger, more fecund females as mates,