Female mimicry in garter snakes.
In many diverse taxa, males of the same species often exhibit multiple mating strategies. One well-documented alternative male reproductive pattern is 'female mimicry', whereby males assume a female-like morphology or mimic female behaviour patterns. In some species males mimic both female morphology and behaviour. We report here female mimicry in a reptile, the red-sided garter snake (Thamnophis sirtalis parietalis). This form of mimicry is unique in that it is expressed as a physiological feminization. Courting male red-sided garter snakes detect a female-specific pheromone and normally avoid courting other males. However, a small proportion of males release a pheromone that attracts other males, as though they were females. In the field, mating aggregations of 5-17 males were observed formed around these individual attractive males, which we have termed 'she-males'. In competitive mating trails, she-males mated with females significantly more often than did normal males, demonstrating not only reproductive competence but also a possible selective advantage to males with this female-like pheromone.
D000818:Animals; D005260:Female; D012739:Gonadal Steroid Hormones / Q000097:blood; D006801:Humans; D008297:Male; D010675:Pheromones / Q000096:biosynthesis; D012726:Sexual Behavior, Animal; D012911:Snakes / Q000502:physiology*
D012739:Gonadal Steroid Hormones; D010675:Pheromones