Female mimicry in garter snakes

Area of Science:

• * Evolutionary Biology
• * Animal Behavior
• * Herpetology

Background:

• * Males in many species display diverse mating strategies, including alternative reproductive patterns.
• * Female mimicry, where males adopt female morphology or behavior, is observed across taxa.
• * Previous research has documented female mimicry in various animals, but not previously in reptiles.

Purpose of the Study:

• * To investigate the phenomenon of female mimicry in the red-sided garter snake (Thamnophis sirtalis parietalis).
• * To identify the specific mechanism of female mimicry in this reptile species.
• * To assess the reproductive advantage of males exhibiting this unique trait.

Main Methods:

• * Field observations of mating aggregations in red-sided garter snakes.
• * Identification and analysis of pheromones released by males.
• * Competitive mating trials comparing 'she-males' with normal males.

Main Results:

• * A subset of male red-sided garter snakes exhibit physiological feminization, releasing female-specific pheromones.
• * These 'she-males' attracted mating aggregations of 5-17 other males in field observations.
• * In competitive trials, 'she-males' achieved significantly higher mating success with females compared to normal males.

Conclusions:

• * Female mimicry, characterized by physiological feminization and pheromone release, is a novel reproductive strategy in the red-sided garter snake.
• * This strategy appears to confer a selective advantage, enhancing mating opportunities with females.
• * The discovery highlights the complexity of male reproductive behaviors and the evolution of alternative mating strategies in reptiles.