My dissertation focuses on the factors that influence variation in female reproductive success in plethodontid salamanders and in toads. Variation in reproductive success fuels evolutionary change. Although, females often have been overlooked in studies of reproductive success due to perceived lower levels of variation when compared to variation in male reproductive success, understanding factors influencing variation in female reproductive success is critical for several reasons. First, female reproduction is usually the limiting factor on population growth. Second, the factors affecting female reproduction provide the impetus for current and evolving patterns of sexual dimorphism. Lastly, male reproductive success inevitably is determined by the reproductive success of the females with which they mate. Recent theoretical developments of sexual conflict have contributed significantly to a renewed emphasis on studies of female reproductive success. Sexual conflict theory elucidates important factors, from the perspective of females, affecting female behavior and reproductive success. Sexual conflict assumes that a female will benefit, in terms of reproductive success and offspring viability, when she is able to freely choose among males, unconstrained by social and environmental factors. Female choice would be constrained if a non-preferred male (i.e., one that would be rejected by a freely choosing female) coerced a female to mate in order to increase his own mating success. The dynamics between discriminating females and non-preferred males will lead to a coevolutionary "arms race", referred to as sexual conflict. From this perspective, secondary male traits may not reflect their intrinsic quality, but rather their ability to manipulate or coerce female mating decisions. The current debate lies in the importance and pervasiveness of sexual conflict. To address the current view of sexual conflict, I investigated whether sexual conflict plays a role in the mating systems of amphibians. In particular, my results support the main assumption that females benefit from freely expressed female mate choice in toads. In addition, I explored the potential influence of sexual conflict in plethodontid salamanders. During mating trials, I documented novel female courtship behaviors. I also examined the effects of male courtship pheromones on female reproductive success to assess the potential role of male pheromones in sexual conflict. My results suggest that sexual conflict also may be an important factor in plethodontid mating systems. My investigations of sexual conflict theory have provided new insights and novel predictions for understanding sexual selection and sexual dimorphism. / Graduation date: 2005