How female size and male displays influence mate preference in a swordtail

Building a complete model of animal behaviour requires knowing both the internal and external factors that influence behaviour. As recent genomic and neural studies begin to establish the northern swordtail, Xiphophorus nigrensis, as a model for proximate explorations of female mate preference, it is important to recognize the complexity of other factors that can drive variation in female preference. In this study, we determined how different experiential and social factors correlate with interindividual variation in female mate preference: female body size, sexual experience and male behavioural displays. We found a significant positive correlation between female size and female preference for large males, as well as a significant relationship between male activity and female preference. We also demonstrate that copulating at least once may be sufficient to increase preference for large males. Our identification of these relationships emphasizes the multiple and diverse types of mechanisms that can influence variation in female mate preference and encourage their consideration in future studies when trying to assess why and how females choose males.