Recurrent evolution of small body size and loss of the sword ornament in Northern swordtail fish.

Across the tree of life, species have repeatedly evolved similar phenotypes. While well-studied for ecological traits, there is also evidence for recurrent evolution of sexually selected traits. Swordtail fish (Xiphophorus) is a classic model system for studying sexual selection, and female Xiphophorus exhibit strong mate preferences for large male body sizes and a range of sexually dimorphic ornaments.

Strength of female mate preferences in temperature manipulation study supports the signal reliability hypothesis.

Both sexually selected traits and mate preferences for these traits can be context dependent, yet how variation in preferred traits could select for context dependent preferences has rarely been examined. The signal reliability hypothesis predicts that mate preferences vary across contexts (e.g.

Genotype and growth rate influence female mate preference in Xiphophorus multilineatus: Potential selection to optimize mortality-growth rate tradeoff.

The extent to which mate preferences are adaptive requires a better understanding of the factors that influence variation in mate preferences. Xiphophorus multilineatus is a live-bearing fish with males that exhibit alternative reproductive tactics (courter/sneaker). We examined the influence of a female's genotype (courter vs sneaker lineage), growth rate, and social experience on mate preference for courter as compared to sneaker males.