Behavioral and Molecular Ecology Group, Department of Biological Sciences, University of Wisconsin-Milwaukee, Milwaukee, WI 53201, United States.
J Evol Biol. 2024 Nov 2;37(11):1278-1287. doi: 10.1093/jeb/voae109.
The mate choice behaviours of females can greatly affect patterns of reproductive success in males and influence the evolution of sexually selected male traits. Population-level estimates of display preferences may provide an accurate estimate of the strength and direction of selection by female choice if all females in the population show homogeneous preferences. However, population-level estimates may yield misleading estimates if there is within-population variation in mate preferences. While it is increasingly clear that the latter situation is common in nature, empirical data on the magnitude of variation in female preferences are required to improve our current understanding of its potential evolutionary consequences. We explored variations in female preference functions for 3 male call properties in a treefrog. We document substantial within-population variation not only in peak preferences but also in preference function shape (open, closed, flat), with at best 62% of females sharing a preference function shape with the respective population curve. Our findings suggest that population curves may accurately capture the direction of sexual selection, but depending on the properties of the constituting individual functions they may over- or underestimate the strength of selection. Particularly population estimates suggesting weak selection may in fact hide the presence of individual females with strong but opposing preferences. Moreover, due to the high within-population variation in both peak preferences and preference function shapes, the population functions drastically underestimate the predicted variation in male mating success in the population.
雌性的择偶行为会极大地影响雄性的繁殖成功率模式，并影响性选择雄性特征的进化。如果种群中的所有雌性都表现出同质的偏好，那么对展示偏好的种群水平估计可能会对雌性选择的强度和方向提供准确的估计。然而，如果存在种群内的配偶偏好差异，那么种群水平的估计可能会产生误导性的估计。虽然越来越明显的是，在后一种情况下，这种情况在自然界中很常见，但需要有关雌性偏好变化幅度的经验数据，以提高我们目前对其潜在进化后果的理解。我们探索了树蛙中 3 种雄性叫声特性的雌性偏好函数的变化。我们记录到不仅在峰值偏好方面，而且在偏好函数形状（开放、封闭、平坦）方面都存在着大量的种群内变异，只有最好的 62%的雌性与各自的种群曲线具有相同的偏好函数形状。我们的发现表明，种群曲线可能准确地捕捉到了性选择的方向，但取决于构成个体函数的性质，它们可能会高估或低估选择的强度。特别是，种群估计表明弱选择的情况实际上可能隐藏了具有强烈但相反偏好的个体雌性的存在。此外，由于峰值偏好和偏好函数形状的种群内变异都很高，种群函数极大地低估了种群中雄性交配成功率的预测变化。
