Male mate choice occurs in several animal species, but we know little about the factors that influence the expression of this behaviour. Males vary in their capacity to acquire mates (i.e. male quality), which could be crucial to male mate choice expression but it is often overlooked. Using a meta-analytical approach, we explore interindividual variation in the expression of male mate choice by comparing the mating investment of males of different qualities and phenotypes to high- and low-quality females. We used two datasets that together contained information from 60 empirical studies, comprising 52 species. We found that males of all qualities and phenotypes prefer high-quality females, but differ in the strength of such preference. High- and medium-quality males are choosier than low-quality males. Similarly, males that are larger or in greater body condition are choosier than their counterparts. In contrast, male body mass and age are not associated with changes in male mate choice. We also show that experimental design may influence our understanding of male mating investment patterns, which may limit the generalisation of our findings. Nonetheless, we argue that male quality may be an important feature in the expression of male mate choice.

中文翻译：

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越选择越好：男性择偶个体差异的荟萃分析

雄性配偶选择发生在几种动物中，但我们对影响这种行为表现的因素知之甚少。雄性获得配偶的能力（即雄性品质）各不相同，这可能对雄性择偶表达至关重要，但往往被忽视。使用元分析方法，我们通过比较不同品质和表型的雄性与高品质和低品质雌性的交配投资来探索雄性交配选择表达的个体间差异。我们使用了两个数据集，它们共同包含来自 60 项实证研究的信息，包括 52 个物种。我们发现，所有品质和表型的男性都更喜欢高品质的女性，但这种偏好的强度不同。高品质和中等品质的雄性比低品质的雄性更挑剔。相似地，体型较大或身体状况较好的男性比同龄人更挑剔。相比之下，男性体重和年龄与男性配偶选择的变化无关。我们还表明，实验设计可能会影响我们对雄性交配投资模式的理解，这可能会限制我们研究结果的推广。尽管如此，我们认为男性品质可能是男性配偶选择表达的一个重要特征。