Multiple biological mechanisms result in correlations between pre- and post-mating traits that differ among versus within individuals and genotypes

Reproductive traits involved in mate acquisition (pre-mating traits) are predicted to covary with those involved in fertilization success (post-mating traits). Variation in male quality may give rise to positive, and resource allocation trade-offs to negative, covariances between pre- and post-mating traits. Empirical studies have yielded mixed results. Progress is hampered as researchers often fail to appreciate that mentioned biological mechanisms can act simultaneously but at different hierarchical levels of biological variation: genetic correlations may, for example, be negative due to genetic trade-offs but environmental correlations instead positive due to individual variation in resource acquisition. We measured pre-mating (aggression, body weight) and post-mating (ejaculate size) reproductive traits in a pedigreed population of southern field crickets (Gryllus bimaculatus). To create environmental variation, crickets were raised on either a low or a high nymphal density treatmen...

与配偶获取相关的繁殖性状（交配前繁殖性状，pre-mating traits），预计会与介导受精成功的繁殖性状（交配后繁殖性状，post-mating traits）存在协变关系。雄性质量的变异可能会导致交配前与交配后性状间的协变呈正向，而资源分配权衡则会使其呈现负向协变。相关实证研究的结果并不一致。研究进展受阻，原因在于研究者往往未能意识到，所提及的生物学机制可同时发挥作用，但作用于生物变异的不同层级：例如，遗传相关性可能因遗传权衡而呈负值，而环境相关性则会因个体资源获取能力的差异而呈正值。我们在具有完整谱系记录的南方田野蟋蟀（Gryllus bimaculatus）种群中，测量了其交配前（攻击性、体重）与交配后（射精量）的繁殖性状。为构建环境变异梯度，我们将蟋蟀分别置于低若虫密度与高若虫密度的处理组中饲养……