Data from: Sources of (co)variation in alternative siring routes available to male great tits (Parus major)

Males of socially monogamous species can increase their siring success via within-pair and extra-pair fertilizations. In this study, we focused on the different sources of (co)variation between these siring routes, and asked how each contributes to total siring success. We quantified the fertilization routes to siring success, as well as behaviors that have been hypothesized to affect siring success, over a five-year period for a wild population of great tits Parus major. We considered siring success and its fertilization routes as “interactive phenotypes” arising from phenotypic contributions of both members of the social pair. We show that siring success is strongly affected by the fecundity of the social (female) partner. We also demonstrate that a strong positive correlation between extra-pair fertilization success and paternity loss likely constrains the evolution of these two routes. Moreover, we show that more explorative and aggressive males had less extra-pair fertilizations, whereas more explorative females laid larger clutches. This study thus demonstrates that (co)variation in siring routes is caused by multiple factors not necessarily related to characteristics of males. We thereby highlight the importance of acknowledging the multi-level structure of male fertilization routes when studying the evolution of male mating strategies.

社会一夫一妻制物种的雄性可通过配对内受精与配对外受精两种途径提升其父本繁殖成功率。本研究聚焦于这两种父权获得途径间（共）变异的不同来源，探究二者分别对总父本繁殖成功率的贡献。我们针对野生大山雀（Parus major）种群开展了为期五年的研究，量化了影响父本繁殖成功率的受精途径，以及已被假说认为可影响父本繁殖成功率的各类行为。我们将父本繁殖成功率及其受精途径视为由社会配对双方的表型贡献共同形成的"交互表型"。研究结果表明，父本繁殖成功率会受到社会配偶（雌性）的繁殖力的显著影响。此外我们还发现，配对外受精成功率与父权丧失间存在极强的正相关关系，这可能会限制这两种受精途径的演化。同时，我们观察到探索性与攻击性更强的雄性获得的配对外受精次数更少，而探索性更强的雌性所产的窝卵数更大。因此，本研究证明，父权获得途径的（共）变异由多种因素共同导致，且这些因素未必与雄性自身的特征相关。由此，我们强调，在探究雄性交配策略的演化过程中，需重视雄性受精途径的多层次结构这一研究视角的重要性。