Data from: Passerine extrapair mating dynamics: a Bayesian modeling approach comparing four species

In many socially monogamous animals, females engage in extrapair copulation (EPC), causing some broods to contain both within‐pair and extrapair young (EPY). The proportion of all young that are EPY varies across populations and species. Because an EPC that does not result in EPY leaves no forensic trace, this variation in the proportion of EPY reflects both variation in the tendency to engage in EPC and variation in the extrapair fertilization (EPF) process across populations and species. We analyzed data on the distribution of EPY in broods of four passerines (blue tit, great tit, collared flycatcher, and pied flycatcher), with 18,564 genotyped nestlings from 2,346 broods in two to nine populations per species. Our Bayesian modeling approach estimated the underlying probability function of EPC (assumed to be a Poisson function) and conditional binomial EPF probability. We used an information theoretical approach to show that the expected distribution of EPC per female varies across populations but that EPF probabilities vary on the above‐species level (tits vs. flycatchers). Hence, for these four passerines, our model suggests that the probability of an EPC mainly is determined by ecological (population‐specific) conditions, whereas EPF probabilities reflect processes that are fixed above the species level.

在诸多社会单配制动物中，雌性个体常会进行额外配对交配（extrapair copulation, EPC），这会使得部分窝卵同时包含配对内幼体与额外配对幼体（extrapair young, EPY）。所有幼体中额外配对幼体的占比会因种群与物种的不同而存在差异。由于未产生额外配对幼体的额外配对交配不会留下任何可追溯的遗传痕迹，因此额外配对幼体占比的变异，既反映了不同种群与物种间发生额外配对交配的倾向差异，也体现了额外配对受精（extrapair fertilization, EPF）过程的类群间差异。我们针对4种雀形目鸟类（蓝山雀、大山雀、领姬鹟、斑姬鹟）的窝卵内额外配对幼体分布数据展开分析，数据集涵盖每个物种2至9个种群的2346窝，共计18564只经基因分型的雏鸟。我们采用贝叶斯建模方法，估算了额外配对交配的潜在概率函数（假定为泊松分布函数）与条件二项式额外配对受精概率。我们借助信息论方法证实，雌性个体的额外配对交配期望分布会因种群而异，但额外配对受精概率则在物种以上水平存在分化（山雀类与姬鹟类之间）。因此，针对这4种雀形目鸟类，我们的模型表明：额外配对交配的概率主要由种群特异性的生态条件所决定，而额外配对受精概率则反映了物种以上水平的固定演化过程。