Data from: Using probability modelling and genetic parentage assignment to test the role of local mate availability in mating system variation.

The formal testing of mating system theories with empirical data is important for evaluating the relative importance of different processes in shaping mating systems in wild populations. Here we present a generally applicable probability modelling framework to test the role of local mate availability in determining a population’s level of genetic monogamy. We provide a significance test for detecting departures in observed mating patterns from model expectations based on mate availability alone, allowing the presence and direction of behavioural effects to be inferred. The assessment of mate availability can be flexible and in this study it was based on population density, sex ratio and spatial arrangement. This approach provides a useful tool for (1) isolating the effect of mate availability in variable mating systems and (2) in combination with genetic parentage analyses, gaining insights into the nature of mating behaviours in elusive species. To illustrate this modelling approach, we have applied it to investigate the variable mating system of the mountain brushtail possum (Trichosurus cunninghami) and compared the model expectations with the outcomes of genetic parentage analysis over an 18 year study. The observed level of monogamy was higher than predicted under the model. Thus, behavioural traits, such as mate guarding or selective mate choice, may increase the population level of monogamy. We show that combining genetic parentage data with probability modelling can facilitate an improved understanding of the complex interactions between behavioural adaptations and demographic dynamics in driving mating system variation.利用实证数据对交配系统（mating system）理论进行正式检验，对于评估野生种群交配系统形成过程中不同机制的相对重要性具有重要意义。在此，我们提出一套通用的概率建模框架，用以检验本地配偶可获得性对种群遗传单配制水平的决定作用。我们提供了一种显著性检验方法，可检测观测交配模式与仅基于配偶可获得性的模型预期之间的偏差，从而推断行为效应的存在性与方向。配偶可获得性的评估方式具有灵活性，本研究中该评估基于种群密度、性比与空间分布格局。该方法为两项研究方向提供了实用工具：（1）分离可变交配系统中配偶可获得性的效应；（2）结合遗传父权分析（genetic parentage analysis），深入探究隐匿物种交配行为的本质。为阐释该建模方法，我们将其应用于研究山袋貂（Trichosurus cunninghami）的可变交配系统，并将模型预期与长达18年的研究中遗传父权分析的结果进行对比。观测到的单配制水平高于模型预测值。因此，配偶守护或选择性择偶等行为特征，可能会提升种群的单配制水平。我们证实，将遗传父权数据与概率建模相结合，可助力我们更深入理解行为适应与种群动态之间的复杂相互作用，进而揭示交配系统变异的驱动机制。