Thraupidae (Tanagers and allies) show a remarkable array of behaviors, ecologies, morphologies and plumage colors, offering a great opportunity to investigate the evolution of avian mating strategies. We characterize the population genetics and mating system of Sicalis flaveola pelzelni, a socially monogamous Neotropical songbird with biparental care. We found moderate to high levels of neutral genetic variation, similar across three breeding seasons, consistent with large and stable populations, and no temporal genetic structure. Parentage analyses of 114 adults and 198 nestlings (54 nests) revealed 31.8% of extra-pair offspring (EPO) and 51.8% of broods with at least one extra-pair chick. Extra-pair paternity (EPP) rates varied across seasons and were significantly higher in 2014/2015. Neither breeding synchrony nor pair genetic relatedness was significantly associated to EPP rates. Males paired with females in nests with and without EPO were equally heterozygous, and EPO were significantly less heterozygous than within-pair offspring, not supporting the ‘indirect genetic benefits’ hypotheses. Females were more related to their extra-pair mates than to their social mates, not supporting the ‘inbreeding avoidance’ hypothesis. The non-monogamous genetic mating system uncovered here seems not to lower the effective size of the population, which was higher than the sample size of adult breeders. We report and discuss possible cases of quasi-parasitism, as indicated by maternity exclusion patterns. We contribute novel information to expand the knowledge about the largely unexplored genetic mating systems of Thraupidae. Our findings also set the stage for further studies examining if plumage coloration or song traits predict paternity gain or loss in Saffron Finches.

中文翻译：

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南美洲南部藏红花雀育种的遗传交配系统、种群遗传学和有效大小

Thraupidae（唐纳雀及其盟友）表现出一系列非凡的行为、生态、形态和羽毛颜色，为研究鸟类交配策略的演变提供了绝佳机会。我们描述了 Sicalis flaveola pelzelni 的种群遗传学和交配系统，这是一种具有双亲照顾的社会一夫一妻制的新热带鸣禽。我们发现中等至高水平的中性遗传变异，在三个繁殖季节相似，与大而稳定的种群一致，并且没有时间遗传结构。对 114 只成年雏鸟和 198 只雏鸟（54 窝）的亲子分析显示，31.8% 的额外后代 (EPO) 和 51.8% 的育雏至少有一只额外的小鸡。额外对亲子关系 (EPP) 率随季节变化，并且在 2014/2015 年明显更高。育种同步性和配对遗传相关性均与 EPP 率无显着相关。在有和没有 EPO 的巢中，雄性与雌性配对的杂合性相同，EPO 的杂合性明显低于成对后代，不支持“间接遗传益处”假设。雌性与他们的一对额外伴侣的关系比与社会伴侣的关系更大，不支持“近亲繁殖回避”假设。这里发现的非一夫一妻制的遗传交配系统似乎并没有降低种群的有效规模，这高于成年育种者的样本规模。我们报告和讨论准寄生的可能案例，如产妇排斥模式所示。我们贡献了新的信息，以扩展有关 Thraupidae 主要未开发的遗传交配系统的知识。