The evolution of matrotrophic viviparity creates new scenarios within which evolutionary processes can operate, including postcopulatory events, family conflicts, and selective processes, which are expected to intensify with polyandry. We evaluated the effect of matrotrophic viviparity and polyandry on the reproductive output and offspring fitness of a bimodal reproductive vertebrate, the fire salamander (Salamandra salamandra), which presents two forms of viviparity: larviparity (i.e. females deliver many aquatic larvae) and pueriparity (i.e. females deliver a few terrestrial juveniles). Polyandry is present in both strategies, but matrotrophy only occurs in pueriparity. Analyses of paternity and offspring life-history traits in 18 pueriparous and 13 larviparous mother–offspring arrays suggest the presence of sibling conflicts in pueriparous salamanders, especially with polyandry. However, these postcopulatory processes did not increase reproductive skew in the pueriparous strategy compared to the larviparous one or lead to fitness differences across sires within a clutch, suggesting other selective processes operating earlier in the reproductive sequence. Observed male–female pairs were found to be genetically more similar than other potential pairings, although no relationship between males’ genetic traits and reproductive success was detected. This work advances our understanding of how sibling conflicts and sexual selection affect the evolution of viviparous matrotrophy and mating strategies.

中文翻译：

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母养和一妻多夫部分调节双峰胎生蝾螈的交配后机制和性选择


母养胎生的进化创造了进化过程可以运作的新场景，包括交配后事件、家庭冲突和选择过程，预计这些过程会随着一妻多夫而加剧。我们评估了母养胎生和一妻多夫对双峰生殖脊椎动物火蝾螈（Salamandra salamandra）的生殖产出和后代适应性的影响，火蝾螈有两种胎生形式：幼生（即雌性产下许多水生幼虫）和产子（即雌性产下许多水生幼虫）。雌性产下一些陆地幼体）。两种策略中都存在一妻多夫制，但母养只发生在产妇中。对 18 个产期蝾螈和 13 个幼体产期母子阵列的亲子关系和后代生活史特征的分析表明，产期蝾螈中存在兄弟姐妹冲突，尤其是一妻多夫制。然而，与幼虫相比，这些交配后过程并没有增加胎生策略中的生殖偏差，也没有导致一窝内公牛之间的适应性差异，这表明其他选择性过程在生殖序列中较早发挥作用。尽管没有检测到雄性遗传特征与繁殖成功之间的关系，但观察到的雄性-雌性配对在遗传上比其他潜在配对更相似。这项工作增进了我们对兄弟姐妹冲突和性选择如何影响胎生母体营养和交配策略进化的理解。