Although communal goods are often critical to society, they are simultaneously susceptible to exploitation and are evolutionarily stable only if mechanisms exist to curtail exploitation. Mechanisms such as punishment and kin selection have been offered as general explanations for how communal resources can be maintained. Evidence for these mechanisms comes largely from humans and social insects, leaving their generality in question. To assess how communal resources are maintained, we observed cooperative nest construction in sociable weavers (Philetairus socius). The communal nest of sociable weavers provides thermal benefits for all individuals but requires continual maintenance. We observed cooperative nest construction and also recorded basic morphological characteristics. We also collected blood samples, performed next-generation sequencing, and isolated 2358 variable single nucleotide polymorphisms (SNPs) to estimate relatedness. We find that relatedness predicts investment in cooperative nest construction, while no other morphological characters significantly explain cooperative output. We argue that indirect benefits are a critical fitness component for maintaining the cooperative behavior that maintains the communal good.

中文翻译：

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关联性预测社交织布工合作筑巢投资的多种衡量标准

尽管公共物品通常对社会至关重要，但它们同时容易受到剥削，并且只有在存在限制剥削的机制时才会进化稳定。诸如惩罚和亲属选择等机制已被用作对如何维护公共资源的一般解释。这些机制的证据主要来自人类和社会昆虫，因此对它们的普遍性存在疑问。为了评估公共资源的维护方式，我们观察了社交编织者（Philetairus socius）的合作巢穴建设。善于交际的编织者的公共巢穴为所有个体提供热效益，但需要持续维护。我们观察了合作筑巢，并记录了基本的形态特征。我们还收集了血液样本，进行了下一代测序，并分离出 2358 个可变单核苷酸多态性 (SNP) 以估计相关性。我们发现相关性预测了合作巢穴建设的投资，而没有其他形态特征显着解释合作产出。我们认为，间接利益是维持共同利益的合作行为的关键适应成分。