Over the past decade, the cause of sociality has been much debated. Inclusive fitness [br in Hamilton's rule (br - c > 0)] has been criticized but is still useful in the organization of a framework by elucidating mechanisms through which br (benefit × relatedness) becomes larger than c (cost). The bee Lasioglossum baleicum is suitable for investigation of this issue because of the sympatric occurrence of both social and solitary nesting in its populations. We show that a large part (approximately 92%) of the inclusive fitness of a eusocial worker can be attributed to the benefits of grouping. A 1.5-fold relatedness asymmetry benefit in singly mated haplo-diploids explains a small part (approximately 8.5%) of the observed inclusive fitness. Sociality enables this species to conduct foraging and nest defense simultaneously, which is not the case in solitary nests. Our results indicate that this benefit of grouping is the main source of the increased inclusive fitness of eusocial workers.

中文翻译：

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分组作为金丝雀蜜蜂社会进化的主要动力的好处。

在过去的十年中，社会原因引起了很多争论。包容性健身[ BR在汉密尔顿法则（BR - ç > 0）]一直被人诟病，但仍然是通过阐明机制框架的组织有用的BR（利益关联×）变得大于Ç（成本）。蜜蜂番茄由于在其种群中同时发生了社会嵌套和孤立嵌套，因此适合于对此问题进行调查。我们表明，社会工作者的包容性的很大一部分（大约92％）可归因于分组的好处。单交配单倍体的1.5倍相关性不对称性优势说明了所观察到的包容性适应度的一小部分（约8.5％）。社交使该物种能够同时进行觅食和筑巢防御，而在单独的筑巢中则并非如此。我们的结果表明，分组的好处是增加了社会工作者的包容性的主要来源。