Department of Ecology and Evolutionary Biology, University of California, Los Angeles, Los Angeles, California, 90095.
Evolution. 2022 Jan;76(1):101-113. doi: 10.1111/evo.14402. Epub 2021 Dec 18.
Large body sizes have evolved structures to facilitate resource transport. Like unitary organisms, social insect colonies must transport information and resources. Colonies with more individuals may experience transport challenges similar to large-bodied organisms. In ant colonies, transport occurs in the nest, which may consist of structures that facilitate movement. We examine three attributes of nests that might have evolved to mitigate transport challenges related to colony size: (1) subdivision-nests of species with large colonies are more subdivided to reduce crowd viscosity; (2) branching-nest tunnels increase branching in species with large colonies to reduce travel distances; and (3) shortcuts-nests of species with large colonies have cross-linking tunnels to connect distant parts of the nest and create alternative routes. We test these hypotheses by comparing nest structures of species with different colony sizes in phylogenetically controlled meta-analyses. Our findings support the hypothesis that nest subdivision and branching evolved to mitigate transport challenges related to colony size. Nests of species with large colonies contain more chambers and branching tunnels. The similarity in how ant nests and bodies of unitary organisms have evolved in response to increasing size suggests common solutions across taxa and levels of biological organization.
大型生物体进化出了结构来促进资源运输。就像单体生物一样，社会性昆虫群体必须运输信息和资源。个体数量较多的群体可能会遇到类似于大型生物体的运输挑战。在蚂蚁群体中，运输发生在巢中，巢中可能包含有助于移动的结构。我们研究了三个可能是为了减轻与群体大小相关的运输挑战而进化出来的巢的属性：（1）细分——具有大群体的物种的巢更加细分，以减少群体的粘性；（2）分支——具有大群体的物种的巢隧道增加分支，以减少旅行距离；（3）捷径——具有大群体的物种的巢有交叉连接的隧道，以连接巢的遥远部分，并创建替代路线。我们通过在系统发育控制的荟萃分析中比较不同群体大小物种的巢结构来检验这些假设。我们的研究结果支持了这样一种假设，即巢的细分和分支是为了减轻与群体大小相关的运输挑战而进化的。具有大群体的物种的巢包含更多的腔室和分支隧道。蚂蚁巢和单体生物的身体在应对体型增大时的进化方式相似，这表明在分类群和生物组织层次上存在共同的解决方案。
