The evolution of a complex trait: cuticular hydrocarbons in ants evolve independent from phylogenetic constraints

Cuticular hydrocarbons (CHC) are ubiquitous and highly diverse in insects, serving as communication signal and waterproofing agent. Despite their vital function, the causes, mechanisms and constraints on CHC diversification are still poorly understood. Here, we investigated phylogenetic constraints on the evolution of CHC profiles, using a global dataset of the species-rich and chemically diverse ant genus Crematogaster. We decomposed CHC profiles into quantitative (relative abundances, chain length) and qualitative traits (presence/absence of CHC classes). A species-level phylogeny was estimated using newly generated and previously published sequences from five nuclear markers. Moreover, we reconstructed a phylogeny for the chemically diverse C. levior species group using cytochrome oxidase I. Phylogenetic signal was measured for these traits on genus and clade level and within the chemically diverse C. levior group.

For most quantitative CHC traits, phylogenetic signal was low and ...

表皮碳氢化合物（Cuticular hydrocarbons, CHC）在昆虫中分布广泛且多样性极高，兼具通讯信号与防水剂的功能。尽管其功能至关重要，但学界对表皮碳氢化合物多样化的成因、机制及限制因素仍缺乏深入认知。本研究以物种丰富、化学多样性突出的举腹蚁属（Crematogaster）全球数据集为研究材料，探讨了其表皮碳氢化合物谱演化的系统发育限制。我们将表皮碳氢化合物谱分解为定量性状（相对丰度、碳链长度）与定性性状（表皮碳氢化合物类别的存在/缺失情况）。研究中，我们利用新生成及已发表的5个核标记序列，构建了物种水平的系统发育树；此外，针对化学多样性丰富的C. levior物种群，我们基于细胞色素氧化酶I（cytochrome oxidase I）序列重建了其系统发育关系。最后，我们分别在属水平、演化支水平以及化学多样性丰富的C. levior物种群内，对上述性状的系统发育信号进行了检测。
对于大多数定量表皮碳氢化合物性状而言，其系统发育信号较弱且……