Chen Nan, Bai Yu, Fan Yong-Liang, Liu Tong-Xian
State Key Laboratory of Crop Stress Biology for Arid Areas, and Key Laboratory of Integrated Pest Management on the Loess Plateau of Ministry of Agriculture, Northwest A&F University, Yangling, Shaanxi, China.
PLoS One. 2017 Aug 31;12(8):e0184243. doi: 10.1371/journal.pone.0184243. eCollection 2017.
Insect cuticular hydrocarbons (CHCs) play critical roles in reducing water loss and chemical communication. Species-specific CHC profiles have been used increasingly as an excellent character for species classification. However, considerably less is known about their potential for population delimitation within species. The aims of this study were to develop a solid-phase microextraction (SPME)-based CHC collection method and to investigate whether CHC profiles could serve as potential chemotaxonomic tools for intraspecific delimitation in Acyrthosiphon pisum. Optimization of fibers for SPME sampling revealed that 7 μm polydimethylsiloxane (PDMS) demonstrated the most efficient adsorption of CHCs among five different tested fibers. SPME sampling showed good reproducibility with repeated collections of CHCs from a single aphid. Validation of SPME was performed by comparing CHC profiles with those from conventional hexane extractions. The two methods showed no qualitative differences in CHCs, although SPME appeared to extract relatively fewer short-chained CHCs. While CHC profiles of a given population differed among developmental stages, wing dimorphism types, and host plants, wingless adult aphids showed very low variance in relative proportions of individual CHC components. Reproducibility of CHC profiles was explored further to classify wingless adult morphs of A. pisum from five different geographic regions that showed no variation in mitochondrial COI gene sequences. Our results demonstrate that CHC profiles are useful in intraspecific delimitation in the field of insect chemotaxonomy.
昆虫表皮碳氢化合物（CHCs）在减少水分流失和化学通讯中发挥着关键作用。物种特异性的CHC谱越来越多地被用作物种分类的优良特征。然而，对于它们在物种内种群界定方面的潜力，人们了解得要少得多。本研究的目的是开发一种基于固相微萃取（SPME）的CHC收集方法，并研究CHC谱是否可以作为豌豆蚜种内界定的潜在化学分类学工具。SPME采样纤维的优化显示，在五种不同测试纤维中，7μm聚二甲基硅氧烷（PDMS）对CHCs的吸附效率最高。SPME采样对从单个蚜虫重复收集CHCs具有良好的重现性。通过将CHC谱与传统己烷萃取的谱进行比较来验证SPME。尽管SPME似乎提取的短链CHCs相对较少，但两种方法在CHCs上没有质的差异。虽然给定种群的CHC谱在发育阶段、翅型二态性类型和寄主植物之间存在差异，但无翅成年蚜虫在各个CHC组分的相对比例上显示出非常低的变异性。进一步探索了CHC谱的重现性，以对来自五个不同地理区域、线粒体COI基因序列无变异的豌豆蚜无翅成年形态进行分类。我们的结果表明，CHC谱在昆虫化学分类学领域的种内界定中是有用的。
