Huang Xianliang, Liu Deguang, Gao Suxia, Chen Hui
State Key Laboratory of Crop Stress Biology for Arid Areas (Northwest A&F University), Yangling, Shaanxi 712100, China.
Environ Entomol. 2013 Dec;42(6):1174-83. doi: 10.1603/EN13132. Epub 2013 Nov 18.
Sitobion avenae (F.) is a cosmopolitan cereal pest, but geographic barriers like the Qinling Mountains in the Shaanxi Province of China may lead to isolation among its populations, thus causing allopatric speciation. We sampled S. avenae populations from areas north (mean annual temperature, ≍9°C) and south (mean annual temperature, ≍14°C) of the Qinling Mountains, and tested them at 20°C in common garden experiments. The results showed that northern populations had reduced developmental time for first-instar nymphs but prolonged for third- and fourth-instar nymphs compared with southern populations. The postreproductive time and total lifespan of adults from southern populations were longer than those from northern populations, but no significant differences were found in reproductive time or age at first reproduction. Southern populations showed higher lifetime and daily fecundities than northern ones. Significant differences were found in correlation of life-history traits between northern and southern populations. Principal component analyses (PCAs) of S. avenae's vital life-history traits showed separation of populations from three southern locations, indicating their local adaptation. The clustering patterns generated by PCA also showed divergence between northern and southern populations. Alatae of S. avenae seemed to be able to disperse across the Qinling Mountains, which was indicated by the clustering together of some individuals from one side of the mountains with those from the other side. The impacts of the Qinling Mountains on the divergence and gene flow among S. avenae populations, as well as the potential of allopatric speciation for this species, are discussed.
麦长管蚜是一种世界性的谷物害虫，但诸如中国陕西省秦岭等地理屏障可能导致其种群间的隔离，从而引发异域物种形成。我们从秦岭以北（年平均温度约9°C）和以南（年平均温度约14°C）的地区采集了麦长管蚜种群，并在20°C的条件下进行了共同花园实验。结果表明，与南方种群相比，北方种群一龄若虫的发育时间缩短，但三龄和四龄若虫的发育时间延长。南方种群成虫的繁殖后期时间和总寿命比北方种群长，但在繁殖时间或首次繁殖年龄方面未发现显著差异。南方种群的终生繁殖力和每日繁殖力高于北方种群。北方和南方种群在生活史特征的相关性方面存在显著差异。对麦长管蚜重要生活史特征的主成分分析（PCA）表明，来自南方三个地点的种群相互分离，表明它们具有局部适应性。PCA产生的聚类模式也显示了北方和南方种群之间的差异。麦长管蚜的有翅蚜似乎能够跨越秦岭扩散，这一点从山脉一侧的一些个体与另一侧的个体聚类在一起得到了证明。本文讨论了秦岭对麦长管蚜种群分化和基因流动的影响，以及该物种异域物种形成的潜力。
