Araki Yoshifumi, Sota Teiji
Department of Zoology, Graduate School of Science Kyoto University Kyoto Japan.
Ecol Evol. 2023 Jan 24;13(1):e9765. doi: 10.1002/ece3.9765. eCollection 2023 Jan.
Knowledge of population divergence history is key to understanding organism diversification mechanisms. The geotrupid dung beetle , which inhabits montane forests and exhibits three color forms (red, green, and indigo), diverged into five local populations (west/red, south/green, south/indigo, south/red, and east/red) in the Kinki District of Honshu, Japan, based on the combined interpretation of genetic cluster and color-form data. Here, we estimated the demographic histories of these local populations using the newly assembled draft genome sequence of and whole-genome resequencing data obtained from each local population. Using coalescent simulation analysis, we estimated population divergences at ca. 3800, 2100, 600, and 200 years ago, with no substantial gene flow between diverged populations, implying the existence of persistent barriers to gene flow. Notably, the last two divergence events led to three local populations with different color forms. The initial divergence may have been affected by climatic cooling around that time, and the last three divergence events may have been associated with the increasing impact of human activities. Both climatic cooling and increasing human activity may have caused habitat fragmentation and a reduction in the numbers of large mammals supplying food (dung) for , thereby promoting the decline, segregation, and divergence of local populations. Our research demonstrates that geographic population divergence in an insect with conspicuous differences in traits such as body color may have occurred rapidly under the influence of human activity.
了解种群分化历史是理解生物多样化机制的关键。地嗡蜣螂栖息于山地森林，呈现三种颜色形态（红色、绿色和靛蓝色），基于遗传聚类和颜色形态数据的综合解读，在日本本州的近畿地区分化为五个本地种群（西部/红色、南部/绿色、南部/靛蓝色、南部/红色和东部/红色）。在此，我们利用新组装的[物种名称]基因组草图序列以及从每个本地种群获得的全基因组重测序数据，估计了这些本地种群的种群历史。通过溯祖模拟分析，我们估计种群在约3800、2100、600和200年前发生了分化，分化后的种群之间没有大量基因流动，这意味着存在持续的基因流动障碍。值得注意的是，最后两次分化事件导致了三个具有不同颜色形态的本地种群。最初的分化可能受到当时气候变冷的影响，而最后三次分化事件可能与人类活动影响的增加有关。气候变暖和人类活动增加都可能导致栖息地破碎化，以及为[物种名称]提供食物（粪便）的大型哺乳动物数量减少，从而促使本地种群数量下降、隔离和分化。我们的研究表明，在人类活动的影响下，具有体色等显著性状差异的昆虫地理种群分化可能迅速发生。
