黄纹长腹扇蟌胸部色斑变异研究

Aresearch of color pattern variation on thorax of Coeliccia cyanomelas (Odonata: Coenagrionoidea: Platycnemididae)

不同种群的雄性黄纹长腹扇蟌胸部色斑存在较大的变异,主要表现在前胸背板斑纹的有无、合胸背面及侧面斑纹的面积大小、形状及数量等方面。本文通过几何形态学方法,以及对前胸背板斑纹的观察比较,对34个地里样点共319头雄性黄纹长腹扇蟌的胸部斑纹变异情况进行分析。几何形态学分析显示,依据合胸斑纹轮廓形状可将黄纹长腹扇蟌划分为东南(Southeast)与西北(Northwest)两群组,且在分布重叠区的种群中同时存在两种特征的个体;对前胸背板斑纹的观察统计显示,几乎所有分布于西北群组的样本前胸背板具一对蓝色斑纹,而东南群组的样本几乎都缺失这对斑纹。本研究使用的两方面证据所揭示的变异趋势相吻合,均证明雄性黄纹长腹扇蟌胸部斑纹随地理分布存在明显的变异规律。研究结果显示雄性黄纹长腹扇蟌胸部斑纹存在明显变异多样性,几何形态学可用于蜻蜓目昆虫色斑变异规律的研究,也为该物种的演化与地理格局的形成等后续研究提供证据支持。

The color pattern on thorax of male Coeliccia cyanomelas varied obviously between populations. This was mainly reflected in whether a pair of spots on the pronotum or not, as well as the size, shape and quantity of the marks on dorsal and lateral surface of synthorax. The geometric morphometrics, and observation of spots on the pronotum, were conducted based on 319 individuals of male C.cyanomelas from 34 populations. Almost all individuals from northwest region had a pair of spots on the pronotum, while those in the southeast were missing. The analyses of geometric morphometrics reflected that all samples can be divided into northwest and southeast types based on the shape of marks on lateral synthorax. Individuals of both types occurred in the overlapping area. Results from two methods in this study were coincident, which indicated a significant variation on color pattern of male C.cyanomelas . Geometric morphometric is very useful in analysis of the variation tendency of color pattern of Odonata, and can provide evidences for the evolutionary history and the formation of geographical pattern of species.