基于几何形态学的北二星蝽种内形态差异分析(半翅目:蝽科)（英文）

Intraspecific variation in Eysarcoris aeneus revealed by geometric morphometrics( Hemiptera: Pentatomidae)

【目的】北二星蝽Eysarcoris aeneus是一种广泛分布于古北区的重要农业害虫,可危害多种经济作物。其刺肩型和钝肩型前胸背板后侧角长度存在差异,暗示其种内变异的存在。【方法】基于几何形态学的多元回归分析(multivariate regression)、主成分分析(principal component analysis,PCA)、典型变量分析(canonical variate analysis,CVA)和判别函数分析(discriminant function analysis,DFA),对采集于中国19个地区的142头标本(98头北二星蝽标本和44头作为外群的广二星蝽E. ventralis标本)的前翅、后翅、头和小盾片4个性状进行分析比较,研究北二星蝽钝肩型和刺肩型之间的形态变异。【结果】对于所研究的4个性状来说,北二星蝽钝肩型和刺肩型标本间均未检测到异速生长的存在。主成分分析中,钝肩型和刺肩型的标本均有重叠,典型变量分析则显示它们之间存在显著差异(马氏距离和普氏距离的P值均小于0. 01)。判别函数分析显示,依据这4个性状两型样本间的正确判别率在67%~89%之间。【结论】结果表明,前翅、后翅、头和小盾片都可以作为北二星蝽钝肩型和刺肩型之间形态变异的评价指标,小盾片特征具有最高水平的鉴别价值;对于所研究的这4个性状来说,北二星蝽钝肩型和刺肩型之间都表现出显著的形状差异,而它们的质心距离差异不显著,说明相对于体型大小差异分析,形状差异分析能更灵敏地揭示谱系间的变异。本研究表明几何形态学可以有效地描述北二星蝽的种内形态变异,为蝽类昆虫种内变异的研究奠定了基础。

【Aim】Eysarcoris aeneus,a main pest of many economic crops,is widely distributed in Palaearctic region with humeri variable. Difference in the humerus length of "rounded humerus form"and "needle-like humerus form"suggests that intraspecific variation may exist in E. aeneus.【Methods 】In this study,142 specimens( 98 for E. aeneus and 44 for the outgroup E. ventralis) from 19 regions of China were examined to ascertain the morphological variation of four characters( forewing,hindwing,head and scutellum) between the two forms,"rounded humerus form"and "needle-like humerus form",respectively,of E. aeneus with the use of geometric morphometrics approaches, including multivariate regression, principal component analysis( PCA),canonical variate analysis( CVA) and discriminant function analysis( DFA).【Results】Allometry was not found in all of the four characters( forewing,hindwing,head and scutellum) examined. For the four characters,though the principal component analysis showed overlap between the two forms of E. aeneus,the canonical variate analysis showed significant differences between them( P-values for Procrustes distance and Mahalanobis distance were all less than 0. 01). The correctly assigned percentages of "rounded humerus form"and "needle-like humerus form"ranged from 67% to 89% specimens based on the four characters using the discriminant function analysis.【Conclusion】This study proved that forewing,hindwing,head and scutellum can serve efficient evaluation criteria in describing intraspecific morphological difference of E. aeneus,and scutellum is the most informative character. The geometric morphometric descriptors showed significant shape differences and overlapped centroid size between the two forms of E. aeneus,indicating that the analysis of shape is more sensitive for detecting differences among lineages than that of size. Our study shows that geometric morphometrics is efficient in describing intraspecific morphological difference of E. aeneus,and lays a foundation for intraspecific variation studies of stink bugs in future.