【摘要】 为了探究大瓶螺(Pomacea canaliculata)体色、性别与贝壳形态之间的关系,运用几何形态测量学方法,对来自于人工繁育的F5纯合体色品系37只深褐色个体(26♀♀,11♂♂)、34只黄色个体(14♀♀,20♂♂)贝壳的正壳口观、壳口观、壳顶观进行地标标点,获得贝壳的形态信息。运用主成分分析和典型变量分析,检测出不同体色、性别个体间的差异。通过各个标点对于相对扭曲的贡献率,探究其形态变化趋势。主成分分析结果表明,不同体色个体的贝壳形态存在着明显差异,正壳口观较壳口观及壳顶观更能体现贝壳差异;而不同体色的贝壳差异均不及相同体色不同性别个体间贝壳的差异。典型变量分析结果通过普氏距离和马氏距离得以反映,所有组别间的马氏距离均有显著性差异,而普氏距离仅在壳顶观的深褐色和黄色雌螺间以及壳顶观的深褐色和黄色雄螺间无显著差异;对正壳口观各标点对相对扭曲的贡献率分析表明,贝壳形态的变化主要集中在壳口上半部,支持不同体色和性别的大瓶螺在贝壳形态上存在显著差异的结论。发掘大瓶螺中所存在的这些差异对探究不同体色个体的适应性差异提供了重要参考,也表明几何形态测量学可以作为贝壳形态研究的有效方法应用于贝类形态学和种群分析等研究中。更多还原

【Abstract】 Pomacea canaliculata,an invasive freshwater gastropod,has become an increasingly serious pest snail in China. The shell shape of Pomacea canaliculata is thought to be determined by both genetic and environmental conditions. In this study,we performed geometric morphometric analysis to detect possible shape differentiations in shells of different colors and both sexes of the golden apple snail. Mature P. canaliculata individuals were used for this study,all homozygous at the loci associated to shell coloration. The snails were F5 generation wild P. canaliculata from the Nansheng River of Wuzhishan Community,sampled on March 15 th,2009,and included 37 snails with dark brown shells( 26 ♀♀,11 ♂♂) and 34 snails with yellow shells( 14 ♀♀,20 ♂♂). Landmarks and semi-landmarks were determined using photographs of mature shells from different views and the morphological data was analyzed using geometric morphometrics. Shape differentiations of the shells of each body color and both sexes were then studied using principal component analysis,canonical variable analysis and the thin-plate spline graphical technique. The principal component analysis suggested that the shell shape variation between the two shell coloration strains of P. canaliculata was significant and was more representative in the landmark data obtained from the front view of aperture than from the other two views,while the variation representing sexual dimorphism within the same shell-coloration individuals was more pronounced than that between the two shell coloration strains. The results of canonical variable analysis were presented as Procrustes distance and Mahalanobis distance. The Mahalanobis distances among all tested groups were significantly different. The Procrustes distances between dark brown and yellow female groups in apical view,and between dark brown and yellow male group in apical view,were not obviously different,while the other groups were all significantly different. The analysis of relative distortion contributed by each landmark set on the shell photographs from the front view of the aperture reveals that the shell morphological changes mainly occur on the upper part of the aperture. This study supports the conclusion that the two coloration strains of the golden apple snail each have two morphotypes and that sexual dimorphism is displayed in the shell shape. The results also provides information on the adaptive differences among P. canaliculata individuals of different body colors and demonstrates that geometric morphometrics is an effective research method for shell fish morphology and population analysis.更多还原