Evolutionary biology of enantiomorphy and mirror-image populations in tree snails.

我们已经成功地在电影中记录的交配行为，可以解释如何在物种的树蜗牛Amphidromus的对映体。目前认为，对映异构体在面对面配对的模式下不能实现手性间配对，其中两个配偶体同时进行相互配对。通过野外观察和实验室观察，我们惊奇地发现了一种手性双态物种-录像分析证实了他们面对面的双向交配，根据我们对照片和视频图像的视觉信息的分析，很明显，具有左右反转生殖器的对映体可以进行阴茎的相互插入，这在物理上是不可能的。因此，目前的研究结果暴露了一个新的问题：它们如何同时实现对映体之间的相互交配。我们还没有发现他们的行为有任何独特之处，表现出典型的面对面交配。相反，视觉记录表明，它们可能有生殖器和插入行为，使他们能够通过克服物理约束相互交配。分子系统发育分析的结果表明，手性二态组的物种是单系的。在最初的分歧组的祖先从一个右旋物种，对映体已演变为祖先的状态保持整个辐射的Amphidromus属。这种手性差异的模式表明，种群内的对映异构体可以通过进化获得一个特定的字符来维持。

We have succeeded in film recording a mating behavior that may explain how the enantiomorphy within species of tree snails Amphidromus. It is currently believed that the enantiomorphs could not achieve inter-chiral mating in the mode of face-to-face mating in which the two partners perform reciprocal matings simultaneously. Surprisingly we have discovered that one of chirally dimorphic species Amphidromus atricallosus copulates in this mode by means of field observations and experimental observations in the laboratory. The video-film analysis has confirmed their two-way copulation in the face-to-face position.According to our analysis of visual information based on photographs and video images, it is clear that the enantiomorphs with left-right reversed genitalia can perform reciprocal insertion of penes which are supposed to be physically hardly possible. Therefore, the current results have exposed a new question ; how do they achieve the reciprocal copulation between the enantiomorphs simultaneously. We have not detected any uniqueness in their behavior that exhibit a typical face-to-face mating. Instead, the visual record suggests that they may have genitalia and insertion behavior that allows them to copulate each other by overcoming the physical constraint.The results of molecular phylogenetic analysis have demonstrated that the chirally dimorphic group of species is monophyletic. At the initial divergence of the ancestor of the group from a dextral species, the enantiomorphy has evolved as the ancestral state maintained throughout the radiation of the genus Amphidromus. This pattern of chiral divergence suggests that the enantiomorphy within populations could be maintained by evolutionary acquisition of a particular character.