基底颜色对两种沙蜥体色变异的影响

Effects of substrate color on the body color variation of two agamid lizards, Phrynocephalus versicolor and P.frontalis

生存在不同基底颜色环境下的爬行动物种群通常表现出丰富的体色地理变异,其体色变化的潜在机制具有多样性。变色沙蜥(Phrynocephalus versicolor)和草原沙蜥(P.frontalis)具有较近的遗传关系,曾被认为与荒漠沙蜥(P.przewalskii)组成同一系统发育种组。本文应用光纤光谱仪(Ava Spec-2048),通过记录沙蜥背部体表12个部位的皮肤光反射率,定量比较在黑化环境下的深色变色沙蜥与非黑化环境下的浅色草原沙蜥自然体色变异,研究其种群体色变异是否具有时间可逆性,并探讨基底颜色对沙蜥体色的影响机制。研究结果表明,黑化生境下的变色沙蜥体色显著深于非黑化枯黄色生境下的草原沙蜥。此外,对黑化与非黑化样本开展的生境互换移植围栏实验,即把枯黄色生境中非黑化的草原沙蜥移植于黑色的基底环境中饲养,把黑化生境中黑化的变色沙蜥移植于枯黄色生境中饲养。结果表明,饲养1周后黑化群体背部6个检测部位的光反射率显著变大,其他部位均无显著变化;而非黑化群体只有左后肢和背部右上方2个部位的皮肤光反射率发生显著变化,其他部位反射率无显著变化。结果表明,变色沙蜥体色变异能力比草原沙蜥强,体色表型可能已经在两个近缘沙蜥物种中稳定遗传,基底生境颜色的短期变化在统计学上能引起肉眼难以识别的轻微的体色变异,个体发育相关的一些遗传因素可能对体色变异起控制作用。

Geographical variation of body color is widely present in reptile populations that survive in different substrate habitats, multiple potential mechanisms can account for this color variation. Phrynocephalus versicolor and P. frontalis, close genetic relatives, constitute a phylogenetic species group together with P. przewalskii. In this study, a fiber spectrophotometer （AvaSpec-2048） was used to record the skin luminous refleetivity of 12 sites across the lizard＇s body, and we quantitatively compared the natural color variation of dark P. versicolor and light R frontalis that lived in ＂melanistic＂ and ＂non-melanistic＂ habitats, respectively. We aimed to determine whether the color variations of both populations were time reversible, and further discuss potential mechanisms that substrate color may have on color variation of Phrynocephalus lizards. Our results showed that the body color ofP. versicolor in ＂melanistic＂ habitat was significantly darker than P. frontalis in the ＂non-melanistic＂ withered yellow habitat. We also conducted a reciprocal transplantation experiments （i.e. ＂non-melanistic＂ withered yellow P. frontalis individuals were transplanted and fed in ＂melanistic＂ substrate environment, while ＂melanistic＂ P. versicolor individuals were transplanted and fed in withered yellow substrate environment）. For ＂melanistic＂ P. versicolor, the skin reflectivity of six sites increased significantly after one week, while no significant changes were detected in other sites. For ＂non-melanistic＂ P. frontalis, except the skin reflectivity of two sites （left hind limb and top right on the back） significantly changed, compared to corresponding values one week previously, other sites showed no significant changes. Our results suggest that P versicolor possesses stronger color variation ability than P frontalis, and the color phenotypes are likely inherited in both species. Short-term changes of substrate color can cause slightly color variations that are difficult to hereditary factors may also play a controlling role. distinguish by naked eyes, suggesting ontogeny related