The Chinese skink ( Eumeces chinensis) is sexually dimorphic in both body size and head size,and males are the larger.A comprehensive analysis of the ecological and evolutionary sources of sex differences in growth an...The Chinese skink ( Eumeces chinensis) is sexually dimorphic in both body size and head size,and males are the larger.A comprehensive analysis of the ecological and evolutionary sources of sex differences in growth and size of head requires a detailed understanding of growth trajectories during ontogeny.Here,we pay particular attention to the point during ontogeny at which males and females diverge.Hatchlings (newly emerged young) and juveniles smaller than 70 mm SVL do not exhibit sexual dimorphism in head size,whereas males and females larger than 70mm SVL begin to diverge.The sexual dimorphism in head size is much more pronounced in adults than in juveniles sharing this character.Adult females partition relatively less resources into head growth but more into carcass growth,thereby leaving a larger space for eggs so as to increase reproductive output.Adult males,on the contrary,partition relatively more resources into head growth,thereby increasing their reproductive success and enhancing their ability to defend predators.Skinks at different ontogenetic stages slightly differ in food niche width and breadth.However,no direct evidence shows a substantial contribution of the divergence in head size to the segregation of food niche between males and females.Our results indicate that sexual selection is the main evolutionary source of sexual dimorphism in body and head sizes in E.chinensis .展开更多
动物在野外生境中的活动能力通常会受到许多方面(例如,运动基质表面粗糙程度、遭遇障碍物的大小与形状)的影响。在特定体温(30℃)条件下,测量主要分布区重叠的两蜥蜴种类(北草蜥和中国石龙子)在四种不同基质表面(塑料草坪;表面粗糙不透...动物在野外生境中的活动能力通常会受到许多方面(例如,运动基质表面粗糙程度、遭遇障碍物的大小与形状)的影响。在特定体温(30℃)条件下,测量主要分布区重叠的两蜥蜴种类(北草蜥和中国石龙子)在四种不同基质表面(塑料草坪;表面粗糙不透底的塑料地毯;光滑具透底网格的塑料地毯和表面光滑的塑料地毯)的运动表现,以及两者的攀附能力和最大游泳耐力。基质类型显著影响两种蜥蜴的运动表现。两种蜥蜴在粗糙表面运动时的疾跑速明显大于光滑表面(例如,塑料草坪上北草蜥为15.7 SVL/s,中国石龙子为8.1 SVL/s;光滑塑料地毯上则分别为11.4 SVL/s和3.5 SVL/s)。中国石龙子在光滑塑料地毯上具有最大的持续运动距离(10.6 SVL)和最少的停顿次数(1.9次)。北草蜥在光滑塑料地毯上具有最多的停顿次数(4.6次)。两种蜥蜴运动能力的种间差异显著。北草蜥具有较大的相对疾跑速度(北草蜥和中国石龙子:13.5 SVL/s vs 5.8 SVL/s)和攀附能力(143.8°vs 101.2°),但较小的游泳耐力(83.5 s vs 238.5 s)。运动速度与耐力之间存在种间权衡关系而与攀爬能力无进化冲突的结论。展开更多
文摘The Chinese skink ( Eumeces chinensis) is sexually dimorphic in both body size and head size,and males are the larger.A comprehensive analysis of the ecological and evolutionary sources of sex differences in growth and size of head requires a detailed understanding of growth trajectories during ontogeny.Here,we pay particular attention to the point during ontogeny at which males and females diverge.Hatchlings (newly emerged young) and juveniles smaller than 70 mm SVL do not exhibit sexual dimorphism in head size,whereas males and females larger than 70mm SVL begin to diverge.The sexual dimorphism in head size is much more pronounced in adults than in juveniles sharing this character.Adult females partition relatively less resources into head growth but more into carcass growth,thereby leaving a larger space for eggs so as to increase reproductive output.Adult males,on the contrary,partition relatively more resources into head growth,thereby increasing their reproductive success and enhancing their ability to defend predators.Skinks at different ontogenetic stages slightly differ in food niche width and breadth.However,no direct evidence shows a substantial contribution of the divergence in head size to the segregation of food niche between males and females.Our results indicate that sexual selection is the main evolutionary source of sexual dimorphism in body and head sizes in E.chinensis .
文摘动物在野外生境中的活动能力通常会受到许多方面(例如,运动基质表面粗糙程度、遭遇障碍物的大小与形状)的影响。在特定体温(30℃)条件下,测量主要分布区重叠的两蜥蜴种类(北草蜥和中国石龙子)在四种不同基质表面(塑料草坪;表面粗糙不透底的塑料地毯;光滑具透底网格的塑料地毯和表面光滑的塑料地毯)的运动表现,以及两者的攀附能力和最大游泳耐力。基质类型显著影响两种蜥蜴的运动表现。两种蜥蜴在粗糙表面运动时的疾跑速明显大于光滑表面(例如,塑料草坪上北草蜥为15.7 SVL/s,中国石龙子为8.1 SVL/s;光滑塑料地毯上则分别为11.4 SVL/s和3.5 SVL/s)。中国石龙子在光滑塑料地毯上具有最大的持续运动距离(10.6 SVL)和最少的停顿次数(1.9次)。北草蜥在光滑塑料地毯上具有最多的停顿次数(4.6次)。两种蜥蜴运动能力的种间差异显著。北草蜥具有较大的相对疾跑速度(北草蜥和中国石龙子:13.5 SVL/s vs 5.8 SVL/s)和攀附能力(143.8°vs 101.2°),但较小的游泳耐力(83.5 s vs 238.5 s)。运动速度与耐力之间存在种间权衡关系而与攀爬能力无进化冲突的结论。
