The Intersexual Differences of Sexual Dimorphism,Feeding Habits and Locomotor Performance at Different Temperatures of Southern Grass Lizard(Takydromus sexlineatus) in Zhaoqing,China

Abstract

通过测量头、尾、体和胃检,研究肇庆南草蜥TAkydrOMuS SEXlInEATuS个体发育过程中两性异形和食性差异。南草蜥成体个体两性大小无显著差异,雄性头部显著大于雌性,两性头部大小异形可能是受到性选择压力的结果。雌雄个体食物生态位重叠度较高,两性生态位差异微弱,食性差异与两性头部异形无明显相关性。通过设计13种不同的环境温度,研究体温变化对南草蜥两性个体运动能力表现的影响。结果显示环境温度通过影响体温而影响南草蜥的运动表现,两性个体疾跑速均具有在低体温范围内随体温升高而加快、在高体温范围内随体温升高而降低的模式。在多数测试温度下,雄体的疾跑速均略大于雌体,但两者平均值在统计上无显著差异。体温对南草蜥的最大持续运动距离和停顿次数的影响显著,两性个体的疾跑速和最大持续运动距离呈显著正相关。雄性和雌性分别在26℃和30℃具有最佳的运动表现。Southern grass lizard( Takydromus sexlineatus) was collected from Zhaoqing,Guandong province to determine the sexual dimorphism and dietary habits by measuring the lengths of head,tail and body,and examining the items in the stomach.The results showed that there was no significant difference in body size.However,male individuals had significantly larger head size than females,which might be due to the divergent sexual selection pressure.A relatively high food niche overlap was observed between the sexes.There was little relationship between food habits and head dimorphism.By designing 13 different ambient temperatures,we determined the relationship between body temperature and locomotor performance of the adults.Ambient temperature affected locomotor performance by influencing the body temperature.Sprint speed increased with increasing body temperature at lower body temperature,while decreasing with increasing body temperatures at higher body temperatures,which was similar between the sexes.However,males ran slightly faster than females in most cases,but intersexual difference of sprint speed was not statistically significant.Body temperature also influenced the maximal move distance and pause times.Sprint speed was positively correlated with the maximal move distance.The optimal temperatures of locomotor performance differed between the sexes: about 26℃ for males and 30 ℃ for females,respectively.国家自然科学基金资助项目(31271124); 广东省自然科学基金(06300177); 广东省高等教育教学改革项目(粤财教[2012]361号); 大学生创新性实验计划项目(DC201316)共同资