草原蜥两性的咬合力及头部形态特征比较

咬合力作为衡量动物生存能力的重要指标,可以在一定程度上反映动物捕食、反捕食和争夺配偶的能力。对于蜥蜴类动物而言,头部形态和咬合力大小之间常呈现显著线性关系。通过测量2018年7月采集于新疆霍城县图开沙漠的24号草原蜥(Trapelussanguinolenta)(雌13,雄11)的头部形态指标,并使用薄膜压力测试仪测定咬合力,采用单因素方差分析(ANOVA)、主成分分析、模型拟合及逐步回归4种方法探究草原蜥咬合力的两性差异及其与头部形态指标的关系。结果表明,草原蜥头体长、头长、头宽、头高、口宽和下颌长在两性个体间均无显著差异,草原蜥两性个体之间咬合力也没有显著差异。主成分分析及赤池信息模型拟合结果均显示,头长、头宽和下颌长是影响草原蜥咬合力的重要因素,逐步回归分析揭示草原蜥的咬合力主要受头宽影响。上述研究结果表明,草原蜥的咬合力受头部形态大小的影响,但两性个体之间咬合力却不存在显著差异,这与头部形态特征未表现出两性差异一致,这可能是草原蜥对灌丛生活的适应,具体而言,是头部大小与运动权衡的结果。

Comparison of Bite Force Performance and Head Shape between Males and Females of Trapelus sanguinolenta

Bite force of animals can reflect the ability of anti-predation, and attracting the opposite sex. For lizards, there is usually a significant linear relationship between head shape of individuals and their bite force. We performed the head morphometric analysis using species Trapelus sanguinolenta(♀13, ♂11) collected in Tukai Desert of Huocheng County, western Xinjiang, in July 2018. We measured the bite force of each individuals by a membrane pressure tester to analyze the relationship of the bite force with the sexual dimorphism in head. Then we employed the analysis of variance(ANOVA), principal component analysis, Akaike information model and stepwise regression analysis to analyze the difference in the head shape and bite force between females and males of the lizard species. The results showed that no significant intraspecific difference in the head morphological indexes for this lizard(Table 1), as well as no significant difference was found in the bite force between females and males. However, there was a difference of bite force in slope coefficients of head depth between males and females(Fig. 2). The bite force of the males increased faster with the head depth than the females did. The results of Principal component analysis and Akaike information model showed that head length, head width and lower jaw length were important factors affecting the bite force(Fig. 1, Table 2). Stepwise regression analysis revealed that the bite force was mainly affected by head width(Table 3). The results indicated that the bite force of T. sanguinolenta is affected by the size of the head. No significant intraspecific difference in the bite force is consistent with the morphological characteristics of the head, which may indicate an adaptation of this species to the shrub habitat. Specifically, it is the result of a trade-off between head size and movement balance.