Sexual dimorphism of head size in Gallotia galloti:: testing the niche divergence hypothesis by functional analyses
Sexual dimorphism of head size in Gallotia galloti:: testing the niche divergence hypothesis by functional analyses
复制标题
DOI：
10.1046/j.1365-2435.1999.00305.x
复制
发表时间：
1999-06-01
影响因子：
5.2
通讯作者：
De Vree, F
中科院分区：
文献类型：
--
作者：
Herrel, A;Spithoven, L;De Vree, F
1.两个经常被引用的解释蜥蜴两性头部大小二型性的假说是：性选择作用于在性内竞争中重要的结构，以及通过食物生态位分离减少性间竞争.在这项研究中，后一种假设的一些隐含的假设进行了测试，即在张口距离和咬合力的增加应伴随着所观察到的头部大小的增加。这些假设进行测试，记录咬合力，在体内，蜥蜴的物种Gallotia galloti。在这个物种中，雄性蜥蜴的头部明显大于相似的口鼻长度的雌性同类。此外，粉碎几个潜在的猎物物种所需的平均力的实验确定和咬合力数据进行比较。这种比较清楚地表明，动物的性别可以咬更难比大多数昆虫的食物项目，这并不支持生态位分歧假说。雌雄个体咬合力明显“过剩”可能与动物的部分食草性饮食有关。要解开的起源性别之间的差异，在咬能力，粉碎相建模。该模型的结果显示了不同的策略，在分配的肌肉组织之间的性别。讨论了这种差异的起源，并提供了一个可能的进化途径的发展的性别二型的物种。
1. Two often cited hypotheses explaining sexual head size dimorphism in lizards are: sexual selection acting on structures important in intrasexual competition, and reduction of intersexual competition through food niche separation.2. In this study some implicit assumptions of the latter hypothesis were tested, namely that an increase in gape distance and bite force should accompany the observed increase in head size. These assumptions are tested by recording bite forces, in vivo, for lizards of the species Gallotia galloti. In this species, male lizards have significantly larger heads than female conspecifics of similar snout-vent length.3. Additionally, the average force needed to crush several potential prey species was determined experimentally and compared with the bite force data. This comparison clearly illustrates that animals of both sexes can bite much harder than required for most insect food items, which does not support the niche divergence hypothesis. The apparent 'excess' bite force in both sexes might be related to the partially herbivorous diet of the animals.4. To unravel the origin of differences between sexes in bite capacity, the crushing phase of biting was modelled. The results of this model show different strategies in allocation of muscle tissue between both sexes. The origin of this difference is discussed and a possible evolutionary pathway of the development of the sexual dimorphism in the species is provided.