INTERSEXUAL DIETARY DIVERGENCE AND THE EVOLUTION OF SEXUAL DIMORPHISM IN SNAKES
INTERSEXUAL DIETARY DIVERGENCE AND THE EVOLUTION OF SEXUAL DIMORPHISM IN SNAKES
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DOI：
10.1086/285207
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发表时间：
1991-07-01
影响因子：
2.9
通讯作者：
SHINE, R
中科院分区：
文献类型：
--
作者：
SHINE, R
只有当两性在形态或摄食器官的相对大小上存在差异时，才能有把握地推断出两性二型性进化的生态原因，而这种差异的方向与性选择的预期方向不一致。 蛇非常适合这样的分析，因为这一群体的头部大小对进食很重要，但对生殖行为不重要。 我的数据显示显着的两性异形头的大小（相对于口鼻的长度）在47%的114种检查从7个家庭。 在种内种群、属内种群和科内属间种群的比较中，雄性和雌性之间的头部大小相对于身体大小具有很强的相关性。 因此，两性之间的相关性可能会有力地限制二态性的进化转变。 尽管如此，系统发育分析确定了许多独立的起源和二态性的损失。 在广泛分布的物种中，相对头部大小的地理变异和头部大小的两性异形是明显的。 两性之间的饮食差异发生在一个分类学和生态学上多样化的蛇类群体中。 头部大小二型性的生态优势可能并不涉及两性之间的竞争置换。 我推断，性别最初分歧的身体大小或生态，因为在生殖生物学的差异，与随后的进化，通过独立的适应觅食在每一个性别的饮食结构的两性异形。
Ecological causes for the evolution of sexual dimorphism can be confidently inferred only when the sexes differ in morphology or relative size of the feeding apparatus, in a direction inconsistent with that expected from sexual selection. Snakes are well suited for such an analysis because head sizes in this group are important for feeding but not for reproductive behavior. My data reveal significant sexual dimorphism in head size (relative to snout-vent length) in 47% of 114 species examined from seven families. Head size relative to body size is strongly correlated between males and females in comparisons among populations within species, among species within genera, and among genera within families. Hence, correlation between the sexes may powerfully constrain evolutionary shifts in dimorphism. Nonetheless, phylogenetic analysis identifies many independent origins and losses of the dimorphism. Geographic variation in relative head size and sexual dimorphism in head size are evident within wide-ranging species. Dietary divergence between the sexes occurs in a taxonomically and ecologically diverse group of snakes. The ecological advantages of head-size dimorphism probably do not involve competitive displacement between the sexes. I infer that the sexes originally diverged in body sizes or ecology because of differences in reproductive biology, with the subsequent evolution of sexual dimorphism in feeding structures through independent adaptations to foraging in each sex.