Andrew meets Rensch: sexual size dimorphism and the inverse of Rensch's rule in Andrew's toad (Bufo andrewsi)
Andrew meets Rensch: sexual size dimorphism and the inverse of Rensch's rule in Andrew's toad (Bufo andrewsi)
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DOI：
10.1007/s00442-014-3147-8
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发表时间：
2015-02-01
期刊：
影响因子：
2.7
通讯作者：
Merila, Juha
中科院分区：
文献类型：
--
作者：
Liao, Wen Bo;Liu, Wen Chao;Merila, Juha
性别大小二态性（SSD）的变化是一种普遍的现象，通常归因于性别特异性选择模式的变化。根据Rensch的规则，当男性是较大的性别时，SSD随着身体大小的增加而增加，而当女性是较大的性别时，SSD随着身体大小的增加而减少。利用17个种群的数据，我们检验了SSD的模式是否符合Rensch规则。利用田间试验，我们还评估了假设，性选择有利于大的男性身体的大小和繁殖力的选择有利于大的女性身体的大小。结果表明，SSD的程度增加的平均大小的女性，符合反Rensch的规则。虽然实验显示的证据大男性交配优势，大男性尺寸的选择是弱在最好的，因此不太可能是一个重要的来源，在SSD的变化。然而，生育力选择有利于大女性是显而易见的，并可能解释观察到的逆Rensch的规则。校正男性和女性的身体大小的年龄差异后，SSD的模式保持不变，这表明SSD的种群内和种群间的变化不是由年龄结构的性别差异驱动的。因此，这些研究结果表明，强大的生殖力选择有利于大的女性驱动的女性偏向SSD在B的演变。andrewsi，提供了一个解释的逆Rensch的规则。因此，这项研究提供了一个重要的补充，以小机构的文献，使用种内的方法来证明逆Rensch的规则。
Variation in sexual size dimorphism (SSD) is a widespread phenomenon and is commonly attributed to variation in sex-specific patterns of selection. According to Rensch's rule, SSD increases with increasing body size when males are the larger sex, and decreases when females are the larger sex. Using data from 17 populations of Andrew's toad (Bufo andrewsi), we tested whether the patterns of SSD conform to Rensch's rule. Using field experiments, we also evaluated the hypothesis that sexual selection favours large male body size and that fecundity selection favours large female body size. The results revealed that the degree of SSD increased with increasing mean size in females, consistent with the inverse of Rensch's rule. Although experiments revealed evidence for a large-male mating advantage, selection for large male size was weak at best, and hence unlikely to be an important source of variation in SSD. However, fecundity selection favouring large females was evident, and likely to explain the observed inverse of Rensch's rule. After correcting male and female body size for age differences, the patterns of SSD remained the same, suggesting that the intra- and interpopulational variation in SSD is not driven by sex differences in age structure. Hence, these findings suggest that the strong fecundity selection favouring large females drives the evolution of female-biased SSD in B. andrewsi, providing an explanation for the inverse of Rensch's rule. As such, the study provides an important addition to the small body of literature that uses an intraspecific approach to demonstrate the inverse of Rensch's rule.