Latitudinal variation in sexual size dimorphism of sea-run masu salmon, Oncorhynchus masou
Latitudinal variation in sexual size dimorphism of sea-run masu salmon, Oncorhynchus masou
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DOI：
10.1111/j.0014-3820.2006.tb01094.x
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发表时间：
2006-01-01
期刊：
影响因子：
3.3
通讯作者：
Maekawa, K
中科院分区：
文献类型：
--
作者：
Tamate, T;Maekawa, K
性别大小二态性（SSD），两性之间的身体大小差异，发生在许多动物物种中。虽然较大的性别往往被认为是不变的物种内，模式的选择可能会导致种群间的变化，甚至逆转SSD。我们评估了纬度和女性的身体大小，男性的身体大小，和相对身体大小（男性身体大小/女性身体大小）在22个种群（范围从37度N到49度N）的海运行的马苏鲑鱼（Oncorhynchus masou），产卵在河流沿着日本海沿岸。雄性个体大小和相对个体大小随纬度的增加而增加，而雌性个体大小与纬度无关。此外，男性体型随纬度的增加足以导致SSD的逆转，转换点在北纬45度左右。我们认为，纬度和男性的大小之间的正相关性是由于增加操作的性比或性选择的海运行男性的身体大小，结果从性别偏见的模式anadromy。总之，我们的研究提供了第一个例子，可预测的地理变化SSD形的明显的性选择模式。
Sexual size dimorphism (SSD), a difference in body size between the sexes, occurs in many animal species. Although the larger sex is often considered invariable within species, patterns of selection may result in interpopulation variation or even reversal of SSD. We evaluated correlations between latitude and female body size, male body size, and relative body size (male body size/female body size) in 22 populations (ranging from 37 degrees N to 49 degrees N) of sea-run masu salmon (Oncorhynchus masou) that spawn in rivers along the Sea of Japan coast. Male size and the relative body size increased with latitude, but female size did not correlate with latitude. In addition, increase in male size with latitude was sufficient to result in a reversal of SSD, the switch-point being around 45 degrees N. We suggest that the positive correlation between latitude and male size is due to increasing operational sex ratios or sexual selection on sea-run male body size that result from sex-biased patterns of anadromy. In conclusion, our study provides the first example of predictable geographic variation in SSD shaped by apparent patterns of sexual selection.