Yu Tong Lei, Lu Xin
Department of Zoology, College of Life Sciences, Wuhan University, Wuhan 430072, China.
Zoolog Sci. 2010 Nov;27(11):856-60. doi: 10.2108/zsj.27.856.
The large-male mating advantage and size-assortative mating are two different size-based patterns, which deviate from random mating in toads. These two pairing patterns may arise due to female choice, male-male competition, male choice, or a combination of these. This study investigated the mating system of Minshan's toad (Bufo minshanicus) from three populations along an altitudinal gradient during two breeding reasons in the northeastern Tibetan plateau. Our study shows that males found in amplexus with females were larger on average than non-amplectant males in two sites with higher operational sex ratios. Similarly, in those sites, males and females found in amplexus maintained an optimal size ratio. These data suggest that male-male competition leads to size-assortative mating in the lack of mate choice (female and male mate choice) by Minshan's toad, as larger males performed higher frequencies for taking-over other low quality ones with amplectant females.
大雄蛙交配优势和体型选配交配是两种不同的基于体型的模式，它们在蟾蜍中偏离了随机交配。这两种配对模式可能是由于雌性选择、雄雄竞争、雄性选择或这些因素的组合而产生的。本研究在青藏高原东北部两个繁殖季节，沿着海拔梯度对岷山蟾蜍（Bufo minshanicus）三个种群的交配系统进行了调查。我们的研究表明，在两个具有较高性操作比的地点，抱对雌蛙的雄蛙平均比未抱对的雄蛙体型更大。同样，在这些地点，抱对的雄蛙和雌蛙维持着最佳体型比。这些数据表明，在岷山蟾蜍缺乏配偶选择（雌性和雄性配偶选择）的情况下，雄雄竞争导致了体型选配交配，因为较大的雄蛙更频繁地从其他低质量雄蛙那里接管抱对雌蛙。
