DOES VARIATION IN SELECTION IMPOSED BY BEARS DRIVE DIVERGENCE AMONG POPULATIONS IN THE SIZE AND SHAPE OF SOCKEYE SALMON?
DOES VARIATION IN SELECTION IMPOSED BY BEARS DRIVE DIVERGENCE AMONG POPULATIONS IN THE SIZE AND SHAPE OF SOCKEYE SALMON?
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DOI：
10.1111/j.1558-5646.2009.00643.x
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发表时间：
2009-05-01
期刊：
影响因子：
3.3
通讯作者：
Quinn, Thomas P.
中科院分区：
文献类型：
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作者：
Carlson, Stephanie M.;Rich, Harry B., Jr.;Quinn, Thomas P.
很少有研究确定选择的正式估计是否解释了种群间的性状分化模式，但这是评估种群是否处于平衡状态的一种方法。如果适应性趋异是完全的，那么方向选择就不存在，而稳定化选择就占了上风。我们估计自然选择，由于熊捕食，在三个繁殖种群的雄性鲑鱼的身体大小和形状，经历不同的捕食制度。我们的方法是：（1）根据繁殖活动的经验估计，估计每个种群内对每个性状的选择作用，（2）检验种群间的性状分歧，（3）检验选择系数是否与种群间的性状分歧相关。稳定选择从来都不重要，这表明这些种群还没有达到平衡。定向选择不同的方式与性状的分歧，表明正在进行的人口分化。具体地说，小溪在选择模式方面的等级顺序超过了在大小和形状方面的等级顺序。最短和最深的身体男性有最高的生殖活动，在最激烈的捕食和较长和身体较深的男性青睐的小溪捕食风险较低。
Few studies have determined whether formal estimates of selection explain patterns of trait divergence among populations, yet this is one approach for evaluating whether the populations are in equilibria. If adaptive divergence is complete, directional selection should be absent and stabilizing selection should prevail. We estimated natural selection, due to bear predation, acting on the body size and shape of male salmon in three breeding populations that experience differing predation regimes. Our approach was to (1) estimate selection acting within each population on each trait based on an empirical estimate of reproductive activity, (2) test for trait divergence among populations, and (3) test whether selection coefficients were correlated with trait divergence among populations. Stabilizing selection was never significant, indicating that these populations have yet to attain equilibria. Directional selection varied among populations in a manner consistent with trait divergence, indicating ongoing population differentiation. Specifically, the rank order of the creeks in terms of patterns of selection paralleled the rank order in terms of size and shape. The shortest and least deep-bodied males had the highest reproductive activity in the creek with the most intense predation and longer and deeper-bodied males were favored in the creeks with lower predation risk.