Trait changes in a harvested population are driven by a dynamic tug-of-war between natural and harvest selection
Trait changes in a harvested population are driven by a dynamic tug-of-war between natural and harvest selection
复制标题
DOI：
10.1073/pnas.0705908104
复制
发表时间：
2007-10-02
影响因子：
11.1
通讯作者：
Stenseth, Nils C.
中科院分区：
文献类型：
--
作者：
Edeline, Eric;Carlson, Stephanie M.;Stenseth, Nils C.
大个体的选择性收获应该改变自然适应性景观，并推动进化减少体细胞生长和增加生殖投资。然而，很少有研究同时考虑了人工和自然选择在驱动野生种群性状变化方面的相对重要性。使用50年的个人为基础的数据温德米尔梭子鱼（狗鱼），我们表明，性状的变化跟踪的适应性高峰，移动的方向所施加的主导选择力。个体一生的体细胞生长在时间序列的开始下降，因为收获选择是强大的，自然选择是太弱，覆盖收获选择的强度。然而，有利于快速体细胞生长的自然选择在整个时间序列中与梭子鱼丰度的增加平行加强，据推测，同类相食。当捕捞努力减少时，自然选择推翻了收获选择，引发了梭子鱼体细胞生长的快速增长。这两种选择性的力量似乎已经采取行动，在只有一个短期的猎物崩溃，有利于缓慢增长的梭子鱼。此外，增加体细胞生长同时发生在年轻和小的雌性梭子鱼生殖投资减少，表明生长和繁殖之间的权衡。这种变化的年龄特定的幅度超过了收获压力的年龄特定的强度，这表明减少投资也是对预期寿命增加的一种反应。这是第一个研究表明，需要考虑自然选择和人工选择，以充分解释收获种群随时间变化的性状动态。
Selective harvest of large individuals should alter natural adaptive landscapes and drive evolution toward reduced somatic growth and increased reproductive investment. However, few studies have simultaneously considered the relative importance of artificial and natural selection in driving trait changes in wild populations. Using 50 years of individual-based data on Windermere pike (Esox lucius), we show that trait changes tracked the adaptive peak, which moved in the direction imposed by the dominating selective force. Individual lifetime somatic growth decreased at the start of the time series because harvest selection was strong and natural selection was too weak to override the strength of harvest selection. However, natural selection favoring fast somatic growth strengthened across the time series in parallel with the increase in pike abundance and, presumably, cannibalism. Harvest selection was overridden by natural selection when the fishing effort dwindled, triggering a rapid increase in pike somatic growth. The two selective forces appear to have acted in concert during only one short period of prey collapse that favored slow-growing pike. Moreover, increased somatic growth occurred concurrently with a reduction in reproductive investment in young and small female pike, indicating a tradeoff between growth and reproduction. The age-specific amplitude of this change paralleled the age-specific strength of harvest pressure, suggesting that reduced investment was also a response to increased life expectancy. This is the first study to demonstrate that a consideration of both natural selection and artificial selection is needed to fully explain time-varying trait dynamics in harvested populations.