Eck Daniel J, Shaw Ruth G, Geyer Charles J, Kingsolver Joel G
School of Statistics, University of Minnesota, 313 Ford Hall, 224 Church Street S.E., Minneapolis, Minnesota, 55455.
Department of Ecology, Evolution, and Behavior and Minnesota Center for Community Genetics, University of Minnesota, 100 Ecology Building, 1987 Upper Buford Circle, St. Paul, Minnesota, 55108.
Evolution. 2015 Sep;69(9):2525-32. doi: 10.1111/evo.12744. Epub 2015 Aug 27.
Most studies of phenotypic selection do not estimate selection or fitness surfaces for multiple components of fitness within a unified statistical framework. This makes it difficult or impossible to assess how selection operates on traits through variation in multiple components of fitness. We describe a new generation of aster models that can evaluate phenotypic selection by accounting for timing of life-history transitions and their effect on population growth rate, in addition to survival and reproductive output. We use this approach to estimate selection on body size and development time for a field population of the herbivorous insect, Manduca sexta (Lepidoptera: Sphingidae). Estimated fitness surfaces revealed strong and significant directional selection favoring both larger adult size (via effects on egg counts) and more rapid rates of early larval development (via effects on larval survival). Incorporating the timing of reproduction and its influence on population growth rate into the analysis resulted in larger values for size in early larval development at which fitness is maximized, and weaker selection on size in early larval development. These results illustrate how the interplay of different components of fitness can influence selection on size and development time. This integrated modeling framework can be readily applied to studies of phenotypic selection via multiple fitness components in other systems.
大多数表型选择研究并未在统一的统计框架内估计适合度多个组成部分的选择或适合度曲面。这使得评估选择如何通过适合度多个组成部分的变异作用于性状变得困难甚至不可能。我们描述了新一代的aster模型，该模型除了考虑生存和繁殖输出外，还能通过考虑生活史转变的时间及其对种群增长率的影响来评估表型选择。我们使用这种方法来估计草食性昆虫烟草天蛾（鳞翅目：天蛾科）田间种群的体型和发育时间的选择。估计的适合度曲面显示出强烈且显著的定向选择，有利于更大的成虫体型（通过对产卵量的影响）和更快的早期幼虫发育速度（通过对幼虫存活的影响）。将繁殖时间及其对种群增长率的影响纳入分析，导致早期幼虫发育中适合度最大化时的体型值更大，且对早期幼虫发育体型的选择较弱。这些结果说明了适合度不同组成部分之间的相互作用如何影响对体型和发育时间的选择。这个综合建模框架可以很容易地应用于其他系统中通过多个适合度组成部分进行的表型选择研究。
