Data from: Relating fitness to long-term environmental variations in natura

Quantifying links between ecological processes and adaptation dynamics in natura remains a crucial challenge. Many studies have documented the strength, form and direction of selection, and its variations in space and time, but only a few managed to link these variations to their proximal causes. This step is, however, crucial, if we are to understand how the variation of selective pressure affects adaptive allele dynamics in natural settings. We used data from a long-term survey (about 30 years) monitoring the adaptation to insecticides of Culex pipiens mosquitoes in Montpellier area (France), focusing on three resistance alleles of the Ester locus. We used a population genetics model taking temporal and spatial variations of selective pressure into account, to assess the quantitative relationships between variations in the proximal agent of selection (amounts of insecticide sprayed) and the fitness of resistance alleles. The response to variations in selective pressure was fast, and the alleles displayed different fitness-to-environment relationships: the analyses revealed that even slight changes in insecticide doses could induce changes of the strength and direction of selection, thus changing the fitness ranking of the adaptive alleles. They also revealed that selective pressures other than the insecticides used for mosquito control affected the resistance allele dynamics. These fitness-to-environment relationships, fast responses and continuous evolution limit our ability to predict the outcome of adaptive allele dynamics in a changing environment, but they clearly contribute to the maintenance of polymorphism in natural populations. Our study also emphasizes the necessity of long-term surveys in evolutionary ecology.

量化自然状态下生态过程与适应性动态之间的关联，仍是一项极具挑战性的核心课题。诸多研究已对自然选择的强度、模式与方向，及其在时空维度上的变异展开了系统记录，但仅有少数研究成功将这些变异与其近因关联起来。然而，若要明晰选择压力的变异如何影响自然环境中的适应性等位基因动态，这一步骤至关重要。本研究使用了法国蒙彼利埃地区为期约30年的长期监测数据，追踪尖音库蚊（Culex pipiens）对杀虫剂的适应性演化过程，重点关注酯酶基因座（Ester locus）上的3个抗性等位基因。本研究采用纳入了选择压力时空变异的种群遗传学模型，评估了选择近因因子（即喷洒的杀虫剂剂量）的变异与抗性等位基因适合度之间的定量关联。种群对选择压力变异的响应速度较快，且不同等位基因展现出各异的适合度-环境关联模式。分析结果显示，即便杀虫剂剂量出现微小变化，也可能引发自然选择强度与方向的改变，进而改变适应性等位基因的适合度排序。研究同时发现，除用于蚊虫防控的杀虫剂之外的其他选择压力，同样会对抗性等位基因的动态产生影响。这类适合度-环境关联模式、快速响应能力以及持续演化过程，限制了我们对变化环境中适应性等位基因动态结果的预测能力，但它们显然有助于维持自然种群中的遗传多态性。本研究同时强调了长期监测在进化生态学研究中的必要性。