Department of Biology, Duke University, Box 90338, Durham, NC, 27708, USA.
New Phytol. 2023 Apr;238(1):405-421. doi: 10.1111/nph.18711. Epub 2023 Jan 22.
The timing of a developmental transition (phenology) can influence the environment experienced by subsequent life stages. When phenology causes an organism to occupy a particular habitat as a consequence of the developmental cues used, it can act as a form of habitat tracking. Evolutionary theory predicts that habitat tracking can alter the strength, direction, and mode of natural selection on subsequently expressed traits. To test whether germination phenology altered natural selection on postgermination traits, we manipulated germination time by planting seedlings in seven germination cohorts spanning 2 yr. We measured selection on postgermination traits relating to drought, freezing, and heat tolerance using a diverse combination of Arabidopsis thaliana mutants and naturally occurring ecotypes. Germination cohorts experienced variable selection: when dry, cold, and hot environments were experienced by seedlings, selection was intensified for drought, freezing, and heat tolerance, respectively. Reciprocally, postgermination traits modified the optimal germination time; genotypes had maximum fitness after germinating in environments that matched their physiological tolerances. Our results support the theoretical predictions of feedbacks between habitat tracking and traits expressed after habitat selection. In natural populations, whether phenological shifts alter selection on subsequently expressed traits will depend on the effectiveness of habitat tracking through phenology.
发育转变（物候）的时间可以影响生物后续生命阶段所经历的环境。当物候导致生物体由于发育线索而占据特定栖息地时，它可以作为一种栖息地跟踪形式。进化理论预测，栖息地跟踪可以改变对随后表达的特征的自然选择的强度、方向和模式。为了测试发芽物候是否改变了对发芽后特征的自然选择，我们通过在跨越 2 年的七个发芽队列中种植幼苗来操纵发芽时间。我们使用多种拟南芥突变体和自然发生的生态型来测量与耐旱性、抗冻性和耐热性有关的发芽后特征的选择。发芽队列经历了不同的选择：当幼苗经历干燥、寒冷和炎热的环境时，耐旱性、抗冻性和耐热性的选择分别得到加强。反过来，发芽后特征改变了最佳发芽时间；在与生理耐受相匹配的环境中发芽的基因型具有最大的适应性。我们的结果支持了栖息地跟踪与栖息地选择后表达的特征之间存在反馈的理论预测。在自然种群中，物候变化是否改变对随后表达的特征的选择，将取决于通过物候进行栖息地跟踪的有效性。
