Chavarie Louise, Voelker Steve, Hansen Michael J, Bronte Charles R, Muir Andrew M, Zimmerman Mara S, Krueger Charles C
Faculty of Environmental Sciences and Natural Resource Management Norwegian University of Life Sciences Ås Norway.
Beaty Biodiversity Research Center University of British Columbia Vancouver BC Canada.
Evol Appl. 2021 Feb 5;14(4):1159-1177. doi: 10.1111/eva.13188. eCollection 2021 Apr.
Pathways through which phenotypic variation among individuals arise can be complex. One assumption often made in relation to intraspecific diversity is that the stability or predictability of the environment will interact with expression of the underlying phenotypic variation. To address biological complexity below the species level, we investigated variability across years in morphology and annual growth increments between and within two sympatric lake charr ecotypes in Rush Lake, USA. A rapid phenotypic shift in body and head shape was found within a decade. The magnitude and direction of the observed phenotypic change were consistent in both ecotypes, which suggests similar pathways caused the variation over time. Over the same time period, annual growth increments declined for both lake charr ecotypes and corresponded with a consistent phenotypic shift of each ecotype. Despite ecotype-specific annual growth changes in response to winter conditions, the observed annual growth shift for both ecotypes was linked, to some degree, with variation in the environment. Particularly, a declining trend in regional cloud cover was associated with an increase of early-stage (ages 1-3) annual growth for lake charr of Rush Lake. Underlying mechanisms causing changes in growth rates and constrained morphological modulation are not fully understood. An improved knowledge of the biology hidden within the expression of phenotypic variation promises to clarify our understanding of temporal morphological diversity and instability.
个体间表型变异产生的途径可能很复杂。关于种内多样性，人们常做的一个假设是环境的稳定性或可预测性将与潜在表型变异的表达相互作用。为了研究物种水平以下的生物复杂性，我们调查了美国拉什湖两种同域分布的湖红点鲑生态型之间以及内部在形态和年生长增量方面多年间的变异性。在十年内发现了身体和头部形状的快速表型转变。在两种生态型中观察到的表型变化的幅度和方向是一致的，这表明相似的途径导致了随时间的变异。在同一时期，两种湖红点鲑生态型的年生长增量都下降了，并且与每种生态型一致的表型转变相对应。尽管生态型对冬季条件有特定的年生长变化响应，但观察到的两种生态型的年生长转变在一定程度上与环境变化有关。特别是，区域云量的下降趋势与拉什湖湖红点鲑早期（1 - 3龄）年生长的增加有关。导致生长率变化和形态调节受限的潜在机制尚未完全了解。对隐藏在表型变异表达中的生物学有更深入的了解，有望澄清我们对时间形态多样性和不稳定性的理解。
