Department of Biological Sciences, University at Buffalo, Buffalo, NY, USA.
Department of Biological Sciences, Auburn University, Auburn, AL, USA.
Commun Biol. 2024 Aug 12;7(1):978. doi: 10.1038/s42003-024-06503-z.
The evolutionary histories of adaptive radiations can be marked by dramatic demographic fluctuations. However, the demographic histories of ecologically-linked co-diversifying lineages remain understudied. The Laurentian Great Lakes provide a unique system of two such radiations that are dispersed across depth gradients with a predator-prey relationship. We show that the North American Coregonus species complex ("ciscoes") radiated rapidly prior to the Last Glacial Maximum (80-90 kya), a globally warm period, followed by rapid expansion in population size. Similar patterns of demographic expansion were observed in the predator species, Lake Charr (Salvelinus namaycush), following a brief time lag, which we hypothesize was driven by predator-prey dynamics. Diversification of prey into deep water created ecological opportunities for the predators, facilitating their demographic expansion, which is consistent with an upward adaptive radiation cascade. This study provides a new timeline and environmental context for the origin of the Laurentian Great Lakes fish fauna, and firmly establishes this system as drivers of ecological diversification and rapid speciation through cyclical glaciation.
适应辐射的进化历史可能具有显著的种群动态波动。然而，生态相关的协同多样化谱系的种群历史仍然研究不足。 Laurentian 大湖为两个这样的辐射系统提供了一个独特的系统，这些辐射系统沿着深度梯度分散，具有捕食者-猎物关系。我们表明，北美核心科鱼类复合体（“鲈鱼”）在末次冰盛期（80-90 千年前）之前迅速辐射，这是一个全球温暖的时期，随后种群规模迅速扩大。在捕食者物种，湖鳟鱼（Salvelinus namaycush）中观察到类似的种群扩张模式，只是存在短暂的时间滞后，我们假设这是由捕食者-猎物动态驱动的。猎物向深水的多样化为捕食者创造了生态机会，促进了它们的种群扩张，这与向上的适应辐射级联一致。本研究为 Laurentian 大湖鱼类区系的起源提供了新的时间线和环境背景，并通过周期性的冰川作用确定了该系统是生态多样化和快速物种形成的驱动力。
