Duncan A B, Dusi E, Jacob F, Ramsayer J, Hochberg M E, Kaltz O
Institut des Sciences de l'Evolution, UMR 5554 (CC065), Université de Montpellier, Montpellier, France.
Institute for Hydrobiology, Technische Universität Dresden, Dresden, Germany.
J Evol Biol. 2017 Jan;30(1):55-65. doi: 10.1111/jeb.12985. Epub 2016 Oct 27.
Antagonistic coevolution between hosts and parasites is a key process in the genesis and maintenance of biological diversity. Whereas coevolutionary dynamics show distinct patterns under favourable environmental conditions, the effects of more realistic, variable conditions are largely unknown. We investigated the impact of a fluctuating environment on antagonistic coevolution in experimental microcosms of Pseudomonas fluorescens SBW25 and lytic phage SBWΦ2. High-frequency temperature fluctuations caused no deviations from typical coevolutionary arms race dynamics. However, coevolution was stalled during periods of high temperature under intermediate- and low-frequency fluctuations, generating temporary coevolutionary cold spots. Temperature variation affected population density, providing evidence that eco-evolutionary feedbacks act through variable bacteria-phage encounter rates. Our study shows that environmental fluctuations can drive antagonistic species interactions into and out of coevolutionary cold and hot spots. Whether coevolution persists or stalls depends on the frequency of change and the environmental optima of both interacting players.
宿主与寄生虫之间的拮抗协同进化是生物多样性产生和维持的关键过程。虽然协同进化动态在有利的环境条件下呈现出不同的模式，但更现实的可变条件的影响在很大程度上尚不清楚。我们在荧光假单胞菌SBW25和裂解性噬菌体SBWΦ2的实验微观世界中研究了波动环境对拮抗协同进化的影响。高频温度波动并未偏离典型的协同进化军备竞赛动态。然而，在中低频波动下的高温时期，协同进化停滞，产生了暂时的协同进化冷点。温度变化影响种群密度，这证明了生态进化反馈通过可变的细菌-噬菌体相遇率起作用。我们的研究表明，环境波动可驱使拮抗物种相互作用进入或脱离协同进化的冷点和热点。协同进化是持续还是停滞取决于变化的频率以及两个相互作用参与者的环境最优值。
