Quan-Guo Zhang ¹* and Angus Buckling²

1. State Key Laboratory of Earth Surface Processes and Resource Ecology; MOE Key Laboratory for Biodiversity Science and Ecological Engineering, Beijing Normal University, Beijing 100875, China

2. Department of Zoology, University of Oxford, South Parks Road, Oxford OX1 3PS, UK; Biosciences, University of Exeter, Cornwall Campus, Penryn TR10 9EZ, UK

ABSTRACT: Understanding the conditions under which rapid evolutionary adaptation can prevent population extinction in deteriorating environments (i.e. evolutionary rescue) is a crucial aim in the face of global climate change. Despite a rapidly growing body of work in this area, little attention has been paid to the importance of interspecific coevolutionary interactions. Antagonistic coevolution commonly observed between hosts and parasites is likely to retard evolutionary rescue because it often reduces population sizes, and results in the evolution of costly host defence and parasite counter-defence. We used experimental populations of a bacterium Pseudomonas fluorescens SBW25 and a bacteriophage virus (SBW25Φ2), to study how host–parasite coevolution impacts viral population persistence in the face of gradually increasing temperature, an environmental stress for the virus but not the bacterium. The virus persisted much longer when it evolved in the presence of an evolutionarily constant host genotype (i.e. in the absence of coevolution) than when the bacterium and virus coevolved. Further experiments suggest that both a reduction in population size and costly infectivity strategies contributed to viral extinction as a result of coevolution. The results highlight the importance of interspecific evolutionary interactions for the evolutionary responses of populations to global climate change.

 

KEYWORD：Adaptation, environmental change, evolutionary rescue, experimental evolution, temperature elevation.