Hidden paths to endless forms most wonderful: Parasite-blind diversification of host quality

Evolutionary diversification can occur in allopatry or sympatry, can be driven by selection or unselected, and can be phenotypically manifested immediately or remain latent until realised in a newly encountered environment. Diversification of host-parasite interactions is frequently studied in the context of intrinsically selective coevolution, but the potential for host-parasite interaction phenotypes to diversify latently during parasite-blind host evolution is rarely considered. Here we use a social bacterium experimentally adapted to several environments in the absence of phage to analyse allopatric diversification of host quality - the degree to which a host population supports a viral epidemic. Phage-blind evolution reduced host quality overall, with some bacteria becoming completely resistant to growth suppression by phage. Selective-environment differences generated only mild divergence in host-quality. However, selective environments nonetheless played a major role in shaping e...

演化分化既可发生于异域（allopatry）亦可出现于同域（sympatry），既可由自然选择驱动，亦可不受选择作用影响，且可即刻以表型形式显现，或维持潜伏状态，直至在新接触的环境中得以表达。宿主-寄生虫相互作用的演化分化，常被置于内在选择性协同进化的研究框架中开展研究，但宿主-寄生虫相互作用表型在无寄生虫的宿主进化过程中发生潜伏式分化的可能性，却极少被纳入考量。本研究利用在无噬菌体（phage）条件下经多环境实验适应性进化的社会性细菌，分析宿主质量（host quality，即宿主种群支持病毒流行的程度）的异域分化模式。无噬菌体的进化整体上降低了宿主质量，部分细菌完全获得了抵抗噬菌体生长抑制的能力。选择环境的差异仅引发了宿主质量层面的微弱分化，但选择环境仍在塑造……