寄宿主-噬菌体动力学模型的稳定性分析

Analysis on the stability of host-phage dynamics model

根据寄宿主-噬菌体相互依存、相互竞争的关系,建立了一种全新的寄宿主-噬菌体种群动力学模型,在寄宿主接近承载能力的条件下,模型的动力学行为表现为噬菌体能力的降低.与现存的捕食-被捕食模型相比,发现存在一个噬菌体不能侵入寄宿主的系统,但可以与寄宿主在低密度下稳定地共同生存的参数条件.这种稳定状态的存在预示着系统的稳定状态与噬菌体生命历史有着清晰的联系.模型的极限分析表明:像捕食-被捕食这样的保守系统并不是不可避免地发生种群循环.

In order to investigate the relation that host and phage depend on and compete with each other, we propose a novel model of host-phage population dynamics that accounts for the decreased ability of phages to lyse hosts as hosts approach their carrying capacity. In contrast to existing predator-prey-like models, we find a parameter regime in which phages cannot invade a host-only system but can stably coexist with hosts at lower densities. The presence of stable states suggests clear linkages between stable states of the system and life history of phages. Analysis of limiting case of the proposed model indicates that conservative predator-prey like systems do not inevitably exhibit population cycles.