Bacteriophages, also known as phages, are viruses that infect bacteria. They are found everywhere in nature, playing vital roles in microbiomes and bacterial evolution due to the selective pressure that they place on their hosts. As obligate endosymbionts, phages depend on bacteria for successful reproduction, and either destroy their hosts through lysis or are maintained within the host through lysogeny. Lysis involves reproduction within the host cell and ultimately results in the disruption or bursting of the cell to release phage progeny. Alternatively, lysogeny is the process by which phage DNA is incorporated into the host DNA or maintained alongside the host chromosome, and thus the phage reproduces when their host reproduces. Recent work has demonstrated that phages can exist along the parasitism-mutualism spectrum, prompting questions of how phage would evolve one reproductive strategy over the other, and in which conditions. In this work, we present an agent-based model of bacteriophage/bacterial co-evolution that enables lysogenized phage to directly impact their host’s fitness by using the software platform Sym-bulation. We demonstrate that a viral population with beneficial lysogenic phage can select against lytic strategies. This result has implications for bottom-up control of vital ecosystems.

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