Experimental setup to test for and measures of evolutionary responses in the virophage when the level of integrated virophage into the host genome is indirectly manipulated. (A) Chemostats were assembled with the ancestral host (Day 1), ancestral virus and ancestral virophage (Day 20 and Day 24) and received no stressor (control), one application of the stressor (pulse) on Day 26, or daily application of the stressor from Day 26 (disturbance) until the end of the experiment (Day 50). From these chemostats we collected data on population dynamics and the level of integration of the virophage into the host genome. (B) To test for evolutionary responses of the virophage, we reisolated virophage from Day 50 of the experiment and compared the virophage traits replication and exploitation of the virus in short-term assays between ancestral and reisolated virophages from each chemostats during infections with ancestral host and ancestral virus. Depending on the stressor exposure, we predict different outcomes for trait evolution (see main text).