Bdellovibrio bacteriovorus is a gram-negative, obligate aerobe that typically preys on a wide variety of gram-negative bacteria. A host-independent (H-I) B. bacteriovorus that grows on rich media has been isolated. To advance the understanding of Bdellovibrio bacteriovorus , we investigated the stability of the Bdellovibrio bacteriovorus as host-independent (H-I B.) and host-dependent (H-D B.) phenotypes with different prey bacteria. Preliminary results show a facile and sequentially repeatable switch from host-independent to host-dependent phenotypes with some prey.