There is another way for hosts to reduce their conflict with their microbes, and it’s an extreme one: they can become so co-dependent that they effectively act as a single entity.42 This happens when bacteria find their way inside the cells of their hosts and are faithfully transmitted from parents to offspring. Their two parties’ fates are now entwined. They still have their own interests, but these overlap to such an extent that any remaining disagreements become negligible.
