FRAGMENT FROM NATURE this next two weekend focuses on a brilliant and inspiring paper by Professor Jennifer J. Wernegreen and her team. It is widely rooted in a biological context, deeply illustrative on a case by case basis, clinical, ecological and touches on the new thinking that is emerging in life sciences. Specifically, it focuses on the ecological intimacy of bacteria and their hosts including humans. And it could equally be rewritten to star the same role of viruses.