As the immunologist Graham Rook is fond of saying, co-evolution invariably leads to codependence.
immunologist im·mu·nol·o·gist (ĭm'yə-nŏl'ə-jĭst)
A specialist in immunology.
immunology im·mu·nol·o·gy (ĭm'yə-nŏl'ə-jē)
The branch of biomedicine that is concerned with the structure and function of the immune system, innate and acquired immunity, and laboratory techniques involving the interaction of antigens with antibodies.