The process of two species evolving together because of interdependence is called coevolution.
Coevolution is the process in which two or more species affect each other’s evolution and mutually depend on each other due to their close ecological interaction. Some pollinators (such as insects, birds) and flowering plants have coevolved for mutual benefit. For example the bird pollinated flowers (ornithophilous) and Humming birds have special adaptions and have evolved a mutualistic relationship. The shape of the flowers fits the birds’ bills and they also possess nectar that suits the bird’s diets. Also, the birds breeding seasons and the blooming period of the flowers have been found to occur at the same time.