The interest of a new approach in taking up the problems of host-parasite relationships with environment is proposed in terms of population biology. Two different integrating levels are considered: a microenvironment that corresponds particularly to the host and a macroenvironment corresponding to the whole host-parasite system. Some examples are given that provide significant reasons in perceiving the biology of Monogenea under these aspects. To conclude we emphasize the importance of developing this new way for the study of hybrids models in relation to parental host systems.

Laboratoire de Parasitologie Comparée Université des Sciences et Techniques du Languedoc Montpellier France