Abstract: | Three parasitic systems of Microsporidia are described: the system of monoxenic Vairimorpha mesnili with paraxenic hosts presented lepidopteran and hymenopteran species; the system of dixenic Amblyospora sp. with metaxenic hosts presented bloodsucking mosquitoes and crustaceans and the system of Metchnikovella sp. as parasite of other obligate parasite. The last case is characterized by very intimate interrelations between hyperparasite (microsporidian species), obligate parasite--host of Microsporidia (gregarine) and hyperhost--host of gregarine (polychaeta). This hyperparasite system is exclusive case of parasitic systems. Parasitic and hyperparasitic systems reflects a population level of host-parasite interactions. On biocenotic level many other organisms such as predators, vectors and reservators of invasion stages of Microsporidia affect parasitic systems giving a chance to one of the members of the system (to the host or to the parasite). These organisms form epiparasitic system. In all cases of the parasitic systems there are two-way communications between parasites and their hosts. In systems on biocenotic level--parasitic consortium--members of epiparasitic systems acts on parasitic systems, but members of parasitic systems don't affect epiparasitic systems. |