[Oribatids (Oribatei, Acari) as intermediate hosts of Ctenotaenia marmotae (Frölich, 1802), a tapeworm parasitic in marmots (author's transl)].

Out of 30 species of Oribatids (from 23 genera), which were provided with eggs of Ctenotaenia marmotae in the laboratory, 24 proved to be potential intermediate hosts. The course of development of the parasite in the intermediate host could be followed up as far as to the cysticercoid (Figs. 2-8). It largely corresponds to the development of other Anoplocephalidae. After 113 days p.i. (test temperature 18-20 degrees C) the cysticercoid stage was reached. In the Pölla valley (Carinthia), at sea level of 2,200 m, the droppings of marmots scattered on the grass andmingled with proglottids of C. marmotae were marked. 9 months later 24 grass samples were taken and examined as to infected Oribatids. Out of a total of 12,100 specimens 49 turned out to be infected with cysticercoids; these specimens, however, belong to the species of Trichoribates incisellus (Kramer) and Trichoribates trimaculatus (C.L. Koch). They were taken from 16 samples with a total of 8,400 Oribatids. This is the first evidence under natural conditions of Oribatids acting as intermediate hosts to C. marmotae. It is presumed that 2 seasonal invasion peaks occur in the final host Marmota marmota (L.).