FRENKELIA PARASITES IN A SMALL MAMMAL COMMUNITY. DYNAMICS OF INFECTION AND EFFECT ON THE HOST

摘要

A community of small mammals, Clethrionomys glareolus, Arvicola terrestris, Microtus arvalis, M. agrestis, M. subterraneus, Apodemus spp. and Sorex spp., was studied as hosts of Frenkelia glareoli and F. microti in Franche-Comté (France). They were monitored in spring, summer and autumn on an area of about 1,350 ha comprising open field, hedgerow network and forest. Among 1,714 small mammals examined between July 1992 and October 1993, 47 (178/376) of C. glareolus, 9.9 (14/139) of A. tefresfrisand 1.3 (4/311) of Apodemus spp were infected by F. glareoli. The prevalence of infection with F. miaoti was 9.2 (66/716) in M. arvalis and 8.2 (6/73) in M. agiestis. M. subtetraneus and Sorex spp. were not infected. The maintenance of each parasite in a rural landscape is assured both by a forest and a grassland host. Multiple logistic regression showed that prevalence was highly age-dependent, with an apparent seasonal pattern. Prevalence varied between 30 in summer and 60 in early spring for F. glareoli in C. glareolus and between 3 in autumn to 30 in early spring for F. microti in M. arvalis. The year, habitat, host sex, relative density had no impact on prevalence. In M. arvalis only, sexually active voles were preferentially uninfected, indicating a possible impact of this parasitism on fertility.