PARASITES OF CARABID BEETLES - PREVALENCE DEPENDS ON HABITAT SELECTION OF THE HOST

The prevalence of endoparasitic nematodes (Mermithoidea and Heterotylenchus sp.) and the ectoparasitic fungi Laboulbenia spp. was examined in 14 riparian species of carabid beetles of the genus Bembidion. The values for Laboulbenia spp. and nematodes (Heterotylenchus sp.) were 41.1 and 11.4%, respectively, in host species living in protected microhabitats (silty, more or less vegetated, often shady sites). In Bembidion species living in open microhabitats (open silty, sandy, or gravelly-stony sites with little or no vegetation) the prevalence of both parasites was less than 1%. The open microhabitats are more subject to floodwater scouring and erosion than the protected ones. This may explain the observed difference in prevalence, since the beetles are infected with the parasites through contact with contaminated soil.