Olpidium gregarium, a chytrid fungus affecting rotifers populations in Rio Grande Reservoir, São Paulo State, Brazil

Abstract

A chytrid fungus Olpidium gregarium was found in Rio Grande Reservoir as rotifers populations' parasite. Along the reservoir central axis, the rotifers density decreased in the dam direction, while the density of affected rotifers by the chytrid fungus increased in the same direction. Moreover, some rotifers species were more affected than others, thus showing certain preference for some rotifers species. Thereby, this parasite may be interfering in the distribution of rotifers population in Rio Grande Reservoir. This is the first report of this species for Brazil.

Symbiont Fauna of Freshwater Zooplankton in Several Water Bodies of the Dnipro River Basin

“…Previously Saprolegnia fungi were found in the body cavity of Cladocera C. sphaericus (Wolska & Mazurkiewicz-Zapalowicz, 2013). Olpidium gregarium Schroter, 1886 belongs to holocarpic fungi which parasitize mainly the freshwater algae, mosses, fl owering plants and microscopic animals such as rotifers (Mierinho et al, 2013). Th is endoparasitic fungus has unicellular vegetative body, which during reproduction develops into zoosporangium with unifl agellate zoospores inside.…”

“…In this case, a the parasitic fungus reveals certain selectivity when choosing a host. In known papers on parasitic fungi in water bodies of Poland and the Volga delta, this fungus was noted as infecting only loricate rotifers with specifi c shape of lorica (Mierinho et al, 2013;Gorbunov, 2008).…”

“…Green later summarized these studies in a well-known review (Green, 1974) with a list of parasites and epibionts of Cladocera. Th ere are some fragmentary data on rotifer parasites (Decksbach, 1928;Miraсle, 1977;Barron, 1980;Cohn, 1902;Glockling, 1998;Mierinho et al, 2013;Gorbunov, 2008).…”