INTERMEDIARY HOST FOR FUNGUS COELOMOMYCES-CHIRONOMI

A population of Chironomus plumosus larvae were found infected with C. chironomi. More than 80% of last-stage larvae were infected. Larvae moving on the mud surface were attacked by the ostracod Heterocypris incongruens, which fed on the last segments of the body of still-moving larvae. Their guts were filled with resting sporangia, zoospores and flagellated zygotes, which are described. The bodies of infected ostracods were more opaque than those of non-infected ones. Flagellate zygotes of C. chironomi were present only in infected pools with C. chironomi. Addition of free zoospores or zygotes to non-infected larval midges caused infection. The biflagellate zygotes were established as the invasive stage of C. chironomi.