New host-parasite associations of Hydrachnidia (Acari) on Chironomidae (Diptera) from Poland

We present the first data from Poland concerning parasitism of Hydrachnidia on Chironomidae. Larvae of Hygrobatessp., H. setosus, Unionicola aculeataand Piona stjoerdalensiswere found attached to adult Chironomidae (Cricotopus triannulatus, Tanytarsussp., Paratanytarsussp., Critocopussp. and Orthocladiussp.). Intensity of infestation ranged between 1 to 2 larvae. All of the parasites were attached to abdomens of the hosts. The determination of parasitism of U. aculeataon Paratanytarsusand Tanytarsusgenera extends the list of the hosts of this water mite species to the mentioned genera of Chironomidae. In case of H. setosus, the parasitism of this water mite on currently known hosts from the family Chironomidae has been confirmed.