Parasitism by Larvae of Unionicola intermedia Koenike, and another Unionicola sp. (Acarina, Pionae), on Chironomids

Abstract

THE majority of water-mites for which the life-histories are known have a parasitic larva and free-living nymphs and adults. The family Unionicolidae, however, has always been separated from the remaining families due to the fact that most species have adults and nymphs which are parasitic in the mantle cavities of fresh-water mussels. It has generally been assumed that these mussel parasites have been free-living as larvae and that the larval stage has been of brief duration and has served merely as a means of dispersal. There have, moreover, apparently been no previous records of these larvae being found outside their hosts.