![Sample our Environment & Agriculture journals, sign in here to start your access, latest two full volumes FREE to you for 14 days]({"type":"image" , "src" : "/sda/5934/TOC-Subject-Sample-2021-Environment-Agriculture.jpg"})
Abstract
Parasitic associations between larval Unionicola formosa and U. foili obtained from the freshwater unionid mussels Pyganodon cataracta and Utterbackia imbecillis, respectively, and the chironomid dipteran Chironomus tentans were established in the laboratory. Several life history characteristics of larvae of both species of water mites were examined during these associations. Larval water mites occurred exclusively on the ventral surface of C. tentans, attached to the articular membranes of the thorax and abdomen. There was no significant difference in the number of larvae parasitizing male and female chironomids, with a mean of approximately 2–3 larvae per host and a maximum of 9 larvae per host. Larval mites remained attached to an insect for an average of 3 days, during which time they increased significantly in size and weight. In the absence of an insect host, the larvae lived approximately 14 days. Larvae that had completed their parasitic phase and had detached from a chironomid lived an average of 3 days. No larvae metamorphosed to the deutonymph prior to their death, suggesting that these species have an obligate requirement for a molluscan host in their life cycles. Larvae of U. formosa were significantly heavier and larger than larval U. foili; however, there was no significant differences in other aspects of the larval biology examined. The life history characteristics of larvae of these two species were similar to those of other species in the genus, suggesting that life history traits of larval Unionicola have been conserved throughout evolution.