MERMITHID PARASITISM OF ADULT MOSQUITOS IN SWEDEN

Parasitism of adult Aedes communis (Diptera: Culicidae) by an undetermined mermithid nematode was investigated near Uppsala, Sweden, during 1989 and 1990. Parasites resided in the head capsules of infected larvae and were found predominantly in the abdominal cavities of adult hosts. Migration between these body regions coincided with host pupation. Nematode postparasites emerged 10-21 days after eclosion of adult hosts. Neither parasite prevalence nor parasite load differed with host gender. Nematodes emerged from both male and female mosquitoes collected as larvae. Postparasites also emerged from adult males collected from swarms and from adult females netted near the larval pool. None emerged from females that took blood meals. Immune responses were observed in both sexes but a significantly higher proportion of female hosts encapsulated parasites. Aedes cantans and Culiseta morsitans from the same site also were infected but higher infection rates and parasite loads suggest that Aedes communis is the principal host.