Evolutionary relationships among California serogroup viruses (Bunyaviridae) and Aedes mosquitoes (Diptera:...

More than 100 published and four unpublished papers recording virus isolations of California (CAL) serogroup viruses from mosquitoes and other arthropods were analyzed, followed by a comparison of a contemporary classification of mosquitoes of the genus Aedes with a contemporary classification of CAL serogroup viruses. Using criteria of five or more total isolations of a given virus from a given species of mosquito, and a minimum infection rate of 1:10,000 or greater (more frequent), Aedes, and to a lesser extent Culiseta, species were found to be the arthropods most frequently involved as vectors. Such a comparison could not explain all virus-vector associations on the basis of coevolution of viruses in Aedes mosquito species, probably because of the crossing over of viruses to other mosquito species through horizontal transmission and because of deficiencies in currently available classifications. Coevolution of host-parasite systems is discussed, as are the inadequacies of contemporary taxonomic treatments of viruses and Aedes mosquitoes. The paper ends with hypothetical reconstructions of virus-mosquito relationships over time and possible routes of dispersal of California serogroup viruses to their present geographical distributions.