Aedes (Finlaya) japonicus(Diptera: Culicidae), a Newly Recognized Mosquito in the United States: Analyses of Genetic Variation in the United States and Putative Source Populations

Abstract

Introduction of potential disease vectors into a new geographic area poses health risks to local human, livestock, and wildlife populations. It is therefore important to gain understanding of the dynamics of these invasions, in particular its sources, modes of spread after the introduction, and vectorial potential. We studied the population genetics of Aedes (Finlaya) japonicus japonicus (Theobald), an Asian mosquito that was recognized for the first time in the United States in 1998. We examined patterns of genetic diversity using random amplified polymorphic DNA and sequences of ND4 of mtDNA by comparing samples from populations spanning the range of this mosquito in Japan (six samples) and the United States (nine samples) as well as specimens intercepted in New Zealand in 1999. We found geographically differentiated populations in Japan, indicating limited gene flow even on small spatial scales. In the United States, we found evidence of significant genetic differentiation between samples from New York, Connecticut, and New Jersey and those from mid-Pennsylvania and Maryland. We were unable to pinpoint the source location(s) in Japan, although some of the U.S. samples are genetically close to samples from south Honshu and western Kyushu. Further studies should include samples from Korean populations. Distinct genetic signatures in U.S. populations undergoing expansion suggest the possibility of local increases in genetic diversity if and where they meet.

West Nile Virus Infection in Birds and Mosquitoes, New York State, 2000

“…Different populations of Ae. japonicus have been described in the eastern United States (18), and differences in vector competence between the populations may explain the discrepancy between the field and experimental data.…”

DNA barcoding for identification of mosquitoes (Diptera: Culicidae) from the Ryukyu Archipelago, Japan

“…saperoi are freshwater mountain forest stream breeders (Toma et al, 2001) and easily a ected by water quality of the breeding stream. With recent urbanization and deforestation, suitable breeding streams are at presently restricted to the northern part of Okinawajima and Iriomotejima.…”

“…ese subspecies show little morphological variation. Fonseca et al (2001) reported that Ae. j. japonicus was distinct from Ae.…”

Evidence that implicit assumptions of ‘no evolution’ of disease vectors in changing environments can be violated on a rapid timescale

“…B 370: 20140136 with other vector species, Ae. j. japonicus is an outstanding model system because we have detailed data on the genetics of its expansion outside its native range [40][41][42][43][44]. This expansion is very recent but already extensive in continental USA, Europe and Hawaii, and occurred at a time when many mosquito surveillance programmes were already 'on alert' monitoring the expansion of Ae.…”