The expanding range of invasive mosquito species Ae. albopictus in the U.S. may have important implications for public health and mosquito community structure. Ae. albopictus is an aggressive day-biter and a potential vector for dengue, chikungunya, and Zika virus. The presence of this species has been associated with the decline in populations of other mosquitoes, such as Ae. aegypti in the Southern U.S. It is not well understood, however, how interactions among these species and others, including the invasive Ae. japonicus and the native Ae. triseriatus, affect community assemblage in the northeastern U.S. The purpose of this study was to assess the composition of mosquito communities among sites in southern New York State. Four sites were selected based on known establishment (two southern locations) or absence (two northern locations) of Ae. albopictus. All sites had populations of Ae. japonicus and Ae. triseriatus. This design allowed us to make comparisons of mosquito communities in the presence and absence of Ae. albopictus. A total of 35 tree-holes, a preferred habitat of mosquito larvae of several Aedes species, were sampled three times each in the summer of 2015.
Ae. albopictus larvae were found in the two southern sites but not in the two northern sites, as expected. In the southernmost site, Ae. albopictus made up 82.8% of the mosquito population with Ae. japonicus and Ae. triseriatus falling under 2% each. Moving northward, Ae. triseriatus was the dominant species with a relative abundance of 83.3% followed byAe. japonicus at 11.8% and Ae. albopictus at 3.0%. In the two northern sites, Ae. triseriatus was the most common species with Ae. japonicus as the second most abundant. The abundance of Ae. japonicus and Ae. albopictus peaked later in the season. It is suspected that the very cold winter of 2014-2015 may have affected the early survivability of the invasive species. Pairwise comparisons found a slightly negative, but significant (p=0.03) correlation between Ae. triseriatus and Ae. albopictus, and a slightly positive, but significant (p=0.01), correlation between Ae. triseriatus and Ae. japonicus. The Simpson’s diversity index did not differ significantly among sites, however, this may have been affected by decreased sample size due to drought. Further studies conducted over multiple seasons and sites will be required to help understand the complex nature of mosquito community assemblages.