Mosquito abundance, blood feeding, and West Nile virus infection in association with woody plant encroachment in the U.S. Great Plains.

Knowledge of the utilization by mosquito species of different habitats is critical for determining risk for the transmission of mosquito-borne pathogens. The Great Plains region of the United States is experiencing a biome-level change as grasslands are being converted to forests through the process of woody plant encroachment by eastern redcedar (ERC). There is a need to evaluate how mosquitoes respond to fine scale habitat characteristics within areas experiencing ERC encroachment. This study examined the influence of fine-scale vegetation differences on mosquito abundance, bloodmeal hosts, and infection with West Nile virus (WNV) in eight ERC-encroached sites across Oklahoma. Mosquito traps were placed in three unique habitats in ERC-encroached sites. Ae. albopictus, Ae. vexans, An. punctipennis, Cx. erraticus, and Cx. tarsalis were most abundant in the ecotone and/or forested areas of ERC trees compared with grass. Ps. columbiae was more abundant in grassland than in forest. Blood meal analysis indicated that mosquitoes fed primarily on mammals, and we detected Anaplasma species in several blood meals. These results suggest that important mosquito vectors may occur throughout much of ERC-encroached areas, a finding that has consequences for blood meal acquisition, pathogen transmission, and thus public health and land management programs throughout the Great Plains.