Habitat-Specific Host Selection Patterns of Culex quinquefasciatus and Culex nigripalpus in Florida.

Abstract

Blood-engorged Culex quinquefasciatus and Cx. nigripalpus were collected from 140 locations throughout Sarasota County, FL, from 2017 to 2020 to determine local, habitat-specific, and seasonal variations in the host usage patterns of these 2 important arbovirus vectors. Mosquitoes were collected using light traps, gravid traps, and via aspiration of resting shelters. Host was determined from 920 samples using multiple polymerase chain reaction protocols that target mitochondrial sequences specific to mammals, birds, and reptiles. The data were analyzed to test for statistical associations between host class and season or with habitat categories (urban, suburban, and rural). Culex quinquefasciatus took significantly more blood meals from birds compared to mammals, though a seasonal shift to a higher ratio of mammalian host usage was observed in fall. There was a habitat-dependent pattern of host usage by Cx. nigripalpus, with significantly more mammalian hosts identified from mosquitoes captured in rural habitats and a similar ratio of mammalian and avian hosts in urban habitats. In general humans were used as hosts by Cx. nigripalpus less often compared to Cx. quinquefasciatus. In contrast to previous studies, Cx. nigripalpus utilized ectothermic hosts (mostly reptiles) at a much higher ratio and exhibited no apparent seasonal shift in host selection.