Reptile rumpus: Invasive lizard-mediated risk of mosquito-borne virus transmission

In Florida, invasive lizards are a growing problem, with at least 29 species firmly established. Peters’s rock agama (Agama picticauda), a large and colorful reptile native to eastern Africa, is currently expanding its range (northward) in Florida and in doing so, is displacing the brown anole (Anolis sagrei), a smaller nonnative lizard, through competition and predation. The brown anole is an important blood meal host for Culex nigripalpus and Culiseta melanura, mosquito species that transmit West Nile virus and eastern equine encephalitis virus, whereas mosquitoes rarely bite agamas. We predict that the regional displacement of brown anoles will cause vector mosquitoes to shift toward biting birds more frequently, which could increase risk of amplification and spillover of arboviruses. In this way, an invasive lizard may indirectly impact the transmission ecology of mosquito-borne disease of both humans and wildlife. We investigated potential impacts of Peters’s rock agama on mosquito host use through manipulative field experiments in eastern Florida. Agamas were actively removed from infested sites, and blood meal analysis conducted on blood-engorged mosquitoes captured from removal and non-removal sites. Anoles constituted a higher fraction of total mosquito blood meals at agama removal sites (16.4%) compared to non-removal sites (6.9%), however this did not result in a higher fraction of total blood meals from birds at agama removal sites (18.2%) compared to non-removal sites (24.1%). Differences in mosquito species assemblages between sites and their innate host preferences likely mediates the overall pattern of host use observed.