While most people may associate mosquitoes with Florida’s swamps, Arizona’s deserts and mountains are also home to a surprising variety of mosquito species. A University of Florida mosquito scientist has documented one of those species for the first time in the U.S.
The mosquito, scientifically known as Aedes amateuri, was previously recorded only in Mexico. Researchers at UF’s Institute of Food and Agricultural Sciences (UF/IFAS) have identified the species in southeastern Arizona’s Madrean Sky Islands. The area, a rugged network of isolated mountain ranges, surrounded by a “sea” of desert, is known for its unusual biological diversity, said Lawrence Reeves, lead author and an assistant professor of entomology at the UF/IFAS Florida Medical Entomology Laboratory (FMEL).
The mosquito’s identity, confirmed by using both physical characteristics and DNA analysis, serves as the first documented record of the species in the U.S. and the northernmost record known, according to the study published in the Journal of Medical Entomology.
The finding underscores how much researchers still must learn about the diversity of mosquitoes in the U.S. and their potential to spread disease.
Photo by Lawrence Reeves
“This discovery shows how important it is to remain vigilant in monitoring mosquitoes, because we are still detecting species that were previously unknown in the U.S., a region where they have been intensively studied for more than a century,” said Reeves. “It highlights how much we still have to learn about our country’s mosquito fauna, an understanding of which is essential for mitigating the impacts of mosquitoes.”
The newly documented mosquito appears to be rare in Arizona. In 2022, UF/IFAS researchers found one specimen in the Santa Rita Mountains and 19 in the Dragoon Mountains. Reeves returned to Arizona to collect specimens in July and August 2026. The researchers found the species in Arizona’s Peloncillo Mountains, within a mile of the New Mexico border. Reeves suspects the species has spread to New Mexico as well.
The mosquitoes were collected in mountainous wilderness areas, and the discovery may represent an established population or a recent northward expansion from Mexico.
The mosquito’s habitat and biology also make it challenging to detect. In Mexico, its immature stages have been associated with temporary pools of water. In Arizona’s arid climate, those habitats appear only after sufficient monsoon rainfall, meaning adult mosquitoes may occur only for short periods, and only when the right amount of rainfall hits the right place.
Little is currently known about the species, including whether it transmits diseases. For this reason, researchers emphasize there is currently no evidence that the species has public health significance. However, like some related mosquitoes, the species is known to feed on humans and other large mammals, including deer, making continued surveillance important as scientists learn more about them.
While the discovery occurred nearly 2,000 miles from Florida, it reflects the breadth of mosquito research conducted at FMEL, whose researchers work to better understand mosquitoes, their impacts and their control across state lines and national borders.
“Florida has long been a focal point for mosquito surveillance because of its diverse mosquito fauna and its connections to the Caribbean, Latin America and other parts of the world,” said Reeves. “Since 1999, 14 mosquito species not previously recorded in Florida have been detected in the state, and FMEL faculty have been involved in the initial detection of 11 of them.”
Two species are believed to have moved east into Florida from the Southwest, highlighting the state’s importance in understanding mosquito species across the American South.
FMEL’s reach also extends beyond the Sunshine State. Since 1999, eight mosquito species not previously recorded in the mainland U.S. have been detected in the country, and FMEL faculty have been involved in the detection of six of those eight species. These discoveries are believed to represent exotic species that did not previously occur in the U.S., though it can be challenging to determine if a species came from elsewhere or has long existed in the country, undetected.
“The finding demonstrates that even in well-studied regions like the U.S., where there has arguably been more research on mosquitoes than any other country, new species are still turning up, reinforcing the value of ongoing research and monitoring to better understand mosquito diversity, distribution and any potential implications for public health,” said Reeves.
4
