As a battle for territory unfolds between two different species of lizards invasive to Florida, a team of University of Florida scientists is trying to determine what it could mean for public health.
The non-native Peters’s rock agama lizard, which can be kept as a pet in Florida, is spreading north throughout the state. In Central Florida, it’s been seen in Seminole, Polk and Volusia counties, per UF’s Institute of Food and Agricultural Sciences (UF/IFAS).
As the rock agama becomes more widespread, “it somehow reduces the density of the brown anole lizard,” said Nathan Burkett-Cadena, associate professor at UF/IFAS’ Florida Medical Entomology Laboratory. That could be happening because the rock agamas, which tend to be larger and more aggressive, are eating the anoles, and simply outcompeting them for territory.
The brown anole lizard, also invasive to Florida, has been in the state at least 100 years. Anoles are a beloved treat for mosquitoes that can transmit deadly human pathogens, like the West Nile virus.
But since anoles don’t appear to be a host for those viruses, Burkett-Cadena said, the lizards may have unintentionally — and helpfully — been reducing the overall impact of such diseases on people.
“Every time a mosquito bites a lizard, it's not biting a bird. It's not biting a human being,” Burkett-Cadena said. “So those lizards, by kind of absorbing mosquito bites, they reduce the number of bites that go to birds and people — and that could have this overall effect of protecting people from these viruses, or at least reducing the number of illnesses.”
On the flip side, as anole populations decline, the concern is whether mosquitoes might start transmitting more serious diseases to humans.
“Mosquitoes are not going to be able to bite the brown anole, so what are they going to bite? Really, they're probably going to turn to biting birds, humans and domestic animals more,” Burkett-Cadena said.
For now, that’s only a hypothesis, one of several that Burkett-Cadena’s team of scientists is testing at different areas in St. Lucie County, where both rock agama and brown anole lizards are still plentiful. The scientists are collecting mosquitoes to analyze the blood in their stomachs, and physically removing the rock agamas from certain areas, to see if it changes which animals are being bitten.
As is true for most invasive species, it’s a highly nuanced dynamic, one Burkett-Cadena’s team hopes to better understand through their ongoing study.
“When I start thinking about all the other invasive species, plants as well as animals, how they can impact these natural communities that we have here … Maybe these natural communities are protecting us in ways that we don't even see,” Burkett-Cadena said.
You can report sightings of any nonnative animal species to the Florida Fish and Wildlife Conservation Commission.
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