MIAMI (AP) — University of Florida researchers have more data showing invasive Burmese pythons decimating populations of native mammals in the Everglades.

Entomology professor Nathan Burkett-Cadena led a team collecting Culex cedecei mosquitoes in Everglades National Park. They analyzed animal DNA in the mosquitoes’ guts to determine what they had bitten.

The researchers compared their 2016 findings to a similar 1979 study.

Before pythons arrived, hispid cotton rats comprised about 15 percent of the mosquitoes’ diet. The rest included raccoons, opossums and deer.

Burkett-Cadena says rats now make up three-quarters of the mosquitoes’ diet because pythons have eaten so many other mammals.

The mosquitoes can spread Everglades virus from rats. Burkett-Cadena says it’s unclear whether increased feeding on rats raises the risk of the virus spreading.

The journal Biology Letters published the data Wednesday.