Thomas Brown via Wikimedia Commons
Fire ants. Nutria. Scale insects. Apple snails. Spring breakers. The list of invasive populations landing on Louisiana’s shores, deciding they like the place, and running rampant seems destined to grow indefinitely, and this year has brought an especially icky example: the Cuban tree frog (Osteopilus septentrionalis), which secretes an irritating mucus and chows down on its brethren.
Occasional Cuban tree frogs have shown up in New Orleans (and Baton Rouge, the Northshore, and Lafayette) for a while now; they arrived in Florida in the 1920s and by now range as far north as Jacksonville, providing a teeming nearby population. Individual frogs have caught rides on vehicles or in nursery plants—they especially love to conceal themselves in the spiky lushness of bromeliads—but only recently has an entrenched breeding population been observed. Eight individuals were found at Audubon Zoo in 2015, and since they were of different sizes, this meant that there was probably a population allowing the presence of individuals at different stages of development. More, including tadpoles, were found in the summer of 2017; by the time of a formal survey this spring, there were many, many more, in the Fly as well as the zoo and Audubon Park.
The frogs are a problem for the usual reasons: they’re meaner, hungrier, and grosser than our native species. They can reach the size of a fist, and their irritating skin makes them unappetizing to predators; a few snakes fed these frogs in a study actually lost weight. (Country Roads does not recommend the tree frog diet, regardless of how quickly that summer wedding you bought optimistically sized pants for is approaching.) They eat native species, including other frogs, even of their own species. Native tree frogs have a certain degree of inborn resistance to fungal infections, which the Cuban tree frogs seem to lack—so if the Cuban frogs get sick, they may spread the disease to our resistant-but-not-immune native frogs.
In terms of human impact, the irritating mucus is “merely” unpleasant (no poison dart murder plots here), but can be substantially more painful on broken skin or in the eyes—it’s especially wise to watch kids in potentially infested areas. The real problem in Florida has been their tendency to get pregnant and crawl into electrical systems: large or densely clustered frogs can short-circuit a system, frying the power as well as the animal. They can also, appallingly, clog plumbing.
The wonderfully named Brad “Bones” Glorioso, a research ecologist with the USGS Wetland and Aquatic Research Center in Lafayette, says that the population probably can’t be extirpated at this point; they’re small, hide easily, and breed eagerly, so it would be next to impossible to be fully rid of them. The zoo and other naturalist teams are euthanizing those they find to help with control; the species’ Wikipedia page recommends rubbing Orajel on their bellies to sedate them before placing them in the freezer for guilt-free euthanasia; Glorioso says either one will send the frog to the great bromeliad in the sky. (Presumably for extra fun, you can ask your spouse to get something from the same freezer later and listen for a yelp of surprise.) Be cautious, though; it's best to be certain you know the difference between invasive and native frogs before removing frogs. Homeowners in affected and surrounding areas of New Orleans should check their property for invaders and report sightings outside the immediate Audubon/the Fly area to Glorioso at gloriosob@usgs.gov; for the rest of us, it’s time to get outside and enjoy one last poison cannibal frog-free summer.
This article originally appeared in our June 2018 issue. Subscribe to our print magazine today.
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