Invasive Trap-Jaw Ants Spread in the Southeast

Trap-jaw ants are predatory hunters with venomous stings and jaws powerful enough to fling themselves through the air. Now, this species is spreading into new territory in the southeastern U.S., and may have actually started to evolve into a separate species.

Trap-jaw ant species are in the genus Ondontomachus. And while O. Ondontomachus can be found in the United States, it's actually native to South America. It was first recorded, unofficially, in Alabama in 1956. Since then, the species has spread across the Gulf Coast and at least as far east as Pensacola, Florida.

"Haemotodus is particularly interesting because it is larger and more aggressive than other trap-jaw ants in the United States," said Magdalena Sorger, one of the researchers, in a news release. "The fact that some of these species are spread is interesting, in part, because these giant ants have managed to expand their territory without anyone noticing. We know very little about these ants, including how they interact with native ant species in the areas they're invading."

What was interesting is that the researchers found that O. ruginodis has been expanding its territory. In fact, only a few years ago, this ant species was thought to be confined to the Orlando region. Yet this seems to not be the case. Instead, it can be found more than a hundred miles north of Orlando and may have even spread farther than Gainesville.

More interestingly, the scientists found that relictus ants on separate ridges in Florida's endangered scrub habitat on ancient sand ridges display different behaviors and had distinct genetic profiles. This indicates that they may have evolved into two separate species.

"If these two O. relictus populations are, in fact, distinct species, it would make them the rarest ants in North America," said Sorger in a news release.

The findings reveal a bit more about these under-studied ants, and show that they may be spreading into new territory. It's important to understand how this might impact native species of ants in the future.

The findings are published in the journal Zootaxa.