Of the 57 ant species established in Hawaii, a relative few cause the most trouble. Count among them the little fire ant, a stinging pest that has infested some of Hilo’s beach parks and the nearby Pana­‘ewa Rainforest Zoo & Gardens. Smaller populations on Maui and Kauai are the focus of aggressive eradication efforts, says Paul Kru­shel­nycky, a University of Hawaii entomologist.

“It’s a really insidious species because it is really hard to detect until it is fairly abundant and dense, because it is so small, but by then it can become very hard to control,” he says. “They reach really high densities, and they infest people’s homes and agricultural fields and orchards.”

Coffee fields are particularly vulnerable to the little fire ant, Wasmannia auropunctata, a native of the Americas first noticed at Hawaiian Paradise Park in Puna in 1999.

Conventional wisdom holds that Hawaii is one of the few places with no native ant species, but Kru­shel­nycky says that is not 100 percent certain.

What is clear is that all manner of ant invaders have made Hawaii home. They include the Argentine ant, Linepithema humile, and the white-footed ant, Technomyrmex albipes, a common household pest.

For humans, ants are mostly a nuisance, but for native spiders and other arthropods and some crops, they pose a dire threat.

“Ants have long been recognized to be pretty devastating to native insects, and that can potentially have cascading effects,” says Kru­shel­nycky.