A "big urban pest" in the continental United States has been found on the Valley Isle.
A "supercolony" of odorous house ants has established itself in abandoned buildings and farm areas in Kula, Maui, scientists confirmed.
The ant, found throughout the mainland, does not sting humans or cause major damage to building structures.
But scientists fear it could cause major problems to Hawaii’s ecosystem if it attacks native insects that help to pollinate native plants.
For instance, yellow-faced bees, a native of Hawaii, nest in the cold ground on Haleakala, where they pollinate the endangered silversword plants, said Karl Magnacca, a researcher at the University of Hawaii at Hilo.
Magnacca said the yellow-faced bees aren’t found where there are invasive Argentine ants that might attack the nests.
The odorous house ant — so named because it tends to invade houses and smell like coconut when smashed — looks similar to the Argentine ant and is from the same subfamily of insects.
The odorous ant, scientifically known as Tapinoma sessile, is also difficult to eradicate because it can spread fast and also relocate.
"It can be very invasive," said Grzegorz Buczkowski, an insect researcher at Purdue University in Indiana. "It’s a big urban pest."
He said on the mainland, odorous house ants are dormant in the winter, but the ants could expand faster in Hawaii’s year-round warm climate.
He said on the campus of Purdue University where he works, he has found a colony with 5 million workers and about 25,000 queens.
Buczkowski said he doesn’t know what the odorous ants feed on in Hawaii, but they tend to like liquid sugar and will take honeydew from aphids, nectar from flowers, and steal honey from bee colonies.
Scientists said on Maui the ants appear to have spread across a wide area of about 45 acres and formed a single supercolony with more than 300 nests and multiple queens.
Paul Krushelnycky, a UH-Manoa entomologist who discovered the odorous house ant in Kula, said the ant, initially found in Waipoli at about the 3,775-foot elevation, has been able to thrive among other inhospitable ant species, including the Argentine and big-headed ants.
Krushelnycky said eliminating the odorous house ant would be "pretty difficult" for a number of reasons.
"We really don’t know where else on the island they might be," he said.
Krushelnycky said scientists also don’t know how the ants arrived on Maui and whether the method of transport occurred once or is continuing.
The study of the Maui colony by Buczkowski and Krushelnycky appears in the current issue of the journal Myrmecological News.