UH team helps knock back little fire ants in Lanikai

Little fire ant queen and workers (Photo courtesy: Hawaiʻi Ant Lab)

UH staff with community members preparing to conduct a reassessment survey in February 2025.

Map from an assessment in February 2024 showing locations where little fire ants were detected

Updated map from February 2025 reassessment

Nearly all little fire ants along the Lanikai loop in Windward Oʻahu are on track for eradication thanks to the efforts of University of Hawaiʻi researchers working with community members.

During an assessment in February 2024, dozens of locations along the Lanikai loop and beach areas were found to harbor invasive little fire ants. Researchers with the Hawaiʻi Ant Lab and Oʻahu Invasive Species Committee, both in the Pacific Cooperative Studies Unit in the UH Mānoa College of Natural Sciences, conducted a large-scale treatment effort over 26 acres to combat the infestation. Between March 2024 and January 2025, ant baits were applied eight times across affected areas. To assess the extent of the invasion, more than 3,600 ant samples were collected, and treatment was carried out at 85 residences and 1.5 acres of the beach.

The latest survey, conducted in February 2025, collected more than 2,000 samples, with only a single ant detected. The affected area was immediately re-treated, and the project has now entered a long-term monitoring phase to ensure the infestation does not resume.

“This project demonstrates that with persistence, community involvement and science-based treatments, we can effectively control little fire ants,” said Hawaiʻi Ant Lab Manager Michelle Montgomery. “Continued monitoring and stable funding are essential to ensure these invasive pests do not return and threaten our ecosystems again.”

To be considered fully eradicated, no little fire ants can be detected for a minimum of three consecutive years. Since the ants were first identified in Lanikai in 2019, residents have struggled to manage infestations, with limited resources making large-scale control efforts difficult.

Little fire ants are a highly invasive pest known for their painful stings, which can harm people, pets and wildlife while disrupting ecosystems.

The Hawaiʻi Ant Lab and Oʻahu Invasive Species Committee continue to support community-driven little fire ant control efforts across Hawaiʻi. Both organizations rely on funding from the Hawaiʻi Invasive Species Council, the Department of Land and Natural Resources, the Department of Defense, and other government and non-profit sources. Officials stress that stable, long-term funding is crucial to ensuring sustained efforts to eliminate invasive species and protect local ecosystems and communities.