One of the world’s worst invasive ant species is now in Mindanao. Where does it go next?

The start of an invasion

In late October 2025, researchers found Wasmannia auropunctata, better known as the little fire ant, at two sites in Barangay Rogongon, Iligan City, about 20 kilometers east of the city center. The species is considered not only one of the world’s most invasive ants, but also one of the most damaging. It was the first confirmed detection in the Philippines.

The discovery was made by April Rose P. Monding and Olga M. Nuñeza of the Department of Biological Sciences, Mindanao State University – Iligan Institute of Technology, together with Philip S. Ward of the University of California, Davis. The ants turned up in every sampling method and in several microhabitats, a sign of “local establishment rather than a transient introduction,” the researchers wrote. It could be the start of an invasion of local habitats in Mindanao, and possibly other parts of the country.

Their study, published in BioInvasions Records in August 2026, found that the little fire ant now dominates most of the microhabitats surveyed, with native ants largely absent or displaced. The researchers caution that the ant’s local effects in the Philippines have not been thoroughly studied. That loss of native ants could be an early sign of a bigger problem looming for nearby farms and communities if no effective intervention is done.

Another shocking discovery

The study confirmed little fire ant colonies at two sites in Barangay Rogongon, Lagcong and Sikyop, both along the road connecting Bukidnon Province and Iligan City. Surveys at the same sites in 2021 did not detect the ant, but by 2025 the researchers found it common there. They used several standardized methods to look for ants, including cookie crumb baits, beating vegetation, sifting leaf litter and searching by hand.

How far the infestation reaches is still unknown. “I do not know exactly how large an area the infestation covered at Lagcong and Sikyop in October 2025, as we did not measure its full extent,” April Rose Monding, the study’s lead author, said in an email on Oct. 7, 2026. “The locations reported in the paper should therefore be treated as occurrence sites rather than boundaries of the infestation.”

The discovery itself was incidental, Monding said in an email on Oct. 9, 2026: “we were conducting a general search for ants rather than a targeted survey for the little fire ant.” She added that October 2025 “was the date of detection, rather than necessarily the date of introduction. The ants may have been present earlier.”

The ant may also have been photographed elsewhere in the country. A 2025 review of little fire ant photos on iNaturalist, a citizen-science app where people share wildlife sightings, had three reviewers check each photo. It accepted four from the Philippines: two from Luzon, in Manila and San Jose del Monte, one from Marawi and one from Mambajao in Camiguin. All four were uploaded in January and February 2025, months before the Rogongon find. The review’s authors call them potential records that still need to be confirmed by surveys (Arcos et al., 2025). Monding, who pointed to the review in an email on Oct. 10, 2026, said such photo observations should be kept apart from specimen-based records like those in her study. The Rogongon study remains the first confirmed detection in the country, based on collected specimens.

An excellent hitchhiker

“Itong Little Fire Ant, excellent hitchhiker. Pwede siyang mag-hitchhike sa ating mga sapatos, pwede sa mga gulong ng sasakyan, pwede rin siya mag-hitchhike doon sa mga agricultural products.”

Little fire ants are slow on their own, but they can spread much faster by hitchhiking on people and vehicles. That is not a special ability of this species, Nuñeza explained in comments relayed by Monding on Oct. 10, 2026. Invasive ants can be carried unnoticed in soil, plants, logs and other materials, and transport by people is a major reason they spread. On their own, colonies spread slowly, from tens to a few hundred meters a year in studies elsewhere. At the 75 meters a year this story’s model uses, crossing the roughly 20 kilometers from Rogongon to Iligan’s city center would take more than 250 years. A single ride on a truck, a pair of shoes or a load of plants could cover it in a day.

“Nagpadala na ng mga expert ’yung ating regional field office, ’yung ating Regional Crop Protection Center doon para i-check ’yung veracity.”

On Sept. 21, 2026, Department of Agriculture spokesperson Assistant Secretary Arnel de Mesa said the DA’s regional field office and Regional Crop Protection Center had sent experts to check the report of little fire ants found by researchers from MSU-IIT and the University of California, Davis.

In a GMA News report published the next day, the Department of Environment and Natural Resources’ Biodiversity Management Bureau said it would work with the DA’s Bureau of Plant Industry on quarantine measures to monitor and control the ant. It asked the public to report sightings right away and not to move soil, plants or other materials out of affected areas.

Outside Mindanao, the DA’s Negros Island Region office said on Sept. 11 that it had not received any reports of the ant, but that local agriculturists were monitoring for it.

In their paper, the researchers recommend:

1. targeted monitoring and precautionary management in Rogongon;
2. more surveys to decide between eradication and control;
3. monitoring in port cities across northern Mindanao;
4. strict border checks; and
5. public awareness campaigns.

The Department of Agriculture’s Northern Mindanao regional office was asked by email on Oct. 7, 2026, about its findings and plans. It had not responded as of publication.

The sad reality

In most places the little fire ant has invaded, it has never been fully eradicated. Individual sites have been cleared in Hawaiʻi, the Galápagos and Australia, but new infestations keep appearing, often carried in plants and soil, so treatment and monitoring continue. Hawaiʻi has been fighting the ant since 1999, and Australia has been trying to eradicate it for about 20 years. Hawaiʻi cleared a six-acre neighborhood on Oʻahu, and the Galápagos cleared a 21-hectare infestation on Marchena Island, only to find the ant elsewhere on the island in 2007 and 2008. But no one yet knows how large the infestation in Rogongon is.

Even a small infestation takes years to clear, and complete eradication may not be realistic.

For people in Rogongon, the sting is what they will notice first. The damage to farms, if it comes, will be slower and quieter. Without intervention, that quiet damage could become loud.

Where the ant goes next may depend less on the ant than on the people around it. How fast it spreads will be shaped by what the government, experts and the public do. Early intervention may sting, too, in money, time and effort. But it would likely hurt far less than being stung left and right by an ant that has spread across the country.