Amy Tsuneyoshi
Hawai‘i Herald Columnist
There are many kinds of ants in Hawai‘i, but the one to stop right now is the little fire ants (LFA), or Wasmannia auropunctata. They are tiny, orange, slow-moving ants that have a nasty sting. LFA are much smaller than other ants, only one-sixteenths inch long or the thickness of a penny. Native to the rainforests of South America, they are well-adapted to Hawai‘i and can be found in trees or on the ground. It’s believed they hitched a ride to Hawai‘i in a shipment of potted palms from Florida, and by the time they were detected in Puna (1999), the ants were already widely dispersed on Hawai‘i Island.
As of July 2023, LFA is widespread in east Hawai‘i with isolated sites in each district. For the other islands, there are two known sites on Kaua‘i, 41 sites (30 active, seven monitoring, and four eradicated) on O‘ahu, 19 sites (seven active, five monitoring and seven eradicated) on Maui. No LFA have been detected on Moloka‘i and Läna‘i. The Hawai‘i Ant Lab was established to research and develop methods for the eradication and control of LFA.
LFA colonies can thrive undetected within a small space, for example, an entire colony (queen with worker ants) can fit within the shell of a macadamia nut. Colonies spread very slowly on their own but can be easily transported unintentionally to create new populations. LFA spreads by hitching a ride in plants, soil, equipment or practically anything that has been sitting in an infested area. Colonies often overlap and over time meld into one large super colony with multiple queens. These ants don’t cling to surfaces like other ants so when you accidentally bump a tree or pick a fruit it is nesting in, the ants fall and most often will sting your neck or torso. They are great defenders of their space and will push out or prey on other ant species. Without competition or predators to control the population, colonies grow undetected until one day it starts raining ants.
LFA can be harmful to people and pets and can negatively impact the environment, as well as the agriculture and tourism industry. The painful stings result in a long-lasting itchy rash or welt and some people can suffer from anaphylactic shock from the sting. It’s a good practice to check items before bringing them to your home, especially if you are visiting a known infested area. Quarantine items and survey for ants.
Survey for LFA is done by placing sticks lightly coated with peanut butter in or around the new items for about an hour. If there are ants on the sticks, carefully place the ant covered sticks in a small zip-top bag without knocking the ants off, close the bag securely and place in the freezer for a day.
The link below provides detailed testing information and the appropriate organization to send your samples. You will be contacted if your sample contains LFA, and the organization will help with treatment or provide the appropriate training. It is important to know what type of ant you have because LFA requires specific control methods to target the queen ant. It’s helpful to do ant surveys annually even if you don’t think you have LFA. Ant samples can help the state identify new undetected ant species in the state.
Check out the website below and request your free ant collection kit.
Spot the Ant, Stop the Ant!
