Institute of Food and Agricultural Sciences
Hendry County Horticulture News
White-footed Ants - Our Newest Home Pest
Most Floridians have probably ceased to marvel at the many types of ants that may be found in and around the home from time to time. The newest ant to invade Florida is the white-footed ant, Technomyrmex albipes. White-footed ants were first collected in Florida at a nursery in Homestead in 1986.
The white-footed ant is native to the Okinawa, and several islands around Japan where it inhabits dry grasslands and forest margins. The species has spread throughout the tropics and subtropical areas and is now found in Asia, Papua New Guinea, Guam, Australia, New Zealand, South Africa, Florida and Hawaii. During the past few years, reports of white-footed ants infesting homes in south Florida have increased considerably and they are now present throughout most of South Florida.
Fortunately, white-footed ants do not bite or sting, nor have they been reported to cause any type of structural damage. They exist in very large colonies made up of several hundred thousand individuals and due to their numbers may become a nuisance to homeowners.
The white-footed ant is a relatively small (< 3 mm in length), black to brownish-black ant with yellowish-white tibia and tarsi (feet) and a one-segmented waist. At first glance they may look similar to some of the other small ant species that are attracted to sweets.
The white-footed ant has an unusual life cycle. There are two morphologically different forms of males and females, and each disperses from the mother colony in different ways. Winged females who mate with winged males during a mating flight found new colonies. Winged females die about 400 days after starting a colony. The queen is then replaced by a wingless daughter that mates with a wingless male who is capable of multiple matings. The wingless reproductives look very much like workers. The reproductive potential of the multiple queen white-footed ant society is much greater than that of other ant species that have single queens.
In addition, white-footed ants can initiate new colonies by budding. Budding is a process where many workers and a mated, wingless female leaves the mother nest and crawl some distance to start a new colony.
White-footed ants are strongly attracted to sweets. Typically, white-footed ants show up at food sources in large numbers, resulting in easily observed foraging trails leading to and from the food.
Workers of many related sweet-feeding ants, such as the ghost ant ingest food and bring it back to the nest where it is shared with others. This is why baits are so effective on these species. White-footed ants are unusual in that food is not shared with others. Therefore toxic baits affect only those ants that directly contact and ingest baits.
In Florida, white-footed ants can be found outside under loose bark, within natural or artificially created cavities in the stem, in rotten trunks or limbs, and in galleries created at one time by termites. In addition, white-footed ants have been observed nesting in attics, under roof shingles, in wall voids, in cardboard boxes, in the petiole bases of palms, under leaf litter, in compost piles, under rocks, along fence lines, and in outdoor furniture. Many other damp locations may serve as suitable nest sites for this species.
Although a colony may be made up of a million individuals, they usually do not all nest in one location. Colonies tend to be "spread out" as interconnected satellite colonies. Therefore, ants within the same colony may be found nesting at several locations around a structure. Nesting sites usually contain eggs, the developing offspring, and pupae as well as adult ants.
Several attributes of their biology help make white-footed ants a very successful species and an extremely difficult pest to control. An integrated approach including prevention, inspection, sanitation, and chemical control has proven to be most effective.
Prevention is the best line of defense against the establishment of any pest insect. If entry points can be located, they can be blocked by application of caulk. Sanitation can also help to prevent or reduce infestation by white-footed ants, as well as other ant species. Eliminate ant access to sugars within the home. Clean areas where food is handled and quickly and thoroughly clean up spilled sugar-based foods. In addition, store food in containers with tight fitting lids, rinse items before tossing them in the recycle bin, and empty the recycling bin frequently.
A thorough inspection of the home and yard for ant activity can reveal potential problems and potential treatment solutions for the white-footed ant. These spots may require additional attention when spraying insecticide or baiting.
Management has only been accomplished by treating infested homes exclusively with baits containing borates. It is critical that all populations of WFA on the property being treated are identified so that baits can be made available to each population. Since liquid baits tend to dry out over time, it is important that fresh baits are always available until the target population has been controlled. Although bait toxicants are not transferred between workers, they can still kill enough workers to cause death of brood by starvation. For more tips on controlling ants and other insect pests, contact the Hendry County Extension Office.
The white-footed is an exception to the structure-infesting ants normally encountered in Florida. The white-footed ant is a very difficult species to control. Effective management requires a lot of time and patience.
Good luck and good gardening.
Gene McAvoy is the horticulture agent with the Hendry County Extension Service. Direct your horticulture questions to PO Box 68, LaBelle, FL 33975, e-mail - firstname.lastname@example.org or phone 863-674-4092 or 863-983-1598. You are also welcome to visit the Hendry County Extension Office at 225 Pratt Blvd., LaBelle. Office hours are from 8:00 - 5:00.
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