|White-footed ants have been confirmed in the
following Florida counties:
Dade, Broward, Collier, Palm Beach, Orange and Sarasota
|These ants have been reported (but not
officially confirmed) in:
Martin and St. Lucie Counties, Florida.
White-footed ants do not bite or sting, nor have they been reported to cause any type
of structural damage. They are, however, attracted to sweet foods. Thus, it is common to
find them foraging indoors and outside on hedges infested with honey-dew producing insects
such as aphids and scales.
Several biological aspects of the white footed ant make a difficult pest to control, almost impossible to totally eliminate from an infested home:
Armed with the knowledge of the white footed ant colony structure, methods of reproduction, food preferences/ feeding habits, nesting habits and ant colony structure, you will be successful in your ant control program.
|Colony Structure||Reproduction||Feeding Habits||Nesting Habits|
Estimations vary, but most agree that the average number of ants in a white-footed ant colony will range from 400,000 to well over 1 million ants. The sheer size of these colonies puts food at a premium; these pests must forage over a wide range and feed on several food sources. Colonies tend to be "spread out" as interconnected satellite colonies.
Approximately one half of the colony is made up of sterile, female workers. These worker ants forage for food, are responsible for brood care, and nest maintenance. The other half of the white-footed ant colony is made up of "intercastes." These are wingless males and females, that in addition to the founding king and queen, mate and lay fertile eggs. Thus, the reproductive potential of the multiple queen white-footed ant society is much greater than that of many other ant species.
Like many other ants, white-footed ant colonies produce winged males and females which, at certain times of the year, leave their nest to start new colonies. This is called "swarming." Winged females who mate with winged males during a mating flight found new colonies. Winged males mate once before they die. 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.
In addition, white-footed ants can initiate new colonies by budding. Budding is a process where many workers and wingless reproductive males and females leave the mother nest and crawl some distance to start a new colony. The wingless reproductives look very much like workers, and in many cases cannot be distinguished from sterile workers by external appearance. These worker look-alikes, called intercastes, make up almost 50% of a colony. Thus, mass movements of white-footed ants carrying their whitish-colored larvae and pupae may be observed during the budding process.
Workers of many sweet-feeding ants, such as the ghost ant, ingest
liquefied food and carry it within their crop (first of three stomachs) back to the nest.
Within the nest, workers regurgitate this food and share it with members of
the colony that never leave the nest, such as workers tending offspring, the queen, and
the developing brood.
This is why baits are so effective with certain other ant species, but not on white-footed ants: a worker ingests toxic food and takes it back to the nest where it is shared with others. As you will see in Feeding Habits of White-Footed Ants, baits only effect about half of the colony.
Even with only half the colony feeding on food outside the nests, this large population obviously needs a great deal of food to survive. One of their preferred foods is dead insects. White-footed ants are strongly attracted to sweet foods but have been observed in the laboratory feeding on termites and dead cockroaches. Sources of sugar can be found at many locations within structures and in the surrounding landscape. Indoor locations include the recycle bin, the kitchen, pantry, and wherever else food is stored, consumed or prepared. Outdoors, sugary food sources are found at extrafloral nectaries, within flowers, at wounds in trees, and as honeydew (excrement from sap sucking insects such as aphids and mealy bugs). With all of these potential food sources available, it is common to find white-footed ants foraging indoors and outside. Typically, white-footed ants show up at food sources in large numbers, resulting in easily observed foraging trails leading to and from the food. Most foraging occurs at night during the summer, but may be at any time of the day when temperatures moderate.
White footed ants will protect and feed on aphids and scales which attack certain ornamental plants. Not only do they feed on these plant pests, but will actually nurture them, collecting and feeding on sweet honey-dew produced by aphids. This behavior has been observed in other ant species as well. The alarming aspect of this behavior in white-footed ants is the abnormally large supply of food needed by the colony. This "farming" of plant pests can put your ornamentals at great risk.
White-footed ants are unusual in that food ingested by foraging workers is not regurgitated, nor is it shared with others. The sterile workers of the white-footed ant are capable of laying unfertilized eggs. These eggs, called trophic eggs, are sterile, and are thinner and more fragile than fertile eggs. Trophic eggs are fed to adults within the colony that are not actively foraging and also to the developing offspring. Therefore, toxic baits affect only those members of the colony that directly ingest baits. Baits are not shared with the other half of the colony.
White-footed ant nests have been observed in many locations in the landscape, and in
the home. In Japan, favored nest sites are within old trees. In Florida, trees
also serve as an ideal nesting location. White-footed ants can be found 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.
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This small (about 1/8 inch or 3 mm long) ant is easily confused with Crazy ants and Odorous House Ants if not properly identified. Although the body of the white-footed ant closely resembles that of the crazy ant, its legs and first segment of its antennae are much shorter. This ant's body color is darker than that of the odorous house ant. The white-footed ant (which has one node) has one distinguishing characteristic which sets apart from similar ants: the tarsi (section at the end of the legs) are a very light yellow or yellowish white in color. This gives it the appearance of having "white feet," hence its name. Click on the thumbnail image (above) to enlarge and view the white-footed ant.
1. Thomas J. Weissling, Betty Ferster, and Monica Carpio, University of
Project Coordinator: Thomas R. Fasulo, University of Florida
Publication Number: EENY-51
Publication Date: August 1998
Copyright 1998 University of Florida
2. Document ENY-635, one of a series of the Entomology and Nematology Department, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida. First published: April 1998.
Thomas Weissling, Rudolf Scheffrahn and Betty Ferster, Ft. Lauderdale Research and Education Center, Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida, Gainesville, 32611.
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