Pest Information - Ants
There are almost 9,000 species of ants and they can be found from the Arctic Circle to the Tropics. This site will focus on the ants most commonly found in Hawaii. Learn about their Appearance, Habitat, Diet, Type of Damage, and Life Cycle.
Acrobat Ant
Scientific Name
Hymenoptera: Formicidae
Appearance
Acrobat ants are small to medium sized ants, generally 2.6 to 3.2 mm long. They have very shiny bodies that are variable in color from light red to brown or black. Acrobat ants are often very shiny. Some common species have a 'patent leather' look. The final segment, or gaster, of the ant appears heart-shaped when viewed from above. This ant is known as the acrobat ant because, when frightened, a worker raises the tip of its abdomen up over its head. Individual acrobat ants may occasionally be seen foraging near a source of food or water. This ant, unlike some other common pest species, does not generally form long lines of foragers.
Habitat
These ants may be found both indoors and outdoors. They will not colonize wood that is in sound condition, but frequently nest in dead or decaying wood. Outdoors, they are frequently found nesting in logs, stumps, and hollow tree cavities. They also nest beneath tarps, leaf litter, stones, or anyplace where the soil is likely to be damp.
Infestations of acrobat ants are generally associated with homes constructed on wooded lots or adjacent to forestland. When nesting in structures, acrobat ants are usually associated with moist or rotting wood and are frequently found in window frames or adjacent to downspouts. They may create cavities in wood kept damp by leaks or condensation from plumbing fixtures. Acrobat ants have also been known to nest in foam board or insulation, especially if it is damp.
Diet
Acrobat ants feed on a variety of foods including sweets and other insects. They have frequently been observed feeding on termites. Acrobat ant workers prefer the honeydew secreted by aphids and mealy bugs. These ants will protect bugs from predators, insuring the safety of their living food source. In homes they forage for sweets and proteins.
Type of Damage
Acrobat ants can be nuisance pests in and around structures. The workers can be aggressive if disturbed and may sting or bite. Some species also produce a foul odor. This ant prefers to forage outside. Workers may travel over 100 feet from the nest in search of food. Structural damage associated with this ant is minimal. Occasionally, this ant will expel fine frass (a sawdust like excrement) from the nest, which cause homeowners concern.
Life Cycle
Like all ants, this species has a complex life cycle developing from eggs into white legless larvae then pupae before emerging as adults. Development from egg to pupa takes place within the nest and immatures are rarely seen. Like all ant species, acrobat ants produce winged individuals known as swarmers. Swarmers are fertile adult males and females whose only function is to reproduce and found new colonies. They do not forage for food, bite, or sting. The males (drones) and females (queens) emerge, take flight, and mate while in flight. The females then land, shed their wings and seek soft soil in which to create a nest. The males die shortly after mating. Acrobat ant swarmers usually emerge in the fall although flights have been observed as early as June.
Interesting Facts
They are called acrobat ants because they can raise their abdomen over their heads.
Argentine Ant
Scientific Name
Linepithema humile (Mayr) Hymenoptera: Formicidae
Appearance
Argentine ants are small (2.5-3mm) brown ants with a single node in the waist. They are typically found traveling in well defined trails between nests and food sources. Unlike other common small brown ant species, such as the coastal brown ant, Pheidole megacephala (Fabricius), Argentine ants do not have a soldier caste, so all the individuals out scavenging for food are the same size.
Habitat
The population of a colony may vary from a dozen to many thousands and the number of queens from one to hundreds. During the warmer months, satellite nests are usually established close to food sources and these satellite nests are highly mobile, with the workers moving in with eggs and larvae over a short period and abandoning the nest if it is disturbed or the food used up. The adult winged males, which are larger than the workers but much smaller than the winged queens, usually fertilize the queens in the nest and the new queens establish nests nearby after losing their wings. In midsummer and early autumn there is a very large increase in numbers. It has been estimated that infestations grow at a rate of more than 200 meters per year.
Diet
Argentine ants eat a wide range of foods including nectar, insects, seeds, carrion, and honeydew secreted by aphids and scale insects. Workers have a mostly sugar based diet, while larvae and queens feed mostly on protein.
Type of Damage
Because of the nature of the infestation, Argentine ants need to utilize and monopolize every available food source in order to feed the vast numbers of ants that eventually build up in a single infestation. They also compete very effectively with all other ant species, both by fighting and by monopolizing all available food sources. Virtually all other ants are replaced by Argentine ants. Argentine ants become a major domestic pest by invading houses and swarming over foodstuffs, including entering fridges, unopened packets and have even been known to follow the spiral down inside screw-top jars to get at the contents, particularly if the contents are sweet. They invade beds at night seeking moisture and can swarm over sleeping babies, although they are not known to do any harm. Unlike many other domestic pest species, Argentine ants do not nest in houses but nest outside and enter houses in dense trails which can resemble miniature multi-lane highways.
These ants may "cultivate" aphids, scale insects, or mealybugs on fruit trees, houseplants, or ornamental plantings. These sucking insects produce a sweet excretion called honeydew that Argentine ants use for food. Argentine ants also feed on the honeydew-producing insects themselves.
Infestations of mealybugs, aphids, and other sucking pests can damage the health of the affected plant or cause it to become unsightly. Because Argentine ants will harass natural predators to protect their "livestock" they frequently interfere with integrated pest management programs involving biological control. (Biological control is the use of a natural enemy to control a pest organism.) This ant is an important agricultural pest in citrus orchards and vineyards. Argentine ants will also attack and destroy hives of domesticated honeybees.
Life Cycle
The eggs of Argentine ants are elliptical in outline, pearly-white in color, and take from 12 days to nearly 2 months to hatch. The larval stage may be completed in from 11 to 60 days. The pupal period may extend over 10 to 25 days. The minimum period from egg to adult is about 1 month but it may be 4 to 5 months and averages 2-3 months.
Interesting Facts
Argentine ants are a serious threat to the ecosystem. They may eat nestling birds. They out-compete native insects for food and habitat and consume or displace natural predators such as lizards, snakes, and spiders.
Big-Headed Ant
Scientific Name
Pheidole megacephala (Fabricius)
Appearance
Big-headed ants are light brown to dark reddish brown, a have two sizes of workers. One size is 1/8 inch long, has an enormous head and is sometimes called a seed cracker worker. The minor workers (1/16 inch) do not have enlarged heads but can be recognized by the shape of their heads, which narrow abruptly behind the eyes. Big headed ants have two nodes on their pedicel, one pair of spines on its thorax and 12-segmented antennae with a 3-segmented club.
Habitat
Big-headed ants are found in warmer and dryer sections of the United States, and have very similar habits to fire ants. Nests are found in exposed soil or under cover and in rotting wood. They rarely nest indoors, but may invade homes to forage for food. Big-headed ants prefer meats, greases, and breads. They superficially resemble fire ants but can be distinguished from them by the presence of 12 segments in the antenna, with a 3-segmented antennal club.
These ants can be found nesting in the soil around homes in many areas of the United States. They have become a persistent problem in the South, with reports of workers invading homes in their search for food.
Diet
Big-headed ants feed on live and dead insects, seeds, and the honeydew produced by homopterous insects (e.g., aphids, mealy bugs and scale insects). In houses, they seem to prefer protein foods, such as meats and peanut butter, but will also feed on greases and sweets such as fruit juices.
Type of Damage
This ant displaces most native invertebrate faunas directly through aggression, and as such is a serious threat to biodiversity. Evidence also exists of reductions in vertebrate populations where this ant is extremely abundant. Effects on plants and horticultural crops can be direct through the likes of seed harvesting, or indirect through the likes of harboring aphids and scales to feed on their honeydew, which reduce plant productivity. It is known to facilitate the invasion of introduced plant species. This ant is known to chew on irrigation, telephone cabling, and electrical wires.
Life Cycle
This ant's life-cycle developmental time and longevity of each stage is highly dependent on temperature. Incubation time of eggs ranges from13 to 32 days. Duration of the larval stage ranges from 23 to 29 days. Duration of the pupal stage ranges from 10 to 20+ days. The lifespan of minor workers has been shown to be 78 days at 21°C, and 38 days at 27°C.
Interesting Facts
Big headed ants nest in soil, sometimes with donut of dirt around the hole.
Hawaiian Carpener Ant
Scientific Name
Camponotus variegatus
Appearance
Adult Hawaiian Carpenter ants measure from 5 mm to 1.27 cm in length and are Hawaii 's largest ant species. They are typically yellowish-brown with dark brown stripes across the top of the abdomen. Because of their size and color, winged adults of the Hawaiian carpenter ant are often confused with the winged adults of the West Indian drywood termite and the Formosan subterranean termite, since both groups tend to swarm (appear) at approximately the same time of the year. Several morphological characteristics can be used to differentiate these individuals, one of which is that ants have a “waist” and termites do not.
Habitat
Found primarily outdoors, the Hawaiian carpenter ant will make nests indoors in undisturbed areas such as inside storage boxes, cupboards that are seldom used, even in office equipment. The workers are nocturnal in habit, and their foraging behavior may extend to midnight or later. If the carpenter ant has established a nest in a home, it is not unusual to see them on the walls and ceiling at night. These individuals may be the winged sexual reproductives after a swarm and/or foraging workers looking for food. Finding and eradicating the nests is important in the elimination of this pest.
Diet
These ants will feed on small insects, honeydew from aphids, and most foods found in a home, including meat and grease.
Type of Damage
Although it is primarily found outdoors, the Hawaiian carpenter ant will establish nests in wood that has previously been hollowed out by termites or inside rotting logs and tree stumps. For this reason and because of its name, it is often incriminated as a wood destroyer. Although it may do some excavation of wood, it does not consume wood like termites and does little to no damage to wooden structures. Species of carpenter ants in the Pacific Northwest and eastern parts of the United States, however, are serious wood destroyers and have rivaled termites in their importance.
Life Cycle
The elongated, whitish eggs hatch in about 20 days. The queen feeds the larvae a fluid secreted from her mouth. This nourishment is derived from her stored fat bodies. The larvae grow for about 28 days before spinning cocoons around themselves and pupating. The pupal stage lasts about 22 days. It is this stage that is often mistaken for eggs. The small workers chew their way out of the cocoons and begin to assist the queen.
Interesting Facts
A total of 44 ant species have been recorded in Hawaii, none of them native. They have been brought to the islands by people.
