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Ants

CARPENTER ANTS

Carpenter ants excavate wood, not as a source of food, but merely for nesting. Carpenter ant galleries have sandpapered appearance and never contain soil, mud, or pellets. Piles of fibrous sawdust containing bits of dead ants or other insects often accumulate below infested wood. The powder produced by wood-boring beetles does not have a fibrous, shredded consistency and does not contain evidence of dead insects. Carpenter ants have one segmented petiole in the form of a vertical scale, and a terminal acidopore with a circular orifice fringed with hairs. The workers are polymorphic and characterized by their evenly convex thoracic dorsum. The most common species on the west coast is the Western Black Carpenter Ant and is the principal structural pest.

BIOLOGY & HABITS

Carpenter ants enter buildings to nest and forage. They are called “carpenters” because they excavate their nests in wood, creating smooth tunnels and galleries. They generally excavate in wood that is decayed or damaged by other insects, however they can also be found in wood that is structurally sound. The colonies begin from a single queen. She often starts the nest in a small cavity in a dead or live tree where she lays her first eggs. In two to three weeks, the eggs hatch into larvae that are fed by the queen. At the end of larval development, they pupate and later emerge as minor workers, numbering 10 to 25 individuals. The minors begin foraging, excavating, and brood rearing for the colony. In two years a population of workers ranging in size from large to small minors will be present. Carpenter ants are polymorphic, meaning the colony has many sizes of workers. More than 50,000 workers have been found in colonies. This is relatively small in comparison with Odorous House Ant colonies that can reach upwards of 100,000 workers with as many as 41 functional queens. Mature, or parent colonies, establish satellite colonies nearby whenever a needs exists for more territory, more resources, or a drier, warmer nesting site. The queen , workers, and small larvae are always present in the parent colony whereas the satellite colonies contain workers, large larvae, and pupae. Workers can travel between the various satellites of a colony on well-defined trails. The d distance between parent and satellite nests varies, but has been measured as far as 750 ft. Colonies are perennial and may exist for more than twenty years. Carpenter ants with wings are known as “swarmers”. They are the reproducers and are responsible for setting up satellite colonies.

INFESTATIONS

In structural infestations of carpenter ants, the parent colony is generally located outside in a tree, stump, stack of firewood, or landscape logging. In a tree, nests are frequently found in hollows or dead limbs. Satellite colonies may be found in similar sites in one or more neighboring trees and in adjacent structures. Such colonies can be found in a variety of places, including attic rafters, roof overhangs, bay windows, fascia boards, floor joists, box headers, wall voids, hollow curtain & shower rods, hollow doors or columns, behind dishwashers, under or behind insulation in attics and crawl spaces, bath traps, under cabinets, and in ceiling voids next to skylights and chimneys. If a parent colony is found inside it is usually associated with a water leak or other constant source of moisture.

(Left to right: a carpenter ant doing damage to wood, carpenter ant close-up, diagram of female reproductive (l), male reproductive (r) and worker (bottom)).

ODOROUS HOUSE ANTS

The dreaded odorous house ant. This ant will put your exterminator to the test. Experience and knowledge is the key to controlling this pest.

These ants are a uniform brown to black and when crushed emit a rotten coconut like odor. Some find it to smell like ammonia or nail polish also. These ant are also commonly known as the “sugar ant” or “soil ant”. The odorous house ant is found throughout the US and southern Canada from sea level to 11,000 feet. It is common in parts of Tennessee, Arkansas, Mississippi, California, and the Pacific Northwest, and it is becoming a serious pest in much of the Midwest .

BIOLOGY & HABITS

The colonies range in size from 50,000 to 1,000,000 ants and contain numerous reproductive females. Multiple colonies can consist of sometimes millions with multiple queens. The winged male and female reproductives mate either in the nest or after a nuptial flight. Colonies are established by newly mated queens or by budding from pre-existing colonies. Ants from other colonies are not aggressive toward one another. The duration of each stage of development varies depending on the season of the year. 11 to 26 days for eggs, 13 to 29 days for larvae; two to three days for prepupae, and eight to 25 days for pupae. In selecting a nest site, the odorous house ant is opportunistic. Nests in soil are usually shallow and often located beneath an object such as a board or stone. Stacked material such as fire wood, bricks, rocks, card board are also favorite nesting sites.

INFESTATION

When odorous house ants invade a building, their nests are often located outside. Indoors their nests are usually found associated with moisture, such as within wall voids near pipes, heaters, bathtraps, wood damaged by termites, and beneath toilets. The workers forage both day and night to collect honey dew, one of their favorite foods. They also feed on both live and dead insects. Indoors this ant can be active throughout the year and has been seen foraging outdoors in temperatures as low as 50o F.


(Left to right: a close up of the odorous house ant, worker ants gathering around a spoon, a trail of the house ants)

PAVEMENT ANTS

The workers are 2.5 to 3mm long and monomorphic (one size). They have two-segmented petiole and a stinger. It is not known, however, if they can bite or sting. Their antennae are 12-segmented with three-segmented club. The propodeum has a pair of small spines. The head and thorax are sculptured with numerous parallel grooves. The body color varies from light to dark brown to blackish. Queens have a similar appearance but are larger (6mm). Pavement ants move slowly.

BIOLOGY & HABITS & INFESTATION

The pavement ant derives it’s name from it’s habit of nesting beside and under sidewalks, driveways, and foundations. New colonies are established after mating flights that usually take place in the spring but may occur at other times of the year if the ants are nesting indoors. The alates (reproductives or winged) typically emerge from under baseboards, expansion joints, or from floor registers connected to heating ducts. In commercial buildings, they often become a nuisance when the alates emerge from openings in walls above false ceilings, then drop into the room below. This may go on for weeks as more alates emerge.Nests are located in soil in the open or under stones and pavement, and in masonry or rotting wood. The ants usually leave conspicuous piles of excavated soil. During winter, they will move inside, preferably to be near a heat source such as a radiator or heating duct.
Pavement ants tend homopterans for honeydew, especially subterranean forms, and feed on live and dead insects and a variety of plants. As household pests, they are attracted to both greasy and sweet foods.


(Left to right: pavement ant female reproductive (swarmer), pavement ants gathering (look how numerous they can be!), colony in gravel (notice how in a crack in the sidewalk or driveway, they can appear as a mound of "dirt" with a small hole in the center))