Pest Control St. Louis

Argentine Ant

Latin Name: Iridomyrmex humilis

Features: It is a tiny, dark-colored ant about 3 mm (1/8 inch) long that invades homes looking for food and water..

Color: dark-colored

Other: It is in addition light to dark brown in color, and it has six legs, as with other insects. The Argentine ants' antennae have twelve segments. The thorax joins the abdomen by a thin pedicel, a thin stalk.

Where can they be found? Outdoors in soil, under timber, slabs, debris, mulch, or in branches and cavities of trees and shrubs

Shallow, 1- to 2-inch deep mounds in open, often disturbed habitats, either moist or dry

The most frequent ant in southern California is the Argentine ant (Iridomyrmex humilis). This ant can also be located in the low eastern US area. According to Wild (2004), this species was originally described in the genus Linepithema by Mayr in 1866; consequently, the proper binomial should be Linepithema humile. It is a small, dark-colored ant about 3 mm (1/8 inch) long that invades homes in search of food and water. They are especially fond of sweets, but will feed on practically any food. They love hard boiled eggs and carry small yellow clumps of yolk back to their nest in endless ant columns.

These ants are exceedingly well adapted to urbanized areas of the United States with mild climates and well-watered gardens. They pose a difficult threat to native wildlife by upsetting delicate food webs. They are especially formidable attributable to their aggressive behavior and the huge size of their colonies that can literally "team up" with other colonies.

If you reside in southern California, you likely have noticed endless single file columns of uninvited six-legged guests strolling through your house. They follow a pre-marked pheromone "scent" trail first off established by scouts who were searching for goodies in your pantry. Although they choose to outdoor lifestyle, they primarily enter houses for food and water. They are like sweets, tuna, syrups (even cough syrup), juices, eggs, dead spiders and rodents, puke, feces and almost any other organic material they can find. They are essentially scavengers and they play a valuable role in the natural ecosystem–but preferably in Argentina. In hot, dry weather they often times search your house for water, including bathroom faucets and drains. I once followed an ant safari into my washroom where they were neatly stacking their precious cargo of tiny eggs inside my toilet tank. They also relish the "honeydew" secretion of aphids, and look after their aphid friends from natural predators. In the fall months as the nights get very cold, they once again seek the warmth and shelter of your cozy home.

The first Argentine ants set foot on U.S. soils in the late 1890's, as coffee ships from Brazil unloaded their freight in New Orleans. Being prolific breeders and constantly active, they moved across the southern half of the US. A single colony may contain 10,000 female workers, and there can be many hundreds of colonies around your house; the whole number of ants could reach a million. Although they cannot sting, they can bite; still, they are merely about 3 mm long and there tiny mandibles are too small to hurt humans. But, globally of insects, these ants are truly a living terror. They are very aggressive and readily overtake other ant species, even ants that are much larger and with powerful stings. Argentine ants are relentless and just outnumber their adversaries until the enemy colony is destroyed. They even attack paper wasp nests under the eaves of a house, forcing the huge wasps to flee their nests in terror. Even nests of large carpenter bees are no match for these relentless ants. A "killer bee" nest probably couldn't withstand an invasion of Argentine ants. They also will attack bird nests, driving off the mother bird and killing the helpless young. One possible redeeming quality about these little warriors is that they might attack dry- wood (aerial) termite colonies in your house. I have seen this Lilliputian massacre in a termite infested table in the Palomar College greenhouse.

Most ant colonies are very territorial, and will fight different colonies of the same species. Since Argentine ants in the United States originated from the original colonizers in Louisiana, they are all intimately linked with alike DNA. They apparently will accept ants from different colonies as members of their gigantic family. In fact, Argentine ants from different colonies will actually "team up" and attack together in vast swarms. They simply outnumber and overpower their enemy.

Argentine ants have become a serious threat to the coast horned lizard (Phrynosoma coronatum) in southern California. The primary food source for these endangered lizards are native harvester ants, particularly the California harvester ant (Pogonomyrmex californicus). I spent a number of years observing this interesting red ant while grown up in San Gabriel Valley, and I am in a position to personally testify that it has a traumatic sting. As of 2006, this large red ant is seldom seen in urbanized areas of coastal southern California.

California harvester ant (Pogonomyrmex californicus), primary diet of coast horned lizard.

Urbanization has certainly been a factor in the demise of California harvester ants, but an even greater factor resulting in the excretion of native ants and coast horned lizards is the aggressive Argentine ant. Apparently the horned lizard is not fond of Argentine ants, and is in reality attacked by them in enormous swarms. Colonies of Argentine ants need a damp area to survive, and have not invaded a few of the dry habitats where native harvester ants and desert horned lizards (P. platyrhinos) still live. Of course, they can readily colonize urbanized desert areas inhabited by people. Well-watered gardens with stepping stones and concrete slabs provide the idea living requirements for these ants. In their native Argentina they live under rocks.

Coast horned lizard (Phrynosoma coronatum).

Argentine ants are a terrible nuisance in gardens and orchards because they tend and safeguard scale insects and aphids. They even carry aphids to the tender buds of your prized roses. In return, the ants consume a sweet secretion from the aphids called "honeydew." In addition, swarms of these ants will invade orchard trees, destroying the fruit crop. This is specially serious in figs (Ficus carica) where the symbiotic pollinator wasps are destroyed.

Metallic green fig beetles (Cotinus texana) gorging themselves inside a fleshy, ripe syconium of the Calimyrna fig (Ficus carica). Although masses of minute, aggressive Argentine ants (Linepithema humile) are likewise foraging in the syconium (white arrow), the beetles are safe by their tough, impervious exoskeleton. These attractive beetles spend their juvenile larval stage in the earth, often beneath manure piles, compost and haystacks.

As reported by entomologist David Faulkner, if you have a 10 x10 foot (3 x 3 m ) patio slab, you might have a million or more individuals and possibly 20 or 30 queens. They interact fine because they're all connected with the original colonizers in Lousiana, perhaps from the original gravid (pregnant) female who arrived there. Workers live a month or more as adults, but queens live up to 10 years or more. With other ants, when the queen dies, the one-queen colony dies because no more ants are being produced. With multi-queen Argentine ants, another queen simply moves in and takes over the role of the deceased queen. In fact, a queen from San Diego would in all probability be accepted in a colony elsewhere in California.

Argentine ants (Linepithema humile): A wingless queen and a number of workers. Although these ants are only 3 mm long, they're very aggressive and quickly annihilate other ant species, even larger ants with powerful jaws and stings. They overpower other species by their sheer numbers. Argentine ants in the U.S. are descendants of original colonizers that entered Louisiana in the late 1890's, as coffee ships from Brazil unloaded their freight in New Orleans. U.S. populations are so closely linked that different colonies with multiple queens can literally merge together into supercolonies. Image taken with Nikon D-90 and 60mm Micro Nikkor AF-S F/2.8G ED Macro Lens using a Phoenix Ring Flash; hand-held at 640 ISO, F-32, 1/125th sec.

In their native homeland of Argentina, different colonies of Argentine ants are not so friendly to one another because their DNA has developed much greater variation. Neighboring colonies may fight each other, although they are just 200 yards (200 m) apart. Also there are many native predators in Argentina, including fungal parasites and bacterias. The narrow genetic variability that has kept all the California populations on friendly terms may eventually backfire owing to abnormal inbreeding. Perhaps some day these ants may not have the genetic variability to adapt to a changing environment.

How To Control Invasions of Argentine Ants"

Empty your trash often and make sure your property is free of crums and food particles that might attract ants. Ensure that food containers are tightly closed, without residual traces of the food on the sides of containers. These ants can also get into screw-top jars without seals. They follow the spiral threads until they are inside!

Try not to use toxic aerosol insecticides inside your home–unless you don't care about your lungs or your bone marrow.

Try spraying a deodorant detergent (Pine Sol

Carpenter ants are a nuisance by their presence when located in parts of the home such as the kitchen, bathroom, parlor and several quarters. When 20 or more large winged and/or wingless ants are found indoors, in the daylight near one location, it is achievable that the colony is more developed in the house and the nest may have been extended into sound timber, often times causing structural damage. They don't eat timber, but often remove quantities of it to expand their nest size. Yet, but only if one to two large wingless ants are erratically crawling, they could simply be foraging for food with the nest located outside. Outdoors, they are regularly seen running over plants and tree trunks or living in moist, partly rotten wood stumps. All the same, carpenter ant inquiries rank first over all other household/structural pests in Ohio.

Identification

Carpenter ants are among the largest ants located in homes and live in colonies containing three castes consisting of winged and wingless queens, winged males and various sized workers. Winged males are much smaller than winged queens. Wingless queens measure 5/8 inch, winged queens 3/4 inch to the tips of their folded brownish wings, small minor workers 1/4 inch and large major workers 1/2 inch. Workers have some brown on them while queens are black. Workers have large heads and a tiny thorax while adult swarmers have a smaller head and large thorax. Carpenter ants have a smoothly rounded arched (convex) shape to the top of the thorax when considered from the side and a pedicel between the thorax and abdomen comprising of just one segment or node. They have constricted waists, elbowed antennas and the reproductive's forewings are bigger than the hindwings, transparent or brownish and not easily taking away. Adults are commonly black with some species red, brown or yellow occurring on areas of the body and legs. Eggs are about 1/8-inch long, cream colored and oval. Larvae are legless and grub-like, later pupating in tough silken, tan-colored cocoons erroneously remarked as "ant eggs."

Life Cycle and Habits

Queen Worker

Winged male and female carpenter ants (swarmers) emerge from mature colonies usually from March to July. After mating, males die and newly fertilized females (mated forever), establish a new colony in a tiny cavity in timber, under bark, etc. and each lays 15 to 20 eggs in 15 days. The egg stage takes about 24 days, larval stage 21 days and pupal stage 21 days or about 66 days from egg to adult at 70 to 90 degrees F. Cool weather may lengthen this period up to 10 months. The colony does not produce swarmers until about three years later. A mature colony, after three to six years, has 2,000 to 4,000 individuals. During the first breed, larvae are fed entirely by a fluid secreted from the queen's mouth where she does not take food, but uses stored fat reserves and wing muscles for her nourishment. The few workers emerging from the first brood assume duties of the colony, collecting food, excavating galleries to enlarge the nest and tending the eggs, larvae and pupae of the second generation. Workers regurgitate food for nourishment of the developing larvae and queen. She has few duties except to lay eggs.

In later generations, workers or various sizes are produced (polymorphism) into major and minor workers, that are all sterile females. Males formed are winged swarmers. Larger "major" workers guard the nest, battle intruders, explore and forage for food while smaller "minor" workers expand the nest and care for the young. workers, when disturbed, carry off the larvae and pupa, which must be fed and tended or they die. In a mature colony, there is usually one queen with 200 to 400 winged individuals produced as swarmers. Workers have strong jaws and readily bite (sharp pinch) when contacted.

Nests are usually established in soft, moist (not wet), decayed wood or sometimes in a current wood cavity or void area in a structure that is perfectly dry. Workers cut galleries in the timber, expanding the nest size for the enlarging colony. Galleries are intermittent, usually excavated with the timber grain ( often times across the cereal) into softer portions of the wood. The walls of the nest are smooth and clean (sandpapered appearance) with shredded sawdust-like timber fragments, like chewed up toothpicks (frass), carried from the nest and deposited outside. These piles of timber fragments, often found beneath special openings (windows) or nest openings, may contain portions of insects, empty seed coats, etc.

Carpenter ants do not eat wood but excavate wood galleries to rear their young ants and carry aphids to plants, placing them on leaves for the manufacture of honey dew. The food diet is of great variety (omnivorous) of both plant and animal origin like plant juices, fresh fruits, insects (living or dead), meats, syrup, honey, jelly, sugar, grease, fat, honey dew (aphid excrement), etc. They feed readily on termites and usually never live with them in a home. Workers are known to forage for food as far as 100 yards from their nest.

Control Measures

The most significant and often most challenging part of carpenter ant control is locating the nest or nests. Once the nest location is discovered, control is very simple and simple. Sometimes more than one colony is present in the structure or on its grounds, so a thorough inspection is extremely important. Steps to a productive inspection include an interview with relatives, inspection indoors, inspection outside and sound detection.

Interview

Often children and adults of the residence know where ants are seen, where large numbers are most prevalent, movement patterns, moisture in the structure, moisture problems of earlier times, if swarmers were seen, location of sawdust-like material in piles, populations outdoors, etc.

Inspection Indoors

Nests can be located in either moist or dry timber. Nonetheless, carpenter ants prefer to nest in moist wood with a moisture content considerable over 15 percent, often caused by rain, leaks, condensation, etc. Structural timber is about 12 to 15 percent moisture. A moisture meter can find wet places to pinpoint possible nest locations. Inspect behind restroom tiles, around tubs, showers, sinks, dishwashers, washing machines, refrigerator drip pans, etc. Check timber affected by moisture from contact with the soil such as steps, porch supports, siding, seepage from plugged drain gutters, chimney flashing, wooden shingle roofs, hollow porch posts, columns, leaking window and door frames, window boxes, crawl spaces, pipes, poor pitch of porch roofs, flat deck porch roofs, under porches, attics, etc. Sometimes, nests are located in dry environments, such as hollow veneer doors, curtain rods, small void areas between the door casing and ceiling, false beams, or under insulating material in attics. Look for damaged timbers, swarmers in spider webs, timber piles indoors, piles of wood debris removed from the colony (pencil sharpener shaving-like), "windows" or small opening to a nest, etc. Gently tap floor joists, etc. with a hammer. A nest cavity gives a hollow ring. A knife blade will penetrate the wood if infested.

Baiting

Some may make use of tiny piles of sugar at two or three feet intervals around the kitchen, restroom, etc. in attempt to determine where the nest is located. Others use drops of honey or corn syrup placed on the back of masking tape. Make observations late at night, following ants back to their nest entrance.

Flushing Agent

A household aerosol spray, containing pyrethrins and piperonyl butoxide, applied directly into cracks, crevices or holes, will excite the ants (repellent action) causing them to come running out informative the presence of their nest in some instances.

Inspection Outdoors

Look for ants traveling from a tree or stump to the structure. They may travel over tree branches or vines touching the roof, electrical and telephone wires, fences with the house, piles of firewood, logs, or railroad ties nearby or hollow living trees with entrance knot holes, etc. Workers are most active at night (midnight), traveling from their nest to a food source following trails but no particular trail leading directly to the nest. They do establish chemical (pheromone) trails.

Sound Detection

An energetic colony may produce a unusual, dry rustling sound ( sometimes loud), much in-line with the crinkling of cellophane. It may be heard in a wall when standing in a room. A listening device, like a stethoscope, may be of assistance when conditions are quiet and outside noises are at a minimum. Even a cat may hear noises in a house the result of ant mandibles (jaws) not from chewing wood or eating food, but as their form of correspondence, particularly when the colony is disturbed.

Prevention

Homeowners should trim all trees and bushes so branches do not touch or come in contact with the house. Correct moisture problems such as leaking roofs, leaking chimney flashing, or plumbing, poorly aired attics or crawl spaces and blocked gutters. Replace rotted or water-damaged timber and eradicate wood to soil contact. Remove dead stumps within 50 feet of the house, if practical, and repair trees with damage at broken limbs, and holes in the trunk. Seal fractures and crevices in the foundation, especially where utility pipes and wiring occur from outside. Be sure to shop firewood off the land far from the house and bring in only enough firewood (first examining it) to be employed quickly . Consider non-organic mulches near the house in heavily infested ant areas. High moisture conditions must be eliminated to help control carpenter ants, prevent future attacks and stop " wood decay" fungus infection.

This journal incorporates pesticide recommendations that are subject to change any time. These testimonials are given just as a guide. It is always the pesticide applicator's responsibility, legally, to read and follow all current label directions for the specific pesticide being used. As a result of never stand still labels and product registration, a few of the suggestions given in this writing may no longer be legal by the time you read them. If any facts in these recommendations disagrees with the label, the recommendation must be dismissed. No endorsement is meant for products mentioned, nor is criticism intended for products not mentioned. The author, The Ohio State University and Ohio State University Extension assume no liability resulting from the application of these suggestions.