A little about ants

It’s that time of year again. Everywhere you look, you see them. Little black ants; stinging little red ants; huge ants lumbering along your landscaping and ants so tiny you can’t even tell what color they are. So what to do about it? First things first. You’re here because you have had, or are having what you conceive as a problem with one or more of these ant species and are looking for the most efficient remedy to your problem.

My first recommendation is that you call Venning Pest Control at 813-685-PEST. You can be assured that your ant problems will be handled in a timely, cost effective manner and at the exact, scheduled appointment time of your preference.

Just as all people are not alike, there are many different species of ants. And each one has different characteristics. But all ants also have one thing in common: the continued betterment of their colony. This one attribute makes ants the perfect social being. They do not think for themselves. Their sole purpose is to enrich the colony and ensure survival of the queen(s); so that more ants can be produced.

So let’s take a close look at several common varieties of these little invaders.

Carpenter Ant.

One of the more common ants found outdoors in Florida is the carpenter ant. The Florida carpenter ant complex is comprised of several species, two of which are common around structures: Camponotus floridanus (Buckley) and Camponotus tortuganus (Emery). These bicolored arboreal ants are among the largest ants found in Florida, making them apparent as they forage or fly indoors and out. In a survey of common urban pest ant species covering four metropolitan areas of Florida (Daytona-Orlando, Tampa Bay area, Sarasota-Ft. Myers, and the greater Miami area) in 1995, it was determined that infestations of Florida carpenter ants accounted for approximately 20% of all ant complaints by homeowners.

During the flight season, carpenter ants can often be found in alarming numbers. Sometimes homeowners are concerned about damage to the structural integrity of their homes, which they sometimes incorrectly learn, is caused by Florida carpenter ants. However, unlike the wood-damaging black carpenter ant, Camponotus pennsylvanicus (DeGreer), found in Florida’s panhandle and a few other western U.S. species, Florida carpenter ants seek either existing voids in which to nest or excavate only soft materials such as rotten or pithy wood and Styrofoam. Other concerns are that these ants sting (they do not) and bite (they do).

Description

The antennae of Florida carpenter ants are 12-segmented, with the terminal segment being slightly elongated and bullet-shaped, and without a club. There is a circular ring of hair at the end of the abdomen. The waist consists of one petiolar segment. The antennal scape is flattened basally and broad throughout. Workers vary in size, ranging from 5.5 to 11 mm in length. Smaller workers are called minors while larger workers are called majors. Winged females (alates) are the largest caste reaching up to 20 mm in length. There is no sting, but workers can bite and spray formic acid for defense. The thorax is evenly convex; a key characteristic of carpenter ants. The thorax and head are ash brown to rusty-orange and the gaster is black. Body hairs are abundant, long, and golden. Male reproductives are much smaller than queens with proportionally smaller heads and larger wings. Specific characters for C. floridanus include legs and antennal scapes with numerous long, coarse brown to golden erect hairs, shorter than those on the body. For C. tortuganus, specific characters include a major worker with head longer than broad; tibia of all legs and antennal scapes without erect hairs; and thinner than C. floridanus and paler with less color contrast.

Life Cycle

As with all members of the Order Hymenoptera, carpenter ants develop by complete metamorphosis, going through stages of the egg, larva, pupa, and adult worker or reproductive. Larvae are maggot-like, and pupae reside in silk cocoons and are often mistaken for eggs. Winged reproductives fly in the evening or night during the rainy season (May through November). Typically, a single queen, fertilized by a smaller short-lived male, will start a new colony, caring for her first brood of larvae until they develop into workers, which then begin to forage for food. Workers then care for the queen and ensuing brood. The colony will continue to grow and populations may reach several thousand workers. When the colony is two to five years old, depending on environmental conditions, new winged reproductives, or alates, will usually be sent out. Alates (winged reproductives) are observed from spring to fall, depending on the area and environmental conditions. Queenless satellite nests are often founded within 20 to 100 feet of a mature nest. Proximity of nests can lead to fighting among neighboring colonies.

Pest Status

Carpenter ants are one of the most common indoor insect pests in Florida. Alarmed homeowners often see these ants foraging (especially at night) and either attempt to control the ants with spray insecticides or call their local pest control operator (PCO). PCOs report going to innumerable homes to speak with frantic homeowners who have failed to control foraging or flying carpenter ants. Many PCOs and seasoned entomologists have resigned to failure after not being able to treat hidden nesting sites, sometimes after years of trying! An experienced pest control operator, or a determined homeowner, can usually follow a trail of ants back to the ants’ nesting site and treat it (see Management below).

Complaints are numerous during the spring swarm season, usually between April and June, when winged reproductives are often found in homes in such places as along window ledges and near sliding glass doors. It is common to mistake winged ants for winged termites.

Foraging and Feeding

Florida carpenter ants tend to forage at night. The peak foraging hours are just before sunset until two hours after sunset, then again around dawn. Foraging proceeds in very loosely defined trails or by individual ants that seem to wander aimlessly. These ants have a fondness for sweets and can be found in campgrounds near soda machines and other areas where sweets are readily accessible. Similarly, they are fond of sweet floral nectars and honeydews produced by sucking insects, especially aphids, scales, and mealybugs. Trees and shrubs which are infested with these honeydew-producing insects or produce nectars will have ants wandering in all directions over leaf surfaces, up and down the stems and trunk. Carpenter ants will also seek out other insects, both living and dead, for food.

Carpenter ants foraging in homes can be in search of sweets or moisture, or even new nesting sites, especially in kitchens and bathrooms, or other rooms that have water leaks from plumbing or leaks around doors and windows. Otherwise, they might simply be trailing from an interior nest to an exterior food source.

Carpenter ants, like many other ants, will trail along wires or cables that may be attached to homes and serve frequently as access routes for them to enter attics and other above ground areas. Tall trees touching structures cause “bridges” which provide foraging access into buildings.

Nest Sites

Carpenter ants seem to prefer voids for nesting which have these characteristics:

  • Close to moisture and food sources
  • Safe from predators such as birds and lizards
  • Safe from flooding, heat, and other environmental stresses
  • Easily accessible (for them, but inaccessible for their predators!)

They will hollow out wood softened by moisture and/or fungi to create nests. This wood can be in tree stumps or dead tree limbs, or in any part of a structure having damaged wood. They will not excavate nesting galleries in sound wood. Bits of debris, called frass, are often ejected from nesting sites. Frass consists of bits of excavated materials and pieces of dead insects, including carpenter ants.

Common exterior nesting sites include old drywood termite galleries and wooden objects that have had previous damage from other organisms including insects or fungi; rotting tree stumps and tree holes or crotches between limbs; under old leaf petioles in palms, especially in and around the inflorescence of palms; under bark, in roots of trees, especially citrus trees; in old wooden fences, sheds, old wooden decks, bamboo poles (even thin or short pieces) or tree supports, debris of almost any kind, coconuts left on the ground, under mulch, inside logs or wooden borders in gardens, railroad ties, old shoes, in voids in ceramic or concrete decorations, walls or support pillars, in expansion joints either not filled in or filled with rubbery materials, under stones, in home exterior coverings, especially wood panels, and so on.

Common interior nesting sites include wall voids (especially walls that have moisture seepage), under attic insulation and usually near the eaves where they are very difficult to reach, under bath tubs, very common under windows and door frames which have moisture intrusion from rain or sprinklers, around skylights, in boxes or paper bags, in closets which are not often used, under appliances, especially dish washers, in flat roofs (one of the most difficult problems due to lack of adequate access), behind wood panels, in wood furniture, cracks in floors, under bathroom fixtures, and many other places! Carpenter ants are sometimes found in electrical boxes, such as fuse, meter, or timer boxes or appliances. Unusual nest sites have included a computer printer, a radio, and a pay phone. Also check hollow supports of patio screens or voids in patio ceilings.

Management

Direct treatment of nesting sites is recommended because these sites harbor the brood, queen, and a bulk of the workers and winged reproductives, however, finding the nest sites can be difficult. A small amount of insecticidal dust or spray applied directly to the nest area is usually successful. Excessive treatment can become repellent, actually causing the nest to move to another location if the dust or spray is applied near-to but not directly on the nest.

Observation of foragers entering voids is the best means of finding the nest. Watch for trailing ants at their peak nocturnal foraging hours and follow them. Look for areas of higher ant population density indicating closer proximity to the nest. Placing a few drops of sugar water, honey or dead insects along a trail can cause other nest mates to be recruited to the area. Try to follow the foragers back to the nest and then treat the nest.

There are many situations in which the nest is not accessible, or cannot be found. In those cases use one of the baits made for carpenter ants, and follow the label directions. Usually baits are simply placed along the trail and foragers bring the toxic baits back to the nest where food and toxicant are shared via trophallaxis (communal food sharing). Carpenter ants are finicky eaters and tend not to recruit in large numbers to any food source thus decreasing the efficacy of insecticidal baits. Residual sprays in foraging areas can also be helpful. Be sure to spray areas where ants are feeding, such as trees and shrubs. A systemic insecticide can help control aphids and other honeydew producers to reduce food for the carpenter ants.

Eliminate “bridges” caused by trees and shrubs touching house exteriors. If wires or power cables are being used as bridges, it may be possible to have a professional treat the wires or areas where the wires attach to the structure. There are a number of “pest barrier” substances available that are sticky and can be used on tree trunks and other places to stop ants from passing. Caulking exterior openings and weather stripping may also aid in control. Read and follow label instructions and precautions before using any insecticide.

Red Imported Fire Ant.

Two species of fire ants are found in Florida. Most notorious is Solenopsis invicta Buren, the red imported fire ant (RIFA), followed by the much less common S. geminata (Fabricius), the tropical or native fire ant. Other more common U.S. members of this genus include S. xyloni McCook, the southern fire ant; S. aurea Wheeler, found in western states; and S. richteri Forel, the black imported fire ant, confined to northeastern Mississippi and northwestern Alabama. In the U.S., RIFA was first introduced from Brazil into either Mobile, Alabama, or Pensacola, Florida, between 1933 and 1945. However, the RIFA infests Puerto Rico, and all or part of many southern and western states from Maryland to southern California.

As of August 2008, the following U.S. states have established infestations: Alabama, Arkansas, California, Florida, Georgia, Louisiana, Maryland, Mississippi, New Mexico, North Carolina, South Carolina, Oklahoma, Tennessee, Texas, and Virginia. The infestations in Maryland and Virginia are sparse and still not formally recognized on USDA maps. Small, localized populations exist in the San Francisco Bay area.

Identification

The pedicel, or “waist” in the RIFA consists of two segments. Workers consist of many sizes between 1/8 to 1/4 in. The mandible has four distinct teeth and the antennae are 10-segmented, ending in a two-segmented club. Body color is usually red to brown in color with a black gaster.

Mounds are built of soil and are seldom larger than 18” in diameter. When a mound is disturbed, ants emerge aggressively to bite and sting the intruder. A white pustule usually appears the next day at the site of the sting.

Biology and Life Cycle

The lifespan of RIFA workers depends on their size. Minor workers may live 30 to 60 days, media workers 60 to 90 days, major workers 90 to 180 days, and queens may live two to six years. Complete lifecycle from egg to adult takes between 22 and 38 days.

Mating flights are the primary means of colony propagation, secondarily, budding can occur in which a portion of a colony becomes an autonomous unit. After the colony reaches one year of age, reproductive alates are produced. Six to eight mating flights consisting of up to 4,500 alates each occur between the spring and fall. Mating flights usually occur midday on a warm (>74°F/24°C), sunny day following rain. Mating occurs during flight and the males die soon after mating with females. In the southern United States, as many as 97,000 queens may be produced per acre of infested land per year. Alates are often attracted to swimming pools where homeowners can find thousands of winged ants trapped on the water’s surface.

After mating flights occur, it is common to find newly-mated queens clustered together under shelter. This clustering and the cooperation of the newly-mated queens aid in establishing a colony. However, as the colony grows all but one queen will be killed, except in the instance of multiple queen colonies.

The first group of workers to emerge are characteristically small due to the limitations in nutrients that the queen provides. These workers, termed “minims,” burrow out of the chamber and begin foraging for food to feed the queen and new larvae. The minims also begin construction of the mound. Within one month, larger workers are being produced and the mound is growing in size. By six months the colony has reached several thousand workers and the mound can be seen in a field or lawn. Colonies of this size generally contain a few large workers (major workers), many medium sized workers (media workers), and a majority of small workers (minor workers). The three types of workers are all sterile females and serve to perform tasks necessary to maintain the colony. The queen is the single producer of eggs and is capable of producing as many as 1,500 eggs per day. Mature RIFA colonies may contain as many as 240,000 workers with a typical colony consisting of 80,000 workers.

The diet of foraging workers consists of dead animals, including insects, earthworms, and vertebrates. Workers also collect honeydew and will forage for sweets, proteins, and fats in homes. They are sometimes attracted to piles of dirty laundry. Larvae are fed only a liquid diet until they reach the third instar. When the larvae reach the fourth instar, they are able to digest solid foods. Worker ants will bring solid food rich in protein and deposit it in a depression in front of the mouth of the larvae. The larvae will secrete digestive enzymes that break down the solid food and regurgitate it back to worker ants. The queen is fed some of the digested protein to support egg production. As long as food is plentiful, egg production is at its maximum.

The sting of the RIFA possesses venom of an alkaloid nature, which exhibits potent necrotoxic activity. Approximately 95% of the venom is composed of these alkaloids, which are responsible for both the pain and white pustule that appears approximately one day after the sting occurs. The remainder of the venom contains an aqueous solution of proteins, peptides, and other small molecules that produce the allergic reaction in hypersensitive individuals. Worker fire ants will attach to the skin using their mandibles and will subsequently lower the tip of the gaster to inject the stinger into the victim. Thus, fire ants both bite and sting, but only the sting is responsible for the pain and pustule.

Management

Fire ants frequently invade home lawns, school yards, athletic fields, golf courses, parks and other recreational areas. Additionally, electrical equipment and utility housing, home gardens, compost piles, mulched flowerbeds, pavement cracks, and the perimeter of bodies of water must all be considered when choosing a method of control.

Two approaches can be taken to effectively manage imported fire ants. Single mound treatments or area-wide broadcast applications usually manage red imported fire ant populations.

Individual Mound Treatments

There are many methods of treating individual mounds. The main advantage to this process is that there are so many choices available to homeowners and pest control operators, though few may actually eliminate the colony. However, the largest disadvantage is that individual mounds must each be located in order to be treated. Individual mound treatments are most beneficial when there are native ants in the same area as imported fire ants. Re-infestation of any treated area, whether by broadcast treatment or individual mound treatment may occur. Six different methods of individual mound treatment are available.

  1. Mound Drenches. Large volumes of liquid toxic to ants are poured over a mound. Liquids can range from using several gallons of hot water to insecticides mixed with several gallons of water. This method may not reach the queen, who may be deep in the nest, thus preventing colony elimination.
  2. Surface Dusts. This method is very similar to mound drenches. A dust or granular insecticide is applied over the top of the mound and then watered into the soil.
  3. Mound Injections. The use of insecticides that may be pressurized and injected into a mound. Often this method is more expensive, but more effective, than mound drenches. However, more time may be required for this method and leakage of the insecticide by the equipment may be hazardous to the handler. Again, the queen may not be affected and thus reinfestation may occur.
  4. Baits. Baits can be used for both individual mound and broadcast applications. A small amount of the bait is sprinkled around the mound and the ants then forage and bring the bait back to the colony to feed on. This method is slower acting, but more effective then drenching, dusting, or fumigating a mound because the workers will feed the bait to the queen and brood, thus gaining effective control of the colony.
  5. Mechanical Control. Certain mechanical and electrical devices are on the market for controlling fire ants, but the efficacy has not been documented (Vinson and Sorenson 1986).
  6. Home Remedies. Many homeowners will choose to pour boiling water or ignite flammable liquids over a mound. While these methods may bring about control, they are not recommended because they are both very dangerous, not only to humans, but also to the environment.

Broadcast Treatments

Presently, there are only a few products available for broadcast treatment of large areas. These products are either granular insecticides or baits composed of soybean oil and toxicant on a corn grit carrier. These granules are broadcast over a large area and, upon discovery by the ants, are carried to the colony and fed to nest mates and the queen. This is a very effective treatment but does present problems because (1) some of the bait may be dropped where the ants may not find it, (2) some colonies are well fed so do not feed upon the bait, (3) some baits are light sensitive (as with hydramethylnon) and may inactivate before discovery by the ants, and (4) the baits are not specific to the imported fire ant.

Pharaoh Ant.

The ant, Monomorium pharaonis (Linnaeus), is commonly known as the Pharaoh ant. The name possibly arises from the mistaken tradition that it was one of the plagues of ancient Egypt. This ant is distributed worldwide, is one of the more common household ants, and carries the dubious distinction of being the most difficult household ant to control.

Distribution

Monomorium pharaonis (Linnaeus) has been carried by commerce to all inhabited regions of the earth. This ant, which is probably a native of Africa, does not nest outdoors except in southern latitudes and has been able to adapt to field conditions in southern Florida. In colder climates, it has become established in heated buildings.

Description

The workers of Monomorium pharaonis (L.) while monomorphic (same size), do vary slightly in length and are approximately 1.5 to 2 mm long. The antennae have 12 segments with each segment of the 3-segmented antennal clubs increasing in size toward the apex of the club. The prothorax has subangular shoulders, and the thorax has a well- defined mesoepinotal impression. Erect hairs are sparse on the body, and body pubescence is sparse and closely appresssed. The head, thorax, petiole and postpetiole (the petiole, or the petiole and postpetiole, in ants is also called the pedicel) are densely (but weakly) punctulate, dull, or subopaque. The clypeus, gaster, and mandibles are shiny. The body color ranges from yellowish or light brown to red, with the abdomen often darker to blackish. A stinger is present but is rarely exerted.

Biology and Nesting Habits

The Pharaoh ant colony consists of queens, males, workers, and immature stages (eggs, larvae, pre- pupae, and pupae). Nesting occurs in inaccessible warm (80 to 86°F), humid (80%) areas near sources of food and/or water, such as in wall voids. The size of the colony tends to be large but can vary from a few dozen to several thousand or even several hundred thousand individuals. Approximately 38 days are required for development of workers from egg to adult.

Mating takes place in the nest, and no swarms are known to occur. Males and queens usually take 42 days to develop from egg to adult. The males are the same size as the workers (2 mm), are black in color and have straight, not elbowed, antennae. Males are not often found in the colony. The queens are about 4 mm long and are slightly darker than the workers. Queens can produce 400 or more eggs in batches of 10 to 12. Queens can live four to 12 months, while males die within three to five weeks after mating.

Part of the success and persistence of this ant undoubtedly relates to the budding or splitting habits of the colonies. Numerous daughter colonies are produced from the mother colony when a queen and a few workers break off and establish a new colony. Even in the absence of a queen, workers can develop a queen from the brood which is transported from the mother country. In large colonies there may be as many as several hundred reproductive females.

Economic Importance

The Pharaoh ant is a major indoor pest in the United States. The ant has the ability to survive most conventional household pest control treatments and to establish colonies throughout a building. More than just the food it consumes or spoils, this ant is considered a serious pest simply due to its ability for “getting into things.” Pharaoh ants are reported to have even penetrated the security of recombinant DNA laboratories.

In some areas, this ant has become a major pest of residences, commercial bakeries, factories, office buildings, apartments, and hospitals or other areas where food is handled. Infestations in hospitals have become a chronic problem in Europe and the United States. In ant- infested hospitals, burn victims and newborns are subjected to increased risk because the Pharaoh ant can transmit over a dozen pathogenic pathogens such as Salmonella spp., Staphylococcus spp., and Streptococcus spp.

This ant infests almost all areas of a building where food is available and infests many areas where food is not commonly found. Pharaoh ants have a wide preference in the types of food consumed. In infested areas, if sweet, fatty, or oily foods are left uncovered for only a short period of time, one can likely find a trail of Pharaoh ants to the food. As a consequence, they cause much food to be discarded due to contamination.

Survey and Detection

Workers of the Pharaoh ant can often be observed on their feeding trails, often using wiring or hot water pipes to travel through walls and between floors. Once a worker has located a food source, it lays a chemical trail from the food to the nest. These ants are attracted to sweet and fatty foods, which may be used to determine their presence. Pharaoh ants will nest in the oddest places, such as between sheets of stationary, layers of bed linen and clothes, in appliances, or even piles of trash.

Management

Control of Pharaoh ants is difficult, due to their nesting in inaccessible areas. Treatment must be thorough and complete at all nesting sites, as well as the foraging area. Thus, treatment must include walls, ceilings, floor voids, and electrical wall outlets. Baits are now the preferred method of control for Pharaoh ants and several baits (insecticides) are labeled for indoor ant control. A Pharaoh ant infestation of a multifamily building requires treatment of the entire building to control the infestation. Ants nesting on the outside may be controlled by also using a perimeter barrier treatment.

Baits cannot be placed in just any location and be expected to work. Pharaoh ant trails and their resources (both food and water) must be located for proper placement of baits and effective control. Non-repellent baits (such as boric acid, hydramethylon or sulfonamide) should be used, as repellent baits can worsen the situation by causing the colony to fracture and bud. As a result, ant activity will briefly diminish as the new colonies establish themselves, then again become a problem as the foragers resume activity.

In addition, insect growth regulators (IGRs) are marketed for indoor control of Pharaoh ants. The IGR is used as a bait, and ants must be allowed to transport the bait back to their nests. The IGR prevents the production of worker ants and sterilizes the queen. Therefore, it is necessary to allow up to several weeks or months (depending on the size of the colonies or number of colonies) for ants to die naturally with the use of IGRs.

Crazy Ant.

Beginning about 2000, reports have escalated of a golden-brown to reddish-brown “crazy ant” infesting properties in and around West Palm Beach, Florida. Thick foraging trails with thousands of ants occur along sidewalks, around buildings, and on trees and shrubs. Pest control operators using liquid and/or granular broad-range insecticides appeared unable to control this nuisance ant.

Description

Nylanderia pubens is part of a group of ants referred to as “crazy ants” due to their quick and erratic movements. The Caribbean crazy ant is a medium-small (2.6 to 3 mm long), monomorphic, golden-brown to reddish-brown ant. The body surface is smooth and glossy, and covered with dense pubescence (hairs). After feeding, the ant’s gaster (rear portion of the abdomen) will appear to be striped due to stretching of the light-colored membrane connecting segments of the gaster. Antennae have 12 segments with no club. The antennal scape is nearly twice the width of the head. This ant has one petiolar segment and does not sting.

Life Cycle

Little is known of the N. pubens life cycle. During a cold winter morning in West Palm Beach, Florida, one de-alate queen and several winged males were observed in a soil nest under a log, but the entire colony was not examined. In Paratrechina longicornis (Latreille), a related species, a single colony may have eight to 40 queens. It is assumed from observations at West Palm Beach that colonies have several hundred thousand individuals and appear to be polydomous (nesting in several locations) and polygamous (multiple queens).

Foraging and Feeding

Trails were not observed on a cold morning (approximately 48°F), but as the temperature increased (60°F), ants foraged from nest sites. Although thick trails were seen along sidewalks, trees, shrubs, and structures, no feeding activity was observed. It is assumed that as other Nylanderia species, N. pubens will scavenge for food, feed on dead insects, and tend honeydew producers. Sweet liquid ant bait was fed upon when placed directly on an active trail, but recruitment to the bait was not observed.

Nest Sites

Ants were observed emerging from soffits, between railroad ties used in landscaping, under wooden debris, underground electrical conduits, and cracks in cement. They will probably nest in numerous locations.

Pest Status

Most of the reports of N. pubens infestations have come from pest control operators in and around the southeast Florida “Treasure Coast” from West Palm Beach north to Port St. Lucie, where trails consisting of thousands of ants have been observed along sidewalks, buildings, and gardens, causing property owners to complain. Sprays and granular applications of residual insecticides seemingly have had little or no effect in controlling this non-biting nuisance ant.

Management

Until research is done on management techniques, we recommend the use of contact residual insecticides sprayed along active trails and nest sites to reduce ant populations, followed a few days later by sweet ant baits placed at numerous locations along trails and frequently replaced with fresh bait. Always follow label directions.

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