J U L Y / A U G 2 0 0 3 N P M A L I B R A R Y U P D A T E Insert this update into the NPMA Pest Management Library, which can be Updatepurchased from the Resource Center. phone: 703-573-8330 fax: 703-573-4116 Common Ants: A Pull-Out Guide for Use in the Field This Library Update is designed to of acrobat ants. Workers are 1/16” to 1/8” assist technicians in identification and in length and are normally brown to control of ants while servicing accounts. black in color. The pedicel, or front joint This update is not designed for of the abdomen has two nodes or instruction in basic ant biology, segments. Looking down on the ant nomenclature of the anatomy of the ant, under hand lens magnification, one pair or to be used as a key. For more detailed of spines is found on the thorax. Various information on those topics, refer to the species of acrobat ants are found Field Guide or other technical materials. throughout the United States. In the field, a great aid to identification Acrobat ants are named for their is the use of a hand lens. Many of these tendency to raise their abdomens in the ants are small and positive identification air when disturbed. As the abdomen is is not easy without a hand lens. This heart shaped and is frequently black and article focuses on common, non-wood- shiny, the acrobat motion is readily destroying ants, including: acrobat, observable. white-footed, odorous house, pavement, Acrobat ants frequently nest in damp pharaoh, Argentine, and red imported mulch areas, under stones, in tree stumps fire ants. As always, when selecting a and under dirt filled porches. It is control method, read, understand, and common to see an Acrobat ant trail follow the label. moving from flower beds up the side of a dirt filled stoop where they might Acrobat Ants: Crematogaster spp. disappear into the stoop and resurface Acrobat ant Acrobat ants are small ants and all inside a structure. workers are roughly the same size These ants prefer honeydew excreted (monomorphic). There are several species from aphids and other insects. They will also feed on small insects and, inside houses, will feed on sweets. Acrobat ants will give off a pungent odor when disturbed. These ants will bite under the right conditions, but are not usually known as a stinging insect. The first step to control is a thorough inspection and tracking activity to a source. Sometimes tracking is best done Left: Acrobat ant N P M A at night. Drying of an area may help. A Odorous House Ant: spot treatment can be performed, and a Tapinoma sessile (Say) L I B R A R Y perimeter treatment of a residual also Odorous house ants are common U P D A T E works well. If ants are getting into a throughout the U.S. and parts of Canada. structure, holes and cracks should be It is perhaps the most challenging type of sealed prior to any application. ant to control, since it readily infests buildings. The common name originates White-Footed Ant: Technomyrmex due to the pungent, coconut-type odor albipes (Fr. Smith) emitted when crushed. The white-footed ant is currently Odorous house ants are small, 1/16”- found in Florida and is slowly spreading 1/8” long, with dark bodies. There is a north. As the name implies, the ant has small node on the pedicel, but it is whitish coloring on its lower legs to the usually hidden. Colonies are not huge, tarsi. The other parts of the with a typical colony numbering not anatomy are dark brownish to more than about 100,000. black. Chances are that the Odorous house ants have a tendency white-footed ant was to nest in structures around pipes, accidentally imported, perhaps cupboards and cabinets, in walls, and through landscaping between insulation and subflooring in materials. The white-footed crawlspaces. Commonly, several nests ant is primarily a nuisance pest may be found in one structure. Recently, and can have a colony size of nine nests were removed from a small up to several million. The house crawlspace. They may also nest average worker ant length is outside under stones or other approximately 1/10” to 1/8”. obstructions, in dirt-filled porches, and White-footed ant White-footed ants can mulch areas. reproduce quickly and in large Odorous house ants will forage great numbers since up to half of distances, with one recent observation the population are fertile being a foraging distance of more than females. The colonies will also 100 feet from the nest; however, typically readily bud into satellite the foraging distance is less. These ants colonies. The preferred food is prefer sweet materials such as honey, honeydew and they will sugar, and baked goods. Some areas of protect some of the insects the country call these ants “sweet ants” that produce honeydew. These or “sugar ants.” They will, however, feed ants have no real defense on fats such as bacon grease found in mechanism, so sheer containers under kitchen sinks. population accounts for its Odorous house ant control requires survival. thorough inspection to find the source. It Odorous house ant These pest ants will may take several trips to find all nests. readily invade structures, Baiting works well, but may not work following lines to gain entry. quickly for full control and may be best They will nest in areas similar to those suited to help find the source. Bait preferred by acrobat ants. preference varies from time to time and Some baits, dusts, granules, and residuals have been effective against this ant. It is best to use several control strategies after reducing moisture, including finding nesting sites and sealing entrances into structures. Odorous house ant N P M A L I B R A R Y U P D A T E Pavement ant Pharaoh ants from colony to colony so several types Pharaoh Ants: Monomorium may be used. Residual sprays and aerosols pharaonis (L.) can help gain control. Remove insulation These small ants are found infested by the ants, as it is impossible to throughout the U.S. These ants go gain full control of the ants in insulation. beyond being a nuisance; they have been implicated in pathogen transfer. The ant Pavement Ants: Tetramorium got its name by the mistaken thought caespitum (L.) that this ant was one of the plagues of Pavement ants are commonly first ancient Egypt. Native to Africa, this ant observed by finding piles of granular has done well in the United States. excavated soil from between cracks on This ant is strikingly small (1/16” for sidewalks and driveways. Pavement ants workers) and is typically light brown or are found in the eastern U.S. and on tan. Workers are monomorphic, and much of the west coast. there are many fertile females in the These ants look similar to odorous nest. While sometimes winged, house ants but can be distinguished from reproductives do not fly and reproduce odorous house ants by a hand lens. The inside the nest. The workers have two pavement ant has groves on the “face” nodes that can be seen using a hand and has two nodes on the pedicel. These lens. ants are also small, 1/16”-1/8” long, with Nesting sites preferred by these ants flying reproductives about three times include walls and ceilings where a the length of the workers. Reproductives suitable humidity and temperature may may emerge any time of the year. The be found. Other common sites include thorax of workers has one pair of spines. electrical boxes, phone boxes and dead Habits of pavement ants are similar to spaces behind decorative wood trim. those of odorous house ants, although Pharaoh ants prefer sweet and fatty pavement ants are opportunistic feeders. foods. It is common to find pharaoh ants These ants will eat insects, honeydew and feeding on baked and fried pastries. sweets, but prefer protein and fats. If At one time, pharaoh ants were very pavement ants invade a structure, they difficult to control. With the advance of usually prefer food spills found near easy baits, control has become much more access to pathways back to nesting sites. achievable. Residual pesticides, Inspection of entry points should repellents, and dusts will have a negative include foundations and weep holes in effect by encouraging the colony to split brick veneer. into several populations that require Baiting using several types of baits control. Baits should be placed adjacent may be effective or at least will aid in to foraging lines of ants. Using properly tracking a nest site. Residual flushes, placed baits will allow effective control aerosols, and dusts may be used without the use of other products. successfully. Above: Pavement ants N P M A Argentine ants Fire Ants: Solenopsis spp. Linepithema humile (Mayr) Fire ants are found primarily in the L I B R A R Y Argentine ants were imported from southern half of the U.S. The fire ant’s U P D A T E South America just over a hundred years bites and stings can be very painful and ago. They are found in the south and even fatal. The most common fire ants in west with spotty infestations in northern the U.S. are the red imported fire ant and states. the southern fire ant. The coloring of the Argentine ant is Fire ant workers are polymorphic, brownish. The workers are about the size meaning that the workers are not all the of pharaoh ants (1/16”).