[Ant Control] Teaching Ant ID

Of all the insects and other arthropods encountered by service professionals, ants are one of the most difficult for the non-entomologist to identify. Flies may be the hardest to ID, but ants are a close second. In working with service professionals in the Midwest this past summer, I asked each how often he or she encountered the odorous house ant — a species that is rapidly becoming the predominant pest ant in many parts of the Midwest and Northeast. Most replied they didn’t see them often or "not at all." But during the course of the workday, I found odorous house ants repeatedly outside these service professionals’ customers’ homes and businesses. I also found the expected pavement ant and also field ants, carpenter ants, big headed ants and even one trail of little black ants.

The fault was not totally that of these individuals because they were trained only to identify the few historically prevalent pest ant species in their respective town or city. They could identify the carpenter ant and pavement ant but assumed any small, dark brown ant was a pavement ant without looking closer. An all-too-common mistake, the "ant is an ant is an ant" philosophy leads to persistent infestations and customer complaints.

Ant identification is not that difficult to learn, but it does take effort and repetition. Fortunately for service professionals in most of the United States, five or fewer species need to be learned as identifiable on sight. In Florida and parts of the Gulf Coast, however, a professional may encounter a dozen or more types or species of ants invading a home. I once found nine colonies of seven different ant species either crawling on or nesting next to the foundation of a home in Ft. Lauderdale, Fla.

Due to the ability of many pest ant species to "hitchhike" in items, especially potted plants, a professional needs training in how to identify ants using references, such as the PCT Field Guide to Structure-Infesting Ants or the NPCA Field Guide to Structural Pests. Once in Tulsa, Okla., I found that an ant problem in a recycling center warehouse was actually crazy ants carried in bales of crushed plastic milk jugs. At other times, I have seen ghost ants in apartments in Chicago and crazy ants in zoos and atriums in northern states. Recently in one zoo along the Atlantic seaboard, I found crazy ants, white-footed ants, pavement ants and big headed ants in just two buildings. A more thorough inspection may have uncovered other species.

A key point when teaching ant ID is to impress upon trainees to not assume anything; each ant needs to be carefully identified. If it doesn’t fit the normal key pest species in the area, then what is it? Is it a species common to the area but rarely seen invading buildings? Is it a species possibly imported from another region of the country? Or is it a species that is considered structure-invading but not often seen inside?

About 10 years ago, a sample of ants was sent to me that was collected from a bath trap in a home in north Texas. A county extension agent identified the ants for the pest control company as carpenter ants. I knew immediately they were not carpenter ants because the specimens had no eyes and had two nodes in the pedicel. Carpenter ants have only one node and have well-developed eyes. The ant in question was actually a new world legionary ant, Labidus coecus (Latreille). This species lives its life underground, which is why it is blind. It occasionally nests beneath homes and may excavate soil into bath traps, sometimes filling the space in the trap.

No wonder the pest control company had trouble controlling the ant — they were advised to treat for carpenter ants! Even trained persons, such as county extension agents, can misidentify ants when they don’t take the time to carefully examine the identifying characters of the specimens involved.

THE REAL DEAL. The best way to teach ant identification is with the use of actual specimens. Fortunately, ants are easy to collect and store — a single vial of 70 percent isopropyl alcohol can hold hundreds of small ant species and dozens of a larger ant, such as carpenter ants. An aspirator can be used in the field to collect ants and these then are transferred immediately into a vial of alcohol. I have found, however, that when encountering an ant species you wish to collect, it is best to transfer soil in which they are living into a Ziploc® bag or brush as many ants as possible from stones, bricks, etc., into a Ziploc bag. These ants can then be transported back to the office where individual ants can be leisurely transferred into vials of alcohol.

At the office, a little of the collected soil/material can be poured at a time into a shallow pan and ants can be removed using an aspirator or a pair of flexible "larval" forceps. Ants that are particularly fast moving can be "subdued" by cooling the sample in a refrigerator prior to transferring specimens to a vial.

Collect as many specimens of a particular species as possible when you have the chance. Collecting hundreds of ants can be tedious work, but the good news is it only needs to be done once for each species. I have collected a "teaching collection" of more than two dozen pest ant species that will last me decades. I have found, though, that absolute (99 percent) alcohol works better than 70 percent rubbing alcohol for long-term storage of ants in vials. Vials should also be stored in dark, cool areas for increased longevity.

If you have a small or regional company, you may want to establish a relationship with other such companies in other areas of the country. You can then exchange vials of ant species found in your area for pest ant species found in other parts of the country. Having the actual "bodies" of as many pest ant species as possible improves the learning of ant identification through comparison. Check the "Who’s Who" directory of NPMA and write to companies in other parts of the country to see if they will work with you on this meaningful project.

Another useful teaching tool is video of ants in the field. Collecting such video will require a video camera with good macro-optics, although decent footage can be acquired with a less expensive camera. The purpose in using video is to show trainees how different species look from the top side and how they move in trails. By comparing different species as they will be seen in the field, professionals can usually learn to identify some of the more common species by sight without the need for a magnifier. However, it is always a good idea to teach professionals to confirm their visual ID by examining a specimen under magnification.

Where possible, having samples of live ants in petri dishes available is useful. The well-equipped training room may also have a camera that attaches to a television monitor to further magnify ants for demonstration purposes.

USING ANTS TO TRAIN. Ant specimens can be handled one of two ways in the classroom — wet or dry. If used directly from alcohol in vials, one will need shallow petri dishes, filter paper and tools to manipulate the ants (forceps, pointed tools). Time must be taken by trainees to remove ants, work with them and then return them back into vials.

An easier way for ants (and other small insects) to be used in the classroom is to mount specimens into drymounts. Creating drymounts is not difficult but does take time. I use 2- by 2-inch coin mounts and rubber o-rings to make light, easily handled and long-lasting insect mounts for the classroom (see photo on page 72). Obtain the coin mounts from any coin-collecting store. Index cards can be cut into 2- by 2-inch squares to serve as the inside backing of the mount. The proper size o-ring (see the plumbing supply section at a hardware store, Home Depot or Lowe’s, for example) is then glued in the center of the card. A single ant removed from alcohol (or freshly killed) is dried by touching to filter paper and is then glued on its side to the card in the middle of the o-ring. The glue spots must be tiny, otherwise the ant becomes buried in glue. Use a pointed tool to make glue spots. The legs and antennae of the ant need to be manipulated and possibly secured into place using dots of glue. It is important that all key identifying characters be visible. If you wish, ants can be mounted with the top facing upward, rather than the side.

All of this work must be done under a microscope and it can be tedious. I’ve found, however, a few hours effort provides me with numerous drymounts I can use in teaching for many years to come. I have drymounts of ants, termites and other insects I have used for close to 20 years.

Good magnifying devices need to be used in training and professionals should be equipped with a 30X magnifying device for field identifications. A nice lighted scope is available for about $10 at Radio Shack. Other magnifiers may be found by shopping on the Internet, e.g., BioQuip Products (www.bioquip.com) or UPMA Labs (www.upmalabs.com). Ideally, classroom training should be done using a good stereomicroscope as well as the magnifiers that will be used in the field. Trainees can see the ants under the excellent magnification of a microscope then compare the key identifying characters on specimens using their own, more affordable magnifiers.

TEACHING NEW HIRES. Those just entering the industry generally have no training in insect identification so it is important they be given a good foundation in basic insect anatomy. New service professionals should start out learning the few basic ant species they will most commonly encounter. Additional species can be added later in more advanced classes.

One on one, a trainer can use books to teach ant anatomy and identifying characters. For groups, slides or PowerPoint presentations can be used. Once trainees have been shown photos of ants and their identifying characters pointed out, retention of this knowledge is greatly improved when they look at actual specimens as described earlier. Still, other exercises can be used to create repetition and, thus, better retention (see related story on page 63).

New service professionals should always be encouraged to bring ants they are not sure of back to the office for confirmation of an identification. For example, if a service professional misidentifies Pharaoh ants, the infestation may be treated with residuals rather than baits thus possibly creating a more extensive infestation. New employees need to understand it’s OK to not know something — it’s part of the learning process.

TEACHING THE EXPERIENCED. I’ve found the best way to teach experienced professionals is to let them find out how much they don’t know. That often motivates them to focus on learning what they miss on an exercise. For such training, drymounts and/or specimens in alcohol are used. Occasionally, live specimens can be used. Magnifiers need to be available for all to use.

The workshop can be divided into groups or individuals can work alone to identify numbered, unlabeled specimens you have prepared. Depending on the time available, the exercise includes 10 to 30 or more specimens. I like to include multiple mounts of the same ant species. Participants are asked to identify all the specimens. I find it beneficial to have the participants identify the specimens without reference materials, collect those answer sheets, then let them re-examine the ants using references. This process shows them how much they may have forgotten (or don’t know) and reinforces the use of a reference book or guide.

One technique I’ve used in the past is to have 10 drymounts of larger ants and have each participant identify which of them are carpenter ants. I intentionally made it difficult by putting both large and smaller specimens of carpenter ants together with close "cousins" such as field ants (Formica spp.). Included are different colored species of carpenter ants and ants that are clearly not carpenter ants — to those who are paying attention. For example, I include harvester ants, dealated fire ant queens and even leaf cutter ants. The purpose of comparing so many different ants is to teach the service professional what is important is NOT the color or size, rather it is the number of nodes, shape of the thorax, number of antennal segments, etc. Too often, the non-entomologist gets bogged down with the general appearance of an ant and not the key parts that identify one ant as that of a particular species.

This technique works also with smaller ants. To teach the identification of the Argentine ant, the 10 drymounts could have three to six specimens of actual Argentine workers and then include other small dark brown or black species, such as the odorous house ant, pavement ant, cornfield ant or white-footed ant.

SUMMARY. Planning is important for successful learning of pest ant identification. Putting the time in to acquiring training collections of different pest ant species is well worth the effort. Seeing the actual ant helps service professionals really learn identifying characters of different species. Thought should be given to each training class to improve repetition and thus long-term repetition. Regular workshops, e.g., annually or more often, also improve long-term retention.

The author is a board certified entomologist, a registered sanitarian and manager of technical services for Terminix International, Memphis, Tenn. He can be reached via e-mail at shedges@pctonline.com.