Among the insect pests that are a mainstay of the modern pest management professional’s business, ants, as a whole, rank at the top of the list as being a complex, diverse and a downright intriguing (or perhaps frustrating, depending on how you look at things) pest.
It is now old news that ants have "taken over" as the new No. 1 pest in the pest control business. From the standpoint of behavior and biology, ants are rather highly evolved as far as insects go. According to many surveys throughout the past few years, ants passed cockroaches in pest status and revenue generation for pest management professionals. Some say the roaches will eventually come back and some say not. As a biologist, I’m putting my money on the roaches with 350 million years of evolutionary fitness under their midguts.
THE COMPLEXITY OF ANTS. Ants are at the opposite end of the evolutionary scale of cockroaches and are considered by entomologists to be highly specialized in comparison to other pest complexes. They undergo complete metamorphosis (egg-larvae-pupae-adult), having life stages that are well adapted for a variety of tasks. Furthermore, ants are social insects. There are three major adult castes — workers (females), adult males and reproductive females. With these adult stages and the brood (eggs-larvae-pupae), individual ants work together for the fitness of the entire colony. Many species are specialized to conduct different colony functions within a given life stage, e.g., adult workers can specialize in food gathering, food relaying, food storage, larval feeding (nurses), nest defense and sanitation. Ant colonies have either a single queen or multiple queens, depending on the species. Queens are specialized to do little more than produce eggs for colony growth.
Ants have developed highly elaborate means of chemical communication where dozens of messages or behaviors have been described and documented. These chemicals are know as "pheromones" and can convey all sorts of information. By using these pheromones, each worker ant is potentially capable of communicating with other worker ants of the same colony and can also use chemical compounds to differentiate among members of a rival colony.
Ants are generally opportunistic feeders, capable of deriving energy from a variety of food sources, however some of their feeding strategies are also highly evolved and specialized. Some ants are farmers, deriving energy from honeydew (a liquid by-product of aphids resulting from their feeding on plant juices). The ants in turn protect the aphids from being attacked by other predator insects. Other ant species are true scavengers, searching for dead and dying insects and other animals on the ground. These food sources are then sectioned into small movable pieces and taken back to the nest where they will be further digested and distributed among the entire colony.
While it is true that adult worker ants can only ingest liquids, they certainly forage for solids particles that will be carried back to the nest. Ants will either remove the liquid portion of these "solid" particles or distribute them to the larvae that will further process them. Once the larvae have digested the solid particles, the resulting liquefied nourishment can be distributed among colony members via other workers. This is in part why granular baits that are laden with oils can work well to control some species of ants whereas liquid baits, which are actually consumed by the foraging workers, will work well in other situations.
In short, ants are no push over when it comes to survival.
Ants achieve pest status, as all other pests do, by infringing upon human interests, i.e., food stores, homes, the favorite oak tree in the yard, etc. They also achieve strength in numbers with their (sometimes) huge nests. Depending on what species you are dealing with, colonies can have hundreds to thousands to tens of thousands of individual members and well beyond. Ants have exploited almost every imaginable niche on the planet. Think about this interesting "bug fact" — ants are so abundant in many parts of Central and South American rain forests that if all the ants were weighed against all of other insects put together, the ants would weigh just as much.
Learning proper ant control in a given area can take time to get used to the key pest species in your area and their foraging and nesting preferences. Just when you think you have it figured out, the ants come back with a surprise.
Following are a few main items to remember when thinking about capitalizing on the ant complaints in your area or when training technicians about proper ant control in general. The points here are fundamental, but will hopefully remind the experienced pest management professional just how much there is to know and learn about proper ant treatment. If you already aren’t involved with ant services, perhaps you should be — they are currently at the top of the list of "money bugs" in the business.
KNOW YOUR ENEMY. There are 10,000 species of ants throughout the world, of which about 700 of these can be found in the United States. Only about 40 of these 700 have reached pest status by regularly infesting homes and other buildings. Likely you will not have to deal with all of these species within a given geographical area — depending on what part of the country you are located.
Of these roughly 40 species, the following are arguably the top five when we take into consideration the entire United States: Argentine ants, fire ants (complex), carpenter ants (complex), Pharaoh ants and pavement ants. Depending on what part of the country you are from, there are many other species to consider, many that are (or are gaining) notoriety as a pest species.
The first thing that must be accomplished to provide good ant service is proper pest identification, the cornerstone of all good treatment programs. This point cannot be stressed enough. Secondly, understanding any specifics about the nesting behavior, biology, foraging behavior and feeding preferences of the ants you are working on will ultimately help you choose and properly apply the right "stuff" to obtain control. There are excellent sources of ant information to help you identify and learn about pest species in your area. Talking with other pest management professionals or entomologists in your area, consulting with local university extension personnel, online information from entomologists and educational materials sold by PCT, are all great sources to obtain ant information specific to your area of the country. Just like a general on a battlefield or a coach on the football field, a pest management professional visiting a suburban house to address an ant complaint will do best by knowing the enemy.
If you cannot identify the ants on site, be sure to bring some samples back to the office where they can be examined in further detail using hand lenses or a microscope and a good identification key for the ants in your area. Chances are you will be able to identify most of the common species in your area right away based on observations of foraging behaviors, where the ants are nesting and anecdotal information that the client provides to you in your consultation. Nevertheless, taking the time to get a positive ID can save you callbacks, headaches and unhappy customers in the long run. In certain areas, a fact sheet with the ant species encountered and some specific information about them distributed to the client can provide added professionalism to your service. Some clients will not care, they just want you to get rid of the ants. Others will appreciate the extra service. Time is certainly money, but it is usually time well spent with the willing client to discuss the control strategy you are employing, tips to avoid pests/infestations in the future (sanitation) and what to do if more ants are detected.
KNOW YOUR WEAPONS. There are lots of products available for treating ants. Ant control products can be placed into three major classes: 1) residual treatments, 2) baits, and 3) direct knock-down/residual treatment of nest. Knowing how and when to use these products coupled with structural and sanitation knowledge forms the basis for your ant arsenal.
In general, spraying foraging ants directly or attacking them with a residual insecticide does little to affect the rest of the ant colony. At any given point in time, only a small percentage of a colony is foraging, killing these few foragers may fulfill the client’s desire to "see dead ants" but will do little to affect the bottom line. Furthermore, for most pest species, more workers (foragers) will come back soon enough, especially if there is a food source nearby to be exploited. Residual or barrier treatments can work against you by trapping insects in a structure rather than preventing them from entering in the first place. Many of our worst pest species (fire ants, Pharaoh ants, Argentine ants, etc.) are capable of budding or forming satellite colonies. These polygynous ant species will form alternative colonies in response to a variety of factors, one of which is being unable to rejoin the original colony.
Residual insecticides can be highly effective if you are able to locate the colony and treat it directly with such a product. In fact, this is a primary key to achieving long-term ant control and another reason why a solid thorough inspection and discussion with the client to determine what ants they were seeing and where they were seeing them is so important. Remember to have tools readily available that permit you to conduct these inspections such as flashlights, dental/mechanic mirror and your field guide to common ant species. Residual dusts also can be used in a number of situations as a preventive measure to keep ants from returning once the initial problem has been addressed. Be aware that treatment with these dusts must be thorough to ensure that all areas to be protected are indeed treated. As with any residual treatment, the moment you put the material down it is subject to environment factors that will, over time, decrease the efficacy of your application.
Ant baits have become popular as the preferred method for treating ants for one particular reason — they have a much better potential of affecting the entire colony than do residuals. Visit your local distributor and you will see that there is no shortage of new ant bait formulations — gels, pastes, liquids, solids, granules, etc.
There are, however, no shortcuts to using these baits properly. A given ant colony has complex dietary requirements that change over time and over the course of a season. Entomologists are still trying to understand the complexities of these feeding shifts for many of our most important pest species and the race is still on to create that one perfect ant bait. Will it likely ever happen? Who knows, but meanwhile you still have accounts to which you have to provide control. Even with a thorough sanitation program to remove competitive foods and proper knowledge of where to place baits, your best bait applications have to compete with all of the other food sources naturally available to the foraging ants.
Ants can forage for several hundred feet to a viable food source. In areas where sanitation is difficult, e.g., food-preparation areas, a front yard, etc., there can be an almost endless source of competitive foods. Those pest management professionals that are successful with baits have a few tricks up their sleeve to obtain success.
First, make sure that you have as many bait types available (protein based vs. carbohydrate [sugar] based) as well as different forms, gels, pastes, solids and liquids. Although while at an account ants may prefer a particular bait keep in mind that their preference could shift at any time.
Because there is currently no single bait that will work in all instances, using many to get an idea of what the ants want and by following up to replenish baits that are favored will help your overall program. Placements as near to established trails as possible will help and observing ants returning with a "full tank" may even clue you in towards nest location.
Using ant baits properly is an intensive proposition. It may take several weeks to obtain some level of control and this should be communicated to the client ahead of time. After dealing with a number of the common pest species you may begin to learn what works best when and keep a log of these failures and successes with baiting.
NO SILVER BULLET. Although there are a number of sound control strategies for ants, including a wide variety of bait products as well as residual insecticide applications there still remains nothing close to a "silver bullet." Studying ant pests that are specific to your area and learning their biology, knowing what products to use when and being prepared and flexible enough to use multiple baits or control strategies will lead you towards greater success. Ant control isn’t easy. This is why you have to stay on the top of your game.
The author is a research scientist at SC Johnson & Son Inc., Racine, Wis., in the Insect Control RD&E Division of the company’s Worldwide Consumer Products Group. He can be reached at rkopanic@pctonline.com.
References:
Hedges, S.A. 1998. Field Guide for the Management of Structure-Infesting Ants, GIE Inc. Publishers. Cleveland, Ohio.
Holldobler, B. & Wilson, E. O. 1991. The Ants. Harvard University Press. Cambridge, Massachusetts.
Mallis, A. 1990. Handbook of Pest Control 7th Edition. Franzak & Foster Co., Cleveland, Ohio
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