Using Ants' 'Cool' Characteristics Against Them

When you’re servicing a home or business for ants, there are likely a number of thoughts that float through your mind (some of which surely cannot be repeated in this article). But have you ever thought Oh cool, Wow, these ants really have a sense of humor (albeit a poor one), Now, that’s some magic! or just pulled up a chair to sit and watch an ant mound? 

In his talk at PestWorld 2021, “The curious life of the pest ant … and how to end it,” Texas A&M Assistant Professor and Extension Entomologist Robert Puckett didn’t just discuss ant identification as key to their control, he provided the “cool” details and “magic” solutions that only a veteran ant researcher can bring to the topic. 

As Puckett stated, in focusing on pest ants and their management, his goal in the session is to not only “impress on you how cool a group of ants are, but also how important they are.” In focusing in on the major pest ants of the South and Southeast U.S., particularly those of Texas, he provides these particulars for PMPs to “think of these as models as to how to approach ant management.” And the most important aspect of that, he said, is identification, as not all techniques nor products work the same on all ant species. “Identification is a very, very important first step in being able to successfully manage ants,” he said. 

IDENTIFICATION. The primary form of ant identification is the use of an identification key, in which the PMP walks through the steps of a chart matching the characteristics of the specimen with couplets in the key until reaching the correct species. While it is a fairly simple process, a PMP can spend a lot of time working through it if they are unfamiliar with the technical terms used, Puckett said. For some ants, however, the process can be further simplified if three or four diagnostic characteristics are identified. “If you see those, you’ll know what species it is,” he said. The first step in either case is magnifying the specimen. While this can be done with a hand lens or magnifying glass, Puckett recommended the use of a USB microscopes, which can be purchased for around $100, to project an image of the insect to your computer. The image can then be enlarged to show greater detail for identification or for sending to a supervisor or extension agent for assistance.

Using the magnification, examine the specimen for:

• Antennae. The number of segments on the ant’s antennae is the first key to identification and can significantly narrow down the potential species. When counting segments, be sure to include the first long segment attached to the head, along with all the tiny segments that follow the “elbow.” The most common mistake is to not count the long segment, Puckett said, adding, “If you miss this one, identification is off right from the start.”
• Abdominal nodes. A second key characteristic is number of abdominal nodes, which can often be seen with just a bit of magnification.
• Size. In some species, all workers are the same size, in others, this can vary dramatically. So, while size can sometimes be helpful, it is not always a reliable factor.
• Mound. The presence of an above-ground mound will narrow the number of species to which your specimen may belong, particularly if that mound appears “magically” after a rain.

In presenting these as some of the key characteristics that can help significantly narrow down specimen identification, Puckett provided a few species examples — and control recommendations. Included among these were the following. 

LEAF CUTTER ANTS (ATTA TEXANA). Common in much of Texas, this ant has an 11-segment antennae, two abdominal nodes, extreme size differences between workers and extensive nests. Additionally, it is the only genus that has three pairs of spines on its thorax. This ant is significant because of the massive underground nature of its nests, with large tunnels and trails that can compromise the structure of concrete-slab homes, breaking down the foundation. 

RED IMPORTED FIRE ANT (SOLENOPSIS INVICTA). This ant has a 10-segment antennae with a club, two abdominal nodes that are easily seen, conspicuous mounds — especially after rain, and a “median clypeus tooth” that distinguishes the red imported fire ant from all others. As a key pest of the South, fire ant research is often seen as a model for how to approach scenarios of new invasive ants. 

With its “poorly developed sense of humor,” this ant, Puckett said, “is happy to sting anything that disturbs their mound.” Not only is it very aggressive with a powerful sting, but it has been very successful in expanding throughout the U.S. — and the world.

Puckett espouses baits as the best solution for most ant species, including fire ants, because “ant baits are designed to exploit ant foraging behavior.” However, he added, “not all ants are attracted to the same baits.” That is where identification becomes crucial, as you need to identify the species then look for products that are successful with that species. 

Puckett also presented a video of fire-ant biocontrol based on the natural habits of parasitic flies. In short, the fly injects its egg into the body of an ant. Then feeding on the ant’s blood, the larvae makes its way to the ant’s brain on which it continues feeding, then kills the ant and decapitates it to make its way out. In showing the video to PMPs dealing with fire ants regularly, Puckett termed it as “hopefully a gruesome and satisfying video for you.”

If you want to see another form of biocontrol in person, he said, find a fire ant mound in spring or summer when the temperature is above 75 degrees Fahrenheit. “Poke the mound, post up a chair and wait.” Within five or ten minutes, you’re likely to see phorid flies. “It’s a cool sight,” he said. 

TAWNY CRAZY ANT (NYLANDERIA FULVA). As a single-node ant with a 12-segment antennae and long legs, this ant has two pairs of very small, erect hairs that separate it from other closely related species. It is a prime example of a supercolony species. While native populations are genetically diverse, new invasive species have decreased genetic diversity, recognizing each other as nestmates even when they technically aren’t. Of the more than 12,000 species of ants, supercolony formation has been detected in only 15-20 species. 

This creates a problem because it makes the species more difficult to control. In most cases, an ant colony would be aggressive against other ants, even of the same species, in their territory. But in seeing others of their species as “family,” these ants welcome and share resources with others. This enables populations to grow and expand at a rapid rate with significant impact, as populations will short out electrical equipment, raid honeybee colonies, tend and protect aphids for honeydew and infest cow/calf operations, often blinding them. 

While researchers did find a product that appeared to work well in the lab, it faced challenges in the field. Initially knocking out a significant portion of the population, it was soon seen that new ants rushed in to take the place of those killed, reupping the numbers. PMPs will generally need to get very aggressive to treat for this ant, then determine if it needs another treatment the next quarter. 

Because of the challenges and impacts this ant poses, Puckett said, if you think you may have a tawny crazy ant infestation and you don’t have a good microscope, reach out to him or other expert. “This is uncharted territory for many of us,” he said. “So please reach out. … we want to be able to track their expansion throughout the United States.”

CONCLUSION. As these examples show, identification is essential to the successful management of pest ants. It’s not always easy, but it can be accomplished with the right information.

The author is a freelance writer based in Ohio.