The fate if your garden depends on ants. That might sound like an overstatement, but these insects—which most people think of as pests—play several important roles in your yard’s ecosystem.
Ants are movers and shakers. Many ant species are predators of other insects. Without the millions of ants in your garden, more caterpillars, beetles, and grasshoppers would be left unchecked to devour your plants.
Ants themselves are prey for larger predators. Northern flickers are woodpeckers that specialize in feeding on ants. A flicker laps up ants by the dozen with each flick of its long tongue. Unlike other woodpeckers, flickers—which are found across North America—regularly feed on the ground, where ants are easiest to find. Horned lizards in the desert Southwest also feed on ants, sometimes exclusively. Most backyard birds feed their babies insects, including ants. If your garden lacks a healthy ant population, these other critters will be less likely to visit.
Plants also rely on ants. Ant tunnels channel air, water, and organic matter directly to plant roots and loosen the soil, making it easier for roots to grow. Ants also disperse the seeds of many plants, including trilliums, violets, Dutchman’s breeches, trout lilies, and datura. The seeds of such plants have fleshy, nutritious appendages called eliaosomes, which lure ants. The ants feed the eliaosomes to their larvae and then ditch the seeds in nutrient-rich midden heaps outside the colony, where the seeds germinate.
Ants generally aren’t pests. Only a few ant species become pests. Carpenter ants tunnel through soft wood to create a nest, and can cause damage in homes with decaying wood. Tiny, exotic Argentine ants are common home invaders, where they feed on all sorts of food items and have been known to damage electronic equipment. The red imported fire ant creates huge mounds and has an extremely painful bite.
Unfortunately, we tend to spray first and ask questions later, when in most cases ants are probably providing beneficial services to your garden. Start by identifying the species and determining if it is truly a pest. If poison is your only option, soak bread in a mixture of 3/4 cup water, 1/4 cup sugar, and 1 tablespoon borax and put it in a small plastic container with holes in the side. This method is effective and essentially nontoxic to people and other animals.
Ants have great social skills. Just like humans, ants owe their success to their social nature. Within a colony there’s a complex, tremendously efficient division of labor. Depending on the species, an ant colony could include foragers, warriors, hunters, nannies, janitors, undertakers, engineers, gardeners, herders, guards, egg-laying queens, and even ants that turn their bodies into food-storage units for other ants.
Ants communicate via chemical pheromones, which they detect with their antennae. Some species lay pheromone trails to food sources; foragers from their colony follow and strengthen these trails. When crushed, certain species release a pheromone that causes other ants in the area to attack or to flee. Each colony has its own pheromone; some species will attack ants with a different smell.
As you learn more about these fascinating, diminutive insects, you’ll come to appreciate the role they play in keeping your garden healthy.
David Mizejewski is a naturalist, television personality, and author of Attracting Birds, Butterflies and Other Backyard Wildlife (Creative Homeowner, 2004).