The nine-banded armadillo, a distinctive mammal expanding its range across the Southern United States, frequently crosses paths with the notorious invasive red imported fire ant. This armored insectivore’s presence in infested areas leads to the question of whether it serves as an effective biological control. Armadillos’ unique foraging habits and impact on the ants’ visible mound structures suggest they might hunt and eliminate colonies. Examining the armadillo’s specific dietary choices and behaviors reveals their relationship with the ants.
The Specific Interaction with Fire Ants
Armadillos do consume fire ants, but this consumption is generally incidental to their broader search for food. These armored mammals occasionally dig into the dome-shaped mounds to feed on the colony’s contents. Studies indicate that armadillos primarily target the defenseless pupae and larvae, known as the brood, which are concentrated near the surface. They are one of the few native animals not completely deterred by the fire ant’s painful sting. Consumption is not typically sufficient to eradicate an entire colony, as they rarely reach or consume the queen, which is necessary for elimination.
Understanding Armadillo Dietary Preferences
The armadillo’s diet consists mainly of invertebrates found beneath the soil surface, positioning them as opportunistic insectivores. Their food intake can be composed of up to 90% insects and other invertebrates, which they locate primarily through a highly developed sense of smell. The primary components of their diet include soft-bodied, subsurface prey such as white grubs, beetle larvae, and earthworms. This preference for less-defended, slow-moving prey dictates their general foraging strategy.
Armadillos readily eat other ant species, termites, cockroaches, and caterpillars when encountered. The volume of food consumed is significant; some reports suggest an armadillo can consume tens of thousands of small insects in a single day. This heavy reliance on subsurface food means that while fire ants are consumed, they are just one of many prey items encountered during routine digging. The pursuit of any concentration of insects underground drives their daily foraging activity.
Fire Ant Defense and Palatability
Fire ants are not a preferred dietary staple for most predators due to their aggressive defense mechanisms. Fire ant venom, delivered through a painful sting, contains toxic piperidine alkaloids that serve as a potent defense. A single sting creates a burning sensation, and a coordinated swarm attack can quickly overwhelm an attacker.
Despite this chemical arsenal, armadillos appear to tolerate the fire ant’s defenses better than many other animals. They use their tough, armor-plated hide and quickly consume the less-mobile brood to mitigate the effects of the stinging workers. However, the difficulty and energy expenditure involved in dealing with stinging ants likely makes a fire ant colony less appealing than a concentration of defenseless beetle grubs.
Foraging Behavior and Ecological Disturbance
The armadillo’s most significant impact on fire ant populations comes not from consumption, but from its destructive foraging method. Armadillos locate food by probing the ground with their snout and using powerful claws to dig into the soil, creating characteristic conical holes. When a fire ant mound is detected, the digging activity rips apart the subterranean structure of the colony.
This disturbance collapses the internal tunnels and chambers, including the crucial brood-rearing areas. By exposing the fire ant’s inner workings to the air and to potential secondary predators, the armadillo severely stresses the colony. The resulting chaos forces the workers to expend significant resources on repair and relocation, rather than on reproduction and foraging. This disruption limits the growth and expansion of local fire ant colonies and acts as a form of natural control.