Army ants belong to Ecitoninae (New World) and Dorylinae (Old World). They are a nomadic, swarming kind who are savage hunters. Their influence classifies them among the primary tropical predators.
Eciton burchellii colonies contain 100,000-2,000,000 workers. One queen produces 100,000 eggs within 20 days of a cycle. There are alternating 15-day nomadic and 20-day stationary stages of colonies.
An estimated 200,000 ants are included in the raids. Swarm fronts spread in widths of up to 20 m and traveled at about 15 m/hour. Nomadic raids comprised trails more than 100 m.
Every night, workers were intertwined into bivouacs. Shells remained compact, with the inside supporting brood and queen. Workers had to lift eight times their weight. The nomadic phase involved the colonies’ excursion at night.
A 2022 study by the Department of Organismic and Evolutionary Biology at Harvard University, published in PNAS, suggested that mass-raiding behavior arose spontaneously, as colony size stepped up either way to 5,000 workers.
| Characteristic | Description |
| Scientific Name | Eciton spp., Dorylus spp., and other army ant species |
| Common Name | Army Ant |
| Size | Workers: 4–15 mm depending on species and caste; soldiers can be larger, up to 25 mm; queens are the largest, reaching 30–35 mm. |
| Color & Appearance | Reddish-brown to black; segmented body with strong mandibles; smooth exoskeleton; soldiers have disproportionately large heads and jaws. |
| Legs | Six strong legs adapted for rapid movement; capable of carrying prey many times their body weight over long distances. |
| Eyes | Small or reduced compound eyes; rely primarily on pheromone trails and tactile signals for navigation. |
| Habitat | Rainforests, savannas, and tropical/subtropical regions of Central and South America, Africa, and Asia; highly mobile with no permanent nest. |
| Behavior | Nomadic and highly aggressive; form large raiding columns to hunt insects, spiders, and small vertebrates; no permanent nest, living in temporary bivouacs formed from workers’ bodies. |
| Diet | Carnivorous; feed on insects, other arthropods, and occasionally small vertebrates; prey is captured collectively in raids. |
| Venom | Do not inject venom; rely on strong mandibles to capture and dismember prey quickly. |
| Reproduction | Queens produce a large number of eggs; colony splits between nomadic and stationary phases; colonies can grow to hundreds of thousands of individuals. |
| Lifespan | Workers: 1–2 months; queens: several years; colonies are long-lived with overlapping generations. |
| Geographic Range | Neotropical regions (Central and South America), parts of Africa and Asia depending on species. |
| Adaptations | Highly coordinated raiding behavior; division of labor among castes; rapid movement and cooperative hunting; bivouac formation for protection and mobility. |
| Predators | Anteaters, birds, lizards, and other large insectivores; some parasitic insects target larvae and pupae. |
| Activity Time | Primarily diurnal, though some species can be nocturnal; continuous movement during nomadic phases. |
| Prevention Tips |
Avoid leaving food scraps or fallen fruits outdoors. Minimize leaf litter near buildings. Seal gaps and cracks to prevent entry into structures. Monitor for initial colonies before they expand. |
| How to Get Rid of Them |
Contact professional pest control for large infestations. Apply targeted insecticides along ant trails and temporary bivouacs. Remove potential food sources and debris. Avoid disturbing active raiding columns without protection. |
What Are the Key Physical Features of Army Ants?
Here are the key physical features of army ants:
- Vision: The army ants use pheromones and contact. The majority of the workers are either blind or have shrunken eyes. They do not rely on their sight to sense trails, food, or threats, but with antennae and chemical signals.
- Mandibles: They possess strong mandibles that help them hold, cut, and transport food. Soldiers possess long and curving jaws. These jaws deal with insects, spiders, and small life in the raids.
- Size Range: Queens are the largest (up to 2.5 cm), workers with powerful bodies and a huge head. Workers are small and slender, less than 1 cm. They have their specific jobs.
- Coloration: Army ants are either brown, red, or black. The color varies according to species and habitat. As an illustration, Aenictus types are usually yellow-brown in body, whereas Dorylus are usually dark red or black.
What is the Habitat and Distribution of Army Ants?
The army ants inhabit Central America, South America, Africa, and Southeast Asia. Eciton species are predominant in the Americas, with Dorylus species found in tropical Africa and some parts of Asia. They are adapted to wet environments such as tropical rainforests, the forest floor, and the grassy savanna. Colonies also nest underground, at the roots of trees, or in decaying logs. These locations engage in foraging and movement of the colonies.
Army ant colonies move every 15 to 20 days during brood development and behave collectively when mass-raiding, depending on the colony size. These ants move more than 100 meters in a day during foraging and revocation.
How Do Army Ants Hunt?
Here are the ways army ants hunt:
- Group Raiding: These are group-raiding activities. The Eciton burchellii expands into a swarming front measuring more than 10 m wide. Numerous ants work together in hundreds of thousands to crush prey without any individual scouting.
- Pheromone Trails: These are pheromone-trail functions. Chemical signals are deposited by workers in sternal glands. These tracks lead the ants in the colony and direct attack direction and coordination.
- Diet: These are diet products. Army ants eat insects, spiders, scorpions, cockroaches, and on rare occasions, small vertebrates such as lizard hatchlings and frogs.
- Bivouac Formation: These are details of bivouac. Laborers connect bodies to create a living nest that covers the queen and the brood every night. These make-shift structures disperse in the morning with raids.
What is the Reproduction and Colony Cycle of Army Ants
Here is the complete reproduction and colony cycle of army ants:
- Single Queen: Every colony has a single queen. Every 20 days, she lays almost 100,000 eggs. Her egg-laying schedule regulates the cycle of movement and rest. The queen stays within the bivouac for protection.
- Brood Care: Eggs and larvae are transferred during relocation by the workers. They protect the brood by changing their position within the bivouac. The ants move the brood up or down layers to ensure that it is well-warmed and secured against harm.
- Nomadic Phase: This nomadic stage lasts about 15 days. Daily, colonies travel in search of food. In organized movements, huge numbers move together and raid regions, then move every evening in search of prey to remain near food.
- Statutory Phase: This stage takes 20 days. Colonies remain where they are. The queen is producing eggs, and the workers protect the bivouac. The stationary phase is completed when the larvae hatch and start to activate the next round of hunting and migration.
What are the Unique Adaptations of Army Ants
Here are the unique adaptations of army ants:
- Nomadic Lifestyle: Daily movements occur in the nomadic period of army ants. Colonies move more than 100 meters in search, and they do not utilize every food source in a single location. This daily migration aids them in living in dynamic settings.
- Bivouac Nesting: Army ants never establish permanent nests. Rather, workers utilize their bodies to create the living structure of shelter known as a bivouac. The queen and young ants are guarded in this structure. It extends or contracts according to space and requirement.
- High Coordination: The army ants also use scent trails and follow the touch of their antennae to keep organized. They walk in great numbers within perfect time. Their collaboration enables them to steal and move around successfully.
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How to Get Rid of Army Ants
Here are the ways to get rid of army ants:
- Remove Attractants: Army ants move towards dead or live prey. Dirty surroundings attract them. Remove all foodstuffs and rotten matter from the floors, gardens, and storage places. This minimizes the risk of an army ant raid.
- Disrupt Pheromone Trails: Army ants track chemical trails marked by other ants. Clean the ways that they use with a mix of vinegar and water or soapy water. This eliminates the path and prevents their coordination when moving.
- Chemical Barriers or Natural Barriers: Apply in places of entry. It dehydrates the ants. Some people also prefer cinnamon or citrus oils. These natural materials prevent their scent trails and keep them at a distance.
- Seal Entry Points: Small gaps are crawled by army ants. Seal all the wall, floor, and door cracks. Use the cement or caulk. Blocking these spots prevents them from entering houses and storage facilities.
- Avoid in Outside places: Army ants usually lose their trail within 2 to 3 days in gardens or trails. They should not be disrupted. They do not cease to hunt prey. Just let them walk by unless they are haunting humans or animals.
- Professional Pest Control: Contact a pest control service in cases of frequent attacks by the army ants. Experts use focused and safe treatment. It helps manage ants within one of the aspects in homes, hospitals, or schools without creating a negative impact on the environment.
