A Brief Introduction to All Kinds of Ants

Odd Behaviors and Interesting Adaptations of Ants Groups

Ants may be the most successful insects on Earth. They've evolved into sophisticated social insects that fill all kinds of unique niches. From thief ants that rob from other colonies to weaver ants that sew homes in the treetops, ants are a diverse insect group. This article will introduce you to all kinds of ants.

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Citronella Ants

These are 4 mm long lemon ants (citronella ants) from Maryland.
Matt Reinbold Furryscaly/ Flickr CC

Citronella ants emit a lemon or citronella-like scent, especially when crushed. Workers are usually yellow in color, although the winged reproductives tend to be darker. Citronella ants tend aphids, feeding on the sugary honeydew they excrete. Entomologists aren't sure if citronella ants feed on any other food sources, as much is still unknown about these subterranean insects. Citronella ants tend to invade homes, especially during mating swarms, but are nothing more than a nuisance. They will not damage structures or invade food items.

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Field Ants

Field ants, also known by their genus name as Formica ants, build nest mounds in open areas. One field ant species, the Allegheny mound ant, constructs ant mounds up to 6 feet wide and 3 feet high! Because of this mound-building habit, field ants are sometimes mistaken for fire ants, which are much smaller. Field ants are medium to large ants, and vary in color by species. They may join to create supercolonies with hundreds of millions of ant workers spread across thousands of miles. Formica ants defend themselves by biting and squirting formic acid, an irritating and aromatic chemical, into the wound.

Carpenter ants are among the largest ants people encounter around their homes.
Carpenter ants have an arched thorax, single node between the abdomen and the thorax, and hairs encircling the tip of the abdomen. Photo: Clemson University - USDA Cooperative Extension Slide Series, Bugwood.org

Carpenter ants are definitely something to look for in your home. They don't actually eat the wood like termites do, but they do excavate nests and tunnels in structural lumber. Carpenter ants prefer moist wood, so if you've had a leak or flood in your home, be on the lookout for them to move in. Carpenter ants aren't always pests, though. They actually provide an important service in the ecological cycle as decomposers of dead wood. Carpenter ants are omnivores, and will feed on everything from tree sap to dead insects. They're quite large, with the major workers measuring a full 1/2 inch in length. More »

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Thief Ants

Thief ants, also commonly called grease ants, seek high-protein foods like meats, fats, and grease. They will rob both food and brood from other ants, thus the name thief ants. Thief ants are quite tiny, measuring less than 2 mm long. Thief ants will invade homes in search of food, but usually nest outdoors. If they do take up residence in your home, they can be difficult to get rid of since their tiny size allows them to squeeze into places you might not notice. Thief ants are frequently misidentified as Pharaoh ants.

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Fire ants defend their nests aggressively.
Fire ants defend their nests aggressively. Scott Bauer, USDA Agricultural Research Service

Fire ants defend their nests aggressively, and will swarm any organism they perceive as a threat. The bites and stings of fire ants are said to feel like you're being set on fire – thus the nickname. People with bee and wasp venom allergies may also be allergic to fire ant stings. Though we have native fire ants in North America, it's really the imported fire ants from South America that cause the most problems. Fire ants build mounds, usually in open, sunny places, so parks, farms, and golf courses are particularly vulnerable to fire ant infestations. More »

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Harvester Ants

Harvester ants inflict a painful, venomous sting.
Harvester ants inflict a painful, venomous sting. Flickr user jurvetson

Harvester ants inhabit deserts and prairies, where they harvest plant seeds for food. They store the seeds in underground nests. If the seeds get wet, the harvester ant workers will carry the food stores above ground to dry them and keep them from germinating. Harvester ants build mounds in grassy areas, and defoliate the area around their central nest site. Like fire ants, harvester ants will defend their nest by inflicting painful bites and venomous stings. One harvester ant species, Pogonomyrmex Maricopa, possesses the most toxic insect venom known.

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Amazon Ants

Amazon ants are warriors of the worst kind – they invade the nests of other ants to capture and enslave workers. The Amazon queen will storm a neighboring Formica ant nest and kill the resident queen. Not knowing any better, the Formica workers then do her bidding, even caring for her own Amazon offspring. Once the slaves have reared a new generation of Amazon workers, the Amazons march en masse to another Formica nest, steal their pupae, and carry them home to be raised as the next generation of slaves.

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Leafcutter Ants

Leafcutter ants gather leaves.
Leafcutter ants gather leaves, which they use as a substrate to grow fungus. Photo: Hans Hillewaert (CC-by-SA license)

Leafcutter ants, or fungus gardening ants, were agricultural experts long before man planted seeds in the ground. The leafcutter workers snip off pieces of plant material and carry the leaf bits back to their underground nest. The ants then chew the leaves, and use the partially digested leaf bits as a substrate on which to grow fungus, on which they feed. Leafcutter ants even use antibiotics, produced from strains of Streptomyces bacteria, to inhibit the growth of unwanted fungi. When a queen begins a new colony, she brings a starter culture of fungus with her to the new nest site.

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Crazy Ants

Ants will frequently tend mealybugs for their sugary honeydew excretions.
Ants will frequently tend mealybugs and related insects for the sugary honeydew produced by these insects. Photo: Alton N. Sparks, Jr., University of Georgia, Bugwood.org

Unlike most ants, which tend to move in orderly lines, crazy ants seem to run in all directions with no clear purpose – as if they're a little crazy. They've got long legs and antennae, and coarse hairs on their bodies. Crazy ants like to nest in the soil of potted tropical plants. If they make their way indoors, these ants can be difficult to control. For some reason, crazy ants like to crawl inside the cooling vents of electronic equipment, which can cause computers and other appliances to short out.

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Odorous House Ants

An odorous house ant tending a scale insect.
An odorous house ant tending a scale insect. Photo: Susan Ellis, Bugwood.org

Odorous house ants live up to their name. When the nest is threatened, these ants emit butyric acid, a foul-smelling compound. This defensive stink is often described as an odor of rancid butter, or rotten coconuts. Fortunately, odorous house ants usually stay outdoors, where they nest under stones, logs, or mulch. When they do invade a home, it's usually on a foraging trip to find sweets to eat.

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Honeypot Ants

Honeypot ants live in deserts and other arid regions. Workers feed a sweet liquid, made from foraged nectar and dead insects, to special workers called repletes. Repletes are the true honeypot ants, functioning as living, breathing honeypots. They hang from the nest ceiling, and expand their abdomens into a berry-shaped pouch that can hold 8 times their body weight in "honey." When times get tough, the colony can live off this stored food source. In regions where honeypot ants live, people sometimes eat them.

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Army Ants

Army ants are nomads. They don't make permanent nests, but instead bivouac in empty rodent nests or natural cavities. Army ants are typically nocturnal, with nearly blind workers. These carnivores conduct nighttime raids of other ant nests, stinging their prey and ferociously pulling off their legs and antennae. Army ants stay put occasionally, when the queen begins laying new eggs and larvae start pupating. As soon as the eggs hatch and the new workers emerge, the colony moves on. When on the move, workers carry the colony's young. Contrary to popular belief, most army ants are relatively harmless to mammals, though they do bite. In South America, army ants are called legionary ants, while in Africa they go by the name driver ants.

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Bullet Ants

Photo: Getty Images/Peter Arnold

Bullet ants get their name from the unbearable pain they inflict with their venomous sting, which is ranked as the most excruciating of all insect stings on the Schmidt Sting Pain Index. These enormous ants, which measure a full inch long, inhabit lowland rainforests in Central and South America. Bullet ants live in small colonies of just a few hundred individuals at the base of trees. They forage in the tree canopy for insects and nectar. The Satere-Mawe people of the Amazon basin use bullet ants in a ritual to signify manhood. Several hundred bullet ants are woven into a glove, stings facing in, and young men must wear the glove for a full 10 minutes. They repeat this ritual up to 20 times before they are called warriors.

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Acacia Ants

Acacia ants are so named for their symbiotic relationship with acacia trees. They live within hollow thorns of the tree, and feed at special nectaries at the base its leaves. In exchange for this food and shelter, the acacia ants will vigorously defend their host tree from herbivores. Acacia ants also tend to the tree, pruning off any parasitic plants that try to use it as a host.

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Pharaoh Ants

Tiny Pharaoh ants are pervasive, hard to control pests that invade houses, grocery stores, and hospitals. Pharaoh ants are native to Africa, but now inhabit dwellings worldwide. They're a serious concern when they infest hospitals, as these pests carry a dozen infectious pathogens. Pharaoh ants feed on everything from soda to shoe polish, so just about anything can attract them. The name Pharaoh ant was given to this species because they were once believed to be one of the plagues of ancient Egypt. They're also known as sugar ants or piss ants.

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Trap Jaw Ants

Trap jaw ants hunt with their mandibles locked at 180 degrees. Trigger hairs on the mandibles point forward, toward potential prey. When a trap jaw ant feels another insect brush against these sensitive hairs, it slams its jaws shut with lightning quickness. Scientists have clocked the speed of their jaws at 145 miles per hour! When in danger, a trap jaw ant can point its head down, slam its jaws shut, and propel itself out of harm's way.

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Acrobat Ants

Acrobat ants raise their heart-shaped abdomens when threatened.
Acrobat ants raise their heart-shaped abdomens when threatened. Photo: Tom Allen (CC-by-SA license)

Acrobat ants raise their heart-shaped abdomens when threatened, much like tiny circus animals. They won't back down from a fight, though, and will charge toward the threat and bite. Acrobat ants feed on sweet substances, including the honeydew secreted by aphids. They'll construct tiny barns using plant bits over their aphid "cattle." Acrobat ants sometimes nest indoors, especially in areas with constant moisture.

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Weaver Ants

Weaver ants sewing leaves into a nest.
Weaver ants sewing leaves into a nest. Photo: Robin klein (CC-by-SA license)

Weaver ants construct sophisticated nests in the treetops by sewing leaves together. Workers begin by using their jaws to pull the edges of a pliable leaf together. Other workers then carry larvae to the construction site, and give them a tender squeeze with their mandibles. This makes the larvae exude a silken thread, which the workers can use to affix the leaves together. Over time, the nest might join several trees together. Like acacia ants, weaver ants protect their host trees.