Ants

Social structure, development, and behavior

Mating, reproduction, and life span

Labor management

Defense and offense

Communication

Ants and the ecosystem

Resources

Ants are insects in the family Formicidae in the order Hymenoptera, which also includes bees and wasps. The body of the ant is divided into three sections: head, thorax, and abdomen. The head bears two long, flexible antennae (for touch and chemical detection), two eyes, and a pair of powerful mandibles (jaws) for feeding and defense. Ants have three pairs of long legs that end with a claw on each. The legs are attached to the thorax, which is connected by a narrow petiole, or waist, to the segmented abdomen. At the tip of the abdomen are the reproductive organs and the stinging organ (in some species). Ants live in highly successful social communities called colonies and are found worldwide in cool scrublands, hot deserts, inner cities, and tropical rain forests. Their nests are constructed underground or in tree-top leaf nests woven with silken thread.

Ants weigh 0.28–1.41 oz (1–5 mg), depending on the species. As of 2006, there were almost 12,000 known species of ants.

Mandibles are elongated, saw-toothed, blade-like pinchers that snap together sideways, allowing for the efficient capture of living prey and providing excellent defense against predators. Females of ground-dwelling species of ants secrete an antibiotic substance, which they smear throughout the nest, thus protecting the entire colony from the fungi and bacteria that thrive in damp, decaying vegetation.

Social structure, development, and behavior

Ants live in eusocial communal societies where, typically, members are clearly segregated into breeding and working castes. In the colony, several generations of adults reside together, and the young are fed, nurtured, and protected deep within the mound. A typical colony of the Pheidole tepicana comprises the queen, the males, and six castes of workers.

Mating, reproduction, and life span

Ants undergo complete metamorphosis—from egg, to larva, to pupa, to adult. Each ant colony begins with, and centers on, the queen, whose sole purpose is to reproduce. Although the queen may copulate with several males during her brief mating period, she never mates again. She stores sperm in an internal pouch, the spermatheca, near the tip of her abdomen, where sperm remain immobile until she opens a valve that allows them to enter her reproductive tract to fertilize the eggs.

The queen controls the sex of her offspring. Fertilized eggs produce females (either wingless workers seldom capable of reproduction, or reproductive virgin queens). Unfertilized eggs develop into winged males who do no work, and exist solely to fertilize a virgin queen. The queen produces myriads of workers by secreting a chemical that retards wing growth and ovary development in the female larvae. Virgin queens are produced only when there are sufficient workers to allow for the expansion of the colony.

Queens live long lives in comparison with their workers and are prolific breeders. A queen of Lasius niger, a common ant found in Europe, lived for 29 years in captivity, while the queen of the urban Pharaoh’s ant, Monomorium pharaonis, lives for only three months. The queen of the leaf cutter ant from South America typically produces 150 million workers during her 14-year lifespan.

The first phase of colony development is the founding stage, beginning with mating, when winged males and virgin queens leave the nest in massive swarms called nuptial flights, searching out a mate from another colony. In colonies with large populations, like that of the fire ant Solenopsis, hundreds of thousands of young queens take to the air in less than an hour, but only one or two individuals will survive long enough to reproduce. Most are taken by predators such as birds, frogs, beetles, centipedes, spiders, or by defensive workers of other ant colonies. A similar fate awaits the male ants, none of which survive after mating.

After mating, queen ants and male ants lose their wings. The queen scurries off in search of a site to start her new nest. If she survives, she digs a nest, lays eggs, and single-handedly raises her first brood, which consists entirely of workers. In leafcutter ants, adults emerge 40–60 days after the eggs are laid. The young daughter ants feed, clean, and groom the queen ant. The workers enlarge the nest, excavate elaborate tunnel systems, and transport new eggs into special hatching chambers. Hatchling larvae are fed and cleaned, and pupated larvae in cocoons are protected until the young adults emerge to become workers themselves.

The colony now enters the ergonomic stage, a time entirely devoted to work and expansion. It may take a single season or five years before the colony is large enough to enter the reproductive stage, when the queen ant begins to produce virgin queens and males that leave the nest at mating time to begin the entire cycle anew.

In some species, a new queen founds a new colony alone; in others species, several queens do so together. Sometimes, groups of workers swarm from the nest with a young queen to help her establish her nest. In colonies with several already fertile queens, such as in the Costa Rican army ant Eciton burchelli, entire groups break away with their individual queens to establish individual colonies. In single queen colonies, such as those of the fire ant, the death of the queen means the death of the colony, as she leaves no successors. Colonies with multiple queens survive and thrive.

Labor management

Some species of ant develop a caste of big, strong, major workers (soldiers) responsible for milling (chewing and pulverizing hard seed food), storing liquid food, and defense. Workers gather and store food for the entire colony, lugging loads much larger than themselves back to the nest. The workers of Myrmecocystus mimicus, the honeypot ant of the southwestern United States, collect nectar from flowers, sweet moisture from fruit, and honeydew produced by sucking insects like aphids. The food is carried back to the nest, where it is regurgitated into the crop of storage worker ants, which become living storage barrels. When a hungry ant touches the head or mouth of a storage worker ant, the storage worker responds by regurgitating food for the hungry ant.

Worker ants remove all waste (such as body parts and feces) from the nest, or bury objects too large for removal. Different species use different methods of disposing of their dead. Many simply eat the dead. Others, such as the army ant (Eciton ), carry the corpses out of the nest, while the fire ant (Solenopsis invicta ) scatters the corpses about the nest’s periphery. In some instances, sick and dying ants actually leave the nest to die.

Defense and offense

Ants employ diverse strategies to protect their colony, territory, or food. Ants are aggressive, often

KEY TERMS

Chemoreception— Detection of chemical substances that act as messengers.

Crop— Part of an ant’s digestive tract that expands to form a sac in which liquid food is stored.

Eusocial— Truly social, with complex societal structures.

Mandibles— A pair of biting jaws in insects.

Milling— Chewing and pulverizing hard seed into a powdery texture.

Pheromones— Hormonal and chemical secretions.

Replete— Ants that receive regurgitated liquid food from many worker ants, storing it in the crop for future regurgitation back to other hungry ants.

Spermatheca— Oval pouch or sperm sac.

raiding other ant colonies, fighting to the death, and snapping off limbs, heads, and body parts of enemies with their strong, sharp mandibles. Minor workers grab the enemy by the legs, pinning them down so majors can attack the body. In some species, soldier ants do the fighting, while the minor workers scurry to and from the battleground, dragging corpses of both enemy and kin back to the nest to feed the family. When moving colony sites, workers transport the queen, males, aged or ill workers, pupae, larvae, and eggs.

Communication

Ants secrete substances called pheromones, which are chemical messages detected by other ants through sense organs or the antennae. This process, called chemoreception, is the primary communication vehicle that facilitates mate attraction, as well as kin and non-kin recognition. It is also used for other purposes: discriminating between egg, larva, and pupa; warning signals to other ants of the colony; recruitment to defensive action or a new food source; odor trails from which workers or scouts find their way home or lead an entire colony to a new location; and delineation of territorial boundaries.

Chemoreception is supported by tactile (touch and feel), acoustic (hearing and vibration detection), and visual communication. Ants send tactile signals by touching and stroking each others’ bodies with their antennae and forelegs. Ants produce high-pitched chirps known as stridulations by rubbing together specialized body parts on the abdomen called files and scrapers. Stridulations are sometimes heard, but most often felt; the vibrations are detected by sensitive receptors on the legs. The young queen stridulates frantically during mating season to announce a full sperm sac, deterring other would-be mates and allowing her to escape to begin nesting. Drumming and body-rapping are used primarily by tree-dwelling ants and carpenter ants and involve banging the head or antenna on a hard surface, sending vibrational warning signals to nest mates. Some large-eyed species, such as Gigantiops, can see form and movement, but vision in most ants is virtually nonexistent; it is the least important of all their communication senses.

Ants and the ecosystem

Earth-dwelling species of ants turn and enrich more soil than do earthworms. Predatory species of ants control insect pests and spider populations and devour rotting animal carcasses. Other species of ants spread seeds, thereby propagating valuable vegetation. Ants can also be serious pests; for example, leaf-cutter ants, which grow fungi gardens for food, also strip massive amounts of leaves and flowers. They haul the vegetation to their nests and pulverize it into a paste, which they feed to fungi that grows like mold on bread. Ant colonies can be enormous: one nest of the Brazilian ant Atta sexdens housed about 8 million ants. A colony this size can strip as much vegetation as a cow in just one day, causing serious agricultural destruction.

Research into the complex, highly social biology of ants is an active field today.

Resources

BOOKS

Dorigo, Marco, and Thomas Stutzle. Ant Colony Optimization. Cambridge, MA: MIT Press, 2004.

PERIODICALS

Moreau, Corrie S., et al. “Phylogeny of the Ants: Diversification in the Age of Angiosperms.” Science. 312 (2006): 101-104.

Thomas, Jeremy A., and Josef Settele. “Evolutionary Biology: Butterfly Mimics of Ants.” Nature. 432 (2004): 283-284.

Wilson, Edward O. “Environment: Early Ant Plagues in the New World.” Nature. 433 (2005): 32.

Marie L. Thompson

Ants

Ants are insects in the family Formicidae in the order Hymenoptera, which also includes bees and wasps . The body of ants is divided into three sections: head, thorax, and abdomen. The head bears two long, flexible antennae (for touch and chemical detection), two eyes, and a pair of powerful mandibles (jaws) for feeding and defense. Ants have three pairs of long legs that end with a claw. They are attached to the thorax, which is connected by a narrow petiole, or waist, to the segmented abdomen. At the tip of the abdomen are the reproductive organs and the stinging organ (in some species ). Ants live in highly successful social communities called colonies, and are found worldwide in cool scrublands, hot deserts, inner cities, and tropical rain forests . Their nests are constructed underground or in tree-top leaf nests woven with silken thread.

Ants weigh 0.28–1.41 oz (1–5 mg), depending on the species. In 1994, 9,500 species of ants in 300 genera were recognized, and it is expected that many more species will be added to this total.

Mandibles are elongated, saw-toothed, blade-like pinchers that snap together sideways, allowing for the efficient capture of living prey and providing excellent defense against predators. Females of ground-dwelling species of ants secrete an antibiotic substance, which they smear throughout the nest, thus protecting the entire colony from the fungi and bacteria that thrive in damp, decaying vegetation.

Social structure, development, and behavior

Ants live in eusocial communal societies where, typically, members are clearly segregated into breeding and working castes. In the colony, several generations of adults reside together, and the young are fed, nurtured, and protected deep within the mound. A typical colony of the Pheidole tepicana comprises the queen, the males, and six castes of workers.

Mating, reproduction, and life span

Ants undergo complete metamorphosis—from egg, to larva, to pupa, to adult. Each ant colony begins with, and centers on, the queen, whose sole purpose is to reproduce. Although the queen may copulate with several males during her brief mating period, she never mates again. She stores sperm in an internal pouch, the spermatheca, near the tip of her abdomen, where sperm remain immobile until she opens a valve that allows them to enter her reproductive tract to fertilize the eggs.

The queen controls the sex of her offspring. Fertilized eggs produce females (either wingless workers seldom capable of reproduction, or reproductive virgin queens). Unfertilized eggs develop into winged males who do no work, and exist solely to fertilize a virgin queen. The queen produces myriads of workers by secreting a chemical that retards wing growth and ovary development in the female larvae. Virgin queens are produced only when there are sufficient workers to allow for the expansion of the colony.

Queens live long lives in comparison with their workers and are prolific breeders. A queen of Lasius niger, a common ant found in Europe , lived for 29 years in captivity, while the queen of the urban Pharaoh's ant, Monomorium pharaonis, lives for only three months. The queen of the leafcutter ant from South America produces 150 million workers during her 14-year life span.

The first phase of colony development is the founding stage, beginning with mating, when winged males and virgin queens leave the nest in massive swarms called nuptial flights, searching out a mate from another colony. In colonies with large populations, like that of the fire ant Solenopsis, hundreds of thousands of young queens take to the air in less than an hour, but only one or two individuals will survive long enough to reproduce. Most are taken by predators such as birds , frogs , beetles , centipedes , spiders, or by defensive workers of other ant colonies. A similar fate awaits the male ants, none of which survive after mating.

After mating, queen ants and male ants lose their wings. The queen scurries off in search of a site to start her new nest. If she survives, she digs a nest, lays eggs, and single-handedly raises her first brood that consists entirely of workers. In leafcutter ants, adults emerge 40–60 days after the eggs are laid. The young daughter ants feed, clean, and groom the queen ant. The workers enlarge the nest, excavate elaborate tunnel systems, and transport new eggs into special hatching chambers. Hatchling larvae are fed and cleaned, and pupated larvae in cocoons are protected until the young adults emerge to become workers themselves.

The colony now enters the ergonomic stage, a time entirely devoted to work and expansion. It may take a single season or five years before the colony is large enough to enter the reproductive stage, when the queen ant begins to produce virgin queens and males that leave the nest at mating time to begin the entire cycle anew.

In some species, a new queen founds a new colony alone; in others species, several queens do so together. Sometimes, groups of workers swarm from the nest with a young queen to help her establish her nest. In colonies with several already fertile queens, such as in the Costa Rican army ant Eciton burchelli, entire groups break away with their individual queens to establish individual colonies. In single queen colonies, such as those of the fire ant, the death of the queen means the death of the colony, as she leaves no successors. Colonies with multiple queens survive and thrive.

Labor management

Some species of ant develop a caste of big, strong, major workers (soldiers) responsible for milling (chewing and pulverizing hard seed food), storing liquid food, and defense. Workers gather and store food for the entire colony, lugging loads much larger than themselves back to the nest. The workers of Myrmecocystus mimicus, the honeypot ant of the southwestern United States, collect nectar from flowers, sweet moisture from fruit, and honeydew produced by sucking insects like aphids . The food is carried back to the nest, where it is regurgitated into the crop of storage worker ants, which become living storage barrels. When a hungry ant touches the head or mouth of a storage worker ant, the storage worker responds by regurgitating food for the hungry ant.

Worker ants remove all waste (such as body parts and feces) from the nest, or bury objects too large for removal. Different species use different methods of disposing of their dead. Many simply eat the dead. Others, such as the army ant (Eciton), carry the corpses out of the nest, while the fire ant (Solenopsis invicta) scatters the corpses about the nest's periphery. In some instances, sick and dying ants actually leave the nest to die.

Defense and offense

Ants employ diverse strategies to protect their colony, territory, or food. Ants are aggressive, often raiding other ant colonies, fighting to the death and snapping off limbs, heads, and body parts of enemies with their strong, sharp mandibles. Minor workers grab the enemy by the legs, pinning them down so majors can attack the body. In some species, soldier ants do the fighting, while the minor workers scurry to and from the battleground, dragging corpses of both enemy and kin back to the nest to feed the family. When moving colony sites, workers transport the queen, males, aged or ill workers, pupae, larvae, and eggs.

Communication

Ants secrete substances called pheromones , which are chemical messages detected by other ants through sense organs or the antennae. This process, called chemoreception , is the primary communication vehicle that facilitates mate attraction, kin, and non-kin recognition. It is also used to discriminate between egg, larva, and pupa, as warning signals, recruitment to defensive action or a new food source, the laying of odor trails from which workers or scouts find their way home or lead an entire colony to a new location, and delineation of territorial boundaries.

Chemoreception is supported by tactile (touch and feel), acoustic (hearing and vibration detection), and visual communication. Ants send tactile signals by touching and stroking each others' bodies with their antennae and forelegs. Ants produce high-pitched chirps known as stridulations by rubbing together specialized body parts on the abdomen called files and scrapers. Stridulations are sometimes heard, but most often felt, the vibrations being detected by sensitive receptors on the legs. The young queen stridulates frantically during mating season to announce a full sperm sac, deterring other would-be mates and allowing her to escape to begin nesting. Drumming and body-rapping are used primarily by tree-dwelling ants and carpenter ants, and involve banging the head or antenna on a hard surface, sending vibrational warning signals to nest mates. Some large-eyed species, such as Gigantiops, can see form and movement but vision in most ants is virtually nonexistent and the least important of all their communication senses.

Ants and the ecosystem

Earth-dwelling species of ants turn and enrich more soil than do earthworms; predatory species of ants control insect pests and spider populations, as well as animal litter by devouring rotting carcasses. Other species of ants spread seeds , thereby propagating valuable vegetation. Ants can also be serious pests; for example, leaf-cutter ants, which grow fungi gardens for food, also strip massive amounts of leaves and flowers. They haul the vegetation to their nests and pulverize it into a paste, which they feed to fungi that grows like mold on bread. Ant colonies are enormous: one nest of the Brazilian ant Atta sexdens housed about 8 million ants. A colony this size can strip as much vegetation as a cow in just one day, causing serious agricultural destruction.

Resources

books

Holldobler, Bert and Edward O Wilson. The Ants. Cambridge: Harvard University Press, 1990.

Holldobler, Bert, and Edward O. Wilson. Journey to the Ants. Cambridge: Harvard University Press, 1994.

Williams, David F., ed. Exotic Ants: Biology, Impact, and Control of Introduced Species. Boulder, CO: Westview Press, 1994.

Marie L. Thompson

KEY TERMS

Chemoreception

—Detection of chemical substances which act as messengers.

Crop

—Part of an ant's digestive tract that expands to form a sac in which liquid food is stored.

Eusocial

—Truly social, with complex societal structures.

Mandibles

—A pair of biting jaws in insects.

Milling

—Chewing and pulverizing hard seed into a powdery texture.

Pheromones

—Hormonal and chemical secretions.

Replete

—Ants that receive regurgitated liquid food from many worker ants, storing it in the crop for future regurgitation back to other hungry ants.

Spermatheca

—Oval pouch or sperm sac.

ANT

ANT (Heb. נְמָלָה, nemalah). The ant most frequent in Israel is the "harvest ant," the Messor semirufus. It is this ant which is described as the symbol of diligence and wisdom, preparing for the future by storing food during the harvest, and having no "guide, overseer, or ruler" (Prov. 6:6–7; 30:24–25). Rabbinic literature contains further details of their habits. They gnaw at the corn to extract the ears (Pe'ah 2:7). They cause extensive damage to harvested grain, and as a result R. Simeon b. Gamaliel permitted the destruction of antheaps during the intermediate days of festivals. He put forward an original method for their destruction: "Soil is brought from one heap, placed in the other, and they strangle one another" (mk 6b). This procedure is based on the belief that every antheap has its own peculiar odor which acts as a deterrent to the entry of ants from other heaps. *Simeon b. Ḥalafta also refers to their developed sense of smell. Undertaking experiments to determine their social life, he came to the conclusion that one ant does not take an ear of corn dropped by another since it recognizes its smell (Ḥul. 57b; Yal., Prov. 938). Large amounts of grain are gathered in their nests; according to one statement "three hundred kor" were once found (ibid.). The antheap consists of three chambers; the grain is stored in the upper one and the insects live in the middle, while the lower one is their summer habitat. The same Midrash actually refers to these compartments, but regards the middle one as the storehouse.

bibliography:

Lewysohn, Zool, 328–30; Tristram, Nat Hist, 319–21; S. Bodenheimer, Ha-Ḥai be-Arẓot ha-Mikrah, 2 (1956), index; J. Feliks, Animal World of the Bible (1962), 122. add. bibliography: Feliks, Ha-Ẓome'aḥ, 252.

[Jehuda Feliks]

19. Ants

See also 225. INSECTS .

formicary, formicarium

the dwelling of a colony of ants, as an anthill or nest.

formication

a body sensation that feels as if ants are crawling over the skin.

myrmecology

the branch of entomology that studies ants. —myrmecologist, n. —myrmecologic, myrmecological, adj.

myrmecophilism, myrmecophily

the dependence upon or attraction to ants exhibited by certain plants and insects. —myrmecophile, n. —myrmecophilous, adj,

myrmecophobia

1. an abnormal fear of ants.

2. the repelling of ants by some plants through hairs or glands. —myrmecophobic, adj.

xenobiosis

communal life, such as that of ants, in which colonies of different species live together but do not share the raising of the young.

Ants ★½ Panic at Lakewood Manor; It Happened at Lakewood Manor 1977

A mad bug parable for our planet-obsessed society. Insecticide-infected ants turn militant and check into a local hotel to vent their chemically induced foul mood on the unsuspecting clientele. The guest register includes a gaggle of celebrities who probably wish they'd signed on the Love Boat instead. Made for TV (an ant farm would probably be just too horrible on the big screen). 100m/C VHS, DVD . Suzanne Somers, Robert Fox-worth, Myrna Loy, Lynda Day George, Gerald Gordon, Bernie Casey, Barry Van Dyke, Karen Lamm, Anita Gillette, Moosie Drier, Steve Franken, Brian Dennehy, Bruce French, Stacy Keach Sr., Rene Enriquez, James Storm; D: Robert Scheerer; W: Guerdon (Gordon) Trueblood; C: Bernie Abramson; M: Ken Richmond. TV