Author: Wardrobehypeurban.online

Dragonfly

A dragonfly is a flying insect belonging to the infraorder Anisoptera below the order Odonata. About 3,000 extant species of dragonflies are known. Most are tropical, with fewer species in temperate regions. Loss of wetland habitat threatens dragonfly populations around the world. Adult dragonflies are characterised by a pair of large, multifaceted, compound eyes, two pairs of strong, transparent wings, sometimes with coloured patches, and an elongated body. Many dragonflies have brilliant iridescent or metallic colours produced by structural coloration, making them conspicuous in flight. An adult dragonfly’s compound eyes have nearly 24,000 ommatidia each.

Dragonflies can be mistaken for the closely related damselflies, which make up the other odonatan infraorder (Zygoptera) and are similar in body plan, though usually lighter in build; however, the wings of most dragonflies are held flat and away from the body, while damselflies hold their wings folded at rest, along or above the abdomen. Dragonflies are agile fliers, while damselflies have a weaker, fluttery flight. Dragonflies make use of motion camouflage when attacking prey or rivals.

Dragonflies are predatory insects, both in their aquatic nymphal stage (also known as “naiads”) and as adults. In some species, the nymphal stage lasts up to five years, and the adult stage may be as long as 10 weeks, but most species have an adult lifespan in the order of five weeks or less, and some survive for only a few days.^[4] They are fast, agile fliers capable of highly accurate aerial ambush, sometimes migrating across oceans, and often live near water. They have a uniquely complex mode of reproduction involving indirect insemination, delayed fertilisation, and sperm competition. During mating, the male grasps the female at the back of the head, and the female curls her abdomen under her body to pick up sperm from the male’s secondary genitalia at the front of his abdomen, forming the “heart” or “wheel” posture.

Fossils of very large dragonfly-like insects, sometimes called griffinflies, are found from 325 million years ago (Mya) in Upper Carboniferous rocks; these had wingspans up to about 750 mm (30 in), though they were only distant relatives, not true dragonflies which first appeared during the Early Jurassic.

Dragonflies are represented in human culture on artefacts such as pottery, rock paintings, statues, and Art Nouveau jewellery. They are used in traditional medicine in Japan and China, and caught for food in Indonesia. They are symbols of courage, strength, and happiness in Japan, but seen as sinister in European folklore. Their bright colours and agile flight are admired in the poetry of Lord Tennyson and the prose of H. E. Bates.

Etymology

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The infraorder Anisoptera comes from Greek ἄνισος anisos “unequal”^[5] and πτερόν pteron “wing”^[6] because dragonflies’ hindwings are broader than their forewings.^[7]

Evolution

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Dragonflies and their relatives are similar in structure to an ancient group, the Meganisoptera or griffinflies, from the 325 Mya Upper Carboniferous of Europe, a group that included one of the largest insects that ever lived, Meganeuropsis permiana from the Early Permian, with a wingspan around 750 mm (30 in).^[9] The Protanisoptera, another ancestral group that lacks certain wing-vein characters found in modern Odonata, lived in the Permian.^[10]

Anisoptera first appeared during the Toarcian age of the Early Jurassic,^[11] and the crown group developed in the Middle Jurassic.^[12] They retain some traits of their distant predecessors, and are in a group known as the Palaeoptera, meaning ‘ancient-winged’. Like the gigantic griffinflies, dragonflies lack the ability to fold their wings up against their bodies in the way modern insects do, although some evolved their own different way to do so. The forerunners of modern Odonata are included in a clade called the Panodonata, which include the basal Zygoptera (damselflies) and the Anisoptera (true dragonflies).^[13] Today, some 3,000 species are extant around the world.^[14]^[15]

The relationships of anisopteran families are not fully resolved as of 2021, but all the families are monophyletic except the Corduliidae, and the Austropetaliidae are sister to the Aeshnoidea:^[16]

Anisoptera	Austropetaliidae Aeshnoidea (hawkers)Petaluridae (petaltails)Gomphidae (clubtails)Neopetaliidae Cordulegastridae (goldenrings)Chlorogomphidae Libelluloidea Synthemistidae (tigertails)many Synthemistidae genera, incertae sedisMacromiidae (cruisers)”Corduliidae” (emeralds) [not a true clade]Libellulidae (skimmers)

Distribution and diversity

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About 3,012 species of dragonflies were known in 2010; these are classified into 348 genera in 11 families. The distribution of diversity within the biogeographical regions are summarized below (the world numbers are not ordinary totals, as overlaps in species occur).^[17]

hideFamily	Indomalaya	Neotropical	Australasian	Afrotropical	Palaearctic	Nearctic	Pacific	World
Aeshnidae	149	129	78	44	58	40	13	456
Austropetaliidae		7	4					11
Petaluridae		1	6		1	2		10
Gomphidae	364	277	42	152	127	101		980
Chlorogomphidae	46				5			47
Cordulegastridae	23	1			18			46
Neopetaliidae		1						1
Corduliidae	23	20	33	6	18	51	12	154
Libellulidae	192	354	184	251	120	105	31	1037
Macromiidae	50	2	17	37	7	10		125
Synthemistidae			37				9	46
Incertae sedis	37	24	21	15	2			99

An aggregation of globe skimmers, *Pantala flavescens*, during migration

Dragonflies live on every continent except Antarctica. In contrast to the damselflies (Zygoptera), which tend to have restricted distributions, some genera and species are spread across continents. For example, the blue-eyed darner Rhionaeschna multicolor lives all across North America, and in Central America;^[18] emperors Anax live throughout the Americas from as far north as Newfoundland to as far south as Bahia Blanca in Argentina,^[19] across Europe to central Asia, North Africa, and the Middle East.^[20] The globe skimmer Pantala flavescens is probably the most widespread dragonfly species in the world; it is cosmopolitan, occurring on all continents in the warmer regions. Most Anisoptera species are tropical, with far fewer species in temperate regions.^[21]

Some dragonflies, including libellulids and aeshnids, live in desert pools, for example in the Mojave Desert, where they are active in shade temperatures between 18 and 45 °C (64 and 113 °F); these insects were able to survive body temperatures above the thermal death point of insects of the same species in cooler places.^[22]

Dragonflies live from sea level up to the mountains, decreasing in species diversity with altitude.^[23] Their altitudinal limit is about 3700 m, represented by a species of Aeshna in the Pamirs.^[24]

Dragonflies become scarce at higher latitudes. They are not native to Iceland, but individuals are occasionally swept in by strong winds, including a Hemianax ephippiger native to North Africa, and an unidentified darter species.^[25] In Kamchatka, only a few species of dragonfly including the treeline emerald Somatochlora arctica and some aeshnids such as Aeshna subarctica are found, possibly because of the low temperature of the lakes there.^[26] The treeline emerald also lives in northern Alaska, within the Arctic Circle, making it the most northerly of all dragonflies.^[27]

General description

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Dragonflies (suborder Anisoptera) are heavy-bodied, strong-flying insects that hold their wings horizontally both in flight and at rest. By contrast, damselflies (suborder Zygoptera) have slender bodies and fly more weakly; most species fold their wings over the abdomen when stationary, and the eyes are well separated on the sides of the head.^[17]^[28]

An adult dragonfly has three distinct segments, the head, thorax, and abdomen, as in all insects. It has a chitinous exoskeleton of hard plates held together with flexible membranes. The head is large with very short antennae. It is dominated by the two compound eyes, which cover most of its surface. The compound eyes are made up of ommatidia, the numbers being greater in the larger species. Aeshna interrupta has 22650 ommatidia of two varying sizes, 4500 being large. The facets facing downward tend to be smaller. Petalura gigantea has 23890 ommatidia of just one size. These facets provide complete vision in the frontal hemisphere of the dragonfly.^[29] The compound eyes meet at the top of the head (except in the Petaluridae and Gomphidae, as also in the genus Epiophlebia). Also, they have three simple eyes or ocelli. The mouthparts are adapted for biting with a toothed jaw; the flap-like labrum, at the front of the mouth, can be shot rapidly forward to catch prey.^[30]^[31] The head has a system for locking it in place that consists of muscles and small hairs on the back of the head that grip structures on the front of the first thoracic segment. This arrester system is unique to the Odonata, and is activated when feeding and during tandem flight.^[17]

The thorax consists of three segments as in all insects. The prothorax is small and flattened dorsally into a shield-like disc, which has two transverse ridges. The mesothorax and metathorax are fused into a rigid, box-like structure with internal bracing, and provide a robust attachment for the powerful wing muscles inside.^[32] The thorax bears two pairs of wings and three pairs of legs. The wings are long, veined, and membranous, narrower at the tip and wider at the base. The hindwings are broader than the forewings and the venation is different at the base.^[33] The veins carry haemolymph, which is analogous to blood in vertebrates, and carries out many similar functions, but which also serves a hydraulic function to expand the body between nymphal stages (instars) and to expand and stiffen the wings after the adult emerges from the final nymphal stage. The leading edge of each wing has a node where other veins join the marginal vein, and the wing is able to flex at this point. In most large species of dragonflies, the wings of females are shorter and broader than those of males.^[31] The legs are rarely used for walking, but are used to catch and hold prey, for perching, and for climbing on plants. Each has two short basal joints, two long joints, and a three-jointed foot, armed with a pair of claws. The long leg joints bear rows of spines, and in males, one row of spines on each front leg is modified to form an “eyebrush”, for cleaning the surface of the compound eye.^[32]

The abdomen is long and slender and consists of 10 segments. Three terminal appendages are on segment 10; a pair of superiors (claspers) and an inferior. The second and third segments are enlarged, and in males, the underside of the second segment has a cleft, forming the secondary genitalia consisting of the lamina, hamule, genital lobe, and penis. There are remarkable variations in the presence and the form of the penis and the related structures, the flagellum, cornua, and genital lobes. Sperm is produced at the 9th segment, and is transferred to the secondary genitalia prior to mating. The male holds the female behind the head using a pair of claspers on the terminal segment. In females, the genital opening is on the underside of the eighth segment, and is covered by a simple flap (vulvar lamina) or an ovipositor, depending on species and the method of egg-laying. Dragonflies having simple flaps shed the eggs in water, mostly in flight. Dragonflies having ovipositors use them to puncture soft tissues of plants and place the eggs singly in each puncture they make.^[32]^[34]^[35]^[36]

Dragonfly nymphs vary in form with species, and are loosely classed into claspers, sprawlers, hiders, and burrowers.^[17] The first instar is known as a prolarva, a relatively inactive stage from which it quickly moults into the more active nymphal form.^[37] The general body plan is similar to that of an adult, but the nymph lacks wings and reproductive organs. The lower jaw has a huge, extensible labium, armed with hooks and spines, which is used for catching prey. This labium is folded under the body at rest and struck out at great speed by hydraulic pressure created by the abdominal muscles.^[17] Both damselfly and dragonfly nymphs ventilate the rectum, but just some damselfly nymphs have a rectal epithelium that is rich in trachea, relying mostly on three feathery external gills as their major source of respiration. Only dragonfly nymphs have internal gills, called a branchial chamber, located around the fourth and fifth abdominal segments. These internal gills consist originally of six longitudinal folds, each side supported by cross-folds. But this system has been modified in several families. Water is pumped in and out of the abdomen through an opening at the tip. The naiads of some clubtails (Gomphidae) that burrow into the sediment, have a snorkel-like tube at the end of the abdomen enabling them to draw in clean water while they are buried in mud. Naiads can forcefully expel a jet of water to propel themselves with great rapidity.^[38]^[39]^[40]

Coloration

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Many adult dragonflies have brilliant iridescent or metallic colours produced by structural colouration, making them conspicuous in flight. Their overall coloration is often a combination of yellow, red, brown, and black pigments, with structural colours. Blues are typically created by microstructures in the cuticle that reflect blue light. Greens often combine a structural blue with a yellow pigment. Freshly emerged adults, known as tenerals, are often pale, and obtain their typical colours after a few days.^[33] Some have their bodies covered with a pale blue, waxy powderiness called pruinosity; it wears off when scraped during mating, leaving darker areas.^[41]

Some dragonflies, such as the green darner, Anax junius, have a noniridescent blue that is produced structurally by scatter from arrays of tiny spheres in the endoplasmic reticulum of epidermal cells underneath the cuticle.^[42]

The wings of dragonflies are generally clear, apart from the dark veins and pterostigmata. In the chasers (Libellulidae), however, many genera have areas of colour on the wings: for example, groundlings (Brachythemis) have brown bands on all four wings, while some scarlets (Crocothemis) and dropwings (Trithemis) have bright orange patches at the wing bases. Some aeshnids such as the brown hawker (Aeshna grandis) have translucent, pale yellow wings.^[43]

Dragonfly nymphs are usually a well-camouflaged blend of dull brown, green, and grey.^[38]

Biology

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Ecology

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Dragonflies and damselflies are predatory both in the aquatic nymphal and adult stages. Nymphs feed on a range of freshwater invertebrates and larger ones can prey on tadpoles and small fish.^[44] Naiads of one species, Phanogomphus militaris, may even act as parasites, feeding on the gills of gravid freshwater mussels.^[45] Adults capture insect prey in the air, making use of their acute vision and highly controlled flight.Dragonfly returns to same perch each time it darts out to catch very small flying prey.

The mating system of dragonflies is complex, and they are among the few insect groups that have a system of indirect sperm transfer along with sperm storage, delayed fertilisation, and sperm competition.^[44]

Adult males vigorously defend territories near water; these areas provide suitable habitat for the nymphs to develop, and for females to lay their eggs. Swarms of feeding adults aggregate to prey on swarming prey such as emerging flying ants or termites.^[44]

Dragonflies as a group occupy a considerable variety of habitats, but many species, and some families, have their own specific environmental requirements.^[46] Some species prefer flowing waters, while others prefer standing water. For example, the Gomphidae (clubtails) live in running water, and the Libellulidae (skimmers) live in still water.^[46] Some species live in temporary water pools and are capable of tolerating changes in water level, desiccation, and the resulting variations in temperature, but some genera such as Sympetrum (darters) have eggs and nymphs that can resist drought and are stimulated to grow rapidly in warm, shallow pools, also often benefiting from the absence of predators there.^[46] Vegetation and its characteristics including submerged, floating, emergent, or waterside are also important. Adults may require emergent or waterside plants to use as perches; others may need specific submerged or floating plants on which to lay eggs. Requirements may be highly specific, as in Aeshna viridis (green hawker), which lives in swamps with the water-soldier, Stratiotes aloides.^[46] The chemistry of the water, including its trophic status (degree of enrichment with nutrients) and pH can also affect its use by dragonflies. Most species need moderate conditions, not too eutrophic, not too acidic;^[46] a few species such as Sympetrum danae (black darter) and Libellula quadrimaculata (four-spotted chaser) prefer acidic waters such as peat bogs,^[47] while others such as Libellula fulva (scarce chaser) need slow-moving, eutrophic waters with reeds or similar waterside plants.^[48]^[49]

Behaviour

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Many dragonflies, particularly males, are territorial. Some defend a territory against others of their own species, some against other species of dragonfly and a few against insects in unrelated groups. A particular perch may give a dragonfly a good view over an insect-rich feeding ground; males of many species such as the Pachydiplax longipennis (blue dasher) jostle other dragonflies to maintain the right to alight there.^[50] Defending a breeding territory is common among male dragonflies, especially in species that congregate around ponds. The territory contains desirable features such as a sunlit stretch of shallow water, a special plant species, or the preferred substrate for egg-laying. The territory may be small or large, depending on its quality, the time of day, and the number of competitors, and may be held for a few minutes or several hours. Dragonflies including Tramea lacerata (black saddlebags) may notice landmarks that assist in defining the boundaries of the territory. Landmarks may reduce the costs of territory establishment, or might serve as a spatial reference.^[51] Some dragonflies signal ownership with striking colours on the face, abdomen, legs, or wings. The Plathemis lydia (common whitetail) dashes towards an intruder holding its white abdomen aloft like a flag. Other dragonflies engage in aerial dogfights or high-speed chases. A female must mate with the territory holder before laying her eggs.^[50] There is also conflict between the males and females. Females may sometimes be harassed by males to the extent that it affects their normal activities including foraging and in some dimorphic species females have evolved multiple forms with some forms appearing deceptively like males.^[52] In some species females have evolved behavioural responses such as feigning death to escape the attention of males.^[53] Similarly, selection of habitat by adult dragonflies is not random, and terrestrial habitat patches may be held for up to 3 months. A species tightly linked to its birth site utilises a foraging area that is several orders of magnitude larger than the birth site.^[54]

Reproduction

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Duration: 3 minutes and 3 seconds.3:03Dragonflies over a pond (including female inserting eggs below the water surface.

Mating in dragonflies is a complex, precisely choreographed process. First, the male has to attract a female to his territory, continually driving off rival males. When he is ready to mate, he transfers a packet of sperm from his primary genital opening on segment 9, near the end of his abdomen, to his secondary genitalia on segments 2–3, near the base of his abdomen. The male then grasps the female by the head with the claspers at the end of his abdomen; the structure of the claspers varies between species, and may help to prevent interspecific mating.^[55] The pair flies in tandem with the male in front, typically perching on a twig or plant stem. The female then curls her abdomen downwards and forwards under her body to pick up the sperm from the male’s secondary genitalia, while the male uses his “tail” claspers to grip the female behind the head: this distinctive posture is called the “heart” or “wheel”;^[44]^[56] the pair may also be described as being “in cop”.^[57]

Egg-laying (ovipositing) involves not only the female darting over floating or waterside vegetation to deposit eggs on a suitable substrate, but also the male hovering above her or continuing to clasp her and flying in tandem. This behaviour following the transfer of sperm is termed as mate guarding and the guarding male attempts to increase the probability of his sperm fertilising eggs. Sexual selection with sperm competition occurs within the spermatheca of the female and sperm can remain viable for at least 12 days in some species.^[58]^[59] Females can fertilise their eggs using sperm from the spermatheca at any time.^[44]^[56]^[55] Males use their penis and associated genital structures to compress or scrape out sperm from previous matings; this activity takes up much of the time that a copulating pair remains in the heart posture.^[60] Flying in tandem has the advantage that less effort is needed by the female for flight and more can be expended on egg-laying, and when the female submerges to deposit eggs, the male may help to pull her out of the water.^[59]

Egg-laying takes two different forms depending on the species. The female in some families (Aeshnidae, Petaluridae) has a sharp-edged ovipositor with which she slits open a stem or leaf of a plant on or near the water, so she can push her eggs inside. In other families such as clubtails (Gomphidae), cruisers (Macromiidae), emeralds (Corduliidae), and skimmers (Libellulidae), the female lays eggs by tapping the surface of the water repeatedly with her abdomen, by shaking the eggs out of her abdomen as she flies along, or by placing the eggs on vegetation.^[60] In a few species, the eggs are laid on emergent plants above the water, and development is delayed until these have withered and become immersed.^[38]

Life cycle

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Dragonflies are hemimetabolous insects; they do not have a pupal stage and undergo an incomplete metamorphosis with a series of nymphal stages from which the adult emerges.^[61] Eggs laid inside plant tissues are usually shaped like grains of rice, while other eggs are the size of a pinhead, ellipsoidal, or nearly spherical. A clutch may have as many as 1500 eggs, and they take about a week to hatch into aquatic nymphs or naiads which moult between six and 15 times (depending on species) as they grow.^[17] Most of a dragonfly’s life is spent as a nymph, beneath the water’s surface. The nymph extends its hinged labium (a toothed mouthpart similar to a lower mandible, which is sometimes termed as a “mask” as it is normally folded and held before the face) that can extend forward and retract rapidly to capture prey such as mosquito larvae, tadpoles, and small fish.^[61] They breathe through gills in their rectum, and can rapidly propel themselves by suddenly expelling water through the anus.^[62] Some naiads, such as the later stages of Antipodophlebia asthenes, hunt on land.^[63]

The nymph stage of dragonflies lasts up to five years in large species, and between two months and three years in smaller species. When the naiad is ready to metamorphose into an adult, it stops feeding and makes its way to the surface, generally at night. It remains stationary with its head out of the water, while its respiration system adapts to breathing air, then climbs up a reed or other emergent plant, and moults (ecdysis). Anchoring itself firmly in a vertical position with its claws, its exoskeleton begins to split at a weak spot behind the head. The adult dragonfly crawls out of its nymph exoskeleton, the exuvia, arching backwards when all but the tip of its abdomen is free, to allow its exoskeleton to harden. Curling back upwards, it completes its emergence, swallowing air, which plumps out its body, and pumping haemolymph into its wings, which causes them to expand to their full extent.^[64]

Dragonflies in temperate areas can be categorized into two groups: an early group and a later one. In any one area, individuals of a particular “spring species” emerge within a few days of each other. The springtime darner (Basiaeschna janata), for example, is suddenly very common in the spring, but disappears a few weeks later and is not seen again until the following year. By contrast, a “summer species” emerges over a period of weeks or months, later in the year. They may be seen on the wing for several months, but this may represent a whole series of individuals, with new adults hatching out as earlier ones complete their lifespans.^[65]

Sex ratios

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The sex ratio of male to female dragonflies varies both temporally and spatially. Adult dragonflies have a high male-biased ratio at breeding habitats. The male-bias ratio has contributed partially to the females using different habitats to avoid male harassment. As seen in Hine’s emerald dragonfly (Somatochlora hineana), male populations use wetland habitats, while females use dry meadows and marginal breeding habitats, only migrating to the wetlands to lay their eggs or to find mating partners. Unwanted mating is energetically costly for females because it affects the amount of time that they are able to spend foraging.^[66]

Flight

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Dragonflies are powerful and agile fliers, capable of migrating across the sea, moving in any direction, and changing direction suddenly. In flight, the adult dragonfly can propel itself in six directions: upward, downward, forward, backward, to left and to right.^[67] They have four different styles of flight.^[68]

Counter-stroking, with forewings beating 180° out of phase with the hindwings, is used for hovering and slow flight. This style is efficient and generates a large amount of lift.
Phased-stroking, with the hindwings beating 90° ahead of the forewings, is used for fast flight. This style creates more thrust, but less lift than counter-stroking.
Synchronised-stroking, with forewings and hindwings beating together, is used when changing direction rapidly, as it maximises thrust.
Gliding, with the wings held out, is used in three situations: free gliding, for a few seconds in between bursts of powered flight; gliding in the updraft at the crest of a hill, effectively hovering by falling at the same speed as the updraft; and in certain dragonflies such as darters, when “in cop” with a male, the female sometimes simply glides while the male pulls the pair along by beating his wings.^[68]

The wings are powered directly, unlike most families of insects, with the flight muscles attached to the wing bases. Dragonflies have a high power/weight ratio, and have been documented accelerating at 4 G linearly and 9 G in sharp turns while pursuing prey.^[68]

Dragonflies generate lift in at least four ways at different times, including classical lift like an aircraft wing; supercritical lift with the wing above the critical angle, generating high lift and using very short strokes to avoid stalling; and creating and shedding vortices. Some families appear to use special mechanisms, as for example the Libellulidae which take off rapidly, their wings beginning pointed far forward and twisted almost vertically. Dragonfly wings behave highly dynamically during flight, flexing and twisting during each beat. Among the variables are wing curvature, length and speed of stroke, angle of attack, forward/back position of wing, and phase relative to the other wings.^[68]

Flight speed

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Old and unreliable claims are made that dragonflies such as the southern giant darner can fly up to 97 km/h (60 mph).^[69] However, the greatest reliable flight speed records are for other types of insects.^[70] In general, large dragonflies like the hawkers have a maximum speed of 36–54 km/h (22–34 mph) with average cruising speed of about 16 km/h (9.9 mph).^[71] Dragonflies can travel at 100 body-lengths per second in forward flight, and three lengths per second backwards.^[30]

Motion camouflage

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Further information: Motion camouflage

In high-speed territorial battles between male Australian emperors (Hemianax papuensis), the fighting dragonflies adjust their flight paths to appear stationary to their rivals, minimizing the chance of being detected as they approach.^[a]^[72]^[73] To achieve the effect, the attacking dragonfly flies towards his rival, choosing his path to remain on a line between the rival and the start of his attack path. The attacker thus looms larger as he closes on the rival, but does not otherwise appear to move. Researchers found that six of 15 encounters involved motion camouflage.^[74]

Temperature control

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The flight muscles need to be kept at a suitable temperature for the dragonfly to be able to fly. Being cold-blooded, they can raise their temperature by basking in the sun. Early in the morning, they may choose to perch in a vertical position with the wings outstretched, while in the middle of the day, a horizontal stance may be chosen. Another method of warming up used by some larger dragonflies is wing-whirring, a rapid vibration of the wings that causes heat to be generated in the flight muscles. The green darner (Anax junius) is known for its long-distance migrations, and often resorts to wing-whirring before dawn to enable it to make an early start.^[75]

Becoming too hot is another hazard, and a sunny or shady position for perching can be selected according to the ambient temperature. Some species have dark patches on the wings which can provide shade for the body, and a few use the obelisk posture to avoid overheating. This behaviour involves doing a “handstand“, perching with the body raised and the abdomen pointing towards the sun, thus minimising the amount of solar radiation received. On a hot day, dragonflies sometimes adjust their body temperature by skimming over a water surface and briefly touching it, often three times in quick succession. This may also help to avoid desiccation.^[75]

Feeding

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Adult dragonflies hunt on the wing using their exceptionally acute eyesight and strong, agile flight.^[56] They are almost exclusively carnivorous, eating a wide variety of insects ranging from small midges and mosquitoes to butterflies, moths, damselflies, and smaller dragonflies.^[71] A large prey item is subdued by being bitten on the head and is carried by the legs to a perch. Here, the wings are discarded and the prey usually ingested head first.^[76] A dragonfly may consume as much as a fifth of its body weight in prey per day.^[77] Dragonflies are also some of the most efficient hunters, catching up to 95% of the prey they pursue.^[78]

The nymphs are voracious predators, eating most living things that are smaller than they are. Their staple diet is mostly bloodworms and other insect larvae, but they also feed on tadpoles and small fish.^[71] A few species, especially those that live in temporary waters, are likely to leave the water to feed. Nymphs of Cordulegaster bidentata sometimes hunt small arthropods on the ground at night, while some species in the Anax genus have even been observed leaping out of the water to attack and kill full-grown tree frogs.^[17]^[79]

Eyesight

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Dragonfly vision is thought to be like slow motion for humans. Dragonflies see faster than humans do; they see around 200 images per second.^[80] A dragonfly can see in 360 degrees, and nearly 80 per cent of the insect’s brain is dedicated to its sight.^[81]

Predators

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Although dragonflies are swift and agile fliers, some predators are fast enough to catch them. These include falcons such as the American kestrel, the merlin,^[82] and the hobby;^[83] nighthawks, swifts, flycatchers and swallows also take some adults; some species of wasps, too, prey on dragonflies, using them to provision their nests, laying an egg on each captured insect. In the water, various species of ducks and herons eat dragonfly nymphs^[82] and they are also preyed on by newts, frogs, fish, and water spiders.^[84] Amur falcons, which migrate over the Indian Ocean at a period that coincides with the migration of the globe skimmer dragonfly, Pantala flavescens, may actually be feeding on them while on the wing.^[85]

Parasites

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Dragonflies are affected by three groups of parasites: water mites, gregarine protozoa, and trematode flatworms (flukes). Water mites, Hydracarina, can kill smaller dragonfly nymphs, and may also be seen on adults.^[86] Gregarines infect the gut and may cause blockage and secondary infection.^[87] Trematodes are parasites of vertebrates such as frogs, with complex life cycles often involving a period as a stage called a cercaria in a secondary host, a snail. Dragonfly nymphs may swallow cercariae, or these may tunnel through a nymph’s body wall; they then enter the gut and form a cyst or metacercaria, which remains in the nymph for the whole of its development. If the nymph is eaten by a frog, the amphibian becomes infected by the adult or fluke stage of the trematode.^[88]

Dragonflies and humans

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Conservation

[edit]Dragonflies in Oze National Park

Most odonatologists live in temperate areas and the dragonflies of North America and Europe have been the subject of much research. However, the majority of species live in tropical areas and have been little studied. With the destruction of rainforest habitats, many of these species are in danger of becoming extinct before they have even been named. The greatest cause of decline is forest clearance with the consequent drying up of streams and pools which become clogged with silt. The damming of rivers for hydroelectric schemes and the drainage of low-lying land has reduced suitable habitat, as has pollution and the introduction of alien species.^[89]

In 1997, the International Union for Conservation of Nature set up a status survey and conservation action plan for dragonflies. This proposes the establishment of protected areas around the world and the management of these areas to provide suitable habitat for dragonflies. Outside these areas, encouragement should be given to modify forestry, agricultural, and industrial practices to enhance conservation. At the same time, more research into dragonflies needs to be done, consideration should be given to pollution control and the public should be educated about the importance of biodiversity.^[89]

Habitat degradation has reduced dragonfly populations across the world, for example in Japan.^[90] Over 60% of Japan’s wetlands were lost in the 20th century, so its dragonflies now depend largely on rice fields, ponds, and creeks. Dragonflies feed on pest insects in rice, acting as a natural pest control.^[91]^[92] Dragonflies are steadily declining in Africa, and represent a conservation priority.^[93]

The dragonfly’s long lifespan and low population density makes it vulnerable to disturbance, such as from collisions with vehicles on roads built near wetlands. Species that fly low and slow may be most at risk.^[94]

Dragonflies are attracted to shiny surfaces that produce polarization which they can mistake for water, and they have been known to aggregate close to polished gravestones, solar panels, automobiles, and other such structures on which they attempt to lay eggs. These can have a local impact on dragonfly populations; methods of reducing the attractiveness of structures such as solar panels are under experimentation.^[95]^[96]

In culture

[edit]

A blue-glazed faience dragonfly amulet was found by Flinders Petrie at Lahun, from the Late Middle Kingdom of ancient Egypt.^[97]

For the Navajo, dragonflies symbolize pure water. Often stylized in a double-barred cross design, dragonflies are a common motif in Zuni pottery, as well as Hopi rock art and Pueblo necklaces.^[98]^: 20–26

As a seasonal symbol in Japan, dragonflies are associated with the season of autumn.^[99] In Japan, they are symbols of rebirth, courage, strength, and happiness. They are also depicted frequently in Japanese art and literature, especially haiku poetry. Japanese children catch large dragonflies as a game, using a hair with a small pebble tied to each end, which they throw into the air. The dragonfly mistakes the pebbles for prey, gets tangled in the hair, and is dragged to the ground by the weight.^[98]^: 38

In both China and Japan, dragonflies have been used in traditional medicine. In Indonesia, adult dragonflies are caught on poles made sticky with birdlime, then fried in oil as a delicacy.^[100]

Images of dragonflies are common in Art Nouveau, especially in jewellery designs.^[101] They have also been used as a decorative motif on fabrics and home furnishings.^[102] Douglas, a British motorcycle manufacturer based in Bristol, named its innovatively designed postwar 350-cc flat-twin model the Dragonfly.^[103]

Among the classical names of Japan are Akitsukuni (秋津国), Akitsushima (秋津島), Toyo-akitsushima (豊秋津島). Akitsu is an old word for dragonfly, so one interpretation of Akitsushima is “Dragonfly Island”.^[104] This is attributed to a legend in which Japan’s mythical founder, Emperor Jimmu, was bitten by a mosquito, which was then eaten by a dragonfly.^[105]^[106]

In Europe, dragonflies have often been seen as sinister. Some English vernacular names, such as “horse-stinger”,^[107] “devil‘s darning needle”, and “ear cutter”, link them with evil and injury.^[108] Some of these reference the popular misconception that dragonflies can bite or sting humans.^[109] Swedish folklore holds that the devil uses dragonflies to weigh people’s souls.^[98]^: 25–27 The Norwegian name for dragonflies is Øyenstikker (“eye-poker”), and in Portugal, they are sometimes called tira-olhos (“eyes-snatcher”). They are often associated with snakes, as in the Welsh name gwas-y-neidr, “adder‘s servant”.^[108] The Southern United States terms “snake doctor” and “snake feeder” refer to a folk belief that dragonflies catch insects for snakes or follow snakes around and stitch them back together if they are injured.^[110]^[111]

The watercolourist Moses Harris (1731–1785), known for his The Aurelian or natural history of English insects (1766), published in 1780, the first scientific descriptions of several Odonata including the banded demoiselle, Calopteryx splendens. He was the first English artist to make illustrations of dragonflies accurate enough to be identified to species (Aeshna grandis at top left of plate illustrated), though his rough drawing of a nymph (at lower left) with the mask extended appears to be plagiarised.^[b]^[112]

More recently, dragonfly watching has become popular in America as some birdwatchers seek new groups to observe.^[113]

In heraldry, like other winged insects, the dragonfly is typically depicted tergiant (with its back facing the viewer), with its head to chief (at the top).^[114]

Faience amulets from Memphite region, ancient Egypt Middle Kingdom, 12-13 Dynasty
Dragonfly symbol on a Hopi bowl from Sikyátki, Arizona, c. 1400–1625
Accurately drawn dragonflies by Moses Harris, 1780: At top left, the brown hawker, Aeshna grandis (described by Linnaeus, 1758); the nymph at lower left is shown with the “mask” extended.
Woodcut on paper, after Kitagawa Utamaro, 1788
Tiffany & Co. Japonism vase with dragonfly handles, c. 1879, Walters Art Museum
Tiffany dragonfly pendant lamp, designed c. 1903
Japanese tsuba with a dragonfly, 1931: Shibuichi with gold and silver, Walters Art Museum

In poetry and literature

[edit]

Lafcadio Hearn wrote in his 1901 book A Japanese Miscellany that Japanese poets had created dragonfly haiku “almost as numerous as are the dragonflies themselves in the early autumn.”^[115] The poet Matsuo Bashō (1644–1694) wrote haiku such as “Crimson pepper pod / add two pairs of wings, and look / darting dragonfly”, relating the autumn season to the dragonfly.^[116] Hori Bakusui (1718–1783) similarly wrote “Dyed he is with the / Colour of autumnal days, / O red dragonfly.”^[115]

The poet Lord Tennyson, described a dragonfly splitting its old skin and emerging shining metallic blue like “sapphire mail” in his 1842 poem “The Two Voices”, with the lines “An inner impulse rent the veil / Of his old husk: from head to tail / Came out clear plates of sapphire mail.”^[117]

The novelist H. E. Bates described the rapid, agile flight of dragonflies in his 1937 nonfiction book^[118] Down the River:^[119]

I saw, once, an endless procession, just over an area of water-lilies, of small sapphire dragonflies, a continuous play of blue gauze over the snowy flowers above the sun-glassy water. It was all confined, in true dragonfly fashion, to one small space. It was a continuous turning and returning, an endless darting, poising, striking and hovering, so swift that it was often lost in sunlight.^[120]

In technology

[edit]

A dragonfly has been genetically modified with light-sensitive “steering neurons” in its nerve cord to create a cyborg-like “DragonflEye”. The neurons contain genes like those in the eye to make them sensitive to light. Miniature sensors, a computer chip, and a solar panel were fitted in a “backpack” over the insect’s thorax in front of its wings. Light is sent down flexible light-pipes named optrodes^[c] from the backpack into the nerve cord to give steering commands to the insect. The result is a “micro-aerial vehicle that’s smaller, lighter and stealthier than anything else that’s manmade”.^[121]^[122]

March 24, 2025

Ant

Ants are eusocial insects of the family Formicidae and, along with the related wasps and bees, belong to the order Hymenoptera. Ants evolved from vespoid wasp ancestors in the Cretaceous period. More than 13,800 of an estimated total of 22,000 species have been classified. They are easily identified by their geniculate (elbowed) antennae and the distinctive node-like structure that forms their slender waists.

Ants form colonies that range in size from a few dozen individuals often living in small natural cavities to highly organised colonies that may occupy large territories with sizeable nest that consist of millions of individuals or into the hundreds of millions in super colonies. Typical colonies consist of various castes of sterile, wingless females, most of which are workers (ergates), as well as soldiers (dinergates) and other specialised groups. Nearly all ant colonies also have some fertile males called “drones” and one or more fertile females called “queens” (gynes). The colonies are described as superorganisms because the ants appear to operate as a unified entity, collectively working together to support the colony.

Ants have colonised almost every landmass on Earth. The only places lacking indigenous ants are Antarctica and a few remote or inhospitable islands. Ants thrive in moist tropical ecosystems and may exceed the combined biomass of wild birds and mammals. Their success in so many environments has been attributed to their social organisation and their ability to modify habitats, tap resources, and defend themselves. Their long co-evolution with other species has led to mimetic, commensal, parasitic, and mutualistic relationships.

Ant societies have division of labour, communication between individuals, and an ability to solve complex problems. These parallels with human societies have long been an inspiration and subject of study. Many human cultures make use of ants in cuisine, medication, and rites. Some species are valued in their role as biological pest control agents. Their ability to exploit resources may bring ants into conflict with humans, however, as they can damage crops and invade buildings. Some species, such as the red imported fire ant (Solenopsis invicta) of South America, are regarded as invasive species in other parts of the world, establishing themselves in areas where they have been introduced accidentally.

Etymology

The word ant and the archaic word emmet^[3] are derived from ante, emete of Middle English, which come from ǣmette of Old English; these are all related to Low Saxon e(e)mt, empe and varieties (Old Saxon emeta) and to German Ameise (Old High German āmeiza). All of these words come from West Germanic *ǣmaitjōn, and the original meaning of the word was “the biter” (from Proto-Germanic *ai-, “off, away” + *mait- “cut”).^[4]^[5]

The family name Formicidae is derived from the Latin formīca (“ant”)^[6] from which the words in other Romance languages, such as the Portuguese formiga, Italian formica, Spanish hormiga, Romanian furnică, and French fourmi are derived.

The study of ants is called myrmecology, from Ancient Greek μύρμηξ mýrmēx (“ant”). It has been hypothesised that a Proto-Indo-European word *morwi- was the root for Sanskrit vamrah, Greek μύρμηξ mýrmēx, Latin formīca, Old Church Slavonic mraviji, Old Irish moirb, Old Norse maurr, Dutch mier, Swedish myra, Danish myre, Middle Dutch miere, and Crimean Gothic miera.^[7]^[8]

Taxonomy and evolution

The family Formicidae belongs to the order Hymenoptera, which also includes sawflies, bees, and wasps. Ants evolved from a lineage within the stinging wasps, and a 2013 study suggests that they are a sister group of the Apoidea.^[9] However, since Apoidea is a superfamily, ants must be upgraded to the same rank.^[10] A more detailed basic taxonomy was proposed in 2020. Three species of the extinct mid-Cretaceous genera Camelomecia and Camelosphecia were placed outside of the Formicidae, in a separate clade within the general superfamily Formicoidea, which, together with Apoidea, forms the higher-ranking group Formicapoidina.^[2] Fernández et al. (2021) suggest that the common ancestors of ants and apoids within the Formicapoidina probably existed as early as in the end of the Jurassic period, before divergence in the Cretaceous.^[10]

Aculeata Chrysidoidea Vespidae Rhopalosomatidae Pompilidae Mutillidae Tiphiidae Chyphotidae Scolioidea ApoideaFormicidae

Phylogenetic position of the Formicidae as seen in Johnson et al. (2013)^[9]^[10]

FormicidaeFormicoidMyrmicinaeEctatomminaeHeteroponerinaeFormicinaeDolichoderinaeAneuretinaePseudomyrmecinaeMyrmeciinaeDorylinae‡PoneroidPonerinaeAgroecomyrmecinaeParaponerinaeProceratiinaeAmblyoponinaeApomyrminaeLeptanillinaeMartialinae

A phylogeny of the extant ant subfamilies.^[11]^[12]^[13]*Cerapachyinae is paraphyletic
‡ The previous dorylomorph subfamilies – Ecitoninae, Aenictinae, Aenictogitoninae, Cerapachyinae, Leptanilloidinae – were synonymized under Dorylinae by Brady et al. in 2014^[14]

In 1966, E. O. Wilson and his colleagues identified the fossil remains of an ant (Sphecomyrma) that lived in the Cretaceous period. The specimen, trapped in amber dating back to around 92 million years ago, has features found in some wasps, but not found in modern ants.^[15] The oldest fossils of ants date to the mid-Cretaceous, around 100 million years ago, which belong to extinct stem-groups such as the Haidomyrmecinae, Sphecomyrminae and Zigrasimeciinae, with modern ant subfamilies appearing towards the end of the Cretaceous around 80–70 million years ago.^[16] Ants diversified extensively during the Angiosperm Terrestrial Revolution^[17] and assumed ecological dominance around 60 million years ago.^[18]^[1]^[19]^[20] Some groups, such as the Leptanillinae and Martialinae, are suggested to have diversified from early primitive ants that were likely to have been predators underneath the surface of the soil.^[13]^[21]

During the Cretaceous period, a few species of primitive ants ranged widely on the Laurasian supercontinent (the Northern Hemisphere). Their representation in the fossil record is poor, in comparison to the populations of other insects, representing only about 1% of fossil evidence of insects in the era. Ants became dominant after adaptive radiation at the beginning of the Paleogene period. By the Oligocene and Miocene, ants had come to represent 20–40% of all insects found in major fossil deposits. Of the species that lived in the Eocene epoch, around one in 10 genera survive to the present. Genera surviving today comprise 56% of the genera in Baltic amber fossils (early Oligocene), and 92% of the genera in Dominican amber fossils (apparently early Miocene).^[18]^[22]

Termites live in colonies and are sometimes called “white ants”, but termites are only distantly related to ants. They are the sub-order Isoptera, and together with cockroaches, they form the order Blattodea. Blattodeans are related to mantids, crickets, and other winged insects that do not undergo complete metamorphosis. Like ants, termites are eusocial, with sterile workers, but they differ greatly in the genetics of reproduction. The similarity of their social structure to that of ants is attributed to convergent evolution.^[23] Velvet ants look like large ants, but are wingless female wasps.^[24]^[25]

Distribution and diversity

Region	Number of species ^[26]
Neotropics	2,162
Nearctic	580
Europe	180
Africa	2,500
Asia	2,080
Melanesia	275
Australia	985
Polynesia	42

Ants have a cosmopolitan distribution. They are found on all continents except Antarctica, and only a few large islands, such as Greenland, Iceland, parts of Polynesia and the Hawaiian Islands lack native ant species.^[27]^[28] Ants occupy a wide range of ecological niches and exploit many different food resources as direct or indirect herbivores, predators and scavengers. Most ant species are omnivorous generalists, but a few are specialist feeders. There is considerable variation in ant abundance across habitats, peaking in the moist tropics to nearly six times that found in less suitable habitats.^[29] Their ecological dominance has been examined primarily using estimates of their biomass: myrmecologist E. O. Wilson had estimated in 2009 that at any one time the total number of ants was between one and ten quadrillion (short scale) (i.e., between 10¹⁵ and 10¹⁶) and using this estimate he had suggested that the total biomass of all the ants in the world was approximately equal to the total biomass of the entire human race.^[30] More careful estimates made in 2022 which take into account regional variations puts the global ant contribution at 12 megatons of dry carbon, which is about 20% of the total human contribution, but greater than that of the wild birds and mammals combined. This study also puts a conservative estimate of the ants at about 20 × 10¹⁵ (20 quadrillion).^[31]^[32]^[33]

Ants range in size from 0.75 to 52 millimetres (0.030–2.0 in),^[34]^[35] the largest species being the fossil Titanomyrma giganteum, the queen of which was 6 cm (2+¹⁄₂ in) long with a wingspan of 15 cm (6 in).^[36] Ants vary in colour; most ants are yellow to red or brown to black, but a few species are green and some tropical species have a metallic lustre. More than 13,800 species are currently known^[37] (with upper estimates of the potential existence of about 22,000; see the article List of ant genera), with the greatest diversity in the tropics. Taxonomic studies continue to resolve the classification and systematics of ants. Online databases of ant species, including AntWeb and the Hymenoptera Name Server, help to keep track of the known and newly described species.^[37] The relative ease with which ants may be sampled and studied in ecosystems has made them useful as indicator species in biodiversity studies.^[38]^[39]

Morphology

Ants are distinct in their morphology from other insects in having geniculate (elbowed) antennae, metapleural glands, and a strong constriction of their second abdominal segment into a node-like petiole. The body is divided into three distinct sections (formally known as tagmata): the head, mesosoma, and metasoma. The petiole forms a narrow waist between their mesosoma (thorax plus the first abdominal segment, which is fused to it) and gaster (abdomen less the abdominal segments in the petiole). The petiole may be formed by one or two nodes (the second alone, or the second and third abdominal segments).^[40] Tergosternal fusion, when the tergite and sternite of a segment fuse together, can occur partly or fully on the second, third and fourth abdominal segment and is used in identification. Fourth abdominal tergosternal fusion was formerly used as character that defined the poneromorph subfamilies, Ponerinae and relatives within their clade, but this is no longer considered a synapomorphic character.^[41]

Like other arthropods, ants have an exoskeleton, an external covering that provides a protective casing around the body and a point of attachment for muscles, in contrast to the internal skeletons of humans and other vertebrates. Insects do not have lungs; oxygen and other gases, such as carbon dioxide, pass through their exoskeleton via tiny valves called spiracles. Insects also lack closed blood vessels; instead, they have a long, thin, perforated tube along the top of the body (called the “dorsal aorta”) that functions like a heart, and pumps haemolymph toward the head, thus driving the circulation of the internal fluids. The nervous system consists of a ventral nerve cord that runs the length of the body, with several ganglia and branches along the way reaching into the extremities of the appendages.^[42]

Head

An ant’s head contains many sensory organs. Like most insects, ants have compound eyes made from numerous tiny lenses attached together. Ant eyes are good for acute movement detection, but do not offer a high resolution image. They also have three small ocelli (simple eyes) on the top of the head that detect light levels and polarization.^[43] Compared to vertebrates, ants tend to have blurrier eyesight, particularly in smaller species,^[44] and a few subterranean taxa are completely blind.^[12] However, some ants, such as Australia’s bulldog ant, have excellent vision and are capable of discriminating the distance and size of objects moving nearly a meter away.^[45] Based on experiments conducted to test their ability to differentiate between selected wavelengths of light, some ant species such as Camponotus blandus, Solenopsis invicta, and Formica cunicularia are thought to possess a degree of colour vision.^[46]

Two antennae (“feelers”) are attached to the head; these organs detect chemicals, air currents, and vibrations; they also are used to transmit and receive signals through touch. The head has two strong jaws, the mandibles, used to carry food, manipulate objects, construct nests, and for defence.^[42] In some species, a small pocket (infrabuccal chamber) inside the mouth stores food, so it may be passed to other ants or their larvae.^[47]

Mesosoma

Both the legs and wings of the ant are attached to the mesosoma (“thorax”). The legs terminate in a hooked claw which allows them to hook on and climb surfaces.^[48] Only reproductive ants (queens and males) have wings. Queens shed their wings after the nuptial flight, leaving visible stubs, a distinguishing feature of queens. In a few species, wingless queens (ergatoids) and males occur.^[42]

Metasoma

The metasoma (the “abdomen”) of the ant houses important internal organs, including those of the reproductive, respiratory (tracheae), and excretory systems. Workers of many species have their egg-laying structures modified into stings that are used for subduing prey and defending their nests.^[42]

Polymorphism

Seven leafcutter ant workers of various castes (left) and two queens (right)

In the colonies of a few ant species, there are physical castes—workers in distinct size-classes, called minor (micrergates), median, and major ergates (macrergates). Often, the larger ants have disproportionately larger heads, and correspondingly stronger mandibles. Although formally known as dinergates, such individuals are sometimes called “soldier” ants because their stronger mandibles make them more effective in fighting, although they still are workers and their “duties” typically do not vary greatly from the minor or median workers.^[49] In a few species, the median workers are absent, creating a sharp divide between the minors and majors.^[50] Weaver ants, for example, have a distinct bimodal size distribution.^[51]^[52] Some other species show continuous variation in the size of workers. The smallest and largest workers in Carebara diversa show nearly a 500-fold difference in their dry weights.^[53]

Workers cannot mate; however, because of the haplodiploid sex-determination system in ants, workers of a number of species can lay unfertilised eggs that become fully fertile, haploid males. The role of workers may change with their age and in some species, such as honeypot ants, young workers are fed until their gasters are distended, and act as living food storage vessels. These food storage workers are called repletes.^[54] For instance, these replete workers develop in the North American honeypot ant Myrmecocystus mexicanus. Usually the largest workers in the colony develop into repletes; and, if repletes are removed from the colony, other workers become repletes, demonstrating the flexibility of this particular polymorphism.^[55] This polymorphism in morphology and behaviour of workers initially was thought to be determined by environmental factors such as nutrition and hormones that led to different developmental paths; however, genetic differences between worker castes have been noted in Acromyrmex sp.^[56] These polymorphisms are caused by relatively small genetic changes; differences in a single gene of Solenopsis invicta can decide whether the colony will have single or multiple queens.^[57] The Australian jack jumper ant (Myrmecia pilosula) has only a single pair of chromosomes (with the males having just one chromosome as they are haploid), the lowest number known for any animal, making it an interesting subject for studies in the genetics and developmental biology of social insects.^[58]^[59]

Genome size

Genome size is a fundamental characteristic of an organism. Ants have been found to have tiny genomes, with the evolution of genome size suggested to occur through loss and accumulation of non-coding regions, mainly transposable elements, and occasionally by whole genome duplication.^[60] This may be related to colonisation processes, but further studies are needed to verify this.^[60]

Life cycle

The life of an ant starts from an egg; if the egg is fertilised, the progeny will be female diploid, if not, it will be male haploid. Ants develop by complete metamorphosis with the larva stages passing through a pupal stage before emerging as an adult. The larva is largely immobile and is fed and cared for by workers. Food is given to the larvae by trophallaxis, a process in which an ant regurgitates liquid food held in its crop. This is also how adults share food, stored in the “social stomach”. Larvae, especially in the later stages, may also be provided solid food, such as trophic eggs, pieces of prey, and seeds brought by workers.^[61]

The larvae grow through a series of four or five moults and enter the pupal stage. The pupa has the appendages free and not fused to the body as in a butterfly pupa.^[62] The differentiation into queens and workers (which are both female), and different castes of workers, is influenced in some species by the nutrition the larvae obtain. Genetic influences and the control of gene expression by the developmental environment are complex and the determination of caste continues to be a subject of research.^[63] Winged male ants, called drones (termed “aner” in old literature^[49]), emerge from pupae along with the usually winged breeding females. Some species, such as army ants, have wingless queens. Larvae and pupae need to be kept at fairly constant temperatures to ensure proper development, and so often are moved around among the various brood chambers within the colony.^[64]

A new ergate spends the first few days of its adult life caring for the queen and young. She then graduates to digging and other nest work, and later to defending the nest and foraging. These changes are sometimes fairly sudden, and define what are called temporal castes. Such age-based task-specialization or polyethism has been suggested as having evolved due to the high casualties involved in foraging and defence, making it an acceptable risk only for ants who are older and likely to die sooner from natural causes.^[65]^[66] In the Brazilian ant Forelius pusillus, the nest entrance is closed from the outside to protect the colony from predatory ant species at sunset each day. About one to eight workers seal the nest entrance from the outside and they have no chance of returning to the nest and are in effect sacrificed.^[67] Whether these seemingly suicidal workers are older workers has not been determined.^[68]

Ant colonies can be long-lived. The queens can live for up to 30 years, and workers live from 1 to 3 years. Males, however, are more transitory, being quite short-lived and surviving for only a few weeks.^[69] Ant queens are estimated to live 100 times as long as solitary insects of a similar size.^[70]

Ants are active all year long in the tropics; however, in cooler regions, they survive the winter in a state of dormancy known as hibernation. The forms of inactivity are varied and some temperate species have larvae going into the inactive state (diapause), while in others, the adults alone pass the winter in a state of reduced activity.^[71]

Reproduction

Honey ant (*Prenolepis imparis*) mating, the drone is much smaller than the queen

A wide range of reproductive strategies have been noted in ant species. Females of many species are known to be capable of reproducing asexually through thelytokous parthenogenesis.^[72] Secretions from the male accessory glands in some species can plug the female genital opening and prevent females from re-mating.^[73] Most ant species have a system in which only the queen and breeding females have the ability to mate. Contrary to popular belief, some ant nests have multiple queens, while others may exist without queens. Workers with the ability to reproduce are called “gamergates” and colonies that lack queens are then called gamergate colonies; colonies with queens are said to be queen-right.^[74]

Drones can also mate with existing queens by entering a foreign colony, such as in army ants. When the drone is initially attacked by the workers, it releases a mating pheromone. If recognized as a mate, it will be carried to the queen to mate.^[75] Males may also patrol the nest and fight others by grabbing them with their mandibles, piercing their exoskeleton and then marking them with a pheromone. The marked male is interpreted as an invader by worker ants and is killed.^[76]

Most ants are univoltine, producing a new generation each year.^[77] During the species-specific breeding period, winged females and winged males, known to entomologists as alates, leave the colony in what is called a nuptial flight. The nuptial flight usually takes place in the late spring or early summer when the weather is hot and humid. Heat makes flying easier and freshly fallen rain makes the ground softer for mated queens to dig nests.^[78] Males typically take flight before the females. Males then use visual cues to find a common mating ground, for example, a landmark such as a pine tree to which other males in the area converge. Males secrete a mating pheromone that females follow. Males will mount females in the air, but the actual mating process usually takes place on the ground. Females of some species mate with just one male but in others they may mate with as many as ten or more different males, storing the sperm in their spermathecae.^[79] The genus Cardiocondyla have species with both winged and wingless males, where the latter will only mate with females living in the same nest. Some species in the genus have lost winged males completely, and only produce wingless males.^[80] In C. elegans, workers may transport newly emerged queens to other conspecific nests where the wingless males from unrelated colonies can mate with them, a behavioural adaptation that may reduce the chances of inbreeding.^[81]

Mated females then seek a suitable place to begin a colony. There, they break off their wings using their tibial spurs and begin to lay and care for eggs. The females can selectively fertilise future eggs with the sperm stored to produce diploid workers or lay unfertilized haploid eggs to produce drones. The first workers to hatch, known as nanitics,^[82] are weaker and smaller than later workers but they begin to serve the colony immediately. They enlarge the nest, forage for food, and care for the other eggs. Species that have multiple queens may have a queen leaving the nest along with some workers to found a colony at a new site,^[79] a process akin to swarming in honeybees.

Nests, colonies, and supercolonies

The typical ant species has a colony occupying a single nest, housing one or more queens, where the brood is raised. There are however more than 150 species of ants in 49 genera that are known to have colonies consisting of multiple spatially separated nests. These polydomous (as opposed to monodomous) colonies have food and workers moving between the nests.^[83] Membership to a colony is identified by the response of worker ants which identify whether another individual belongs to their own colony or not. A signature cocktail of body surface chemicals (also known as cuticular hydrocarbons or CHCs) forms the so-called colony odor which other members can recognize.^[84] Some ant species appear to be less discriminating and in the Argentine ant Linepithema humile, workers carried from a colony anywhere in the southern US and Mexico are acceptable within other colonies in the same region. Similarly workers from colonies that have established in Europe are accepted by any other colonies within Europe but not by the colonies in the Americas. The interpretation of these observations has been debated and some have been termed these large populations as supercolonies^[85]^[86]^[87] while others have termed the populations as unicolonial.^[88]

Behaviour and ecology

Communication

Defence

Learning

Many animals can learn behaviours by imitation, but ants may be the only group apart from mammals where interactive teaching has been observed. A knowledgeable forager of Temnothorax albipennis can lead a naïve nest-mate to newly discovered food by the process of tandem running. The follower obtains knowledge through its leading tutor. The leader is acutely sensitive to the progress of the follower and slows down when the follower lags and speeds up when the follower gets too close.^[116]

Controlled experiments with colonies of Cerapachys biroi suggest that an individual may choose nest roles based on her previous experience. An entire generation of identical workers was divided into two groups whose outcome in food foraging was controlled. One group was continually rewarded with prey, while it was made certain that the other failed. As a result, members of the successful group intensified their foraging attempts while the unsuccessful group ventured out fewer and fewer times. A month later, the successful foragers continued in their role while the others had moved to specialise in brood care.^[117]

Nest construction

Main article: Ant colony

Leaf nest of weaver ants, Pamalican, Philippines

Complex nests are built by many ant species, but other species are nomadic and do not build permanent structures. Ants may form subterranean nests or build them on trees. These nests may be found in the ground, under stones or logs, inside logs, hollow stems, or even acorns. The materials used for construction include soil and plant matter,^[79] and ants carefully select their nest sites; Temnothorax albipennis will avoid sites with dead ants, as these may indicate the presence of pests or disease. They are quick to abandon established nests at the first sign of threats.^[118]

The army ants of South America, such as the Eciton burchellii species, and the driver ants of Africa do not build permanent nests, but instead, alternate between nomadism and stages where the workers form a temporary nest (bivouac) from their own bodies, by holding each other together.^[119]

Weaver ant (Oecophylla spp.) workers build nests in trees by attaching leaves together, first pulling them together with bridges of workers and then inducing their larvae to produce silk as they are moved along the leaf edges. Similar forms of nest construction are seen in some species of Polyrhachis.^[120]

Formica polyctena, among other ant species, constructs nests that maintain a relatively constant interior temperature that aids in the development of larvae. The ants maintain the nest temperature by choosing the location, nest materials, controlling ventilation and maintaining the heat from solar radiation, worker activity and metabolism, and in some moist nests, microbial activity in the nest materials.^[121]^[122]

Some ant species, such as those that use natural cavities, can be opportunistic and make use of the controlled micro-climate provided inside human dwellings and other artificial structures to house their colonies and nest structures.^[123]^[124]

Cultivation of food

Main article: Ant–fungus mutualism

*Myrmecocystus*, honeypot ants, store food to prevent colony famine.

Most ants are generalist predators, scavengers, and indirect herbivores,^[19] but a few have evolved specialised ways of obtaining nutrition. It is believed that many ant species that engage in indirect herbivory rely on specialized symbiosis with their gut microbes^[125] to upgrade the nutritional value of the food they collect^[126] and allow them to survive in nitrogen poor regions, such as rainforest canopies.^[127] Leafcutter ants (Atta and Acromyrmex) feed exclusively on a fungus that grows only within their colonies. They continually collect leaves which are taken to the colony, cut into tiny pieces and placed in fungal gardens. Ergates specialise in related tasks according to their sizes. The largest ants cut stalks, smaller workers chew the leaves and the smallest tend the fungus. Leafcutter ants are sensitive enough to recognise the reaction of the fungus to different plant material, apparently detecting chemical signals from the fungus. If a particular type of leaf is found to be toxic to the fungus, the colony will no longer collect it. The ants feed on structures produced by the fungi called gongylidia. Symbiotic bacteria on the exterior surface of the ants produce antibiotics that kill bacteria introduced into the nest that may harm the fungi.^[128]

Navigation

Foraging ants travel distances of up to 200 metres (700 ft) from their nest^[129] and scent trails allow them to find their way back even in the dark. In hot and arid regions, day-foraging ants face death by desiccation, so the ability to find the shortest route back to the nest reduces that risk. Diurnal desert ants of the genus Cataglyphis such as the Sahara desert ant navigate by keeping track of direction as well as distance travelled. Distances travelled are measured using an internal pedometer that keeps count of the steps taken^[130] and also by evaluating the movement of objects in their visual field (optical flow).^[131] Directions are measured using the position of the sun.^[132] They integrate this information to find the shortest route back to their nest.^[133] Like all ants, they can also make use of visual landmarks when available^[134] as well as olfactory and tactile cues to navigate.^[135]^[136] Some species of ant are able to use the Earth’s magnetic field for navigation.^[137] The compound eyes of ants have specialised cells that detect polarised light from the Sun, which is used to determine direction.^[138]^[139] These polarization detectors are sensitive in the ultraviolet region of the light spectrum.^[140] In some army ant species, a group of foragers who become separated from the main column may sometimes turn back on themselves and form a circular ant mill. The workers may then run around continuously until they die of exhaustion.^[141]

Locomotion

The female worker ants do not have wings and reproductive females lose their wings after their mating flights in order to begin their colonies. Therefore, unlike their wasp ancestors, most ants travel by walking. Some species are capable of leaping. For example, Jerdon’s jumping ant (Harpegnathos saltator) is able to jump by synchronising the action of its mid and hind pairs of legs.^[142] There are several species of gliding ant including Cephalotes atratus; this may be a common trait among arboreal ants with small colonies. Ants with this ability are able to control their horizontal movement so as to catch tree trunks when they fall from atop the forest canopy.^[143]

Other species of ants can form chains to bridge gaps over water, underground, or through spaces in vegetation. Some species also form floating rafts that help them survive floods.^[144] These rafts may also have a role in allowing ants to colonise islands.^[145] Polyrhachis sokolova, a species of ant found in Australian mangrove swamps, can swim and live in underwater nests. Since they lack gills, they go to trapped pockets of air in the submerged nests to breathe.^[146]

Cooperation and competition

Not all ants have the same kind of societies. The Australian bulldog ants are among the biggest and most basal of ants. Like virtually all ants, they are eusocial, but their social behaviour is poorly developed compared to other species. Each individual hunts alone, using her large eyes instead of chemical senses to find prey.^[147]

Some species attack and take over neighbouring ant colonies. Extreme specialists among these slave-raiding ants, such as the Amazon ants, are incapable of feeding themselves and need captured workers to survive.^[148] Captured workers of enslaved Temnothorax species have evolved a counter-strategy, destroying just the female pupae of the slave-making Temnothorax americanus, but sparing the males (who do not take part in slave-raiding as adults).^[149]

Ants identify kin and nestmates through their scent, which comes from hydrocarbon-laced secretions that coat their exoskeletons. If an ant is separated from its original colony, it will eventually lose the colony scent. Any ant that enters a colony without a matching scent will be attacked.^[150]

Parasitic ant species enter the colonies of host ants and establish themselves as social parasites; species such as Strumigenys xenos are entirely parasitic and do not have workers, but instead, rely on the food gathered by their Strumigenys perplexa hosts.^[151]^[152] This form of parasitism is seen across many ant genera, but the parasitic ant is usually a species that is closely related to its host. A variety of methods are employed to enter the nest of the host ant. A parasitic queen may enter the host nest before the first brood has hatched, establishing herself prior to development of a colony scent. Other species use pheromones to confuse the host ants or to trick them into carrying the parasitic queen into the nest. Some simply fight their way into the nest.^[153]

A conflict between the sexes of a species is seen in some species of ants with these reproducers apparently competing to produce offspring that are as closely related to them as possible. The most extreme form involves the production of clonal offspring. An extreme of sexual conflict is seen in Wasmannia auropunctata, where the queens produce diploid daughters by thelytokous parthenogenesis and males produce clones by a process whereby a diploid egg loses its maternal contribution to produce haploid males who are clones of the father.^[154]

Relationships with other organisms

Ants form symbiotic associations with a range of species, including other ant species, other insects, plants, and fungi. They also are preyed on by many animals and even certain fungi. Some arthropod species spend part of their lives within ant nests, either preying on ants, their larvae, and eggs, consuming the food stores of the ants, or avoiding predators. These inquilines may bear a close resemblance to ants. The nature of this ant mimicry (myrmecomorphy) varies, with some cases involving Batesian mimicry, where the mimic reduces the risk of predation. Others show Wasmannian mimicry, a form of mimicry seen only in inquilines.^[155]^[156]

Duration: 2 minutes and 9 seconds.2:09Ants collecting honeydew from Calico scales (Eulecanium cerasorum) then played at 30 times speed to show the pumping action of the scale.

Aphids and other hemipteran insects secrete a sweet liquid called honeydew, when they feed on plant sap. The sugars in honeydew are a high-energy food source, which many ant species collect.^[157] In some cases, the aphids secrete the honeydew in response to ants tapping them with their antennae. The ants in turn keep predators away from the aphids and will move them from one feeding location to another. When migrating to a new area, many colonies will take the aphids with them, to ensure a continued supply of honeydew. Ants also tend mealybugs to harvest their honeydew. Mealybugs may become a serious pest of pineapples if ants are present to protect mealybugs from their natural enemies.^[158]

Myrmecophilous (ant-loving) caterpillars of the butterfly family Lycaenidae (e.g., blues, coppers, or hairstreaks) are herded by the ants, led to feeding areas in the daytime, and brought inside the ants’ nest at night. The caterpillars have a gland which secretes honeydew when the ants massage them. The chemicals in the secretions of Narathura japonica alter the behavior of attendant Pristomyrmex punctatus workers, making them less aggressive and stationary. The relationship, formerly characterized as “mutualistic”, is now considered as possibly a case of the ants being parasitically manipulated by the caterpillars.^[159] Some caterpillars produce vibrations and sounds that are perceived by the ants.^[160] A similar adaptation can be seen in Grizzled skipper butterflies that emit vibrations by expanding their wings in order to communicate with ants, which are natural predators of these butterflies.^[161] Other caterpillars have evolved from ant-loving to ant-eating: these myrmecophagous caterpillars secrete a pheromone that makes the ants act as if the caterpillar is one of their own larvae. The caterpillar is then taken into the ant nest where it feeds on the ant larvae.^[162] A number of specialized bacteria have been found as endosymbionts in ant guts. Some of the dominant bacteria belong to the order Hyphomicrobiales whose members are known for being nitrogen-fixing symbionts in legumes but the species found in ant lack the ability to fix nitrogen.^[163]^[164] Fungus-growing ants that make up the tribe Attini, including leafcutter ants, cultivate certain species of fungus in the genera Leucoagaricus or Leucocoprinus of the family Agaricaceae. In this ant-fungus mutualism, both species depend on each other for survival. The ant Allomerus decemarticulatus has evolved a three-way association with the host plant, Hirtella physophora (Chrysobalanaceae), and a sticky fungus which is used to trap their insect prey.^[165]

Ants tending aphids and collecting honeydew secreted. A wrinkled solder beetle flies in and eats an aphid before being chased away by the ants.

Lemon ants make devil’s gardens by killing surrounding plants with their stings and leaving a pure patch of lemon ant trees, (Duroia hirsuta). This modification of the forest provides the ants with more nesting sites inside the stems of the Duroia trees.^[166] Although some ants obtain nectar from flowers, pollination by ants is somewhat rare, one example being of the pollination of the orchid Leporella fimbriata which induces male Myrmecia urens to pseudocopulate with the flowers, transferring pollen in the process.^[167] One theory that has been proposed for the rarity of pollination is that the secretions of the metapleural gland inactivate and reduce the viability of pollen.^[168]^[169] Some plants, mostly angiosperms but also some ferns,^[170] have special nectar exuding structures, extrafloral nectaries, that provide food for ants, which in turn protect the plant from more damaging herbivorous insects.^[171] Species such as the bullhorn acacia (Acacia cornigera) in Central America have hollow thorns that house colonies of stinging ants (Pseudomyrmex ferruginea) who defend the tree against insects, browsing mammals, and epiphytic vines. Isotopic labelling studies suggest that plants also obtain nitrogen from the ants.^[172] In return, the ants obtain food from protein- and lipid-rich Beltian bodies. In Fiji Philidris nagasau (Dolichoderinae) are known to selectively grow species of epiphytic Squamellaria (Rubiaceae) which produce large domatia inside which the ant colonies nest. The ants plant the seeds and the domatia of young seedling are immediately occupied and the ant faeces in them contribute to rapid growth.^[173] Similar dispersal associations are found with other dolichoderines in the region as well.^[174] Another example of this type of ectosymbiosis comes from the Macaranga tree, which has stems adapted to house colonies of Crematogaster ants.^[175]

Many plant species have seeds that are adapted for dispersal by ants.^[176] Seed dispersal by ants or myrmecochory is widespread, and new estimates suggest that nearly 9% of all plant species may have such ant associations.^[177]^[176] Often, seed-dispersing ants perform directed dispersal, depositing the seeds in locations that increase the likelihood of seed survival to reproduction.^[178] Some plants in arid, fire-prone systems are particularly dependent on ants for their survival and dispersal as the seeds are transported to safety below the ground.^[179] Many ant-dispersed seeds have special external structures, elaiosomes, that are sought after by ants as food.^[180] Ants can substantially alter rate of decomposition and nutrient cycling in their nest.^[181]^[182] By myrmecochory and modification of soil conditions they substantially alter vegetation and nutrient cycling in surrounding ecosystem.^[183]

A convergence, possibly a form of mimicry, is seen in the eggs of stick insects. They have an edible elaiosome-like structure and are taken into the ant nest where the young hatch.^[184]

Bold Jumping Spider (Phidippus audax) with a cutworm (tribe Noctuini) and then lost to ants (Family Formicidae)Ants from different colonies steal the cranefly that a pair of Long-jawed orb weaver spiders were consuming.

Most ants are predatory and some prey on and obtain food from other social insects including other ants. Some species specialise in preying on termites (Megaponera and Termitopone) while a few Cerapachyinae prey on other ants.^[129] Some termites, including Nasutitermes corniger, form associations with certain ant species to keep away predatory ant species.^[185] The tropical wasp Mischocyttarus drewseni coats the pedicel of its nest with an ant-repellent chemical.^[186] It is suggested that many tropical wasps may build their nests in trees and cover them to protect themselves from ants. Other wasps, such as A. multipicta, defend against ants by blasting them off the nest with bursts of wing buzzing.^[187] Stingless bees (Trigona and Melipona) use chemical defences against ants.^[129]

Flies in the Old World genus Bengalia (Calliphoridae) prey on ants and are kleptoparasites, snatching prey or brood from the mandibles of adult ants.^[188] Wingless and legless females of the Malaysian phorid fly (Vestigipoda myrmolarvoidea) live in the nests of ants of the genus Aenictus and are cared for by the ants.^[188]

Fungi in the genera Cordyceps and Ophiocordyceps infect ants. Ants react to their infection by climbing up plants and sinking their mandibles into plant tissue. The fungus kills the ants, grows on their remains, and produces a fruiting body. It appears that the fungus alters the behaviour of the ant to help disperse its spores^[189] in a microhabitat that best suits the fungus.^[190] Strepsipteran parasites also manipulate their ant host to climb grass stems, to help the parasite find mates.^[191]

A nematode (Myrmeconema neotropicum) that infects canopy ants (Cephalotes atratus) causes the black-coloured gasters of workers to turn red. The parasite also alters the behaviour of the ant, causing them to carry their gasters high. The conspicuous red gasters are mistaken by birds for ripe fruits, such as Hyeronima alchorneoides, and eaten. The droppings of the bird are collected by other ants and fed to their young, leading to further spread of the nematode.^[192]

A study of Temnothorax nylanderi colonies in Germany found that workers parasitized by the tapeworm Anomotaenia brevis (ants are intermediate hosts, the definitive hosts are woodpeckers) lived much longer than unparasitized workers and had a reduced mortality rate, comparable to that of the queens of the same species, which live for as long as two decades.^[193]

South American poison dart frogs in the genus Dendrobates feed mainly on ants, and the toxins in the skin of some species come from the ants.^[194]^[195] Formicine ants in the genera Brachymyrmex and Paratrechina have been found to contain pumiliotoxin found in Dendrobates pumilio.^[196] The West African frog Phrynomantis microps is able to move within the nests of Paltothyreus tarsatus ants, producing peptides on its skin that prevent the ants from stinging them.^[197]

Army ants which is the toxin found in forage in a wide roving column, attacking any animals in that path that are unable to escape. In Central and South America, Eciton burchellii is the swarming ant most commonly attended by “ant-following” birds such as antbirds and woodcreepers.^[198]^[199] This behaviour was once considered mutualistic, but later studies found the birds to be parasitic. Direct kleptoparasitism (birds stealing food from the ants’ grasp) is rare and has been noted in Inca doves which pick seeds at nest entrances as they are being transported by species of Pogonomyrmex.^[200] Birds that follow ants eat many prey insects and thus decrease the foraging success of ants.^[201] Birds indulge in a peculiar behaviour called anting that, as yet, is not fully understood. Here birds rest on ant nests, or pick and drop ants onto their wings and feathers; this may be a means to remove ectoparasites from the birds.

Anteaters, aardvarks, pangolins, echidnas and numbats have special adaptations for living on a diet of ants. These adaptations include long, sticky tongues to capture ants and strong claws to break into ant nests. Brown bears (Ursus arctos) have been found to feed on ants. About 12%, 16%, and 4% of their faecal volume in spring, summer and autumn, respectively, is composed of ants.^[202]

Relationship with humans

Weaver ants are used as a biological control for citrus cultivation in southern China.

Ants perform many ecological roles that are beneficial to humans, including the suppression of pest populations and aeration of the soil. The use of weaver ants in citrus cultivation in southern China is considered one of the oldest known applications of biological control.^[203] On the other hand, ants may become nuisances when they invade buildings or cause economic losses.

In some parts of the world (mainly Africa and South America), large ants, especially army ants, are used as surgical sutures. The wound is pressed together and ants are applied along it. The ant seizes the edges of the wound in its mandibles and locks in place. The body is then cut off and the head and mandibles remain in place to close the wound.^[204]^[205]^[206] The large heads of the dinergates (soldiers) of the leafcutting ant Atta cephalotes are also used by native surgeons in closing wounds.^[207]

Some ants have toxic venom and are of medical importance. The species include Paraponera clavata (tocandira) and Dinoponera spp. (false tocandiras) of South America^[208] and the Myrmecia ants of Australia.^[209]

In South Africa, ants are used to help harvest the seeds of rooibos (Aspalathus linearis), a plant used to make a herbal tea. The plant disperses its seeds widely, making manual collection difficult. Black ants collect and store these and other seeds in their nest, where humans can gather them en masse. Up to half a pound (200 g) of seeds may be collected from one ant-heap.^[210]^[211]

Although most ants survive attempts by humans to eradicate them, a few are highly endangered. These tend to be island species that have evolved specialized traits and risk being displaced by introduced ant species. Examples include the critically endangered Sri Lankan relict ant (Aneuretus simoni) and Adetomyrma venatrix of Madagascar.^[212]

As food

As pests

In science and technology

*Camponotus nearcticus* workers travelling between two formicaria through connector tubing

Observed by humans since the dawn of history, the behaviour of ants has been documented and the subject of early writings and fables passed from one century to another. Those using scientific methods, myrmecologists, study ants in the laboratory and in their natural conditions. Their complex and variable social structures have made ants ideal model organisms. Ultraviolet vision was first discovered in ants by Sir John Lubbock in 1881.^[219] Studies on ants have tested hypotheses in ecology and sociobiology, and have been particularly important in examining the predictions of theories of kin selection and evolutionarily stable strategies.^[220] Ant colonies may be studied by rearing or temporarily maintaining them in formicaria, specially constructed glass framed enclosures.^[221] Individuals may be tracked for study by marking them with dots of colours.^[222]

The successful techniques used by ant colonies have been studied in computer science and robotics to produce distributed and fault-tolerant systems for solving problems, for example Ant colony optimization and Ant robotics. This area of biomimetics has led to studies of ant locomotion, search engines that make use of “foraging trails”, fault-tolerant storage, and networking algorithms.^[223]

As pets

Main article: Ant-keeping

From the late 1950s through the late 1970s, ant farms were popular educational children’s toys in the United States. Some later commercial versions use transparent gel instead of soil, allowing greater visibility at the cost of stressing the ants with unnatural light.^[224]

In culture

Anthropomorphised ants have often been used in fables, children’s stories, and religious texts to represent industriousness and cooperative effort, such as in the Aesop fable The Ant and the Grasshopper.^[225]^[226] In the Quran, Sulayman is said to have heard and understood an ant warning other ants to return home to avoid being accidentally crushed by Sulayman and his marching army.^{[Quran 27:18]},^[227]^[228] In parts of Africa, ants are considered to be the messengers of the deities. Some Native American mythology, such as the Hopi mythology, considers ants as the first animals. Ant bites are often said to have curative properties. The sting of some species of Pseudomyrmex is claimed to give fever relief.^[229] Ant bites are used in the initiation ceremonies of some Amazon Indian cultures as a test of endurance.^[230]^[231] In Greek mythology, the goddess Athena turned the maiden Myrmex into an ant when the latter claimed to have invented the plough, when in fact it was Athena’s own invention.^[232]

Ant society has always fascinated humans and has been written about both humorously and seriously. Mark Twain wrote about ants in his 1880 book A Tramp Abroad.^[233] Some modern authors have used the example of the ants to comment on the relationship between society and the individual. Examples are Robert Frost in his poem “Departmental” and T. H. White in his fantasy novel The Once and Future King. The plot in French entomologist and writer Bernard Werber‘s Les Fourmis science-fiction trilogy is divided between the worlds of ants and humans; ants and their behaviour are described using contemporary scientific knowledge. H. G. Wells wrote about intelligent ants destroying human settlements in Brazil and threatening human civilization in his 1905 science-fiction short story, The Empire of the Ants. A similar German story involving army ants, Leiningen Versus the Ants, was written in 1937 and recreated in movie form as The Naked Jungle in 1954.^[234] In more recent times, animated cartoons and 3-D animated films featuring ants have been produced including Antz, A Bug’s Life, The Ant Bully, The Ant and the Aardvark, Ferdy the Ant and Atom Ant. Renowned myrmecologist E. O. Wilson wrote a short story, “Trailhead” in 2010 for The New Yorker magazine, which describes the life and death of an ant-queen and the rise and fall of her colony, from an ants’ point of view.^[235]

Ants also are quite popular inspiration for many science-fiction insectoids, such as the Formics of Ender’s Game, the Bugs of Starship Troopers, the giant ants in the films Them! and Empire of the Ants, Marvel Comics‘ super hero Ant-Man, and ants mutated into super-intelligence in Phase IV. In computer strategy games, ant-based species often benefit from increased production rates due to their single-minded focus, such as the Klackons in the Master of Orion series of games or the ChCht in Deadlock II. These characters are often credited with a hive mind, a common misconception about ant colonies.^[236] In the early 1990s, the video game SimAnt, which simulated an ant colony, won the 1992 Codie award for “Best Simulation Program”.^[237]

March 24, 2025