49 Fun Facts About Dragonfly

Dragonflies and damselflies together make up which order of predatory flying insects?

Odonata covers dragonflies, damselflies and the Epiophlebia damsel-dragonflies; Diptera are the true flies, Neuroptera the lacewings and Ephemeroptera the mayflies.

The dragonfly infraorder Anisoptera means 'unequal wings' because of what?

Anisoptera means 'unequal wings' because a dragonfly's hindwings are broader at the base than its forewings; damselflies, the Zygoptera or 'paired wings', have fore and hind wings of similar shape.

Roughly how many species of dragonfly exist?

About 3,000 dragonfly species are known, classified into 348 genera and 11 families, most of them in the tropics.

An adult dragonfly's compound eye contains nearly how many facets (ommatidia)?

Each compound eye has nearly 24,000 ommatidia; in most families the eyes meet on top of the head and give complete vision of the frontal hemisphere, with three simple ocelli as well.

At rest, how does a dragonfly hold its wings, unlike a damselfly?

Flat and out from the body; damselflies fold theirs along or above the abdomen, and also have widely separated eyes and a weaker, fluttery flight.

What is the immature aquatic stage of a dragonfly called?

A nymph or naiad, and it hunts just like the adult; the underwater phase can last up to five years against a few weeks in the air.

How long is the adult stage for most dragonfly species?

A few live as long as ten weeks; the underwater nymph stage can last up to five years.

The mating posture in which the male grips the female's head and she curls her abdomen forward is called what?

The heart or wheel: the male grips the female's head with his claspers while she curls her abdomen forward to his secondary genitalia, which he charges with sperm beforehand, a system found almost nowhere else in insects.

Giant 'griffenflies', with wingspans up to 75 cm, first appeared in which geological period?

Griffenflies first appeared in the Carboniferous, about 325 million years ago; they were only distant relatives of dragonflies, and true dragonflies (Anisoptera) did not appear until the Early Jurassic.

Fossils of the giant griffenfly Meganeura were first found in 1880 in coal measures in which country?

Meganeura was first found in 1880 in the Commentry coal measures of central France; mining engineer Henri Fayol passed the fossils to palaeoentomologist Charles Brongniart, who described them in 1885.

One hypothesis for Meganeura's giant size links it to high levels of what in the ancient atmosphere?

High Carboniferous oxygen levels, which would let tracheal breathing support a bigger body, are one hypothesis for Meganeura's size; the absence of other aerial predators is another, since griffenflies persisted into the Late Permian after oxygen fell.

Dragonflies belong to a group called Palaeoptera, meaning 'ancient-winged', because they cannot do what?

Mayflies share the trait; most modern insects can tuck their wings flat over the back.

Which is the only continent with no dragonflies?

Antarctica alone has none; they are missing from Iceland too, apart from strays blown in, and the treeline emerald of Arctic Alaska is the most northerly species.

Which dragonfly is probably the most widespread, found on every continent in the warmer regions?

The globe skimmer, Pantala flavescens, also called the wandering glider, occurs in warmer regions of every continent except Antarctica; on Rapa Nui it has a black-winged form.

Pantala flavescens makes an annual multigenerational migration covering roughly how far?

The round trip spans roughly 18,000 km across generations, with individuals flying more than 6,000 km of it, one of the longest insect journeys; Amur falcons crossing the Indian Ocean may feed on them en route.

Dragonfly legs are used for perching and grabbing prey but not for what?

Dragonfly legs perch and grab prey but are not used for walking; a row of spines on each front leg, the 'eyebrush', is used to clean the compound eye.

A dragonfly nymph catches prey by shooting out which extendable mouthpart, sometimes called a mask?

The nymph's labium, a hinged lower lip folded under the head as a 'mask', is fired by hydraulic pressure from the abdominal muscles and takes mosquito larvae, tadpoles and small fish.

How can a dragonfly nymph move with sudden speed through a pond?

The internal gills sit in a chamber in the abdomen; water pumped for breathing doubles as jet propulsion.

Freshly emerged adult dragonflies, still pale before their colours develop, are known as what?

Such soft, pale newcomers are tenerals; the empty nymph skin left behind is the exuvia. A waxy blue 'pruinosity' on some mature adults wears off during mating.

In how many directions can an adult dragonfly propel itself in flight?

Up, down, forward, backward, left and right; the fore and hind wings can beat out of phase for hovering.

Large dragonflies such as hawkers reach top speeds of roughly what?

Large species such as hawkers reach 36-54 km/h; cruising speed is about 16 km/h, and old claims of 97 km/h for the southern giant darner are unreliable.

Dragonflies can fly about 100 body lengths per second forwards; how many backwards?

Counter-stroking, with forewings 180 degrees out of phase with hindwings, powers hovering and slow flight.

Dragonflies have been recorded pulling how many g in a sharp turn while chasing prey?

Dragonflies have been measured pulling 9 g in sharp turns while chasing prey, and 4 g in straight-line acceleration, thanks to a very high power-to-weight ratio.

In an enclosure study, dragonflies caught up to what share of the fruit flies they pursued?

In an enclosure study dragonflies caught up to 95% of the fruit flies they chased, one of the highest success rates recorded for any predator; erratic prey flight was the main way a fly escaped.

Dragonflies use which technique when closing on prey or rivals?

Motion camouflage: by holding a fixed bearing to the target the dragonfly appears not to move against the background, only to grow larger, until it is too late to react.

What do some large dragonflies do before dawn to warm their flight muscles?

Wing-whirring, a rapid shivering of the wings, warms the flight muscles; migratory darners do it before dawn to get an early start, while the obelisk posture is used to avoid overheating.

Dragonflies sometimes lay eggs on cars, gravestones and solar panels because these surfaces mimic water how?

Shiny surfaces polarise light the way a pond does, and the insects gather to lay eggs on them.

Which family of dragonflies, the clubtails, prefers running water rather than still ponds?

Gomphidae, the clubtails, favour rivers and streams; their nymphs burrow in sand or mud, some breathing through a snorkel-like tube, while the Libellulidae, or skimmers, favour still water.

Which large migratory dragonfly is the official state insect of Washington?

The common green darner, Anax junius, became Washington's state insect in 1997; it migrates from the northern United States to Texas and Mexico and is the best-studied North American migrant.

One of Britain's largest dragonflies, a hawker with a blue abdomen, is named after which ruler?

The emperor, Anax imperator, also called the blue emperor, is one of Britain's largest dragonflies; its range has pushed north and uphill since the 1990s.

The helicopter damselflies of tropical America, with wingspans up to 19 cm, feed mainly on what?

They hover near an orb web and snatch the spider or its wrapped prey; Megaloprepus is the widest-winged of all living odonates.

The nymphs of Phanogomphus militaris may act as parasites, feeding on the gills of what?

It is a rare exception in a group that is otherwise a straightforward predator at every stage of life.

Old names for Japan such as Akitsushima have been interpreted as meaning what?

Akitsushima means 'Dragonfly Island': in legend the first emperor Jimmu likened the land's outline to a dragonfly, and the insect became a Japanese emblem of courage, strength and autumn.

For the Navajo, the dragonfly is a symbol of what?

For the Navajo the dragonfly symbolises pure water; stylised as a double-barred cross, it is also a common motif on Zuni pottery and in Hopi rock art.

In which country are adult dragonflies caught on birdlime-coated poles and fried in oil as a delicacy?

In Indonesia, adult dragonflies are caught on poles tipped with sticky birdlime and fried in oil as a delicacy; in China and Japan they have traditionally been used in medicine instead.

Folk names like 'devil's darning needle' reflect which popular misconception about dragonflies?

The belief that they bite or sting humans is a myth; European folklore cast dragonflies as sinister, while Japan made them emblems of happiness and rebirth.

Which art movement made the dragonfly a favourite motif, especially in jewellery?

Art Nouveau designers adored the dragonfly; René Lalique's dragonfly-woman corsage ornament of 1897-98 is the most famous example.

Which Victorian poet described a dragonfly 'like sapphire mail' in The Two Voices (1842)?

H. E. Bates later wrote of an endless procession of small sapphire dragonflies over water lilies in Down the River.

Japanese children traditionally catch large dragonflies using what thrown into the air?

The dragonfly mistakes the whirling pebbles for prey and tangles in the hair.

Which country lost over 60% of its wetlands last century, leaving dragonflies reliant on rice paddies?

Japan lost more than 60% of its wetlands in the 20th century, so its dragonflies depend largely on rice paddies, ponds and creeks; habitat loss is the main threat to dragonflies worldwide.

On a hot day, how do some dragonflies cool down?

They often dip three times in quick succession; others adopt the obelisk posture, pointing the abdomen at the sun to reduce exposure.

Who coined the order name Odonata in 1793?

Johan Christian Fabricius named the order Odonata in 1793, from the Greek 'odon', tooth, probably for the toothed maxillae; Linnaeus had earlier lumped dragonflies into the genus Libellula.

What is the brief first larval stage of a dragonfly, lasting minutes after hatching, called?

The prolarva is the first instar, a legless, wriggling stage that reaches water and moults within minutes to hours into the true nymph.

What colour are dragonfly nymphs usually?

Dull brown, green and grey, a well-camouflaged blend; the adults get the show colours, with blues from cuticle microstructures and greens from a structural blue mixed with yellow pigment.

Which small birds of prey are fast enough to catch adult dragonflies on the wing, as swallows and swifts also do?

Kestrels, merlins and hobbies can all take dragonflies in flight, and Amur falcons crossing the Indian Ocean may time their migration to feed on migrating globe skimmers.

What is the pigmented cell near the leading edge of a dragonfly's wingtip called?

The pterostigma is the thickened, pigmented cell near each wingtip; its extra mass is thought to damp wing vibration and raise the speed at which the dragonfly can glide.

In Hine's emerald dragonfly, where do females spend most of their time, away from the male-dominated wetlands?

Dry meadows and marginal habitats keep them clear of harassment; they visit the wetlands only to lay eggs or find mates, since unwanted mating costs foraging time.

Which parasitic flatworms use dragonfly nymphs as a stepping stone between snails and the frogs they finally infect?

Trematodes travel in stages: the larval cercariae leave a snail, enter the nymph and form a cyst that waits until a frog eats the nymph.

In the cyborg 'DragonflEye' project, how are steering commands delivered to the insect's nerve cord?

Steering commands reach the nerve cord as light pulses through flexible optrodes; the dragonfly is genetically modified with light-sensitive neurons and carries a backpack of sensors, chip and solar panel on its thorax.