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A 'dragonfly' is an insect belonging to the order Odonata, the suborder Epiprocta or, in the strict sense, the infraorder 'Anisoptera'. It is characterized by large multifaceted eyes, two pairs of strong transparent wings, and an elongated body.
Dragonflies typically eat mosquitoes, midges and other small insects like flies, bees, and butterflies. They are usually found around lakes, ponds, streams, and wetlands because their larvae, known as "nymphs", are aquatic. Dragonflies do not normally bite or sting humans (though they will bite in order to escape, for example, if grasped by the abdomen); in fact, they are valued as a predator that helps control the populations of harmful insects, such as mosquitoes. It is because of this that dragonflies are sometimes called "mosquito hawks" in North America along with the Crane Fly (which, in fact, does not eat mosquitoes).

Contents

Life cycle

General facts

Record breakers

Vision

Camouflage

Classification

Ancient dragonflies ("Anisozygoptera")

Dragonflies vs. damselflies

Some common species of the Northern Hemisphere

Some common species of the Southern Hemisphere

Dragonflies in culture

Gallery

References

See also

External links

Life cycle

Female dragonflies lay eggs in or near water, often in or on floating or emergent plants. Some species when laying eggs will submerge themselves completely just to lay their eggs in a suitable place. Most of the life of the dragonfly is spent in the larval, (naiad, aka nymph) form, beneath the water surface, using internal gills to breathe, and using extendable jaws to catch other invertebrates or even vertebrates such as tadpoles and fish. The larvae may live as long as five years of large dragonflies, or two months to three years in smaller species. When the the larva is ready to metamorphosise into an adult, it climbs up a reed or other emergent plant at night, and when it does the breathing pattern changes inside the larvas body. Then the skin splits at a weak spot behind the head and the adult dragonfly crawls out of its old larval skin, waits for the sun to rise, pumps up its wings and flys off to feed on midges and flies. In the adult stage, larger species of dragonfly can live as long as four months.

General facts

Record breakers

Much larger dragonfly species existed in the distant past than occur on earth today. The largest one, found as a fossil, is an extinct Protodonata named ''Meganeura monyi'' from the Permian period with a wingspan of 70–75 cm (27.5–29.5 in). This compares to 19 cm (7.5 in) for the largest modern species of odonates, the Hawaiian endemic dragonfly, ''Anax strenuus''. The smallest modern species recorded is the libellulid dragonfly, ''Nannophya pygmaea'' from East Asia with a wingspan of only 20 mm, or about ¾ of an inch.
Dragonflies are the world's fastest insects and, although estimates of their speed vary wildly, most credible authorities say they are capable of reaching speeds of between 30 and 60 km/h (19 to 38 mph).^[1] A study showed that dragonflies can travel as much as 137 km (85 mi) in one day.^[2]

Vision

Dragonflies have excellent eyesight due to their eye structure. Their compound eyes have up to 30,000 facets, each of which is a separate light-sensing organ or ommatidium, arranged to give nearly a 360° field of vision.

Camouflage

It was recently discovered that dragonflies employ a particular optical illusion, termed ''motion camouflage''^[3], to stalk other insects that invade their territory. The research suggests that a dragonfly can move in such a way as to project itself as a stationary object while speedily attacking its victims. These findings illustrate for the first time how dragonflies use complex camouflaging techniques during aerial combat.

Classification

Ancient dragonflies ("Anisozygoptera")

Conventionally, the Anisoptera were given suborder rank beside the ''ancient dragonflies'' ("Anisozygoptera", two living species and numerous fossil ones), but it has been determined recently that the Anisozygoptera form a paraphyletic assemblage of primitive relatives of the Anisoptera. Thus, the Anisoptera are reduced to an infraorder, forming the new suborder Epiprocta (dragonflies in a general sense). The artificial grouping Anisozygoptera is disbanded, its members being recognized as largely extinct offshoots at various stages of dragonfly evolution.
The oldest known species of dragonfly is the 320 million year old ''Delitzschala bitterfeldensis''. Another old genus is ''Namurotypus''.

Dragonflies vs. damselflies

Damselflies (Suborder Zygoptera) are often confused with dragonflies, but the two insects are distinct: most damselflies at rest hold their wings together above the body or held slightly open above (such as in the family Lestidae), whereas dragonflies at rest hold their wings horizontally or occasionally slightly down and forward. Also, the hindwing of the dragonfly broadens near the base, caudal to the connecting point at the body, while the hindwing of the damselfly is essentially similar to the forewing. The eyes on a damselfly are separated; in most dragonflies the eyes touch, with notable exceptions to this being in the Petaluridae (Petaltails) and the Gomphidae (Clubtails). Both are members of the Odonata, making their life cycles similar.

Some common species of the Northern Hemisphere

★ Emperor, ''Anax imperator'' ★ Keeled Skimmer, ''Orthetrum coerulescens'' ★ Black-tailed Skimmer, ''Orthetrum cancellatum'' ★ Common Whitetail, ''Libellula lydia'' ★ Migrant Hawker, ''Aeshna mixta'' ★ Azure Hawker, ''Aeshna caerulea'' ★ Southern Hawker, ''Aeshna cyanea'' ★ Norfolk Hawker, ''Aeshna isosceles'' ★ Common Hawker, ''Aeshna juncea'' ★ Red-veined Darter, ''Sympetrum fonscolombii'' ★ Common Darter, ''Sympetrum striolatum'' ★ Vagrant Darter, ''Sympetrum vulgatum''

★ Yellow-winged Darter, ''Sympetrum flaveolum'' ★ Broad-bodied Chaser, ''Libellula depressa'' ★ Four-spotted Chaser, ''Libellula quadrimaculata'' ★ Scarce Chaser, ''Libellula fulva'' ★ Green Darner, ''Anax junius'' ★ Downy Emerald, ''Cordulia aenea'' ★ Blue-eyed Darner, ''Aeshna multicolor'' ★ Roseate Skimmer, ''Orthemis ferruginea'' ★ Widow Skimmer, ''Libellula luctuosa'' ★ Great Pondhawk, ''Erythemis vesiculosa'' ★ Comet Darner, ''Anax longipes'' ★ Banded Pennant, ''Celithemis fasciata''

Some common species of the Southern Hemisphere

★ Glistening Demoiselle ''Phaon iridipennis'' ★ Dancing Jewel ''Platycypha caligata'' ★ Mountain Malachite ''Chlorolestes fasciatus'' ★ Common Spreadwing ''Lestes plagiatus'' ★ Common Threadtail ''Elattoneura glauca'' ★ Goldtail ''Allocnemis leucosticta'' ★ Swamp Bluet ''Africallagma glaucum'' ★ Pinhey's Whisp ''Agriocnemis pinheyi'' ★ Black-tailed Bluet ''Azuragrion nigridorsum'' ★ Common Citril ''Ceriagrion glabrum'' ★ Yellow-faced Sprite ''Pseudagrion citricola'' ★ Gambel's Sprite ''Pseudagrion gamblesi'' ★ Hagen's Sprite ''Pseudagrion hageni''

★ Hamon's Sprite ''Pseudagrion hamoni'' ★ Kersten's Sprite ''Psuedagrion kersteni'' ★ Masai Sprite ''Pseudagrion massaicum'' ★ Salisbury Sprite ''Pseudagrion salisburyense'' ★ Natal Sprite ''Pseudagrion spernatum'' ★ Orange Emperor ''Anax speratus'' ★ Common Thorntail ''Ceratogomphus pictus'' ★ Tigertail ''Ictinogomphus ferox'' ★ Yellowjack ''Notogomphus praetorius'' ★ Rock Hooktail ''Paragomphus cognatus'' ★ Pintail ''Acisoma panorpoides'' ★ Banded Groundling ''Brachythemis leucosticta'' ★ Broad Scarlet ''Crocothemis erythraea''

★ Little Scarlet ''Crocothemis sanguinolenta'' ★ Black Percher ''Diplacodes lefebvrii'' ★ Black-tailed Skimmer ''Nesciothemis farinosa'' ★ Two-striped Skimmer ''Orthetrum caffrum'' ★ Epaulet Skimmer ''Orthetrum chrysostigma'' ★ Julia Skimmer ''Orthetrum julia'' ★ St. Lucia Widow ''Palpopleura portia'' ★ Nomad ''Sympetrum fonscolombii'' ★ Red-veined Dropwing ''Trithemas arteriosa'' ★ Navy Dropwing ''Trithemis furva'' ★ Kirby's Dropwing ''Trithemis kirbyi'' ★ Jaunty Dropwing ''Trithemis stictica''

Dragonflies in culture

In Europe, dragonflies have often been viewed as sinister. Some English vernacular names, such as "devil's needle" and "ear cutter", link them with evil or injury.^[4] A Romanian folk tale says that the dragonfly was once a horse possessed by the devil, and Swedish folklore holds that the devil uses dragonflies to weigh people's souls.^[5] Another Swedish legend holds that trolls use the dragonflies as spindles when weaving their clothes (hence the Swedish word for dragonfly ''trollslända'', lit. "troll's spindle") as well as sending them to poke out the eyes of their enemies. The Norwegian name for dragonflies is "Øyenstikker", which literally means Eye Poker. They are often associated with snakes, as in the Welsh name ''gwas-y-neidr'', "adder's servant". The Southern United States term "snake doctor" refers to a folk belief that dragonflies follow snakes around and stitch them back together if they are injured.^[6] The Lithuanian word "" is a composite word meaning "the Lauma's horse", while in Dutch, ''Aeshna mixta'' is called "" or "horse biter". In some South American countries, dragonflies are also called ''matacaballo'' (horse killer), or ''caballito del diablo'' (devil's horse), since they were perceived as harmful, some species being quite large for an insect.
In East Asia and among Native Americans, dragonflies have a far better reputation, one that can also be said to have positively influenced modern day views about dragonflies in most countries.
For some Native American tribes they represent swiftness and activity, and for the Navajo they symbolize pure water. Dragonflies are a common motif in Zuni pottery; stylized as a double-barred cross, they appear in Hopi rock art and on Pueblo necklaces.^[7] It is said in some Native American beliefs that dragonflies are a symbol of renewal after a time of great hardship.
In Japan dragonflies are symbols of courage, strength, and happiness, and they often appear in art and literature, especially haiku. In ancient mythology, Japan was known as ''Akitsushima'', which means "Land of the Dragonflies". The love for dragonflies is reflected by the fact that there are traditional names for almost all of the 200 species of dragonflies found in and around Japan.^[8] 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.^[9]
They also have traditional uses as medicine in Japan and China. In some parts of the world they are a food source, eaten either as adults or larvae; in Indonesia, for example, they are caught on poles made sticky with birdlime, then fried in oil as a delicacy.
Images of dragonflies were common in Art Nouveau, especially in jewelry designs.^[10] They have also been used as a decorative motif on fabrics and home furnishings.^[11]

Gallery

References

1. Dragonflies
2. BBC. "Tiny tags trace dragonfly paths", 10 May 2006
3. Dragonflies prove clever predators
4.
Dragonflies: Behavior and Ecology of Odonata, , Phillip S., Corbet, Cornell University Press, , ISBN 0-8014-2592-1
5. A Dazzle of Dragonflies, , Forrest L., Mitchell, Texas A&M University Press, , ISBN 1-585-44459-6
6. From Idea to Word: Folk Beliefs and Customs Underlying Folk Speech, , Wayland D., Hand, American Speech,
7. Mitchell and Lasswell, 20-26.
8. The Handy Bug Answer Book, , Gilbert, Waldbauer, Visible Ink Press, , ISBN 1-57859-049-3
9. Mitchell and Lasswell, 38.
10. Dragonflies Shimmering as Jewelry Wendy Moonan
11. THE LATEST BUZZ; In the world of design, dragonflies are flying high Elizabeth Large

See also

★ Elliot Pinhey

External links

★

★ Dragonflies of North America - diagnostic photos and information

★ Identification key to dragonflies found in Ireland

★ British Dragonfly Society

★ List of Anisoptera of the World

★ Photos of most British species

★ Dragonflies and Damselflies (Odonata) of the United States

★ Green Explorer - Checklists, photogallery,... Dragonflies of Kerala, South India.

★ Photogallery by Dan Bárta et al. + some texts in Czech

★ DragonflyIndia Group

★ PHAON (Pinhey's Heritage African Odonata Network)

★ Odonatologica

★ Photos of South African species

★ Maps, photographs and additional information pertaining to the Odonata of North America

★ Short film, ''Emergence of a Dragonfly''