Anisoptera

Selys, 1854

Dragonflies

Family Guides

7

is the suborder of , distinguished from damselflies (Zygoptera) by their larger, stouter bodies, that touch or nearly touch at the top of the , and wings held horizontally away from the body at rest. The name derives from Greek roots meaning 'unequal wings,' referring to the broader hindwings compared to forewings. With over 3,000 described globally, dragonflies represent one of the most ancient lineages of flying insects, with fossil relatives dating to the 250 million years ago. are aerial with exceptional capabilities and vision, while larvae are aquatic predators found in diverse freshwater .

Phanogomphus borealis by (c) Nick Block, some rights reserved (CC BY), uploaded by Nick Block. Used under a CC-BY license.Neurocordulia alabamensis by (c) geosesarma, some rights reserved (CC BY), uploaded by geosesarma. Used under a CC-BY license.Neurocordulia obsoleta by (c) Nick Block, some rights reserved (CC BY), uploaded by Nick Block. Used under a CC-BY license.

Pronunciation

How to pronounce Anisoptera: /ˌænɪˈsɒptərə/

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Identification

are distinguished from damselflies (Zygoptera) by three primary characters: that are large and contiguous or nearly contiguous dorsally (damselflies have eyes widely separated); wings held open and horizontally when at rest (damselflies fold wings together above the ); and a generally stouter, more robust body build. The hindwings are distinctly broader at the base than the forewings, creating the 'unequal wing' condition that gives the group its name. dragonflies possess enormous containing up to 30,000 each, providing nearly 360-degree vision.

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Habitat

Aquatic and semi-aquatic environments; larvae develop in freshwater including ponds, lakes, streams, rivers, and wetlands. frequent areas near water bodies where they forage, mate, and oviposit. Specific habitat associations vary considerably among the six recognized in North America: Skimmers (Libellulidae) often inhabit still waters; Darners (Aeshnidae) patrol larger water bodies; Clubtails (Gomphidae) prefer flowing streams; Spiketails (Corduliidae), Cruisers (Macromiidae), and Petaltails (Petaluridae) occupy specialized aquatic .

Distribution

Global distribution across all continents except Antarctica. Highest diversity in tropical and subtropical regions. Over 6300 of dragonflies and damselflies combined worldwide, with () comprising approximately half this total. North America six of Anisoptera. The group has been documented on remote oceanic islands, with some species exhibiting remarkable transcontinental migratory capabilities.

Seasonality

activity period varies by and latitude, generally coinciding with warm seasons. In temperate regions, most species fly from late spring through early autumn. timing is often synchronized to avoid harsh conditions; for example, some gomphid species in Hong Kong forests emerge in late April-May prior to the summer monsoon. Tropical species may fly year-round. Larval stages are longer-lived, with some species requiring up to eight years to complete development before emergence.

Diet

are obligate of flying insects, capturing prey on the wing using spiny legs held in a basket-like arrangement beneath the body. Prey includes mosquitoes, crane flies, bees, butterflies, and other or damselflies; large have been reported capturing hummingbirds. Larvae are aquatic predators utilizing a unique prehensile, foldable that snaps forward to capture prey including mosquito larvae, aquatic beetles, , crustaceans, worms, tadpoles, and small fish.

Life Cycle

Hemimetabolous development with , nymph (naiad), and stages. Eggs are deposited in or near water, either endophytically (into plant tissue) or exophytically (onto water surface or substrates). Nymphs are fully aquatic, breathing through rectal gills; water is pumped in and out of the for respiration and jet-propelled escape locomotion. Nymphs undergo multiple over months to years (up to eight years in some ). Final instar nymphs emerge from water, climb onto vegetation or substrates, and undergo final to winged adults. Adults are short-lived, typically surviving weeks to months.

Behavior

employ two primary foraging strategies: active pursuit relying on speed and endurance, and sit-and-wait ambush relying on stealth and surprise. Hunting success rates reach 97% in some . Adults are , visually oriented . Males frequently patrol and defend territories along water bodies, pursuing and driving away intruding males. Mating typically occurs on the wing in tandem ; males may guard females during oviposition. Some species undertake remarkable long-distance across and between continents.

Ecological Role

Important in both aquatic and terrestrial . Nymphs regulate of mosquito larvae and other aquatic , contributing significantly to secondary production in freshwater (documented at 1019.4 mg dry wt m-2 yr-1 in one Hong Kong stream). control flying insect populations, including pest . serve as bioindicators of water quality and ecosystem health due to their specific requirements and sensitivity to environmental change.

Human Relevance

Subjects of considerable scientific research in , evolution, , and conservation ; serve as model organisms for studies of mechanics, visual systems, and -prey dynamics. Popular with naturalists, photographers, and citizen scientists; contribute to nature-based recreation and education. Nymphs provide biocontrol of mosquito larvae in some contexts. Not venomous or harmful to humans despite historical folklore referring to them as 'devil's darning needles.'

Similar Taxa

  • Zygoptera (damselflies)Similar elongated body form and aquatic larval stage, but distinguished by separated , slender build, wings folded together above body at rest, and smaller size. Damselflies employ only sit-and-wait strategies as , unlike the dual strategies of .

Misconceptions

do not sting or sew up people's ears; the folklore name 'devil's darning needle' and similar myths have no biological basis. The group called 'Darners' ( Aeshnidae) is named for their large size and powerful , not for any sewing . Dragonflies are not venomous and pose no threat to humans.

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Sources and further reading