Aeshnidae

Rambur, 1842

darners, hawkers, aeshnids

Genus Guides

Aeshna(Hawkers)
Anax(Emperors)
Basiaeschna(springtime darner)
Boyeria(spotted darners)
Coryphaeschna(Pilot Darners)
Epiaeschna(Swamp darner)
Gomphaeschna(Pygmy Darners)
Gynacantha(two-spined darners)
Nasiaeschna(Cyrano Darner)

is a of large dragonflies known as darners in North America and hawkers elsewhere. The family includes some of the largest and fastest-flying dragonflies in the order Odonata, with over 450 in more than 50 distributed nearly worldwide. Members are characterized by their powerful , elongated , and large that meet at the top of the . The family name derives from the Greek 'Aechma' meaning 'spear', though the spelling resulted from a printer's error.

Triacanthagyna trifida by (c) Nick Block, some rights reserved (CC BY), uploaded by Nick Block. Used under a CC-BY license.

Aeshna interrupta by (c) Nick Block, some rights reserved (CC BY), uploaded by Nick Block. Used under a CC-BY license.

Pronunciation

How to pronounce Aeshnidae: //ˈiʃnɪdiː//

These audio files are automatically generated. While they are not always 100% accurate, they are a good starting point.

Identification

Distinguished from other by the combination of: large size (among the largest Anisoptera), that meet dorsally at the midline, elongated slender , and powerful sustained . Differs from skimmers (Libellulidae) in having eyes that meet rather than being separated, and from clubtails (Gomphidae) in lacking a clubbed abdomen tip. The family can be separated from petaltails (Petaluridae) and spiketails (Corduliidae) by overall body proportions and wing venation patterns. Larvae identified by the slender body form and distinctive labial .

Images

Habitat

found near freshwater including ponds, lakes, streams, and rivers. Larvae are aquatic, occurring in various freshwater environments. Specific collection records include rainwater pools with leaf litter in Amazonian lowland forest, streams and rivers in Mexican Plateau and Sierra Madre regions, and diverse freshwater systems across temperate and tropical zones worldwide.

Distribution

Nearly worldwide distribution. Present on all continents except Antarctica. North America: 41 in 11 . Europe: predominantly genus Aeshna. Asia: includes Tetracanthagyna plagiata, the world's largest by wingspan and weight. South America: documented in Argentina, Brazil. Africa: Anax tristis and other species. Australia and Pacific islands: including Hawaiian Anax strenuus. Specific documented localities include Aguascalientes State (Mexico), Tucumán (Argentina), Manaus (Brazil), Yunnan (China), and Cat Tien National Park (Vietnam).

Seasonality

active during warmer months in temperate regions; year-round activity in tropical areas. periods vary by and latitude. Green darner (Anax junius) noted as migratory in North America, moving from northern United States south into Texas and Mexico.

Diet

are voracious aerial of other insects, seizing prey on the wing using sharp, biting mouthparts. Prey includes flies, mosquitoes, and other flying insects. Larvae are aquatic predators feeding on other insects, mosquito larvae, and small fish.

Life Cycle

deposited in water or on aquatic vegetation, often inserted into plant stems by females using the ovipositor. Larvae (naiads) are aquatic and pass through multiple instars; final instar larvae have been described for several including Rhionaeschna vigintipunctata and Gynacantha auricularis. Larvae possess a unique prehensile, foldable lower lip () for prey capture. to stage occurs at the water's edge.

Behavior

spend large amounts of time in , appearing to fly tirelessly. Capable of flying forwards, backwards, and hovering. Mating occurs in flight. Oviposition involves females cutting into plant stems with their , creating the appearance of 'darning'. Adults are difficult to capture due to exceptional flying ability and keen vision. Some migrate seasonally.

Ecological Role

at both larval and stages, contributing to regulation of insect including mosquitoes. Larvae serve as predators in aquatic . Adults function as aerial . Bioindicators of freshwater health in some regions.

Human Relevance

Considered beneficial insects due to on pest insects including mosquitoes. Subject of ecological and taxonomic research; well-represented in entomological collections. Green darner (Anax junius) is the official state insect of Washington. 'devil's darning needle' reflects historical folklore, though they do not harm humans. Popular subjects for nature observation and photography.

Similar Taxa

Libellulidae (skimmers)Differ in having that are broadly separated rather than meeting at the midline; generally perch more frequently and have broader wings relative to body size.
Gomphidae (clubtails)Separated by the clubbed tip of the in most ; are separated and do not meet dorsally.
Petaluridae (petaltails)Differ in having widely separated, very long legs, and larvae that burrow in stream banks or muddy substrates rather than being free-swimming .
Corduliidae (spiketails and emeralds)Generally smaller with different wing venation; spiketails have a prominent spine on segment 10 of the .

Misconceptions

Historical folklore name 'devil's darning needle' incorrectly suggested these dragonflies could sew up people's ears. They are not poisonous and pose no threat to humans. The name 'darner' properly refers to the female oviposition resembling darning, not to any harmful capacity.

More Details

Taxonomic history

name first proposed by Elford Leach in 1815. Spelling '' resulted from a printer's error in spelling Greek 'Aechma' (spear); alternative spelling 'Aeschnidae' was intermittently used but is now abandoned, though derived names such as Rhionaeschna retain the 'sch' spelling. Oldest known fossil members from earliest Cretaceous (Berriasian) of Russia include †Gomphaeschna inferna and †Baissaeschna; some studies have placed Gomphaeschna in its own family Gomphaeschnidae, though current checklists retain it in Aeshnidae.

Size records

Includes some of the largest extant dragonflies. Anax among the largest in North America, Europe, and Africa. Asian Tetracanthagyna plagiata holds records for largest wingspan and weight among living dragonflies. Fossil relatives from the had wingspans up to three feet, the largest flying insects known.

Research significance

Well-studied with extensive taxonomic revisions, particularly for New World fauna by including Rosser Garrison. Larval descriptions available for numerous , facilitating identification of nymphs and . Used as model organisms for ecological and evolutionary research.