The green darner or common green darner (''Anax junius''), after its resemblance to a darning needle, is a species of

dragonfly A dragonfly is a flying insect belonging to the infraorder Anisoptera below the order Odonata. About 3,000 extant species of true dragonfly are known. Most are tropical, with fewer species in temperate regions. Loss of wetland habitat threate ...

in the family

Aeshnidae The Aeshnidae, also called aeshnids, hawkers, or darners, is a family of dragonflies. The family includes the largest dragonflies found in North America and Europe and among the largest dragonflies on the planet. Description Common worldwide or ...

. One of the most common and abundant species throughout North America, it also ranges south to

Panama Panama ( , ; es, link=no, Panamá ), officially the Republic of Panama ( es, República de Panamá), is a transcontinental country spanning the southern part of North America and the northern part of South America. It is bordered by Co ...

. It is well known for its great migration distance from the northern

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 U.S. state, states, a Washington, D.C., federal district, five ma ...

south into

Texas Texas (, ; Spanish language, Spanish: ''Texas'', ''Tejas'') is a state in the South Central United States, South Central region of the United States. At 268,596 square miles (695,662 km2), and with more than 29.1 million residents in 2 ...

and

Mexico Mexico ( Spanish: México), officially the United Mexican States, is a country in the southern portion of North America. It is bordered to the north by the United States; to the south and west by the Pacific Ocean; to the southeast by Guate ...

. It also occurs in the Caribbean,

Tahiti Tahiti (; Tahitian ; ; previously also known as Otaheite) is the largest island of the Windward group of the Society Islands in French Polynesia. It is located in the central part of the Pacific Ocean and the nearest major landmass is Aust ...

, and

Asia Asia (, ) is one of the world's most notable geographical regions, which is either considered a continent in its own right or a subcontinent of Eurasia, which shares the continental landmass of Afro-Eurasia with Africa. Asia covers an ...

from Japan to mainland China. It is the official insect for the state of

Washington Washington commonly refers to: * Washington (state), United States * Washington, D.C., the capital of the United States ** A metonym for the federal government of the United States ** Washington metropolitan area, the metropolitan area centered o ...

in the

. The green darner is one of the largest extant dragonflies; males grow to in length with a wingspan up to . Females oviposit in aquatic vegetation, eggs laid beneath the water surface.

Nymphs A nymph ( grc, νύμφη, nýmphē, el, script=Latn, nímfi, label=Modern Greek; , ) in ancient Greek folklore is a minor female nature deity. Different from Greek goddesses, nymphs are generally regarded as personifications of nature, are ty ...

(naiads) are aquatic carnivores, feeding on

insect Insects (from Latin ') are pancrustacean hexapod invertebrates of the class Insecta. They are the largest group within the arthropod phylum. Insects have a chitinous exoskeleton, a three-part body (head, thorax and abdomen), three pairs ...

tadpole A tadpole is the larval stage in the biological life cycle of an amphibian. Most tadpoles are fully aquatic, though some species of amphibians have tadpoles that are terrestrial. Tadpoles have some fish-like features that may not be found ...

s, and small

fish Fish are aquatic, craniate, gill-bearing animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish as well as various extinct related groups. Approximately 95% ...

. Adult darners catch insects on the wing, including

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 22,0 ...

alates,

moth Moths are a paraphyletic group of insects that includes all members of the order Lepidoptera that are not butterflies, with moths making up the vast majority of the order. There are thought to be approximately 160,000 species of moth, many of ...

mosquito Mosquitoes (or mosquitos) are members of a group of almost 3,600 species of small flies within the family Culicidae (from the Latin ''culex'' meaning "gnat"). The word "mosquito" (formed by ''mosca'' and diminutive ''-ito'') is Spanish for "lit ...

es, and

flies Flies are insects of the Order (biology), order Diptera, the name being derived from the Ancient Greek, Greek δι- ''di-'' "two", and πτερόν ''pteron'' "wing". Insects of this order use only a single pair of wings to fly, the hindwing ...

Taxonomy

Dru Drury Dru Drury (4 February 1724 – 15 December 1803) was a British collector of natural history specimens and an entomologist. He had specimens collected from across the world through a network of ship's officers and collectors including Henry Sme ...

described this species as ''Libellula junius'' in 1773. There are not currently any recognized subspecies. There are three recognized synonyms: ''Anax spiniferus'' Rambur, 1842; ''Anax ocellatus'' Hagen, 1867; ''Anax severus'' Hagen, 1867.

Distribution

Common Green Darners are commonly found throughout the continental United States and southern Canada, occasionally ranging as far south as Panama, particularly in the winter. There are also populations in Hawaii and the Caribbean. Vagrant individuals have been seen far outside of their normal range including sightings in Alaska, Russia, China, Japan, France, the United Kingdom, India, and Bermuda. These vagrant sightings are likely migrating individuals blown off-course by strong winds or storms.

Characteristics

Common Green Darners are large dragonflies, ranging from 6.8 to 8 cm (2.7 – 3.1 inches) in length and a wingspan of up to 10 cm (3.9 inches). Both sexes have an unmarked green thorax. Mature males have bluish-purple abdomens (the first few abdominal segments are the brightest) with a black dorsal stripe that broadens near the end of the abdomen. Immature males and most females have reddish-brown abdomens, but some females are patterned like adult males. Wings are initially clear but usually become amber-tinted with age, especially in females. Both sexes have a black ‘bulls-eye’ mark on the face (more precisely, the

frons Insect morphology is the study and description of the physical form of insects. The terminology used to describe insects is similar to that used for other arthropods due to their shared evolutionary history. Three physical features separate insec ...

) in front of their eyes, a distinguishing field mark that separates them from the superficially similar Comet Darner ('' Anax longipes''). This species oviposits in tandem which is a unique behavior among North American darners.

Natural history

Diet and predators

Both the adult and the nymphal stage are predators.

prey upon immature aquatic insects (including conspecifics), small crustaceans, small tadpoles, and even small fish. Adults primarily prey on winged insects, including wasps, flies, butterflies, and other Odonates. The primary predators of Common Green Darner nymphs are fish. Adults are preyed upon by birds and occasionally robber flies, spiders, and other large dragonflies.

Habitat

Nymphs develop in lakes, ponds, and slow streams and rivers. Adults are most frequently seen around nymph habitat but they are strong fliers and can be found in a wide variety of habitats including grasslands, forests, and urban areas.

Migration

There are several species of migratory dragonflies in North America, but Common Green Darners are the best studied. Other migratory species include * ''

Tramea lacerata The black saddlebags (''Tramea lacerata'') is a species of skimmer dragonfly found throughout North America. It has distinctive wings with characteristic black blotches at their proximal ends, which make the dragonfly look as though it is wearin ...

'' (Black Saddlebags) * ''

Pantala flavescens ''Pantala flavescens'', the globe skimmer, globe wanderer or wandering glider, is a wide-ranging dragonfly of the family Libellulidae. This species and '' Pantala hymenaea'', the "spot-winged glider", are the only members of the genus ''Pantala' ...

'' (Wandering Glider) * '' Pantala hymenea'' (Spot-winged Glider) * '' Sympetrum corruptum'' (Variegated Meadowhawk) The large geographic range and migratory behavior of the Common Green Darner has made it a challenge to piece together its complex life history. Recent research has indicated that the annual life cycle of ''Anax junius'' is likely composed of at least three different generations. The first generation emerges in the southern end of its range in early spring and migrates northwards through spring and summer. The second generation emerges in the northern end of its range in summer and migrates southwards in fall. The third generation occurs in the south during the winter and does not migrate. Common Green Darners migrate in fall and spring but for several reasons the southward movement in fall is more noticeable. By attaching micro-radio transmitters to Common Green Darners, researchers have found them to be capable of migrating up to 140 kilometers in a day, though they typically cover less distance per day. A group of researchers used

stable isotope analysis Isotope analysis is the identification of isotopic signature, abundance of certain stable isotopes of chemical elements within organic and inorganic compounds. Isotopic analysis can be used to understand the flow of energy through a food web, ...

on individuals collected between Ontario and Mexico during fall and documented that >90% of individuals moved southward, with an average distance of 900 kilometers. A study published in 2019 attached miniaturized radio transmitters to Common Green Darners in the Great Lakes region and tracked their movement with the Motus Wildlife Tracking System. Individuals moved at an average groundspeed of 16 km/hour.

Gallery

File:Img 041538 mating anax junius.jpg, Mating, wheel position File:Anax_junius-Laying_eggs-2.jpg, Egg-laying File:Dragonfly_Common_Green_Darner_Female_Anax_junius_2010-04-18.jpg, Female File:Common Green Darner, female.jpg, Uncommon blue form female, Ottawa, Canada File:Anax junius-hovering.jpg, Hovering San Joaquin Wildlife Sanctuary

References

External links

Green darner
BugGuide * {{Taxonbar, from=Q175808 Aeshnidae Insects described in 1773 Insects of Asia Insects of the Dominican Republic Odonata of North America Symbols of Washington (state)