Anax junius

This species occurs in nine provinces in Canada, fifty one states in the United States of America, eighteen states in Mexico, Kamchatka in the Russian Federation and many Caribbean Islands within the Greater and Lesser Antilles.

The breeding range of Anax junius extends from the northernmost part of the United States (Alaska) and south to Panama; also occurs from Hawaii east to Nova Scotia; also occurs in West Indies and Tahiti. Known to occur in Asia from Kamchatka south to Japan and mainland China (Cannings et. al., 1991).

occurs (regularly, as a native taxon) in multiple nations

Canada

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Year-round

United States

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Year-round

Global Range: (>2,500,000 square km (greater than 1,000,000 square miles)) This species is widespread in the United States, known from every state (Needham et al., 2000) and southern Canada; and also ranges into the West Indies, Guatemala and Belize south to Costa Rica; and recently in England (Abbott, 2007).

The Green Darner is one of the largest dragonflies, with male sizes ranging from 70-76 millimeters in length and 90-104 millimeters in expanse, and female sizes ranging from about 68-80 millimeters in length and 90-106 millimeters in expanse. Both male and female are characterized by green thoracic region and a reddish-brown coloration ventrally in the abdominal region, with the female having slightly lighter coloration. Both male and female members of this species show light blue abdominal coloration dorsally. Nymphs are fully aquatic, six-legged, with large lateral eyes, elongate wingpads, and underslung mouthparts. Maximum length of nymphs 50-55mm (Jaques 1947, Needham 1927, Bright and O'Brien 1998 ).

In northeastern North America, this is one of only two darners with an entirely green thorax. The Amazon darner (Anax amazili) has a triangular spot on the top of the frons and the abdomen appears ringed. The giant darner (Anax walsinghami) is much larger and great pondhawk (Erythemis vesiculosa) is much smaller (Abbott, 2007). In the south-central U.S., Amazon darner, Anax amazili, has a triangular spot on the top of the frons, and the abdomen appears ringed. Giant darner, A. walsinghami, is much larger, and great pondhawk, Erythemis vesiculosa, is much smaller (Abbott, 2005).

To distinguish from other Anax species, labial palps tapering to a hooded point (Needham et al., 2000).
From Abbott (2005): "The face is pale green, with a distinct black spot on the top of the frons, the spot bordered anteriorly by a blue semicircle conjuring the impression of a bull's eye. The thorax is green, with brown represented only lightly on the lateral sutures. The wings are clear, the costa yellow. The abdomen is mostly blue, with green on segment 1 in males, and greenish brown or reddish brown throughout in females. The brown superior caudal appendages in the male are long, about the length of segments 9 and 10 combined."

Habitat and Ecology

Systems

• Terrestrial
• Freshwater

The Green Darner prefers still or very slow-moving fresh water, with lots of aquatic vegetation, and can only flourish where there are no predatory fish.

Aquatic Biomes: lakes and ponds; rivers and streams

Depth range based on 1 specimen in 1 taxon.

Environmental ranges
  Depth range (m): 0 - 0
 
Note: this information has not been validated. Check this *note*. Your feedback is most welcome.

Habitat Type: Freshwater

Comments: This species inhabits a wide variety of wetlands, including well-vegetated permanent and temporary ponds and lakes. It also occurs in slow-flowing streams with emergent vegetation (Abbott, 2005; 2007).

Non-Migrant: No. All populations of this species make significant seasonal migrations.

Locally Migrant: No. No populations of this species make local extended movements (generally less than 200 km) at particular times of the year (e.g., to breeding or wintering grounds, to hibernation sites).

Locally Migrant: Yes. At least some populations of this species make annual migrations of over 200 km.

This species is one of the few North American dragonflies that migrates and is therefore most common in the spring and fall. Migration may be triggered by seasonal warm fronts. Massive swarm migrations (1.2 million individuals) have been documented in Illinois, New Jersey, and Florida (Russell et al., 1998). Migrants from the south are some of the first dragonflies seen in spring and southbound swarms in Massachusetts in early fall may have thousands of individuals (Nikula et al., 2003). It generally arrives in Minnesota in late April and breeds primarily in marshy lakes and ponds. A new generation of adults fly south in September (Haarstad, 1997). There is evidence that the migratory movements are strongly influenced by seasonal warm fronts (Abbott, 2005).

Green Darner nymphs are wholly carnivorous, usually eating aquatic insects, tadpoles, and very small fish. Adult Darners catch and eat insects on the wing, including moths and mosquitos. Dragonflies are excellent aerial hunters, due to its tremendous flying speed (recorded at up to 18 mph) and incredible eyesight. They use their powerful jaws to tear apart and chew up their prey (Wootton, 1984; Jaques, 1947).

Comments: It is a voracious predator commonly taking wasps, butterflies, mosquitoes, and other dragonflies on the wing. It has even been reported to attack hummingbirds and can be cannibalistic (Abbott, 2007).

Note: For many non-migratory species, occurrences are roughly equivalent to populations.

Estimated Number of Occurrences: > 300

Comments: In Alabama this species is common and probably the most often observed aeshnid. It occurs throughout the state and should be expected in all counties (Tennessen et al., 1995). In the south-central United States, it occurs in the Arkansas, Bayou Bartholomew, Brazos, Canadian, Cimarron, Colorado, Colorado (New Mexico), Guadalupe, Lower Rio Grande, Mississippi, Neches, Nueces, Ouachita, Pecos, Red, Sabine, San Antonio, San Jacinto, St. Francis, Trinity, Upper Rio Grande, and White River watersheds (Abbott, 2005). It was recently found in Fort Sill, Lawton, Camanche Co., Oklahoma (Zuellig et al., 2006). It is common throughout all of Massachusetts (Nikula et al., 2003). In Maine, it occurs in every county across the state (Brunelle and deMaynadier, 2005). This species has been documented in Cuatro Cienegas, Coahuila, Mexico (Dinger et al., 2005).

>1,000,000 individuals

These dragonflies are thought to be migratory. Dr. Michael May, of Rutgers University, has fitted green darner dragonflies (Anax junius) with radio transmitters to determine where they migrate.

Comments: Adults fly from early morning until dusk, often joining late afternoon feeding swarms. It is one of three darner species that perches in low grasses and weeds. Males patrol shorelines, clashing with other males and searching for females (Nikula et al., 2003).

Flight period in Texas is year round (Abbott, 2005). Needham et al. (2000) document flight period as year round in the South, taken every month in Florida; with migrants in Canada in April and normal flight from the first week in August to the second week in October; and May 3 to October 26 in Washington state. In Cape Cod, Massachusetts, it is June-September (Carpenter, 1991). In British Columbia it is April 29 to September 6 (Cannings and Stewart, 1977). In Kansas it is late April to mid-October (Beckemeyer and Higgins, 1997). In California it is April to November (Biggs, 2000). In Florida it is year round but usually migrates northward in summer (Dunkle, 1989). In Georgia it is almost year round except in early January when some migration northwards occurs (Beaton, 2007). In Ohio it is from April 5 to October 25 (Glotzhober and McShaffrey, 2002). In the western Great Lakes, it is mid-April to mid-October (Mead, 2003). In Massachusetts, it it late April to late November (Nikula et al., 2003).

Reproduction usually occurs in the summer months of July and August. Due to the briefness of the adult darner's life cycle (perhaps only a few weeks), they are mainly concerned with reproduction. To prepare for copulation, the male loops his abdomen forward to transfer semen from his true genital opening to a receptacle located in his secondary genitilia. Now the male is ready to select a mate. Once he has done so, the male will fly up to the female and, using his genital claspers located at the tip of his abdomen, he will grab hold of her by the neck to ensure that she will not escape. The two will form what looks like a circle with their bodies as the female aligns her genitilia with the secondary genitilia of the male located at the base of his abdomen. The male will then insert his secondary sex organ into the female's vagina, packing down or removing the sperm of any previous mates. Only after this will the male deposit his own sperm into the female.

After copulation, the male will continue to hold onto the female's neck, probably for the rest of the day, in order to prevent any other males from mating with her, removing his sperm, and replacing it with their own. The male will fly around with the female while she lays her eggs, often guiding her to the most ideal spot for the eggs. Once a location has been selected, the female will insert her ovipositor, a knife-like egg-laying organ, into pieces of rotting wood or in the stems of growing plants at the edge of a pond. This egg-laying procedure is the only form of nurturing that the offspring will receive from their mother. Females always lay copious amounts of eggs in order to ensure that at least some will hatch and fully mature into adult dragonflies (Waldbauer, 1998; Needham, 1929).

Green Darner eggs will hatch within about three weeks and small spider-like nymphs will emerge.

In warm water regions, where food is plentiful, a nymph may develop in as little as one summer, but as more often is the case, in cold water regions, where food is less plentiful, a nymph may take as long as four years to fully develop into an adult darner (Cannings et. al., 1991). Some adults migrate south in winter, and return north to lay eggs the following spring (Bright and O'Brien 1998).

Males patrol shorelines competing with other males in search of females. This is the only darner that often lays eggs in tandem (Abbott, 2005); the female suberges her abdomen and oviposits in aquatic and emergent vegetation (Nikula et al., 2003).

Females oviposit endophytically.

Barcode of Life Data Systems (BOLDS) Stats
Public Records: 2
Specimens with Barcodes: 14
Species With Barcodes: 1

The following is a representative barcode sequence, the centroid of all available sequences for this species.

No available public DNA sequences.

Download FASTA File

Year Assessed

Assessor/s

Reviewer/s

Contributor/s

Justification

This species is fairly common and abundant throughout its range. The main threat to its persistence is destruction of the freshwater habitat it requires to breed.

US Federal List: no special status

CITES: no special status

State of Michigan List: no special status

IUCN Red List of Threatened Species: least concern

Canada

Rounded National Status Rank: N5 - Secure

United States

Rounded National Status Rank: N5 - Secure

Rounded Global Status Rank: G5 - Secure

Reasons: This species is widespread in the United States and southern Canada; and also ranges into the West Indies, Guatemala and Belize south to Costa Rica; and recently in England (Abbott, 2007).

Population

Population Trend

Major Threats

Conservation Actions

Global Protection: Unknown whether any occurrences are appropriately protected and managed

Green Darners sometimes feed on beneficial insects like honeybees.

Green Darners feed on many insects that are harmful to humans and the environment, especially mosquitoes.