Canada darner | |
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Male (top) and female (bottom) | |
Scientific classification
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Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Arthropoda |
Class: | Insecta |
Order: | Odonata |
Infraorder: | Anisoptera |
Family: | Aeshnidae |
Genus: | Aeshna |
Species: | A. canadensis
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Binomial name | |
Aeshna canadensis Walker, 1908
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Range of Aeshna canadensis |
Aeshna canadensis, the Canada darner, is a species of dragonfly in the family Aeshnidae. It is common throughout southern Canada and the northern United States. [2] [3]
Adult Canada darners, similar to other members of the genus Aeshna, are relatively large, slender dragonflies, and are predominantly dark brown with paler blue or green markings. [4] [5] Adults are 64 to 73 mm in total length. [5] The thorax has two vertical stripes on each side, the front with a prominent notch and an extension at the top. [5] The abdomen has spots on most segments. [5] The pale markings are usually blue in males and range from yellow-green to blue in females. The eyes are bluish in males and yellowish or bluish in females. [5] The pale markings may turn gray at colder temperatures. [5]
The green-striped darner is very similar, but is distinguished by minor differences in the shape of the markings and in typically having green thorax stripes. [5] The lake darner is also similar but is larger and has a distinct dark stripe across the face. [5]
The Canada darner was first scientifically described in 1908 by Canadian entomologist Edmund Murton Walker, in the same publication as the first descriptions of black-tipped darner, shadow darner, subarctic darner, and variable darner, . [6]
Canada darners are found from Newfoundland and New Jersey in the east to Yukon in the west. [5] Populations extend further south down the Appalachian Mountains to West Virginia and south in mountain ranges to California and Montana. [5] [7] There is an isolated population in Nebraska. [5]
Canada darners spend most of their lives as an aquatic nymph. [7] Larvae are typically found in lakes and ponds, especially bog ponds and beaver ponds. [5] Breeding ponds typically have abundant emergent vegetation. [5] An Ontario study found that the species was restricted to ponds with a pH of no more than 6.2. [8] One study found that larvae may spend either one or two winters underwater before emerging. [7]
Adult males fly slowly along the shores of breeding ponds, sometimes dropping to the surface to search for females. [5] Mating occurs in shrubs nearby. [5] Females lay eggs at water level, usually in marshy vegetation away from shore. [5] Breeding adults are most active in sunny weather. [4]
Away from breeding sites, adult Canada darners are often found with other darner species in feeding swarms in clearings and along roadways in early evening. [4] [5] Adult Canada darners may be seen from June to October. [5]
Canada darners are often considered to be a common to abundant species where they are found. [4] [8] [9] [7] Although the species has not generally been recognised as migratory, a study in Manitoba and Minnesota found that at least some populations of Canada darners undertake north-south migratory movements within their range. [7]
Canada darner | |
---|---|
![]() | |
![]() | |
Male (top) and female (bottom) | |
Scientific classification
![]() | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Arthropoda |
Class: | Insecta |
Order: | Odonata |
Infraorder: | Anisoptera |
Family: | Aeshnidae |
Genus: | Aeshna |
Species: | A. canadensis
|
Binomial name | |
Aeshna canadensis Walker, 1908
| |
![]() | |
Range of Aeshna canadensis |
Aeshna canadensis, the Canada darner, is a species of dragonfly in the family Aeshnidae. It is common throughout southern Canada and the northern United States. [2] [3]
Adult Canada darners, similar to other members of the genus Aeshna, are relatively large, slender dragonflies, and are predominantly dark brown with paler blue or green markings. [4] [5] Adults are 64 to 73 mm in total length. [5] The thorax has two vertical stripes on each side, the front with a prominent notch and an extension at the top. [5] The abdomen has spots on most segments. [5] The pale markings are usually blue in males and range from yellow-green to blue in females. The eyes are bluish in males and yellowish or bluish in females. [5] The pale markings may turn gray at colder temperatures. [5]
The green-striped darner is very similar, but is distinguished by minor differences in the shape of the markings and in typically having green thorax stripes. [5] The lake darner is also similar but is larger and has a distinct dark stripe across the face. [5]
The Canada darner was first scientifically described in 1908 by Canadian entomologist Edmund Murton Walker, in the same publication as the first descriptions of black-tipped darner, shadow darner, subarctic darner, and variable darner, . [6]
Canada darners are found from Newfoundland and New Jersey in the east to Yukon in the west. [5] Populations extend further south down the Appalachian Mountains to West Virginia and south in mountain ranges to California and Montana. [5] [7] There is an isolated population in Nebraska. [5]
Canada darners spend most of their lives as an aquatic nymph. [7] Larvae are typically found in lakes and ponds, especially bog ponds and beaver ponds. [5] Breeding ponds typically have abundant emergent vegetation. [5] An Ontario study found that the species was restricted to ponds with a pH of no more than 6.2. [8] One study found that larvae may spend either one or two winters underwater before emerging. [7]
Adult males fly slowly along the shores of breeding ponds, sometimes dropping to the surface to search for females. [5] Mating occurs in shrubs nearby. [5] Females lay eggs at water level, usually in marshy vegetation away from shore. [5] Breeding adults are most active in sunny weather. [4]
Away from breeding sites, adult Canada darners are often found with other darner species in feeding swarms in clearings and along roadways in early evening. [4] [5] Adult Canada darners may be seen from June to October. [5]
Canada darners are often considered to be a common to abundant species where they are found. [4] [8] [9] [7] Although the species has not generally been recognised as migratory, a study in Manitoba and Minnesota found that at least some populations of Canada darners undertake north-south migratory movements within their range. [7]