New York Natural Heritage Program
Subarctic Darner
Aeshna subarctica Walker, 1908
Insects

Identifying Characteristics [-]
Like other blue or mosaic darners (genus Aeshna), adult subarctic darners are large dragonflies with large eyes, a brown thorax with two blue-green stripes on the front and two on the side, and a long slender brown abdomen marked by two rows of sky blue spots. Adult subarctic darners average approximately 2.8 inches (7.1 cm) in length. The face is yellow with an obvious black line across the middle and a black "T-spot" above the face. The eyes are blue-gray to greenish. The two stripes on the side of the thorax (the lateral stripes) are bent at the midpoint and tend to be blue or blue-green in the upper portion and yellow or greenish in the lower portion. The forward-most stripe has a long, thin blue "flag" at the top which extends toward the rear. Typically, there are two, nearly connected, very thin yellow to blue lateral spots located between the two lateral thoracic stripes. The wings are usually clear, but are occasionally tinted with amber in females. Some females have green or yellow abdominal spots or thoracic stripes in places where these colors are blue in males.The larvae are elongate, cylindrical shaped aquatic insects that are usually patterned in drab brown and greenish colors and climb and crawl among aquatic vegetation. The antennae are composed of six or seven, small slender segments. Body length is approximately 1.57-1.65 inches (40-42 mm) at maturity (Walker 1958) which may be at 1-3 years.

Characters Most Useful for Identification [-]
Close examination of the thoracic and abdominal pattern and terminal appendages is necessary for positive identification.

Best Life Stage for Proper Identification [-]
Mature adults are the best life stage for the identification of all dragonflies. Larval identification requires the use of detailed taxonomic keys, can be very difficult, and can be very unreliable, especially in the case of larvae that are not yet mature. Larval identification is best done by people with a great deal of expertise in this area.

Behavior [-]
Adults may be found hunting in open areas away from the breeding habitat. At the bogs and fens where this species breeds the males may be seen flying low over wet areas and pools patrolling a territory, chasing other males, and searching for females. Females lay their eggs in patches of sphagnum "soup" in pools of shallow water within the bogs.
Subarctic Darner Images
click to enlarge
The Best Time to See
Flight dates for this species in Massachusetts are from mid-July to mid-September (Nikula 2003), whereas flight dates in the western Great Lakes states extend to the end of September (Mead 2003). Dunkle (2000), gives a somewhat longer flight period of early June to early October. The few observations for New York are from late August and early September, but the full flight season is probably similar to that listed above for other states.
J F M A M J J A S O N D
Present Reproducing
The time of year you would expect to find Subarctic Darner present (blue shading) and reproducing (orange shading) in New York.
Similar Species
  • Green-Striped Darner (Aeshna verticalis)
    As with the Canada darner, the forward-most stripe on the thorax is indented, but not bent in the middle as in the subarctic darner. There is no black cross line on the face.
  • Shadow Darner (Aeshna umbrosa)
    The narrow, straight stripes on the thorax of this species are narrowly outlined in black. There is no black cross line on the face.
  • Black-Tipped Darner (Aeshna tuberculifera)
    The stripes on the side of the thorax in the black-tipped darner are relatively straight and parallel sided as opposed to bent in the middle. As its name implies, the last abdominal segment is black and the male abdominal "clasper" or cerci has a small bump or tubercle on the underside.
  • Canada Darner (Aeshna canadensis)
    Although the forward-most stripe on the thorax is indented in the middle it is not bent as in the subarctic darner. There is often a single, small yellow spot on the side of the thorax located between the two lateral stripes. There is no black cross line on the face.