Similar to the Paddle-tailed Darner, but darker and more slender. Thorax stripes are yellow to green, often blue above and outlined with dark brown; shape shown in figure. The face is pale green with a pale brown line or no line; the rear of the head is partly pale. Spots on top of the abdominal segments are green or blue; segment 10 is usually black on top. The underside of the abdomen has pale blue spots. The pale areas on females are green, yellow or, rarely, blue. Male’s upper appendages flattened. Length: ♂ 70 mm, ♀ 68 mm.
Flight Period
B.C., mid June to mid November.
Genus Description
Mosaic Darners are common in B.C. and the Yukon; they fly everywhere dragonflies are found. All 11 B.C. species are large and can usually be distinguished by their variations on a basic colour pattern. Generally, the body is brown, and each side of the thorax has a pair of blue, green or yellow stripes – their shape is important in identification. Look also for the colour of the face and the line across its middle. Viewed from above, the forehead bears a distinctive T-shaped mark, called the “T-spot”. The abdominal spots on males are usually blue, and on females green, yellow or blue. Male upper appendages come in three types.
Biology
Family Description
Large, swift-flying dragonflies, usually marked with blue, green or yellow. Adults hunt tirelessly for insects over ponds, lakes and streams, and wander widely in search of prey. Most species rest in a vertical position, but a few sit flat on the ground. Females have a prominent ovipositor and lay eggs in water plants or floating wood above or below the water line. Larvae are slender and sleek, with flat labia lacking bristles; they are rapacious hunters among water plants. Recently, A. californica and A. multicolor have been transferred from Aeshna to Rhionaeschna.
Field Notes
More common in the south; rare in the southern Yukon. Partial to forest lakes and slow-moving streams; as its name suggests, it likes shady habitats. Often found alongside the Paddle-tailed Darner, its close and usually more common relative. The Shadow Darner is one of the latest flying species in B.C., especially in the south.
Distribution
Transition. Widespread in B.C. and the southern Yukon.
Recommended citation: Author, Date. Page title. In Klinkenberg, Brian. (Editor) 2021. E-Fauna BC:
Electronic Atlas of the Fauna of British Columbia [efauna.bc.ca]. Lab
for Advanced Spatial Analysis, Department of Geography, University of British
Columbia, Vancouver. [Accessed:
2024-10-09 8:18:59 AM]
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