THE ANIMAL FILES

Canada darner

No verified Chinese common name in our sources; the English name is retained.

Aeshna canadensis

A Canada darner can spend more than one winter underwater before it flies.

Canada darners are slender dragonflies with pale markings on dark bodies. Nymphs develop in ponds and lakes before adults fly around shores and feeding clearings. Some documented population movements are more extensive than the familiar circuit above a single pond.[1]

Follow the evidence ↓
Canada darner
Image: Raphael Carter · Commons · CC BY-SA 2.5
Young habitat
Aquatic, often vegetated ponds[1]
Adult pattern
Two pale side stripes on the thorax[1]
Breeding
Eggs placed near water level in vegetation[1]

Growing underwater

Nymphs occupy lakes and ponds, including bog and beaver ponds. In a studied population, development could include one or two winters underwater. Vegetation around breeding ponds supplies structures for egg placement. An adult on the wing is therefore preceded by an extended aquatic stage rather than hatching directly as a miniature flier.[1]

Markings need several checks

Thoracic stripes, including a notch in the front stripe, help identify adults. Pale colours differ with sex and can grey at low temperatures. Similar darners require comparison of pattern shape and other features. A blue or green patch alone is therefore insufficient to identify the species.[1]

Pond patrols and wider movement

Males patrol breeding shores and search for females; mating occurs in nearby shrubs. Away from breeding sites, adults join feeding swarms with other darners. Research in Manitoba and Minnesota also found north–south movements in some populations. These records prevent local pond patrols from being mistaken for the full movement range.[1]

A COMMON MIX-UP

Does a dragonfly begin life as a tiny winged adult?

No. It develops first as an aquatic nymph.[1]

TRY A LITTLE REASONING

Why protect pond conditions when the animal you notice is flying above a road?

Reveal the explanation

The flying adult developed underwater, so terrestrial feeding sightings do not remove dependence on aquatic juvenile habitat.[1]

Sources & editorial notes

Adapted and translated from the cited Wikipedia revisions, with source-linked reasoning. Image credit and licence are listed separately above.

Adapted and translated from Wikipedia contributors; exact revisions are linked below. CC BY-SA 4.0

  1. Wikipedia contributors — Aeshna canadensis (adapted and translated; exact revision)
  2. NCBI Taxonomy — Aeshna canadensis (identity and game lineage)

Last fact check:

One discovery leads to another

March brown mayflyA winged mayfly can still have one more moult ahead.Rhithrogena germanica ↗American cockroachA name can travel farther than an animal’s origins.Periplaneta americana ↗American bird grasshopperThe same grasshopper can grow up in different colours.Schistocerca americana ↗