New York Natural Heritage Program
Mottled Darner
Aeshna clepsydra Say, 1839
Insects

Identifying Characteristics [-]
Like other blue or mosaic darners (genus Aeshna), adult mottled 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. Unlike other species of Aeshna, the two stripes on the side of the thorax (the lateral stripes) are a broad, complicated pattern of blue, green, and yellow. The abdomen is very constricted at segment 3 giving this species a "wasp-waisted" appearance and the segments are separated by blackish joints. Adult mottled darners average approximately 2.7 in (6.8 cm) in length. The face is greenish with a brown crossline and a heavy black "T-spot" above the face. The eyes are blue-gray to greenish. The wings are clear. Females are similar to males, but pale areas may be more green than blue and may be more extensive than on males (Needham et al. 2000, Nikula et al. 2003, Mead 2003). The larvae are elongate, cylindrical shaped aquatic insects that are usually patterned in drab brown and greenish colors. They climb and crawl among aquatic vegetation. The antennae are composed of six or seven small, slender segments. Body length is approximately 1.42-1.57 in (36-40 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 [-]
Adult males patrol shorelines during the middle of the day defending breeding sites, while females oviposit in emergent vegetation. Adults of both sexes will hunt in sunny clearings and woodland openings and will join other darners in feeding swarms (Dunkle 2000). As with most other darners, mottled darners typically perch vertically on tree trunks (Mead 2003, Nikula et al. 2003).
Mottled Darner Images
click to enlarge
The Best Time to See
Based on available records the peak of the flight season in New York appears to be from mid-July through mid-September. There is just one New York record for June and the latest date is September 22 (Donelly 1992). Publications for Massachusetts (Nikula 2003) and the western Great Lakes area (Mead 2003) list the flight season as beginning in mid-July so the June record is probably an anomaly. Although the latest flight date recorded for New York is September 22, most September records are from the first half of the month, whereas the flight season in Massachusetts appears to extend into early October (Nikula 2003).
J F M A M J J A S O N D
Present Reproducing
The time of year you would expect to find Mottled Darner present (blue shading) and reproducing (orange shading) in New York.
Similar Species
  • Cyrano Darner (Nasiaeschna pentacantha)
    No other Aeshna species has stripes on the side of the thorax that are as broad and mottled as the mottled darner. The cyrano darner, which is also in the Aeshnid family, has very broad blue-green stripes on the side of the thorax and a somewhat similar abdominal pattern, but it is larger and more stocky in appearance and has a large protruding forehead. The cyrano darner's flight season is earlier, winding down in July as the mottled darner's flight season is beginning.