New York Natural Heritage Program
Spatterdock Darner
Rhionaeschna mutata (Hagen, 1861)
Insects

Identifying Characteristics [-]
Like other blue or mosaic darners (genus Aeshna), adult spatterdock darners are large dragonflies with large eyes, a brown thorax with two blue 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 eyes of this species are bright blue, and males have peculiar-shaped, forked terminal appendages. Adult spatterdock darners average approximately 2.8 in (7.1 cm) in length. The wings are clear. Females are similar to males, but the thoracic markings are generally more dull, and the occasional female has yellowish thoracic stripes and greenish abdominal spots (Nikula et al. 2003, Dunkle 2000). 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 seven small, slender segments. Body length is approximately 1.4 in (36 mm) at maturity (Walker 1958), which may be at 1-3 years.

Characters Most Useful for Identification [-]
Close examination of the thoracic pattern is helpful in identification, although the eye color and, for males, the shape of the terminal appendages, are conclusive.

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 hunt along forest edges, dirt roads, and fields, often in the vicinity of the wetland where eggs are laid. Females lay their eggs, on the undersides of aquatic and emergent vegetation, especially spatterdock (Nuphar). Males chase other males and patrol for females while flying low along the wetland shoreline or over the open water, often with a leisurely erratic flight. As with other darners, spatterdock darners rest by hanging verticallyon tree trunks or branches where they can be difficult to detect (Nikula et al. 2003, Dunkle 2000).
Spatterdock Darner Images
click to enlarge
The Best Time to See
This is our only early summer Aeshna, with a flight season of early June through early July, based on New York records (Donnelly 1999). Nikula et al. (2003) show a similar flight season for Massachusetts, but with the season beginning a bit earlier, in late May. The flight season in New York may actually be later than the season in Massachusetts, or the lack of records in late May in New York may simply reflect the overall lack of records for this uncommon species.
J F M A M J J A S O N D
Present Reproducing
The time of year you would expect to find Spatterdock Darner present (blue shading) and reproducing (orange shading) in New York.
Similar Species
  • Cyrano Darner (Nasiaeschna pentacantha)
    Like the spatterdock darner, the Cyrano darner flies in early summer and has blue eyes, but this species has a projecting forehead, green thoracic stripes, and is noticeably heavier in the body.
  • Springtime Darner (Basiaeschna janata)
    The springtime darner has bluish abdominal spots and flies in early summer, but has pale yellow to white (rather than blue) lateral thoracic stripes, has small dark patches at the base of the wings, lacks the sky-blue eyes of the spatterdock darner, and is noticeably smaller in overall body size.