Fall 2016 hadn’t been good for finding Great Spreadwing damselflies (Archilestes grandis) at Huntley Meadows Park. A formerly fishless vernal pool in a remote location at the park was less than productive, yielding only two males as a result of intense searches during September and October. Given this context, imagine my surprise and delight when several Great Spreadwings were spotted on a mild day in early November, including my first sighting of a single female!
The following photo shows a male Great Spreadwing damselfly spotted on the same day and near the same location as the female. Notice its deep blue eyes, familiar yellow racing stripe on the side of its thorax, bluish-white coloration on abdominal segments 9-10 (S9-10), and distinctive terminal appendages (claspers).
Although female Great Spreadwings feature the same yellow thoracic stripe as males, several other field markers are different. Female eyes are paler blue and two-toned. Females have a noticeably thicker abdomen, minus the male coloration on S9-10. And of course, female terminal appendages are different from male appendages.
(See a full-size version of the original photo, without annotation.)
Female Great Spreadwing damselflies, like all female odonates, have two cerci (sing. cercus), superior appendages that have little or no function. Also notice two styli (sing. stylus), structures that serve as sensors (like “curb feelers“) in egg positioning during oviposition.
All three photos of the female are full-frame, that is, uncropped; the photo of the male was cropped slightly, only because I’m almost as obsessed with the way the edges of a photo look as the subject of the photo! Although I’m not opposed to cropping photos for better composition, I prefer to get it right in-camera.
- Great Spreadwing damselfly claspers (male)
- Great Spreadwing (mating pairs, in tandem)
- Fishless? Apparently not.
Editor’s Note: If you check the EXIF for all four photos, then you will see the time stamp is one hour later than the times shown above. 06 November was the first time I used my camera since the end of Daylight Saving Time (at 2:00 a.m. the same day) — I forgot to reset the time in-camera!
Copyright © 2016 Walter Sanford. All rights reserved.
Tags: Archilestes grandis, cerci, claspers, Family Lestidae (Spreadwings), female, Great Spreadwing damselfly, Huntley Meadows Park, male, styli, terminal appendages, vernal pool, wildlife photography