Odonates are aquatic insects that spend most of their life as larvae that live in water; this stage of their life cycle can last from a few months to a few years. Finally, they emerge from the water and metamorphose into adults in order to reproduce; their offspring return to the water and the cycle begins again.
Careful and/or lucky observers will notice exuviae (sing. exuvia), also known as either “cast skins” or “shed skins,” left behind when odonate larvae emerge.
The flash/no-flash debate is settled in my mind, as evidenced by the preceding two-image gallery of photos. Although the photo shown on the left may have a more natural or “artier” look, critical detail is lost in the shadows, including the Long-jawed Orb Weaver (Family Tetragnathidae) lurking in the darkness on the left-most cattail rush!
The next photo shows cast skins from two different species of odonates. Most experts agree it is virtually impossible to identify exuviae to the species level using only photographs, although some cast skins are so distinctive it is possible to identify the family from a photo.
The last photograph shows a cast skin spotted in the central wetland area, near beginning of boardwalk.
Related Resources: Be forewarned — identification of odonate larvae is difficult at best and impossible at worst. If you enjoy a challenge, then here are a few free resources that should be helpful.
- Field Cards for Identifying Dragonfly Larvae to Family – National Park Service
- A General Guide to Dragonfly Exuviae
- Dragonfly Larvae Key
- Dragonfly Larvae Identification Key
- Odonate Nymphs by Steve Krotzer
- Aquatic Insects of Central Virginia
- Dragonfly Exuvia [macro photos]
- Odonate Exuviae, by Walter Sanford
Editor’s Note: Collecting specimens is prohibited at Huntley Meadows Park. Further, a permit for Collection of Wildlife for Scientific and/or Educational Purposes is required anywhere in the Commonwealth of Virginia.
Copyright © 2015 Walter Sanford. All rights reserved.