Hetaerina americana exuvia

An American Rubyspot damselfly (Hetaerina americananymph was collected by Bob Perkins on 06 August 2017 along the New River in Grayson County, Virginia USA. The nymph was reared in captivity, albeit briefly, until it emerged on 09 August 2017.

Pattern recognition can be used to tentatively identify damselfly larvae/exuviae to the family level: the shape of the prementum is characteristic for each of the three families of damselflies that occur in the mid-Atlantic region of the United States of America; mnemonics can be used to remember each distinctive shape.

Family Calopterygidae (Broad-winged Damselflies) features a prementum with a shape that looks somewhat similar to Family Coenagrionidae (Narrow-winged Damselflies). Look for an embedded raindrop shape, located toward the upper-center of the prementum.

Also notice another field mark for Calopterygidae: the first antenna segment is equal to or longer than the length of the other six (6) segments added together. (Editor’s Note: Some of the smaller antennae segments are missing. It’s likely those delicate parts broke off during shipping and/or cleaning.)

No. 2 | Hetaerina americana | exuvia (ventral)

Two field marks verify the genus and species of this specimen as Hetaerina americana: the labial cleft extends only to the base of the palpal lobes, as shown in Photo No. 1; and the external gills are 8.5 mm to 10 mm long (Daigle, 1991), as shown in Photo No. 2.

Before and after

Photo No. 3 shows a dorsal view of the exuvia before it was cleaned in order to remove unknown fibers covering the body and dirt/debris that obscured the labial cleft in the prementum.

No. 3 | Hetaerina americana | exuvia (dorsal)

Photo No. 1, 2 and 4 show the exuvia after cleaning. The operation appears to have been successful, other than collateral damage to two legs.

No. 4 | Hetaerina americana | exuvia (dorsal)

The next photograph shows the damselfly during emergence from one of Bob Perkins‘ holding tanks. Good timing, Bob!

Image used with permission from Bob Perkins.

The last photo shows the adult American Rubyspot damselfly sometime after emergence. Hetaerina americana is 38-46 mm in total length (Paulson, 2011). This individual is a male, as indicated by its hamules and terminal appendages.

Image used with permission from Bob Perkins.

Related Resource: Florida Damselflies (Zygoptera) – A Species Key to the Aquatic Larval Stages, by Jerrell James Daigle. Technical Series, Volume 11, Number 1, December 1991. State of Florida, Department of Environmental Regulation.

Tech Tips

The following equipment was used to shoot Photo No. 2, 3 and 4: Canon EOS 5D Mark II digital camera, in manual mode; Kenko 20mm macro automatic extension tubeCanon EF100mm f/2.8L Macro lens (set for manual focus); Canon MT-26EX-RT Macro Twin Lite. Photo No. 1 , 2 and 4: the Canon MT-26 was set for “Master” mode, and Canon 580 EX- and Canon 580EX II Speedlites were set for “Slave” mode. A Canon MP-E 65mm Macro lens (manual focus only, set for 2x magnification) plus multiple-flash setup was used for Photo No. 1.

Adobe Photoshop CC 2017 was used to annotate selected images.

Bob Perkins’ photos were shot using a Canon EOS Rebel T3i camera body and Canon EF-S 60mm macro lens.

Copyright © 2018 Walter Sanford. All rights reserved.

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2 Responses to “Hetaerina americana exuvia”

  1. American Rubyspot damselfly exuvia | walter sanford's photoblog Says:

    […] (Broad-winged Damselflies), as indicated by the length of antenna segment 1 (shown below). See Hetaerina americana exuvia for a more detailed […]

  2. Why focus stack macro photos? | walter sanford's photoblog Says:

    […] example is one of the better photos from a set of 13. It is the same photo that is featured in Hetaerina americana exuvia, my identification guide for American Rubyspot damselfly […]

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