Posts Tagged ‘Broad-winged Damselflies’

Denizen of the seep

July 8, 2019

An Ebony Jewelwing damselfly (Calopteryx maculata) was spotted near a forest seep located in Occoquan Regional Park, Fairfax County, Virginia USA. This individual is a male, as indicated by the absence of white pterostigma — a field mark used to identify females of the same species.

Look for Ebony Jewelwing beginning in late-May/early-June along almost any small- to mid-size forest stream in Northern Virginia (USA).

Ebony Jewelwing is a member of Family Calopterygidae (Broad-winged Damselflies). American Rubyspot (Hetaerina americana) is the only other species of Broad-winged Damselfly found in Northern Virginia.

Adult flight period

According to records for the Commonwealth of Virginia maintained by Dr. Steve Roble, Staff Zoologist at the Virginia Department of Conservation and Recreation, Division of Natural Heritage, the adult flight period for C. maculata is from April 27 to October 06. The species is classified as common. Its habitat is “streams, rivers.”

Copyright © 2019 Walter Sanford. All rights reserved.

Advertisements

Ebony Jewelwing damselflies (mating pair)

June 26, 2018

A mating pair of Ebony Jewelwing damselflies (Calopteryx maculata) was spotted near a small forest stream at Occoquan Regional Park. The male is shown on the left; the female on the right.

The damselflies are “in wheel,” in which the male uses “claspers” (terminal appendages) at the end of his abdomen to hold the female by her neck/thorax while they are joined at their abdomens. The wheel position is sometimes referred to as “in heart” when damselflies mate.

Copyright © 2018 Walter Sanford. All rights reserved.

Ebony Jewelwing damselfly (male)

June 18, 2018

Look for Ebony Jewelwing damselflies (Calopteryx maculata) beginning in late-May/early-June along almost any small- to mid-size forest stream in Northern Virginia (USA).

This individual is a male, as indicated by the all-black coloration of his wings and by his terminal appendages.

Ebony Jewelwing is a member of Family Calopterygidae (Broad-winged Damselflies). American Rubyspot (Hetaerina americana) is the only other species of Broad-winged Damselfly found in Northern Virginia.

Related Resource: The adult flight period for Ebony Jewelwing is from April 27 to October 06, according to records for the Commonwealth of Virginia maintained by Dr. Steve Roble, a zoologist at the Virginia Department of Conservation and Recreation, Division of Natural Heritage.

Copyright © 2018 Walter Sanford. All rights reserved.

Another focus stacking face-off

April 19, 2018

Here’s another face-off between a single macro photo and a focus-stacked composite image. Let’s start with the composite image this time.

The first example is a composite image created from 14 photos.

In a recent blog post, I wrote…

My goal is to shoot the fewest number of photos (using a relatively small aperture such as f/18) that will show the entire specimen in focus when the photo set is focus-stacked to create a composite image. Source Credit: More Calico Pennant exuvia composite images.

I used to shoot several photos of a single focus point, e.g., the prementum, and select the sharpest image for editing/focus stacking. Now I’m using a wider aperture such as either f/11 or f/8 (for sharpness), shooting more photos, and using every photo that I take. My rationale is simple: A single photo may not be the sharpest photo of a single focus point, but it probably shows other areas that are in focus. In this case, I think more “raw material” is better than less.

The last example is one of the better photos from the set of 14. When you click on the images they open in a new tab automatically. Toggle back-and-forth between tabs and I think you will agree the composite image is clearly better than the following single photo.

The Backstory

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.

Copyright © 2018 Walter Sanford. All rights reserved.

Why focus stack macro photos?

April 17, 2018

Why focus stack macro photos? The answer is obvious: The difference between a single macro photo and a focus-stacked composite image is like night and day.

The first 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 exuviae.

The last example is a composite image created using all 13 photos in the set.

You may not notice the difference in quality unless you look at the full-size version of both images. When you click on the images they open in a new tab automatically. Toggle back-and-forth between tabs and I think you will agree the composite image is clearly better than the single photo.

The Backstory

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.

Copyright © 2018 Walter Sanford. All rights reserved.

Hetaerina americana exuvia

March 18, 2018

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 marker 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 markers 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.

American Rubyspot damselfly exuvia

March 12, 2018

An American Rubyspot damselfly (Hetaerina americana) nymph 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.

This individual is a member of the Family Calopterygidae (Broad-winged Damselflies), as indicated by the length of antenna segment 1 (shown below). See Hetaerina americana exuvia for a more detailed explanation.

No. 1 | Hetaerina americana | exuvia (dorsal)

If you look closely at the full-size version of both photos, then you should notice the specimen is covered by a lot of fibers of unknown origin.

That nymph was in the final instar when I collected it. Therefore it didn’t shed the algae and debris that had collected on its bristles. Source Credit: Personal communication with Bob Perkins.

A quick look at the prementum (below) shows the labial cleft, a key field marker for verifying the species, is obscured by some of the “debris” that Bob mentioned. As of this writing, the exuvia is soaking in a soapy water bath in the hope that it can be cleaned sufficiently to see that marker clearly.

No. 2 | Hetaerina americana | exuvia (ventral)

To be continued

Tech Tips

The following equipment was used to shoot Photo No. 1 and 2: 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); and Canon MT-26EX-RT Macro Twin Lite.

Two Sunpak LED-160 Video Lights (each with a white translucent plastic filter) were used for both photos.

Adobe Photoshop CC 2017 was used to annotate both images.

Copyright © 2018 Walter Sanford. All rights reserved.

American Rubyspot damselfly (female)

July 27, 2017

An American Rubyspot damselfly (Hetaerina americana) was spotted during a photowalk along Bull Run in Fairfax County, Virginia USA. As far as I know, this is the first official record for American Rubyspot at this location.

This individual is a female, as indicated by her terminal appendages and ovipositor.

21 JUN 2017 | Fairfax County, VA | American Rubyspot (female)

Notice one of the damselfly’s wings is either malformed or injured. She was able to fly, although it seemed to be a struggle.

The Backstory

The damselfly landed on my thigh a few minutes before the preceding photograph was taken. It was like she was pleading with me to help her, although I admit I tend to project my thoughts onto the odonates I photograph. I would have tried to unfold her wing, but I never had an opportunity. Two teenage girls and a bear-sized dog startled me! (I never heard/saw them approaching. The girls told me their dog is a Long Hair German Shepherd.) When I flinched the damselfly flew to the perch shown above, just beyond my reach.

Copyright © 2017 Walter Sanford. All rights reserved.

How to Identify Damselfly Exuviae to Family

March 11, 2017

There are five families of damselflies (Suborder Zygoptera) in the United States of America, although only three families occur in the mid-Atlantic region: Family Calopterygidae (Broad-winged Damselflies)Family Coenagrionidae (Narrow-winged Damselflies); and Family Lestidae (Spreadwings).

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; mnemonics can be used to remember each distinctive shape.

Family Calopterygidae (Broad-winged Damselflies)

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

An Ebony Jewelwing damselfly (Calopteryx maculata) exuvia was collected along a small stream located in eastern Fairfax County, Virginia USA.

Family Calopterygidae (Broad-winged Damselflies) | prementum

Family Coenagrionidae (Narrow-winged Damselflies)

The shape of the prementum for Family Coenagrionidae reminds me of a keystone.

A Narrow-winged Damselfly exuvia — probably Argia sp. (it’s a work in progress) — was collected along the Potomac River in Fairfax County, Virginia USA. This individual is a female, as indicated by the rudimentary ovipositor located on the ventral side of her abdomen.

Family Coenagrionidae (Narrow-winged Damselflies) | ventral

The lamellae, also known as caudal lamellae, are external structures used by damselfly larvae for both respiration and locomotion. In contrast, the respiratory system for dragonfly larvae is internal. Characteristics of the caudal lamellae (including shape of/patterns on) are some of the clues that can be used to identify damselflies to the genus/species level.

Family Lestidae (Spreadwings)

The unique shape of the prementum for Family Lestidae reminds me of a rattle (musical instrument).

A damselfly exuvia from the Family Lestidae (Spreadwings) was collected from a small vernal pool located in eastern Fairfax County, Virginia USA. Although the genus/species is unknown (again, it’s a work in progress), both Slender Spreadwing (Lestes rectangularis) adults and Southern Spreadwing (Lestes australis) adults were observed at the vernal pool on the same day this specimen was collected.

Family Lestidae (Spreadwings) | prementum

Related Resources

The first step is the hardest, as the saying goes. In this case, it’s easier to identify damselfly larvae/exuviae to the family level than it is to identify specimens to the genus/species level. There are relatively few resources, especially online resources. The following links to two dichotomous keys and a pattern-matching guide for caudal lamellae should help you get started. Many of the same species of damselflies that are known to occur in Michigan, Florida, and the Carolinas can be found in the mid-Atlantic region.

Copyright © 2017 Walter Sanford. All rights reserved.

American Rubyspot damselfly (male)

January 24, 2017

An American Rubyspot damselfly (Hetaerina americana) was spotted along the Potomac River at Riverbend Park, Fairfax County, Virginia USA. This individual is a male, as indicated by his coloration and hamules.

One and done. That’s the way some wildlife photographers shoot a subject. I like to “work the shot,” that is, shoot the subject from all angles and in different positions.

In this case, the damselfly was perching over deep water. I waded into the water as far as I could go in my knee-high green wellies and made the best of a less than ideal situation.

Since the subject never moved from his perch above the water, I moved so that my viewpoint featured different backgrounds. Also, the damselfly changed position slightly during the shoot. Although all of the photos in this set are similar, each one is different in the way it looks and feels.

Copyright © 2017 Walter Sanford. All rights reserved.


%d bloggers like this: