Archive for the ‘photowalking’ Category

Test shots: Didymops transversa exuvia

September 21, 2021

An exuvia from a Stream Cruiser dragonfly (Didymops transversa) was collected from one of the concrete abutments of a man-made dam located along a mid-size stream at an undisclosed location in Prince William County, Virginia USA.

I prefer to photograph odonate exuvia like this one “as is” — presumably its appearance is similar to the way larva looked when it lived underwater.

13 APR 2021 | PNC. William County, VA | Stream Cruiser exuvia (dorsal)

If so, then I’m guessing D. transversa larvae like to burrow in sediment, as indicated by the dirty dorsal side and relatively clean ventral side of this specimen.

13 APR 2021 | PNC. William County, VA | Stream Cruiser exuvia (ventral)

Post Update

The nymphs are sprawlers that cling to roots or hunker down in sediments of mixed sand and silt particles. Source Credit: K. J. Tennessen, Dragonfly Nymphs of North America, https://doi.org/10.1007/978-3-319-97776-8_10, Macromiidae, p. 330.

The Backstory

The preceding photos were shot using the prototype for a homemade curved clear plastic tray intended for staging subjects against a white background.

With a few minor tweaks, the curved stage performed better than during initial testing. I needed to add a second external flash unit to more evenly illuminate the white background.

Although I’m fairly satisfied with the results of these test shots, more testing is required to be sure the set-up is working the way I want.

Related Resources

Copyright © 2021 Walter Sanford. All rights reserved.

Yellow-sided Skimmer (terminal appendages)

August 24, 2021

Female and male Yellow-sided Skimmer dragonflies (Libellula flavida) were spotted at a small pond at an undisclosed location in Prince William County, Virginia USA.

Female

The first individual is a female, as indicated by her mostly yellow coloration and terminal appendages.

17 JUN 2021 | PNC. Wm. County | Yellow-sided Skimmer (female)

Female dragonflies have a pair of cerci (superior appendages) that have little or no function.

Mature male

The last individual is a mature male, as indicated by his light-blue pruinescence and terminal appendages.

17 JUN 2021 | PNC. Wm. County | Yellow-sided Skimmer (male)

Male dragonflies have three terminal appendages, collectively called “claspers,” that are used to grab and hold female dragonflies during mating: an upper pair of cerci (“superior appendages”) and a lower unpaired epiproct (“inferior appendage”).

Immature male Yellow-sided Skimmers look similar to females of the same species. Terminal appendages can be used to differentiate the sex of immature males and mature females.

Related Resource: Yellow-sided Skimmer (male and female) – a blog post by Walter Sanford.

Copyright © 2021 Walter Sanford. All rights reserved.

Black-shouldered Spinyleg (female)

August 13, 2021

A Black-shouldered Spinyleg dragonfly (Dromogomphus spinosus) was spotted by Michael Powell during a photowalk with me along a mid-size stream at an undisclosed location in Prince William County, Virginia USA.

This individual is a female, as indicated by her rounded hind wings and terminal appendages.

05 AUG 2021 | PNC. Wm. County | Black-shouldered Spinyleg (female)

We followed the female from one location…

05 AUG 2021 | PNC. Wm. County | Black-shouldered Spinyleg (female)

to another.

05 AUG 2021 | PNC. Wm. County | Black-shouldered Spinyleg (female)

I was able to take no more than three shots at each perch before she moved on to the next stop.

05 AUG 2021 | PNC. Wm. County | Black-shouldered Spinyleg (female)

Habitat

I’m not sure I’d call Black-shouldered Spinyleg a habitat specialist. I’ve seen and photographed D. spinosus along small streams in the forest, mid-size streams (like the one in this post), and large rivers.

Habitat: Rocky and muddy streams and rivers from small to large, more often in woodland. Also in rocky lakes in northern part of range. Source Credit: Paulson, Dennis (2011-12-19). Dragonflies and Damselflies of the East (Princeton Field Guides) (Kindle Locations 6416-6417). Princeton University Press. Kindle Edition.

Range map

The following map shows all official records for Dromogomphus spinosus in the United States of America. Given the wide range of lotic habitats where Black-shouldered Spinyleg is found, I’m puzzled by the fact that the species isn’t more widespread than it appears to be.

Related Resource: All posts in my blog tagged with the words “Black-shouldered Spinyleg dragonfly.”

Copyright © 2021 Walter Sanford. All rights reserved.

Bridge across Quantico Creek

August 3, 2021

The following photos show a small wooden bridge across Quantico Creek, near Burma Road in Prince William Forest Park, Prince William County, Virginia USA.

13 MAY 2021 | PNC. Wm. Forest Park | bridge across Quantico Creek

If you like bridges that bounce when you walk across them, then this is the bridge for you! I prefer bridges that are rock-solid.

13 MAY 2021 | PNC. Wm. Forest Park | bridge across Quantico Creek

Related Resource: All posts in my blog tagged with the word “bridge.”

Copyright © 2021 Walter Sanford. All rights reserved.

Ebony Jewelwing damselfly (male)

July 30, 2021

An Ebony Jewelwing damselfly (Calopteryx maculata) was spotted along a small stream located in Occoquan Regional Park, Fairfax County, Virginia USA.

05 JUN 2021 | Fairfax County, VA | Ebony Jewelwing (male)

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

05 JUN 2021 | Fairfax County, VA | Ebony Jewelwing (male)

Habitat

It’s easy to find Ebony Jewelwing. Look for a small stream in the forest.

Slow-flowing woodland streams, usually associated with herbaceous vegetation. Tend to be more at rapids when that habitat is present. Occur on open banks when trees nearby (trees essential for roosting at night). May be abundant at small streams in woods where very few other species are present. Source Credit: Paulson, Dennis (2011-12-19). Dragonflies and Damselflies of the East (Princeton Field Guides) (Kindle Locations 1249-1251). Princeton University Press. Kindle Edition.

Copyright © 2021 Walter Sanford. All rights reserved.

More Bar-winged Skimmers (males)

July 23, 2021

At least two male Bar-winged Skimmer dragonflies (Libellula axilena) were spotted along the shoreline of a small pond at an undisclosed location in Prince William County, Virginia USA.

It’s possible all of the photos featured in this blog post are of the same mature male that is featured in another recent post, as indicated by a distinctive pattern of spider web strands on the wings of the dragonfly.

Look closely along the leading edge of the wings. Notice the dark bars from which the common name for this species is derived are almost invisible.

17 JUN 2021 | PNC. Wm. County |  Bar-winged Skimmer (mature male)

17 JUN 2021 | PNC. Wm. County |  Bar-winged Skimmer (mature male)

17 JUN 2021 | PNC. Wm. County |  Bar-winged Skimmer (mature male)

17 JUN 2021 | PNC. Wm. County |  Bar-winged Skimmer (mature male)

For what it’s worth, the first and last photos in this set are my favorite.

Related Resource: Bar-winged Skimmer dragonfly (male).

Copyright © 2021 Walter Sanford. All rights reserved.

Variable Dancer damselfly (male)

July 20, 2021

A Variable Dancer damselfly (Argia fumipennis) was spotted near a small pond at an undisclosed location in Prince William County, Virginia USA.

17 JUN 2021 | Prince William County | Variable Dancer (male)

This individual is a male, as indicated by his mostly purple coloration.

Variable Dancer is a habitat generalist that can be found almost anywhere there is water. Mature males are easy to recognize due to their unique coloration — there are no other species of violet damselflies found in the eastern one-third of the United States. Female Variable Dancers, like many female odonates, are more challenging to identify than males.

It’s helpful to get shots of mating pairs of damselflies, especially “in tandem,” since males and females of the same species can look quite different. The excellent high-resolution digital scans by Gayle and Jeanelle Strickland, listed under “Related Resources” (below), provide clear views of male and female Variable Dancer damselflies.

Related Resources: High-resolution digital scans created by Gayle and Jeanelle Strickland.

Sidebar: Scientific Classification of Damselflies

The taxonomic classification of Variable Dancer is as follows: Order Odonata (Dragonflies and Damselflies); Suborder Zygoptera (Damselflies); Family Coenagrionidae (Narrow-winged Damselflies); Genus Argia (Dancers); Subspecies Argia fumipennis violacea (Violet Dancer).

The following concise explanation of the scientific classification of damselflies is provided to help the reader understand where Argia (Dancers) fit into the bigger picture of the Order Odonata, Suborder Zygoptera (Damselflies).

There are four families of damselflies in the United States of America, although only three families occur in the mid-Atlantic USA: Broad-winged damselflies; Narrow-winged damselflies (a.k.a., Pond Damselflies); and Spreadwing damselflies.

Family Calopterygidae is comprised of two genera.

Family Coenagrionidae is comprised of 14 genera. Three genera are common in Northern Virginia: Argia (Dancers); Enallagma (American Bluets); and Ischnura (Forktails).

Family Lestidae is comprised of two genera.

  • Archilestes (e.g., Great Spreadwing)
  • Lestes (e.g., Slender Spreadwing, Southern Spreadwing, Swamp Spreadwing)

There are relatively few genera of Broad-winged Damselflies and Spreadwing Damselflies. In contrast, there are many more genera and species of Narrow-winged Damselflies — more species, including many that look similar, makes this family the most challenging to learn!

Editor’s Note: Please comment to let me know whether the preceding information is helpful.

Copyright © 2021 Walter Sanford. All rights reserved.

Zebra Swallowtail butterfly

July 16, 2021

Zebra Swallowtail butterfly (Eurytides marcellusProtographium marcellus) was spotted near a small pond at an undisclosed location in Prince William County, Virginia USA.

17 JUN 2021 | Prince William County | Zebra Swallowtail

Notice the Zebra Swallowtail lost part of one of its tails, possibly the result of a close encounter with predator.

Copyright © 2021 Walter Sanford. All rights reserved.

Gray Petaltail dragonfly (male)

July 13, 2021

A Gray Petaltail dragonfly (Tachopteryx thoreyi) was observed during a photowalk with Michael Powell along the shoreline of a small pond at an undisclosed location in Prince William County, Virginia USA.

Mike spotted the Gray Petaltail first, when we were on opposite sides of the pond. Mike was able to shoot a few photos before the dragonfly flew away and Mike moved on. I thought Mike gave up on the subject too quickly so I decided to use one of my tried and true strategies for finding and photographing odonates: Sit in a good spot and wait for the game to come to me.

I walked around to the other side of the pond and sat down on my small, lightweight camp stool about 12-15 feet from the place where Mike had seen the Gray Petaltail. Sure enough, the dragonfly returned to the same perch soon afterward!

The first photo is the “record shot,” that is, get a shot, any shot.

17 JUN 2021 | PNC. Wm. County | Gray Petaltail (male)

This individual is a male, as indicated by his “indented” hind wings and terminal appendages.

17 JUN 2021 | PNC. Wm. County | Gray Petaltail (male)

The dragonfly would perch briefly, then fly away.

17 JUN 2021 | PNC. Wm. County | Gray Petaltail (male)

The male dragonfly did the same thing repeatedly, always returning to a slightly different perch each time. Turns out he was hunting for food.

17 JUN 2021 | PNC. Wm. County | Gray Petaltail (male)

I would describe T. thoreyi as an “ambush predator” — sometimes Gray Petaltail hunts for prey by waiting for other flying insects to pass by and ambushing them aerially when they do. Like the crane fly shown below that the Gray grabbed before landing on my bucket hat.

Photo used with written permission from Michael Powell.

I was happy to provide a white table cloth for a classy dining experience with one of my favorite species of dragonflies.

Habitat

For habitat-specific odonates such as T. thoreyi, it’s all about location, location, location. “Gray Petaltail dragonfly (male)” is another blog post by Walter Sanford that provides actionable intel regarding ideal habitat for Grays.

Range map

The following map shows all official records for Tachopteryx thoreyi in the United States of America. Gray Petaltail is a habitat specialist that is challenging to find.

Related Resources

  • Tachopteryx thoreyi Gray Petaltail on NatureServe Explorer. The conservation status for T. thoreyi in Virginia is “Apparently Secure (S4).” That’s good news. The bad news: That doesn’t mean it’s easy to find.
  • Gray Petaltail dragonfly (male)” – another blog post by Walter Sanford that provides actionable intel regarding ideal habitat for Grays.

Copyright © 2021 Walter Sanford. All rights reserved.

Bar-winged Skimmer dragonfly (male)

July 9, 2021

A Bar-winged Skimmer dragonfly (Libellula axilena) was spotted along the shoreline of a small pond at an undisclosed location in Prince William County, Virginia USA.

This individual is a mature male, as indicated by his coloration and terminal appendages.

17 JUN 2021 | PNC. Wm. County |  Bar-winged Skimmer (mature male)

This mature male has mated many times, as indicated by the scratches on the light-blue pruinescence covering his abdomen.

Males that have mated often have marks on their abdomen where the female legs have scratched them. This is especially obvious in species in which males develop pruinosity, as the pruinosity on the mid-abdomen is scratched off, and the signs are visible at some distance. Source Credit: Paulson, Dennis (2011-12-19). Dragonflies and Damselflies of the East (Princeton Field Guides) (Kindle Locations 390-392). Princeton University Press. Kindle Edition.

The next photo is full-frame (4,000 x 3,000 pixels), that is, uncropped.

17 JUN 2021 | PNC. Wm. County |  Bar-winged Skimmer (mature male)

Look closely along the leading edge of this individual’s wings. Notice the dark bars from which the common name for this species is derived are almost invisible.

Habitat

According to Dr. Steve Roble’s excellent datasets for the Commonwealth of Virginia, the adult flight period for Bar-winged Skimmer is from May 08 to September 28. Dr. Roble describes its habitat as “ponds.”

“Ponds” is perhaps too simple a descriptor for the habitat preferred by Bar-winged Skimmer, otherwise L. axilena should be more common than a map of its range suggests. Dennis Paulson provides a little more specificity.

Habitat: Wooded slow streams and sloughs, forest pools. Source Credit: Paulson, Dennis (2011-12-19). Dragonflies and Damselflies of the East (Princeton Field Guides) (Kindle Location 9152). Princeton University Press. Kindle Edition.

Kevin Munroe, former manager at Huntley Meadows Park, provides the best description of Bar-winged Skimmer habitat that I’ve seen.

One of our less common skimmers, this dragonfly has relatively specific habitat needs. It prefers very shallow marshy pools in the full sun. If there’s enough water for fish, it’s too deep for Bar-winged Skimmers. And of course shallow pools in the full sun tend to quickly evaporate and dry up, so stable populations in Northern Va. are few and far between. The similar Great Blue Skimmer also likes shallow water, but is much more common. One reason being that they can handle partly shady forest pools and forest swamps, both too dark for Bar-wings. Source Credit: Bar-winged Skimmer, by Kevin Munroe.

I have observed Bar-winged Skimmer dragonflies at two locations in Huntley Meadows Park that provided habitat similar to Kevin’s recipe. Bar-winged Skimmer is no longer found at either place.

I have seen Bar-winged Skimmer at Sundew Bog, located in the Central Tract at Patuxent Research Refuge.

The Central Tract of the refuge is closed to public visitation due to the sensitive nature of much of the scientific work. Source Credit: Patuxent Research Refuge brochure.

Range map

Not all species of Skimmers are as common as I tend to think. For example, the following map shows all official records for Libellula axilena in the United States of America. As you can see, Bar-winged Skimmer is a relatively uncommon species of odonate.

What are the take-aways?

Many species of dragonflies in the Family Libellulidae (Skimmers) are habitat generalists and relatively easy to find almost anywhere there is water. In contrast, I think it’s fair to say Bar-winged Skimmer is a habitat specialist that is challenging to find.

Related Resources

Copyright © 2021 Walter Sanford. All rights reserved.


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