Archive for the ‘education’ Category

Later the same day…

July 2, 2018

Later the same day that I spotted my first-of-year Black-shouldered Spinyleg dragonfly (Dromogomphus spinosus) at Prince William Forest Park (PWFP), Prince William County, Virginia USA, I spotted another one during a photowalk at Occoquan Regional Park in Fairfax County, Virginia.

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

Adult flight period

The adult flight period for Black-shouldered Spinyleg is from 03 June to 12 September (peaks in July to August), according to records for Northern Virginia maintained by Kevin Munroe, former manager at Huntley Meadows Park. My earliest sighting is 21 June; my latest sighting is 08 August.

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, 08 May to 10 October is the adult flight period for Black-shouldered Spinyleg.

Copyright © 2018 Walter Sanford. All rights reserved.

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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 forested 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.

Che bella faccia!

June 4, 2018

The title means “What a beautiful face!” in Italian.

30 MAY 2018 | Northern Virginia | Gray Petaltail (female)

Just look at her — isn’t she beautiful? Rhetorical question. I’m especially fond of the black “T” shape, technically known as the anteclypeus, located between the postclypeus and labrum. Huh?

Zoom in on the full-size version of the preceding photo. Notice her face is comprised of several sections. From top-to-bottom, the sections are as follows: frons (white); postclypeus (white); anteclypeus (black); labrum (white with a black stripe down the middle).

Related Resources

Copyright © 2018 Walter Sanford. All rights reserved.

Another summer species of odonate

May 29, 2018

Blue Dasher (Pachydiplax longipennis) is another summer species of odonate that appears in Northern Virginia in late spring. The following individual — spotted at Hidden Pond during a photowalk at Meadowood Recreation Area (MRA), Fairfax County, Virginia USA — is a male, as indicated by his coloration and terminal appendages.

Blue Dasher is a habitat generalist that “can be found almost anywhere there is still water.” Source Credit: Species Pachydiplax longipennis – Blue Dasher.

Copyright © 2018 Walter Sanford. All rights reserved.

Seamless transition

May 27, 2018

A seamless transition from the spring species of odonates to the summer species is slowly but surely underway.

Spangled Skimmer (Libellula cyanea) is a summer species that starts to appear in Northern Virginia in late spring. The following individual — spotted at Hidden Pond during a photowalk at Meadowood Recreation Area (MRA), Fairfax County, Virginia USA — is a teneral female, as indicated by her tenuous wings and terminal appendages.

21 MAY 2018 | MRA | Spangled Skimmer (teneral female)

Female Spangled Skimmers have a pair of flanges beneath their eighth abdominal segment that are used to scoop and hold a few drops of water when laying eggs (oviposition), hence the family name “Skimmer.” Remember that all dragonflies and damselflies have a 10-segmented abdomen, numbered from front to back.

Copyright © 2018 Walter Sanford. All rights reserved.

Survivors

May 25, 2018

The adult flight period for Blue Corporal dragonfly (Ladona deplanata) is from March 09 to July 09, according to records for the Commonwealth of Virginia maintained by Dr. Steve Roble; records for Northern Virginia maintained by Kevin Munroe show the flight period is from the second week in April to the first week in June. In my experience, the third week in May is late for Blue Corporal.

Meadowood Recreation Area

A single Blue Corporal dragonfly was spotted perched on the dock at Hidden Pond, Meadowood Recreation Area (MRA), Fairfax County, Virginia USA. This individual is a mature male, as indicated by his terminal appendages and dark blue pruinescence covering the body.

21 MAY 2018 | MRA | Blue Corporal (mature male)

Contrast the appearance of a mature male Blue Corporal with teneral males of the same species spotted on 26 April 2018 at Occoquan Bay National Wildlife Refuge, Prince William County, Virginia USA.

21 MAY 2018 | MRA | Blue Corporal (mature male)

Prince William Forest Park

Two days later, another mature male Blue Corporal was spotted perched on the railing of an observation platform at a small pond located in Prince William Forest Park, Prince William County, Virginia USA.

23 MAY 2018 | MRA | Blue Corporal (mature male)

Editor’s Notes: Dr. Steve Roble is a zoologist at the Virginia Department of Conservation and Recreation, Division of Natural Heritage. Kevin Munroe is the former manager of Huntley Meadows Park, Fairfax County, Virginia.

Copyright © 2018 Walter Sanford. All rights reserved.

Springtime Darner (male claspers)

May 19, 2018

A Springtime Darner dragonfly (Basiaeschna janata) was spotted along Popes Head Creek at Hemlock Overlook Regional Park (HORP) in Fairfax County, Virginia USA. This individual is a male, as indicated by his terminal appendages and “indented” hind wings.

23 APR 2017 | HORP | Springtime Darner (male)

(See a full-size version of the original photo, without annotation.)

All 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”).

23 APR 2017 | HORP | Springtime Darner (male)

(See a full-size version of the original photo, without annotation.)

Editor’s Notes

The preceding photos are new, that is, previously unpublished. Both photos are full-frame (uncropped). Springtime Darners can be quite skittish. In this case, I was very close to an unusually cooperative model.

The last photo was shot using Aperture Priority. I prefer shooting in Shutter Priority, but I like to shoot a few shots using Aperture Priority whenever I can use either a monopod or tripod. In this situation, I improvised.

In addition to my photography gear, I usually carry a Coleman camp stool when I go photowalking. The small, lightweight folding chair is good for resting while waiting for “the game to come to me.” The camp stool also enables me to get closer to subjects either on- or near the ground, such as the Springtime Darner featured in this blog post. I think it’s easier to hold my camera rock-steady when I’m sitting on the chair with my elbows resting on my knees.

Copyright © 2018 Walter Sanford. All rights reserved.

Twin-spotted Spiketail (male claspers)

May 17, 2018

All 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”).

Male members of the Family Cordulegastridae (Spiketails), including male Twin-spotted Spiketail dragonflies (Cordulegaster maculata), have relatively small cerci (terminal appendages) that can be mistaken for female cerci.

Male dragonfly secondary genitalia, called hamules, are located below abdominal segments two and three (S2 and S3), as shown in the following annotated image. Hamules come in a variety of sizes and shapes, but their function is identical for all species of odonates.

Related Resources

Copyright © 2018 Walter Sanford. All rights reserved.

Brown Spiketail dragonfly (male claspers)

May 15, 2018

Brown Spiketail dragonflies (Cordulegaster bilineata) were spotted on two days during May 2018 at Occoquan Regional Park. Both individuals featured in this post are male, as indicated by their terminal appendages and slightly “indented” hind wings.

All 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”).

Notice the epiproct for Brown Spiketail is a wide “plate” that spans both cerci, as shown in the full-size version of the following annotated image.

Male dragonfly secondary genitalia, called hamules, are located below abdominal segments two and three (S2 and S3), as shown in the preceding annotated image. Hamules come in a variety of sizes and shapes, but their function is identical for all species of odonates. Some species of dragonflies and damselflies — such as Ashy Clubtail versus Lancet Clubtail and Southern Spreadwing versus Sweetflag Spreadwing, to name a few — can be differentiated/identified with certainty only by examining the hamules under magnification.

Copyright © 2018 Walter Sanford. All rights reserved.

Common Whitetail (immature males)

May 7, 2018

A first-of-season Common Whitetail dragonfly (Plathemis lydia) was spotted perching on the ground near a vernal pool at Huntley Meadows Park, Fairfax County, Virginia USA. This individual is an immature male, as indicated by his terminal appendages, brown colored abdomen, and pattern of wing spots.

30 APR 2018 | Huntley Meadows Park | Common Whitetail (immature male)

Another immature male was spotted along an informal trail at a remote location in the park.

30 APR 2018 | Huntley Meadows Park | Common Whitetail (immature male)

Young male Common Whitetails begin to develop white pruinescence that changes the color of their abdomen from brown to white, hence the common name for this species.

Sexing Common Whitetail dragonflies

For many of the common species of odonates found in Northern Virginia, I created a collection of annotated guides that illustrates how to differentiate gender by looking at terminal appendages. The difference in the pattern of wings spots for male and female Common Whitetails is sufficient to identify gender.

Copyright © 2018 Walter Sanford. All rights reserved.


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