Posts Tagged ‘Anax junius’

Common Green Darner dragonfly (young male)

September 27, 2019

A mini-swarm of Common Green Darner dragonflies (Anax junius) was spotted at a dry vernal pool, Old Colchester Park and Preserve (OCPP), Fairfax County, Virginia USA. A few Black Saddlebags dragonflies were mixed in with the swarm of A. junius.

Some of the dragonflies were hawking smaller insects; others were resting on vegetation. It’s probable members of the swarm had stopped to rest and refuel before continuing their southward migration.

The following Common Green Darner dragonfly was perched in a bed of dried cattails.

18 SEP 2019 | OCPP | Common Green Darner (young male)

This individual is a young male, as indicated by his terminal appendages. Notice there are points on the tips of his cerci, as shown in the full-size version of the preceding photo. Female cerci are pointless, both literally and figuratively.

Related Resources

Copyright © 2019 Walter Sanford. All rights reserved.

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Common Green Darner (female)

May 1, 2019

A Common Green Darner dragonfly (Anax junius) was perched on a tree, approximately one-to-two feet above the ground. My good friend Mike Powell spotted this beautiful specimen while we were hunting for Harlequin Darner alongside Wildlife Loop trail at the North Tract of Patuxent Research Refuge (PRR), Laurel, Maryland USA.

This individual is a female, as indicated by her terminal appendages. Sexing Common Green Darner dragonflies is a photo-illustrated field guide that describes field marks that can be used to differentiate female and male Common Green Darners.

It’s worth noting that both photos featured in this blog post are uncropped, that is, full resolution for the Panasonic Lumix DMC-FZ300 superzoom bridge camera (4,000 x 3,000 pixels).

The following photo is one of my “record shots” for this subject. Whenever I see a dragonfly perched on a tree, I always try to refine the shot until the tree in the background fills the entire frame. If you compare/contrast the two photos, then I think you will agree with me that the composition of the first photo is much better than the second.

Related Resources

Copyright © 2019 Walter Sanford. All rights reserved.

Mosquito Hawks

July 26, 2018

I’m honored to announce several of my dragonfly photographs are featured on new signage at Melvin L. Newman Wetlands Center, Clayton County, Georgia. The info-graphic, entitled “Mosquito Hawks,” was created by Danielle Bunch, Senior Conservationist for Clayton County Water Authority.

Image used with permission from Danielle Bunch.

As a retired K-12 science educator, I know from first-hand experience that informal learning opportunities can be as valuable as formal education in school classrooms. I was glad to contribute several of my photographs of Common Green Darner dragonflies (Anax junius) to the new info-graphic for the wetland area. It’s flattering to share the stage with Giff Beaton, author of Dragonflies and Damselflies of Georgia and the Southeast.

Full-size versions of my photographs (featured on the signage) appear in several previous posts on my photoblog.

Related Resources

Copyright © 2018 Walter Sanford. All rights reserved.

Should I stay or should I go?

October 7, 2017

Two Common Green Darner dragonflies (Anax junius) were observed flying back-and-forth over a field alongside a vernal pool at a remote location in Huntley Meadows Park (HMP), Fairfax County, Virginia USA — typical feeding behavior for Common Green Darners. Sometimes they would land briefly, perching in shady hidey-holes in the thick vegetation covering the ground. I followed one of the two to a couple of perches.

This individual was very skittish! I was able to shoot one photo at the first perch…

03 OCT 2017 | HMP | Common Green Darner (female)

…and another photo at the last perch. The dragonfly flew toward the tree canopy when I tried to move a step closer.

03 OCT 2017 | HMP | Common Green Darner (female)

It’s relatively easy to identify this type of dragonfly to the species level.

The easiest field mark for identification of a Common Green Darner is that “bull’s eye” on the back of the head. No other [odonate] has it. Source Credit: John Gregoire, Kestrel Haven Wildlife Sanctuary.

On the other hand, it can be more challenging to identify the gender.

Several field markers can be used to identify the gender of this dragonfly. The cerci (sing. cercus) of female Common Green Darners look like almonds, both in color and shape. Two more field markers verify this specimen is female.

Note the brown stripe extending onto abdominal segment 2. Segment 2 [S2] is typically all pale on males. Also [viewing the second photo at full resolution and zooming in on the head] the rear margin of the occiput is not straight. Females have blunt dark colored “teeth” back there which makes the margin look wavy. Source Credit: Ed Lam, author and illustrator of Damselflies of the Northeast, Northeast Odonata Facebook group.

Common Green Darner is one of at least five major species of dragonflies known to be migratory in North America. It’s possible the two Common Green Darners that I observed stopped at Huntley Meadows Park in order to “refuel” before continuing their southward migration.

Related Resources

Copyright © 2017 Walter Sanford. All rights reserved.

Exuviart

August 22, 2017

Regular readers of my blog remember when I coined the term “Odonart” and created an “Odonart Portfolio.”

I just coined a new term: “Exuviart.” Exuviart is a concatenation of two words: exuvia; and art. The following photographs are the first additions to the Exuviart wing of my Odonart Portfolio.


Unpublished Photo

An Eastern Amberwing dragonfly (Perithemis tenera) exuvia, from the Family Libellulidae (Skimmers), was collected from the Potomac River in Fairfax County, Virginia USA.

Whenever possible, I like to collect exuviae along with some of the vegetation that was the site for emergence. The vegetation helps to show scale. In this case, the small specimen is approximately 1.4 cm (~0.6″) in length and approximately 0.6 cm (~0.2″) in maximum width. I like the way the desiccated leaf retained its color and gained a velvety texture.

Tech Tips

The following equipment was used to shoot the preceding photograph: Canon EOS 5D Mark II DSLR; Canon EF100mm f/2.8 Macro lens plus Raynox DCR-250 close-up filter; Canon 580EX II Speedlite; Canon 580EX Speedlite; and a coiled six-foot Vello Off-Camera TTL Flash Cord for Canon Cameras. The specimen was staged on a piece of white plastic (12″ square, matte finish).


Published Photos

A Common Green Darner dragonfly (Anax junius) exuvia, from the Family Aeshnidae (Darners), was collected at Hidden Pond, Meadowood Recreation Area (MRA), Fairfax County, Virginia USA.

Tech Tips

The following equipment was used to shoot the preceding photograph: Canon EOS 5D Mark II digital camera, in manual mode; Canon EF100mm f/2.8L Macro lens (set for manual focus); Canon 580EX II external flash, off-camera, in manual mode; Canon 580EX external flash, off-camera, in manual mode; and a Yongnuo YN-622C-TX E-TTL II Wireless Flash Controller for Canon plus a two-pack of Yongnuo YN-622C II E-TTL Wireless Flash Transceivers for Canon.


A Cobra Clubtail dragonfly (Gomphurus vastus) exuvia, from the Family Gomphidae (Clubtails), was collected at Riverbend Park with permission from park staff.

Tech Tips

The following equipment was used to shoot the preceding photograph: Canon EOS 5D Mark II digital camera, in manual mode; Canon EF100mm f/2.8L Macro lens (set for manual focus) plus a Kenko 20mm macro automatic extension tube and Raynox DCR-250 close-up filter; Canon 580EX II external flash, off-camera, in manual mode; Canon 580EX external flash, off-camera, in manual mode; and a Yongnuo YN-622C-TX E-TTL II Wireless Flash Controller for Canon plus a two-pack of Yongnuo YN-622C II E-TTL Wireless Flash Transceivers for Canon.

Copyright © 2017 Walter Sanford. All rights reserved.

Almost perfect

March 17, 2017

Sometimes I get so focused on the subject of a photo that I don’t see the bigger picture. Although I recognize the problem, I can’t think of a simple solution.

04 OCT 2016 | Huntley Meadows Park | predators and prey

The preceding photo shows a Black and Yellow Argiope (Argiope aurantia) spider spotted at Huntley Meadows Park; a Common Green Darner dragonfly (Anax junius) is trapped in the spider web. I was so focused on getting a shot of the spider in a good position relative to the dragonfly that I never noticed the Chinese Mantid (Tenodera sinensis sinensis) on the right side of the photo. That is, until I returned home.

Notice that I clipped one of the mantid’s legs on the left side of its body (right edge of the photo). That’s the sort of thing that drives me crazy! If I had seen the mantid then I would have recomposed the shot in order to capture all three insects completely. Oh well, another hard lesson learned about wildlife photography.

Copyright © 2017 Walter Sanford. All rights reserved.

Anax junius exuvia

January 14, 2017

A dragonfly exuvia from the Family Aeshnidae (Darners) was collected on 21 June 2016 at Hidden Pond, Meadowood Recreation Area, Fairfax County, Virginia USA. This specimen is an exuvia from a Common Green Darner dragonfly (Anax junius).

A two-step process was used to identify the genus and species of the specimen.

  1. Determine the family.
  2. Determine the genus and species.

Step 1. Family

First, determine the family of the specimen. For reference, watch the excellent Vimeo video, Identifying dragonfly larva to family (8:06). Here’s the decision tree I used to identify the exuvia as a member of the Family Aeshnidae (Darners).

  • The specimen has a flat labium that doesn’t cover the face (not mask-like), as shown in Photo No. 1-4.
  • Antennae are thin and thread-like (not club-like, as in Gomphidae larvae), as shown in Photo No. 4.
  • Eyes are large relative to the size of the head, as shown in Photo No. 5.

Step 2. Genus and species

As shown in Photo No. 1, lateral spines along abdominal segments seven, eight, and nine (S7-9) indicate the genus is Anax.

A dragonfly exuvia from the Family Aeshnidae (Darners), collected at Hidden Pond, Meadowood Recreation Area, Fairfax County, Virginia USA. This individual is Anax junius.

No. 1 | Common Green Darner (Anax junius) | exuvia (dorsal-lateral)

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

At this point, you know the species could be either anax (Common Green Darner dragonfly) or longipes (Comet Darner dragonfly). The species is determined by the shape of the palpal lobes (see Photo No. 3) and the length of the specimen (see Photo No. 2).

A dragonfly exuvia from the Family Aeshnidae (Darners), collected at Hidden Pond, Meadowood Recreation Area, Fairfax County, Virginia USA. This individual is Anax junius.

No. 2 | Common Green Darner (Anax junius) | exuvia (lateral)

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

The labium, also known as the mentum, is a two-segment hinged “jaw” that is used to grab food: the prementum is the segment of the labium closer to the mouth; the postmentum is the segment closer to the base of the head.

The specimen is ~4.7 cm (~1.9 in) in length, not counting the bend in the body.

A dragonfly exuvia from the Family Aeshnidae (Darners), collected at Hidden Pond, Meadowood Recreation Area, Fairfax County, Virginia USA. This individual is Anax junius.

No. 3 | Common Green Darner (Anax junius) | exuvia (labium, ventral)

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

The rounded shape of the palpal lobes (see Photo No. 3, above) plus the length of the specimen (see Photo No. 2) indicate the species is juniusAnax junius is one of the more common species of Aeshnidae found in Northern Virginia.

A dragonfly exuvia from the Family Aeshnidae (Darners), collected at Hidden Pond, Meadowood Recreation Area, Fairfax County, Virginia USA. This individual is Anax junius.

No. 4 | Common Green Darner (Anax junius) | exuvia (face-head)

Notice the antennae are thin and thread-like, as shown in the preceding photo. If you are an aquatic animal, this is a face you don’t want to see up-close and personally!

A dragonfly exuvia from the Family Aeshnidae (Darners), collected at Hidden Pond, Meadowood Recreation Area, Fairfax County, Virginia USA. This individual is Anax junius.

No. 5 | Common Green Darner (Anax junius) | exuvia (head, dorsal)

The eyes are large relative to the size of the head.

Tech Tips:

The following equipment was used to shoot all of the preceding photographs: Canon EOS 5D Mark II digital camera, in manual mode; Canon EF100mm f/2.8L Macro lens (set for manual focus); Canon 580EX II external flash, off-camera, in manual mode; Canon 580EX external flash, off-camera, in manual mode; and a Yongnuo YN-622C-TX E-TTL II Wireless Flash Controller for Canon plus a two-pack of Yongnuo YN-622C II E-TTL Wireless Flash Transceivers for Canon. A Raynox DCR-250 close-up filter was used for Photo No. 3-5.

Adobe Photoshop CC 2017 was used to annotate selected images.

The first test shot for this exuvia was photographed using my Canon EF100mm f/2.8L Macro lens plus a Kenko 20mm macro automatic extension tube. As you can see in the following photo, the subject barely fit within the frame. Although the composition isn’t ideal, the resulting photo is dramatic nonetheless! The 20mm extension tube wasn’t used for the rest of the photo set.

A dragonfly exuvia from the Family Aeshnidae (Darners), collected at Hidden Pond, Meadowood Recreation Area, Fairfax County, Virginia USA. This individual is Anax junius.

No. 6 | Common Green Darner (Anax junius) | exuvia (lateral)

The following photograph of the exuvia was taken in-situ along the shoreline of Hidden Pond using a Panasonic Lumix DMC-FZ150 superzoom bridge camera and Canon 580EX Speedlite, my go-to kit for photowalking.

A dragonfly exuvia spotted at Hidden Pond, Meadowood Recreation Area, Fairfax County, Virginia USA. This individual is probably a member of Family Aeshnidae.

No. 7 | 21 JUN 2016 | MRA | Anax junius exuvia (in-situ)

Related Resources:

dichotomous key: a key for the identification of organisms based on a series of choices between alternative characters. Source Credit: Merriam-Webster Dictionary.

In long form, the decision tree is as follows (assuming the convention of labeling the two branches of each dichotomy as “a” and “b”, e.g. 1a, 1b, etc.):

p. 21, Key to the genera of the Family Aeshnidae
1b – Hind angles of head rounded … . (5)
5a – Lateral spines on abdominal segments 7 to 9 only. (6)
6b – Antenna about half as long as this distance [from the base of the antennae to the rear of head]. (Anax)

p. 22, Key to the species of the genus Anax
1a – Lateral lobes of labium tapering to a hooked point; total length about 40 mm. (junius) [Note: The total length of longipes is about 55 mm.]

Copyright © 2017 Walter Sanford. All rights reserved.

What’s my gender?

November 1, 2016

The following Common Green Darner dragonfly (Anax junius) was spotted near a vernal pool in a remote location at Huntley Meadows Park.

Can you identify its gender? You may want to refer to Sexing Common Green Darner dragonflies, my last blog post, before choosing an answer.

Whatever its gender, this individual is what I call a “freshie,” that is, an odonate that emerged recently but may not fit the strict definition of “teneral.” You could call the dragonfly either “post-teneral” or “immature” but it’s definitely not mature, as indicated by the light tan eye color.

Editor’s Note: The dark stripe extending into S2 is the most obvious field marker indicating this dragonfly is female.

Copyright © 2016 Walter Sanford. All rights reserved.

Sexing Common Green Darner dragonflies

October 30, 2016

Several field marks can be used to identify the gender of female and male Common Green Darner dragonflies (Anax junius).

Female

The following individual, spotted at Huntley Meadows Park, is a female. Female dragonflies have a pair of cerci (superior appendages) that have little or no function. The cerci (sing. cercus) of female Common Green Darners look like almonds, both in color and shape.

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

Two more field marks verify this specimen is female.

Note the brown stripe extending onto abdominal segment 2. Segment 2 [S2] is typically all pale on males. Also viewing at full resolution, the rear margin of the occiput is not straight. Females have blunt dark colored “teeth” back there which makes the margin look wavy. Source Credit: Ed Lam, author and illustrator of Damselflies of the Northeast, Northeast Odonata Facebook group.

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”).

The cerci of male Common Green Darners are slightly darker in color and somewhat thicker and more rounded than the cerci of females of the same species. There are points at the tips of the two male cerci, as shown clearly in the full-size version of the following photo; female cerci are pointless, both literally and figuratively.

Male Common Green Darners have a very short epiproct that is used to grip the “teeth” on the back of head of females of the same species.

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

The individual in the preceding image is an immature male, as indicated by the purple coloration on his abdomen. As a mature male, his abdomen will be partially covered by blue pruinescence like the one shown below.

Related Resources: Digital Dragonflies, presenting high-resolution digital scans of living dragonflies.

  • Genus Anax | Anax junius | Common Green Darner | female | top view
  • Genus Anax | Anax junius | Common Green Darner | female | side view
  • Genus Anax | Anax junius | Common Green Darner | male | top view
  • Genus Anax | Anax junius | Common Green Darner | male | side view

Compare and contrast the cerci of female and male Common Green Darners by viewing the full-size versions of the preceding top views for both sexes and Ed Lam’s excellent composite image, shown below.

ed-lam_cgd_male-vs-female

Composite image used with permission from Ed Lam.

Copyright © 2016 Walter Sanford. All rights reserved.

Headfirst

October 22, 2016

Common Green Darner dragonfly (Anax junius) landed a few feet to my left as I was looking for Russet-tipped Clubtail dragonflies during a photowalk around Mulligan Pond at Jackson Miles Abbott Wetland Refuge (JMAWR).

Almost immediately, I realized the Common Green Darner was eating a smaller female Autumn Meadowhawk dragonfly (Sympetrum vicinum).

A Common Green Darner dragonfly (Anax junius) spotted at Mulligan Pond, Jackson Miles Abbott Wetland Refuge, Fairfax County, Virginia USA. This individual is a male, eating a female Autumn Meadowhawk dragonfly (Sympetrum vicinum).

16 OCT 2016 | JMAWR | Common Green Darner (male, eating prey)

Notice the Common Green Darner is eating the Autumn Meadowhawk headfirst, the fastest way for the predator to immobilize its prey.

A Common Green Darner dragonfly (Anax junius) spotted at Mulligan Pond, Jackson Miles Abbott Wetland Refuge, Fairfax County, Virginia USA. This individual is a male, eating a female Autumn Meadowhawk dragonfly (Sympetrum vicinum).

16 OCT 2016 | JMAWR | Common Green Darner (male, eating prey)

The Common Green Darner is an immature- to young male, as indicated by his coloration and terminal appendages. As a mature male, his abdomen will be partially covered by blue pruinescence.

A Common Green Darner dragonfly (Anax junius) spotted at Mulligan Pond, Jackson Miles Abbott Wetland Refuge, Fairfax County, Virginia USA. This individual is a male, eating a female Autumn Meadowhawk dragonfly (Sympetrum vicinum).

16 OCT 2016 | JMAWR | Common Green Darner (male, eating prey)

Copyright © 2016 Walter Sanford. All rights reserved.


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