Posts Tagged ‘Family Aeshnidae (Darners)’

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.

Advertisements

Springtime Darner (terminal appendages)

September 11, 2017

Male and female Springtime Darner dragonflies (Basiaeschna janata) are colored similarly sometimes. Terminal appendages can be used to identify gender.

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”).

A male Springtime Darner was spotted along a mid-size rocky stream located at Hemlock Overlook Regional Park (HORP), Fairfax County, Virginia USA.

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

Female

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

Female Springtime Darners are polymorphic: the spots on their abdomen are either blue (andromorphic) or green (heteromorphic); this female — spotted at a remote location in Huntley Meadows Park (HMP) — is a blue andromorph.

15 APR 2016 | HMP | Springtime Darner (female, blue andromorph)

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

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.

Ashy Clubtail dragonfly (male)

May 20, 2017

An Ashy Clubtail (Phanogomphus lividus) was spotted during a photowalk along a mid-size stream in Fairfax County, Virginia USA.

03 MAY 2017 | Fairfax County, VA | Ashy Clubtail (male)

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

03 MAY 2017 | Fairfax County, VA | Ashy Clubtail (male)

The last photo is uncropped. The wider view shows the Ashy Clubtail is well-camouflaged when perching on the ground.

03 MAY 2017 | Fairfax County, VA | Ashy Clubtail (male)

The Backstory

I visited a new location in Fairfax County, Virginia on 03 May 2017, following my hunch that the spot might be a good place to find some of the more uncommon species of odonates. Turns out my hunch was right!

I saw species from four families of dragonflies: male Stream Cruiser dragonfly (Didymops transversa); male Springtime Darner dragonfly (Basiaeschna janata); female and male Common Baskettail dragonfly (Epitheca cynosura); female and male Spine-crowned Clubtail dragonfly (Hylogomphus abbreviatus); at least two male Lancet Clubtail dragonflies (Phanogomphus exilis); and the male Ashy Clubtail (Phanogomphus lividus) featured in this post.

In addition, I saw lots of teneral damselflies from the Family Coenagrionidae (Pond Damsels), possibly Blue-tipped Dancer (Argia tibialis).

03 MAY 2017 | Fairfax County, VA | teneral damselfly

Copyright © 2017 Walter Sanford. All rights reserved.

Springtime Darner dragonfly (male)

May 6, 2017

(✔︎) Springtime Darner dragonfly (Basiaeschna janata).

Well, now that I’ve seen a Springtime Darner, I can stop hunting for the species this year. Huh? I saw one Springtime Darner in 2015 (my first) and another one in 2016, both females. Apparently, Mother Nature allows me to see one and only one Springtime Darner per year. So check-off Springtime Darner from my target list of species for 2017 and move along, nothing more to see here folks. But seriously, hope springs eternal so I’ll keep looking for this somewhat elusive species.

03 MAY 2017 | Fairfax County, VA | Springtime Darner (male)

This Springtime Darner is a handsome male, as indicated by his terminal appendages and indented hind wings. (The former field marker is shown more clearly than the latter.) The blue coloration along its abdomen also indicates this individual is a male, although less reliably than other field markers since female Springtime Darners are polymorphic including blue and green morphs.

Look closely at the full-size version of the preceding photo — there’s some wild stuff going on in his eyes!

The Backstory

During the dragonfly-hunting “off season,” I had a hunch that a new location in Fairfax County, Virginia USA might be a good place to find some of the more uncommon species of odonates. On 03 May 2017, I visited the spot for the first time. I hiked in and began exploring a mid-size stream. After approximately 30-45 minutes of intensive searching, I hadn’t seen any dragonflies or damselflies and was thinking about moving on to another tried-and-true ode-hunting location.

Fortunately, I noticed something out of the corner of my eye that made me stop: a dragonfly that was perching near the ground made a quick, low flight to a new perch. I didn’t see the exact spot where it landed, but I had an idea of the area where it might be. Turns out it was a male Stream Cruiser dragonfly. The male Springtime Darner (featured in this post) was the next dragonfly I spotted soon afterward. Then it’s like the flood gates opened and I saw lots of other odonates including a new species of dragonfly for my life list.

So what’s the take-away from this experience? It’s a cliche, but persistence pays dividends — don’t give up too soon! Oh, and follow your hunches, otherwise you’ll never know whether you are right. Speaking of hunches, I have a good hunch I’ll revisit the new site soon.

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.

Aeshnidae exuvia

May 15, 2016

An odonate exuvia was spotted on 14 August 2012 along the boardwalk in the central wetland area at Huntley Meadows Park. The specimen was broken into three pieces when I found it: head and thorax; wing pads; and abdomen.

This individual is a member of the Family Aeshnidae (Darners). Here’s the decision tree I used to tentatively identify the exuvia as a member of the Darner Family.

  • The specimen has a flat labium that doesn’t cover the face (not mask-like).
  • Antennae are thin and thread-like (not club-like, as in Gomphidae).

Photo Set 1

Notice the labium is flat and isn’t mask-like, that is, doesn’t cover the face of the larva/exuvia.

An odonate exuviae spotted at Huntley Meadows Park, Fairfax County, Virginia USA. This individual is probably a member of the Aeshnidae Family.

Head and thorax (lateral view).

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

Also notice the antennae are thin and thread-like, as shown in the following annotated image.

An odonate exuviae spotted at Huntley Meadows Park, Fairfax County, Virginia USA. This individual is probably a member of the Aeshnidae Family.

Head and thorax (dorsal side).

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

The shape of the mentum and prementum (especially the rounded palpal blades) indicates this specimen is a Common Green Darner dragonfly (Anax junius), one of the more common species of Aeshnidae found at Huntley Meadows Park.

An odonate exuviae spotted at Huntley Meadows Park, Fairfax County, Virginia USA. This individual is probably a member of the Aeshnidae Family.

Head and thorax (ventral side).

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

Photo Set 2

The next photo shows the wing pads as well as part of abdominal segment one (S1). All odonates have a 10-segmented abdomen. The anterior side is toward the bottom of the photo; posterior toward the top.

An odonate exuviae spotted at Huntley Meadows Park, Fairfax County, Virginia USA. This individual is probably a member of the Aeshnidae Family.

Wing pads (dorsal view).

Abdominal segments two through 10 (S2-10) are shown in the following photo.

An odonate exuviae spotted at Huntley Meadows Park, Fairfax County, Virginia USA. This individual is probably a member of the Aeshnidae Family.

Abdomen (dorsal view).

Lateral spines along abdominal segments seven, eight, and nine (S7-9) verifies the genus and species as Anax junius. Notice the faint feature on segment nine (S9), highlighted by a white circle. This is a “rudimentary ovipositor,” according to SueandJohn KestrelHaven, active members of the “Northeast Odonata” Facebook group. An ovipositor is used for egg-laying by all adult damselflies and some species of adult dragonflies: females have this feature; males do not.

An odonate exuviae spotted at Huntley Meadows Park, Fairfax County, Virginia USA. This individual is probably a member of the Aeshnidae Family.

Abdomen (ventral view).

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

Related Resources

Tech Tips

The following equipment was used to shoot the preceding photographs:

Adobe Photoshop CC 2015 was used to annotate selected images.

The following photo reveals a behind the scenes look at my low-tech solution for staging specimen parts: a plastic toothpick (tan) from a Swiss Army knife held by a small plastic clothespin (green); both parts were held by an alligator clip (silver) mounted on a short, flexible arm.

An odonate exuviae spotted at Huntley Meadows Park, Fairfax County, Virginia USA. This individual is probably a member of the Aeshnidae Family.

All specimens were staged in front of the same opaque white plastic background. Hard to believe, huh? I own an 18% gray scale card; at some point, I should start using it to adjust the white balance in my macro photos!

Copyright © 2016 Walter Sanford. All rights reserved.


%d bloggers like this: