Posts Tagged ‘Family Aeshnidae (Darners)’

MYN – Sometimes it works; sometimes it doesn’t.

January 13, 2020

A Shadow Darner dragonfly (Aeshna umbrosa) exuvia, collected and identified by Andy Davidson near Richmond, Virginia USA, was photographed against a pure white background using the “Meet Your Neighbours” (MYN) technique.

Sometimes the MYN technique works; sometimes it doesn’t work as well. For example, this specimen has clear “eyes” that are clearly shown in the first photo and mostly blown out in the last photo.

I’m fairly certain this problem can be solved by “staging” the subject on a clear surface raised above the white background. In this case, the subject is only a few millimeters above the background. Further experimentation is planned.

Related Resource: Pop quiz: Sex the exuvia.

Copyright © 2020 Walter Sanford. All rights reserved.

Pop quiz: Sex the exuvia

January 10, 2020

An odonate exuvia was photographed against a pure white background using the “Meet Your Neighbours” (MYN) technique.

This specimen is a Shadow Darner dragonfly (Aeshna umbrosa) exuvia, collected and identified by Andy Davidson near Richmond, Virginia USA. Shadow Darner is a member of Family Aeshnidae (Darners).

Can you tell whether the exuvia is from a female or male larva? (Hint: The Related Resource, shown below, might be a helpful reference.)

Related Resource: Post update: Aeshna umbrosa exuvia.

Copyright © 2020 Walter Sanford. All rights reserved.

Post update: Aeshna umbrosa exuvia

January 8, 2020

Male odonates have two sets of sex organs: primary genitalia located on abdominal segment nine (S9); and secondary genitalia located on abdominal segments two-to-three (S2-3).

Closer examination of some test shots of the following Shadow Darner dragonfly (Aeshna umbrosa) exuvia, photographed on 02 December 2018, showed both sets of vestigial genitalia are clearly visible on the ventral side of this specimen.

Aeshna umbrosa (mating pair)

All odonates (dragonflies and damselflies) have a 10-segmented abdomen, numbered from front to back. Male dragonfly secondary genitalia, called hamules, are located in segments two and three (S2 and S3); female genitalia in segment eight (S8). Male and female dragonflies form the mating wheel in order for their genitalia to connect during copulation.

A. umbrosa (in wheel). Photo used with permission from Patrick Boez.

Related Resource: Test shots: Aeshna umbrosa exuvia.

Copyright © 2020 Walter Sanford. All rights reserved.

Luminous beings are we…

December 13, 2019

Master Yoda’s explanation of the Force to Luke Skywalker (see Related Resources, below) features the following memorable quote.

Luminous beings are we,
not this crude matter.

One of many reasons I like the “Meet Your Neighbours” technique for photographing natural subjects against a pure white background is that it seems to reveal the luminous beings that odonate exuviae are. Feel the force by looking at the full-size version of the following image.

Related Resources

Tech Tips

I added a Raynox DCR-250 close-up filter to my Panasonic Lumix DMC-FZ300 24x superzoom bridge camera for a closer view of the anterior of the odonate exuvia.

The camera was set for 1-Area Focusing. The focus-and-recompose technique was used to focus on the eye of the subject.

Godox X2To/p wireless flash trigger for Olympus and Panasonic was used to fire two off-camera flash units.

  1. A Godox TT685C Thinklite Flash for Canon Cameras (manual mode), fitted with a “Vello Bounce Dome (Diffuser) for Canon 580EX II Flash,” was used to light the underside of the translucent white plastic background; the top of the flash unit was ~30 cm from the bottom of the white plastic.
  2. Godox TT685o/p Thinklite Flash for Olympus/Panasonic Cameras (manual mode), fitted with a Lastolite Ezybox Speed-Lite 2 flash modifier, was used to light the subject from above.

Copyright © 2019 Walter Sanford. All rights reserved.

Puzzle solved: Anax junius exuvia (female)

December 11, 2019

Identifying odonate exuviae is a lot like solving a jigsaw puzzle — eventually all of the puzzle pieces fit together to reveal a clear picture. As it turns out, while I’ve been experimenting with the “Meet Your Neighbours” technique for photographing natural subjects against a pure white background, I was also collecting puzzle pieces that would enable me to identify the dragonfly exuvia.

A two-step process was used to identify the genus and species of the specimen featured in my last two blog posts.

  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.
  • Antennae are thin and thread-like (not club-like, as in Gomphidae larvae), as shown in Photo No. 1.
  • Eyes are large relative to the size of the head, as shown in Photo No. 1 and 4.

No. 1 | Common Green Darner (Anax junius) | exuvia (face-head)

Step 2. Genus and species

As shown in Photo No. 2 and 4, lateral spines along abdominal segments seven, eight, and nine (S7-9) indicate the genus is Anax.

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

At this point, you know the species could be either junius (Common Green Darner dragonfly) or longipes (Comet Darner dragonfly). The species is determined by the shape of the palpal lobes (part of the prementum) and the length of the specimen.

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

Notice the palpal lobes are rounded, as shown in Photo No. 3. The specimen is ~4.7 cm (~1.9 in) in length, not counting a slight bend in the body.

No. 4 | Common Green Darner (Anax junius) | exuvia (dorsal view)

The rounded shape of the palpal lobes (see Photo No. 3) plus the length of the specimen (see Photo No. 4) indicate the species is juniusAnax junius is one of the more common species of Aeshnidae found in Northern Virginia.

Finally, the rudimentary ovipositor shown in Photo No. 2 indicates this individual is a female.

Related Resource: Anax junius exuvia, another photo-illustrated identification guide by Walter Sanford.

Copyright © 2019 Walter Sanford. All rights reserved.

Meet Your Neighbours – Aeshnidae exuvia (face)

December 9, 2019

An odonate exuvia was photographed against a pure white background using the “Meet Your Neighbours” (MYN) technique. Yep, this time the background is actually pure white (255, 255, 255). Now that’s the look for which I was striving!

36.1mm (200mm, 35mm equivalent) | ISO 100 | f/7.1 | 1/800 s | 0 ev

This specimen is an unknown species from the Family Aeshnidae (Darners), probably Common Green Darner (Anax junius). Compare/contrast the “MYN look” with a more traditional photo set of another A. junius exuvia.

Related Resources

Tech Tips

I added a Raynox DCR-250 close-up filter to my Panasonic Lumix DMC-FZ300 24x superzoom bridge camera for a closer view of the face/head of the odonate exuvia.

A Godox X2To/p wireless flash trigger for Olympus and Panasonic was used to fire an off-camera Godox TT685C Thinklite Flash for Canon Cameras (manual mode) fitted with a Vello plastic bounce dome diffuser. This flash unit was used to light the underside of the translucent white plastic background; the top of the flash unit was ~20 cm from the bottom of the white plastic. No other flash units were used to shoot the photo.

Although I own better camera gear for shooting macro photos, I like to use my smaller, lighter DMC-FZ300 for proof-of-concept experimentation with new techniques. Look for a transition to one of my Fujifilm- or Canon macro rigs in the near future.

Copyright © 2019 Walter Sanford. All rights reserved.

Meet Your Neighbours – Aeshnidae exuvia

December 4, 2019

An odonate exuvia was photographed against a pure white background using the “Meet Your Neighbours” (MYN) technique. Well, almost pure white. More about that later.

9.9mm (55mm, 35mm equivalent) | ISO 100 | f/7.1 | 1/60 s | 0 ev

This specimen is an unknown species from the Family Aeshnidae (Darners), probably Common Green Darner (Anax junius). Compare/contrast the “MYN look” with a more traditional photo set of another A. junius exuvia.

Take-aways

The MYN technique seems to be simple and straightforward. It isn’t. The challenge is to get the translucent effect without blowing out the thinner parts of the specimen like eyes, legs, etc. In this case, I needed a little separation between the pure white background and the exuvia in order to reduce blow-out. I repurposed the top of a small plastic container from the local delicatessen as the separator. I placed the plastic top on the white background, and the exuvia on the top. The plastic top isn’t perfectly clear, resulting in an off-white background color.

I need to experiment further to refine the technique. A clear glass- or plastic plate should solve the problem with the less than pure white background, and I think more separation between the white plastic background plate and the clear glass/plastic “stage” should help to further reduce blow-out. Trial and error — that’s the way we learn!

Related Resources

Tech Tips

The test photo featured in this post was taken using my Panasonic Lumix DMC-FZ300 24x superzoom digital camera, Godox X2To/p wireless flash trigger for Olympus and PanasonicGodox TT685o/p Thinklite Flash for Olympus/Panasonic Cameras (manual mode) fitted with a Lastolite Ezybox Speed-Lite 2 flash modifier, and a Godox TT685C Thinklite Flash for Canon Cameras (manual mode) fitted with a Vello plastic bounce dome diffuser.

The Godox TT685-series flash head is the same size as a Canon 580EX II Speedlite so slide-on plastic light modifiers that work with a 580EX II will work with TT685s. That said, some work better than others. The “Sto-Fen Omni-Bounce OM-EY” is a tight fit — too tight in my opinion. The “Vello Bounce Dome (Diffuser) for Canon 580EX II Flash” is a perfect fit.

The camera lens was set close to “Wide Macro.” 1-Area Focusing and Spot Metering was used for the photo.

Three external flash units were used to light the scene. The flash power ratio for each flash is critical for proper exposure. Begin by setting the backlight, then add the key light(s) on the subject.

The flash unit used to light the underside of the translucent white plastic background (Group A) was set for 1/8 power; the zoom was set for 50mm in order to spread the beam of light sufficiently to avoid a hotspot on the white plastic background. The top of the flash unit was ~20 cm from the bottom of the white plastic.

Two key lights (Group B and C) — that is, the flash units used to light the top of the subject — were set for 1/16 power and 1/128, respectively. In order to reduce blow-out (see Take-aways, below), I turned off the flash in Group C.

Adobe Photoshop CC 2017 was used to sharpen the final output.

Copyright © 2019 Walter Sanford. All rights reserved.

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.

Fawn Darner dragonfly (male)

August 26, 2019

A Fawn Darner dragonfly (Boyeria vinosa) was spotted, netted, and released unharmed along the Little Patuxent River in the North Tract of Patuxent Research Refuge, Anne Arundel County, Maryland USA.

02 SEP 2012 | Patuxent Research Refuge | Fawn Darner (male)

This individual is a male, as indicated by the secondary genitalia (hamules) located on the underside of abdominal segments two-three (2-3).

02 SEP 2012 | Patuxent Research Refuge | Fawn Darner (male)

Thanks to Louisa Craven, my good friend and photowalking buddy, for holding the specimen in the first two photos while I used her Apple iPhone 4S to take photos. This was our first “stream walk” in search of dragonflies and damselflies and both of us were afraid to carry our camera gear as we waded in the river.

02 SEP 2012 | Patuxent Research Refuge | Fawn Darner (male)

The Backstory

I posted these photos in my Project Noah Nature Journal two days after an Audubon Naturalist Society field trip to the North Tract of the Patuxent Research Refuge, led by Richard Orr, renowned expert on odonates of the mid-Atlantic region of the United States.

Some of the photos from the Project Noah “spotting” were added to my photoblog in order to backfill my Life List of Odonates to include a record of an adult Fawn Darner.

Related Resources

Copyright © 2019 Walter Sanford. All rights reserved.

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.


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