Posts Tagged ‘female’

Test shots: “Generic Gomphid”

February 11, 2019

A larva/nymph in the Family Gomphidae (Clubtails) was collected by Bob Perkins from the New River in southwestern Virginia. The larva died before it metamorphosed into an adult.

Test shots of this beautifully preserved specimen were taken using a small-ish aperture of f/11 for greater depth of field. The following photos are “one-offs,” that is, not composite images.

Dorsal

80mm (120mm, 35mm equivalent) | ISO 200 | f/11 | 1/180 s | 0 ev

Bob’s best guess of the identity of the specimen is Phanogompus sp. I see several similarities between this larva and a Phanogomphus lividus exuvia (Ashy Clubtail) in my collection, so Bob’s tentative identification might be correct. More later after the specimen is keyed out.

Ventral

80mm (120mm, 35mm equivalent) | ISO 200 | f/11 | 1/180 s | 0 ev

This individual might be female, as indicated by the rudimentary ovipositor that can be seen on the ventral side of the specimen along the boundary between abdominal segments eight and nine (S8-9).

Related Resource: Composite images: “Generic Gomphid.”

Tech Tips

The following equipment (shown below) was used to shoot the preceding photos: Fujifilm X-T1 digital camera; Fujifilm MCEX-16 extension tube; Fujinon XF80mm macro lensGodox XProF TTL Wireless Flash Trigger for Fujifilm camerasGodox TT685F Thinklite TTL Flash for Fujifilm CamerasGodox TT685C Thinklite TTL Flash for Canon Cameras fitted with a Lastolite Ezybox Speed-Lite 2 flash modifier; and a Canon 580EX II Speedlite mounted on a Godox X1R-C TTL Wireless Flash Trigger Receiver for Canon. A new Godox TT685O Thinklite TTL Flash for Olympus/Panasonic Cameras was added to an array of radio-controlled external flash units used to light the specimen. All flashes were set for Manual Mode at 1/128 power.

Adobe Photoshop CC 2017 was used to spot-heal and sharpen the final output.

Gear used for studio macro photography.

By the way, in case you looked at the preceding photo and wondered “What’s up with the crazy crop?” I used Photoshop to conceal some of the clutter in my kitchen. I set up my macro photo rig in the kitchen because it’s the largest uncarpeted area in my tiny apartment. Padded carpet is a poor surface for macro photography — the field of view from a tripod-mounted camera-lens-flash trigger combo shifts noticeably (and unacceptably) as one moves around the rig.

Copyright © 2019 Walter Sanford. All rights reserved.

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Top 10 Photos of 2018

January 2, 2019

The following gallery shows 18 finalists for my “Top 10 Photos of 2018.” The photos are presented in reverse-chronological order beginning in September 2018 and ending in February 2018.

No. 1

20 SEP 2018 | Fairfax County, VA | Pandora Sphinx moth

No. 2

23 AUG 2018 | Occoquan Bay NWR | Osprey (male, plus prey)

No. 3

No. 4

No. 5

No. 6

05 JUL 2018 | Fairfax County, VA | Sable Clubtail (female)

No. 7

No. 8

No. 9

12 JUN 2018 | Fairfax County, VA | Sable Clubtail (male)

No. 10

08 JUN 2018 | Fairfax County, VA | Sable Clubtail (male)

No. 11

06 JUN 2018 | Northern Virginia | Gray Petaltail (male)

No. 12

No. 13

No. 14

No. 15

No. 16

No. 17

No. 18

Editor’s Note: The following location codes are used in some photo captions, shown above.

Copyright © 2019 Walter Sanford. All rights reserved.

Test shots: Unknown odonate exuvia

December 12, 2018

An odonate exuvia from an unknown species of dragonfly (Anisoptera) was collected by a good friend during April 2018 in Vienna, Austria.

Based upon the crenulations along the margins of the labium, I think the specimen is a member of either the Family Corduliidae (Emeralds) or Family Libellulidae (Skimmers). I need to clean the anal pyramid for a clearer look at the terminal appendages in order to identify the family.

One-off

The first photo is a “one-off,” that is, not a composite image. The focus point is on the face mask/head; the rest of the subject is in soft focus.

Anisoptera (unknown species) | exuvia (face/head-dorsal)

Composite images

The next two “photos” are three-layer focus-stacked composite images: For each image, the focus point is on the face mask/head in the first photo; the thorax in the second photo; and the terminal appendages in the third photo. The entire body of the exuvia is acceptably in focus, including most of the legs.

The specimen has dorsal hooks on some abdominal segments (exact number unknown without closer examination), and lateral spines on abdominal segments eight and nine (S8-9).

Anisoptera (unknown species) | exuvia (dorsal)

I think this individual might be a female, as indicated by what appears to be a rudimentary ovipositor that is visible on the ventral side of abdominal segment nine (S9).

Anisoptera (unknown species) | exuvia (ventral)

Post Update

Sincere thanks to Benoit Guillon and Christophe Brochard, members of the “Dragonflies and Damselflies – Worldwide Odonata” Facebook group, for kindly identifying this specimen as an exuvia from a Downy Emerald dragonfly (Cordulia aenea). Downy Emerald is a member of the Family Corduliidae (Emeralds).

The following photo shows a plastic container of 20 Downy Emerald dragonfly (Cordulia aenea) exuviae, collected by a good friend during April 2018 in Vienna, Austria. Thanks to field marks shared by Benoit Guillon, I was able to quickly determine that all of the exuviae are the same species as the specimen featured in this blog post.

Related Resource: Cordulia aenea: exuviae (1/2), by Benoit Guillon.

Tech Tips

The following equipment was used to shoot all of the preceding photographs: Canon EOS 5D Mark II digital camera, in manual mode; Kenko 20mm macro automatic extension tubeCanon EF100mm f/2.8L Macro lens (set for manual focus); and Canon MT-26EX-RT Macro Twin Lite set for “Master” mode, and several external flashes set for “Slave” mode including Canon 580 EX- and Canon 580EX II Speedlites and a Godox TT685C Thinklite TTL Flash fitted with a Lastolite Ezybox Speed-Lite 2 flash modifier.

Adobe Photoshop CC 2017 was used to create the two focus-stacked composite images, as well as spot-heal and sharpen the final output.

Copyright © 2018 Walter Sanford. All rights reserved.

Test shots: Brachytron pratense exuvia (female)

December 10, 2018

As if it weren’t challenging enough to identify odonate exuviae from species native to the United States of America (where I live), I just started working with some specimens collected by a good friend during April 2018 in Vienna, Austria.

I decided to start with a specimen that I recognized immediately as a member of the Family Aeshnidae (Darners). Here’s the decision tree used to identify the 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 larvae/euviae).
  • Eyes are large relative to the size of the head.

One-off

The first photo is a “one-off,” that is, not a composite image. The focus point is on the face mask/head; the rest of the subject is in soft focus. I think this is a good way to draw the viewer’s eyes to a specific part of a photo, while adding a sense of depth.

Hairy Dragonfly (Brachytron pratense) | exuvia (face/head-dorsal)

Composite images

The next “photo” is a three-layer focus-stacked composite image: The focus point is on the face mask/head in the first photo; the thorax in the second photo; and the terminal appendages in the third photo. The entire body of the exuvia is acceptably in focus, including the legs.

Notice the unusual shape of the head. Head shape can be used to identify some species in Family Aeshnidae. Source Credit: Sue Gregoire, personal communication. Kestrel Haven Migration Observatory.

In fact, several members of the “Dragonflies and Damselflies – Worldwide Odonata” Facebook group were able to identify this specimen based upon the shape of its head and eyes. Sincere thanks to Tim Termaat, Hartwig Stobbe, and Rob Strik for kindly identifying this specimen as an exuvia from a Hairy Dragonfly (Brachytron pratense), also known as a Hairy Hawker.

Hairy Dragonfly (Brachytron pratense) | exuvia (dorsal-lateral)

The last “photo” is a four-layer focus-stacked composite image: The focus point is on the head in the first and second photos; the thorax in the third photo; and the terminal appendages in the fourth photo. The entire body of the exuvia is acceptably in focus, including the legs.

This individual is a female, as indicated by the rudimentary ovipositor that can be seen clearly on the ventral side of abdominal segment nine (S9).

Hairy Dragonfly (Brachytron pratense) | exuvia (ventral)

Related Resources

Tech Tips

The following equipment was used to shoot all of the preceding photographs: Canon EOS 5D Mark II digital camera, in manual mode; Kenko 20mm macro automatic extension tubeCanon EF100mm f/2.8L Macro lens (set for manual focus); and Canon MT-26EX-RT Macro Twin Lite set for “Master” mode, and several external flashes set for “Slave” mode including Canon 580 EX- and Canon 580EX II Speedlites and a Godox TT685C Thinklite TTL Flash fitted with a Lastolite Ezybox Speed-Lite 2 flash modifier.

Adobe Photoshop CC 2017 was used to create the two focus-stacked composite images, as well as spot-heal and sharpen the final output.

Copyright © 2018 Walter Sanford. All rights reserved.

Do-over

October 24, 2018

The Backstory

An Ashy Clubtail dragonfly (Phanogomphus lividusnymph was collected by Bob Perkins. (The date and location where the specimen was collected are unknown.) The nymph was reared in captivity until it emerged on 21 March 2017 and metamorphosed into an adult female. This specimen is the exuvia from the nymph. P. lividus is a member of the Family Gomphidae (Clubtails).

A focus-stacked composite image was created from 39 photos focused on the face and head of the exuvia. I had relatively little experience using Adobe Photoshop to make focus stacks when I created the first iterations of the Ashy Clubtail composite image. I was never satisfied completely with the final output, so I decided to do a do-over.

After…

The updated version of the composite image was created using my “Latest focus stacking workflow.”

Before…

The version that I published in late-March 2018 was created using the RAW photos (CR2) from my Canon digital camera, without any post-processing. I tried to adjust the white balance and color palette of the resulting composite image, but was unable to get the “look” I wanted. The image is probably over-sharpened too.

Which version do you prefer?

I know the version I like more. Which do you prefer, After or Before?

Tech Tips

The preceding images are composites of 39 photos taken using the following equipment: Canon EOS 5D Mark II digital camera, in manual mode; Canon MP-E 65mm Macro lens (manual focus only, set for 3x magnification); and Canon MT-26EX-RT Macro Twin Lite set for “Master” mode, and Canon 580 EX- and Canon 580EX II Speedlites set for “Slave” mode.

Adobe Photoshop CC 2017 was used to focus stack the photos and post-process the final output.

According to the “Focus Stacking Step Size Calculator” embedded in the “Focus Stacking” Web page, the “safe step size” is 0.213 mm for an aperture of f/11 at 3x magnification using a full-frame DSLR. That’s right, 0.213 mm! The safe step size is the incremental distance at which the in-focus areas of two photos overlap. The ruler on the inexpensive focus rail that I use is marked in millimeters only, so I attempted to move the focus rail in tiny increments in two passes: one pass moving from front-to-back; and a second pass from back-to-front.

Copyright © 2018 Walter Sanford. All rights reserved.

Field marks for identification of S. rogersi

October 22, 2018

The following annotated images illustrate field marks that can be used for identification of Sable Clubtail dragonfly (Stenogomphurus rogersi). Although there is some redundancy among the images, repetition is a good strategy for learning.

Male

Male Sable Clubtails have eyes that are green to turquoise in color, with a black occiput located between the eyes. They have a thin, black abdomen that flares to a small club featuring thin yellow flanges on abdominal segments seven through nine (S7-9).

The abdomen is marked with small pale dorsal triangles (S3-7) and tiny pale lateral spots. The number of dorsal triangles can vary individually and/or geographically, ranging from S3-5 to S3-7.

08 JUN 2018 | Fairfax County, VA | Sable Clubtail (male)

Dennis Paulson, originator of the classification system for thoracic stripes in the Family Gomphidae (Clubtails), describes T1-4 as follows.

T1–2 broad and complete, touching at ends and often with stripe between them restricted and topped with spot; T3–4 fine, T3 incomplete. Source Credit: Paulson, Dennis (2011-12-19). Dragonflies and Damselflies of the East (Princeton Field Guides) (Kindle Locations 6089-6093). Princeton University Press. Kindle Edition.

Note: T1-4 refers to the dark areas located on the sides of the thorax, not the lighter colored lines and spots. Due to space limitations, thoracic stripes are labeled using a numeral only (e.g., “1”) rather than a letter and numeral (e.g., “T1”).

08 JUN 2018 | Fairfax County, VA | Sable Clubtail (male)

Their face is pale, marked with variable black crosslines (as shown in the inset photo, below).

08 JUN 2018 | Fairfax County, VA | Sable Clubtail (male)

Male Sable Clubtails, like all male dragonflies, have three terminal appendages, collectively called “claspers.” All male clubtail dragonflies have indented hind wings.

Female

Female Sable Clubtails have a noticeably thicker abdomen than males. The occiput is a pale color, rather than black. Dorsal triangles, located on abdominal segments three through seven (S3-7), are much larger than those found on males. The lateral spots are somewhat larger as well.

05 JUL 2018 | Fairfax County, VA | Sable Clubtail (female)

Female Sable Clubtails, like all female dragonflies, have a pair of cerci (superior appendages) that have little or no function. All female clubtail dragonflies have rounded hind wings.

Related Resource: Stenogomphurus rogersi exuvia.

Copyright © 2018 Walter Sanford. All rights reserved.

Unicorn Clubtail (female terminal appendages)

September 22, 2018

Two field markers can be used to identify female Unicorn Clubtail dragonflies (Arigomphus villosipes), as shown in the following annotated image: 1) they have two terminal appendages (cerci) rather than three (males); and 2) their hind wings are rounded rather than “indented” (males).

Image used with permission from Bob Blakney.

Editor’s Notes

In my experience, female Unicorn Clubtail dragonflies are seen uncommonly. Sincere thanks to Bob Blakney for kindly granting permission to use his excellent photograph of this uncommon beauty for instructional purposes.

Bob’s photo was taken on 18 May 2012 at Occoquan Bay National Wildlife Refuge using a Canon EOS Rebel T2i digital camera and Tamron AF 18-270mm macro lens.

Copyright © 2018 Walter Sanford. All rights reserved.

Gray Petaltail (female terminal appendages)

September 18, 2018

For those species of dragonflies that do not display sexual dimorphism, males and females are nearly identical in appearance except for their terminal appendages. For example, male and female Gray Petaltail dragonflies (Tachopteryx thoreyi) are similar in appearance.

Two field markers can be used to identify female Gray Petaltails, as shown in the following annotated images: 1) they have two terminal appendages (cerci) rather than three (males); and 2) their hind wings are rounded rather than “indented” (males).

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

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

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

Related Resources

Copyright © 2018 Walter Sanford. All rights reserved.

Blue Dasher dragonfly (female)

August 23, 2018

A Blue Dasher dragonfly (Pachydiplax longipennis) was spotted during a photowalk at Occoquan Regional Park, Fairfax County, Virginia USA. This individual is a female, as indicated by her coloration and terminal appendages.

This camera-shy girl was hiding her face from me behind the thin veil of her left forewing.

Copyright © 2018 Walter Sanford. All rights reserved.

Calico Pennant dragonfly (female)

August 13, 2018

A Calico Pennant dragonfly (Celithemis elisa) was spotted at Painted Turtle Pond, Occoquan Bay National Wildlife Refuge, Prince William County, Virginia USA.

10 AUG 2018 | Occoquan Bay NWR | Calico Pennant (female)

This individual is a female, as indicated by her terminal appendages.

Adult flight period

The adult flight period  for Calico Pennant is from 11 May to 23 September (peaks in June-July), according to records for Northern Virginia maintained by Kevin Munroe, former manager at Huntley Meadows Park. In my experience, mid-August is past peak in Northern Virginia so I was happy to see a beautiful Calico female.

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, 26 April to 27 October is the adult flight period for Calico Pennant.

Copyright © 2018 Walter Sanford. All rights reserved.


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