Bridges

January 20, 2017

As an avid odonate hunter, I photowalk/streamwalk many scenic locations. I’m fond of bridges, especially railroad bridges.

The first photo shows a view of the underside of the new suspension bridge across Accotink Creek at Accotink Bay Wildlife Refuge (ABWR), Fairfax County, Virginia USA.

A scenic view of the underside of the suspension bridge that crosses Accotink Creek at Accotink Bay Wildlife Refuge, Fairfax County, Virginia USA.

07 AUG 2016 | ABWR | new suspension bridge across Accotink Creek

The next photo shows the view looking upstream toward the ruins of a Civil War era railroad bridge that used to cross Pope’s Head Creek at Chapel Road Park, Fairfax County, Virginia USA.

Looking upstream toward the ruins of a Civil War era railroad bridge that used to cross Pope's Head Creek, Chapel Road Park, Fairfax County, Virginia USA.

22 AUG2016 | Chapel Road Park | bridge ruins at Pope’s Head Creek

The last photo shows the view looking downstream toward a modern era railroad bridge across Pope’s Head Creek near Chapel Road Park.

Looking downstream toward modern era railroad bridge that crosses Pope's Head Creek, Chapel Road Park, Fairfax County, Virginia USA.

29 AUG 2016 | Chapel Road Park | railroad bridge at Pope’s Head Creek

Copyright © 2017 Walter Sanford. All rights reserved.

Blue-fronted Dancer damselfly (female)

January 18, 2017

Blue-fronted Dancer damselfly (Argia apicalis) was spotted during a photowalk along Accotink Creek Trail at Accotink Bay Wildlife Refuge (ABWR), Fairfax County, Virginia USA. An old wooden boardwalk is located near the terminus of the trail.

A Blue-fronted Dancer damselfly (Argia apicalis) spotted along Accotink Creek at Accotink Bay Wildlife Refuge, Fairfax County, Virginia USA. This individual is a female.

07 AUG 2016 | ABWR | Blue-fronted Dancer (female andromorph)

This individual is a female andromorph, as indicated by her coloration and terminal appendages. Females have a noticeably thicker abdomen than males.

Female Blue-fronted Dancers are polymorphic: andromorph females are blue like males; heteromorph females are brown. Andromorph females tend to be a lighter shade of blue than males of the same species, and do not feature the same blue coloration as males on abdominal segments eight, nine, and 10 (S8-10).

A Blue-fronted Dancer damselfly (Argia apicalis) spotted along Accotink Creek at Accotink Bay Wildlife Refuge, Fairfax County, Virginia USA. This individual is a female.

07 AUG 2016 | ABWR | Blue-fronted Dancer (female andromorph)

The taxonomic classification of Blue-fronted Dancer is as follows: Order Odonata (Dragonflies and Damselflies); Suborder Zygoptera (Damselflies); Family Coenagrionidae (Narrow-winged Damselflies); Genus Argia (Dancers); Species apicalis.

Related Resources: Excellent digital scans created by Gayle and Jeanelle Strickland. Click on the button labeled “Download file” in order to view full-size version of the graphics.

Editor’s Note: This is the first female Blue-fronted Dancer that I’ve seen/photographed. Thanks to Michael Moore and Ed Lam, members of the Northeast Odonata Facebook group, for verifying my tentative identification. Dr. Michael Moore is an active contributor to the Dragonfly and Damselfly Field Guide and ID App; Ed Lam is author and illustrator of Damselflies of the Northeast.

Copyright © 2017 Walter Sanford. All rights reserved.

Camouflage

January 16, 2017

Some moths are so well camouflaged they’re easy to overlook — a good survival strategy that protects them from predators.

Tulip-tree Beauty moth

A Tulip-tree Beauty moth (Epimecis hortaria) was spotted near Hidden Pond, Meadowood Recreation Area, Fairfax County, Virginia USA.

Editor’s Note: Thanks to Bill Yule, a member of the BugGuide Facebook group, for identifying this specimen. Alonso Abugattas — Natural Resources Manager, Arlington County Parks, Virginia — added the following comment to the thread: “It’s the largest of our local geometrid (inchworm) moths.”

Underwing moth

An unknown species of Underwing moth (Catocala sp.) was spotted along the Hike-Bike Trail at Huntley Meadows Park.

The forest was so dark where this moth was perching that I had to set my external flash unit for high power in order to expose the subject properly, resulting in the underexposed background.

Editor’s Note: Thanks to Teá Kesting-Handly, a member of the BugGuide Facebook group, for identifying this specimen. Ms. Kesting-Handly cautioned that the species is challenging to identify without seeing the hindwings. Quoting a follow-up comment on Facebook, “I looked over my collection of Catocala again, and compared to your photos, and I can say with a high degree of certainty it is Catocala ilia.” Thanks for the extra effort on my behalf, Teá!

Copyright © 2017 Walter Sanford. All rights reserved.

Anax junius exuvia

January 14, 2017

A dragonfly exuvia from the Family Aeshnidae (Darners) was collected 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.

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.

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.

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).

No. 1

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

21 JUN 2016 | MRA | Anax junius exuvia (dorsal-lateral)

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

No. 2

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.

21 JUN 2016 | MRA | Anax junius exuvia (lateral)

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

The rounded shape of the palpal lobes (see Photo No. 3) 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.

No. 3

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

21 JUN 2016 | MRA | Anax junius exuvia (labium, ventral)

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

No. 4

Notice the antennae are thin and thread-like, as shown in the following 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.

21 JUN 2016 | MRA | Anax junius exuvia (face-head)

No. 5

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

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

21 JUN 2016 | MRA | Anax junius exuvia (head, dorsal)

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.

21 JUN 2016 | MRA | Anax junius exuvia (lateral)

The following photograph of the exuvia was taken in-situ along the shoreline of Hidden Pond using a Panasonic 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.

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.

Zebra Swallowtail butterfly

January 12, 2017

A late-season Zebra Swallowtail butterfly (Eurytides marcellus) was spotted during a photowalk along Deephole Point Road at Occoquan Bay National Wildlife Refuge, Prince William County, Virginia USA.

The left hindwing looks like it might be malformed.

Copyright © 2017 Walter Sanford. All rights reserved.

Eastern Shieldbacks

January 10, 2017

Two Eastern Shieldbacks (Atlanticus sp.) were spotted along the Hike-Bike Trail as I was walking out of Huntley Meadows Park. Eastern Shieldbacks are a type of Katydid (Family Tettigoniidae).

Male

This individual is a male. Notice the pair of cerci (sing. cercus) at the tip of his abdomen. Cerci are anatomical structures that are familiar to experienced odonate hunters like me.

Female

The following individual is a female, as indicated by the long ovipositor that extends from the tip of her abdomen.

An Eastern Shieldback (Atlanticus sp.) spotted along the Hike-Bike Trail at Huntley Meadows Park, Fairfax County, Virginia USA. This individual is a female.

24 JUN 2016 | Huntley Meadows Park | Eastern Shieldback (female)

Notice the female has two cerci and an ovipositor.

An Eastern Shieldback (Atlanticus sp.) spotted along the Hike-Bike Trail at Huntley Meadows Park, Fairfax County, Virginia USA. This individual is a female.

24 JUN 2016 | Huntley Meadows Park | Eastern Shieldback (female)

Editor’s Note: Thanks to Arthur V. Evans, a member of the BugGuide Facebook group, for identifying these specimens. Mr. Evans speculates the species of Eastern Shieldback featured in this post could be Protean Shieldback (Atlanticus testaceus).

Copyright © 2017 Walter Sanford. All rights reserved.

Luna Moth

January 8, 2017

A Luna Moth (Actias luna) was spotted during a photowalk along the Hike-Bike Trail at Huntley Meadows Park.

The adults have a life span of only about one week. Adult Luna Moths do not eat; their only object[ive] is to reproduce. Source Credit: Species Actias luna – Luna Moth, BugGuide.com.

Copyright © 2017 Walter Sanford. All rights reserved.

Stylurus spiniceps exuvia

January 6, 2017

I’ve never seen an adult Arrow Clubtail dragonfly (Stylurus spiniceps). That’s not surprising, since many experienced odonate hunters classify them as uncommon to rare.

But I know a place along the Potomac River in Fairfax County, Virginia USA where I am certain Arrow Clubtail dragonflies live. How do I know? Because I collected a Stylurus spiniceps exuvia from that location. In a nutshell, this is one of many reasons I’m learning to identify odonate exuviae.

No. 1

An Arrow Clubtail dragonfly (Stylurus spiniceps) exuvia collected at Riverbend Park, Fairfax County, Virginia USA.

04 AUG 2016 | Potomac River | Arrow Clubtail (exuvia)

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

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 Gomphidae (Clubtails).

  • The specimen has a flat labium that doesn’t cover the face (not mask-like), as shown in photo No. 2 and 3.
  • Antennae are club-like (not thin and thread-like, as in Aeshnidae).
  • Eyes not exceptionally large compared to the size of the head (not large, as in Aeshnidae).

No. 2

An Arrow Clubtail dragonfly (Stylurus spiniceps) exuvia collected at Riverbend Park, Fairfax County, Virginia USA.

04 AUG 2016 | Potomac River | Arrow Clubtail (exuvia, face-head)

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

Genus and species

Gomphidae is the second largest family of dragonflies, so it can be challenging to identify some specimens to the genus and species level. As it turns out, Arrow Clubtail exuviae are easy to identify because their abdominal segment nine (S9) is unique among Gomphidae: S9 is more than twice as long as it is wide at its base, as shown in the following annotated image.

No. 3

The length of the exuvia is approximately 4.2 cm (~1.7 in).

An Arrow Clubtail dragonfly (Stylurus spiniceps) exuvia collected at Riverbend Park, Fairfax County, Virginia USA.

04 AUG 2016 | Potomac River | Arrow Clubtail (exuvia, ventral)

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

More photos of the exuvia are shown below.

No. 4

An Arrow Clubtail dragonfly (Stylurus spiniceps) exuvia collected at Riverbend Park, Fairfax County, Virginia USA.

04 AUG 2016 | Potomac River | Arrow Clubtail (exuvia, dorsal)

No. 5

An Arrow Clubtail dragonfly (Stylurus spiniceps) exuvia collected at Riverbend Park, Fairfax County, Virginia USA.

04 AUG 2016 | Potomac River | Arrow Clubtail (exuvia, dorsal-lateral)

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) plus a Kenko 20mm macro automatic extension tube; Canon 580EX II external flash, off-camera, in manual mode (Master); Canon 580EX external flash, off-camera, in manual mode (Slave); and a coiled six-foot Vello Off-Camera TTL Flash Cord for Canon Cameras. A Raynox DCR-250 close-up filter was used for Photo No. 2.

Adobe Photoshop CC 2017 was used to annotate selected images.

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. 17, Key to the species of the genus Stylurus
1a – Abdominal segment 9 twice as long as wide at base. (spiniceps)

Editor’s Note: This is the 1,000th post on my photoblog. That’s a major milestone, and quite candidly, one I never expected to reach. Who knew I have so much to show-and-tell?

Copyright © 2017 Walter Sanford. All rights reserved.

The Taming of the Shrew

January 4, 2017

A short-tailed shrew carcass was spotted during a photowalk along the Hike-Bike Trail at Huntley Meadows Park. According to Alonso Abugattas — Natural Resources Manager, Arlington County Parks, Virginia — this individual is probably a Kirtland’s Short-tailed Shrew (Blarina brevicauda kirtlandi).

A short-tailed shrew carcass spotted at Huntley Meadows Park, Fairfax County, Virginia USA. This individual is probably a Kirtland's Short-tailed Shrew (Blarina brevicauda kirtlandi). The flies are probably Common Green Bottle Fly (Lucilia sericata).

01 JUN 2016 | Huntley Meadows Park | short-tailed shrew carcass

The colorful flies are probably Common Green Bottle Fly (Lucilia sericata).

A short-tailed shrew carcass spotted at Huntley Meadows Park, Fairfax County, Virginia USA. This individual is probably a Kirtland's Short-tailed Shrew (Blarina brevicauda kirtlandi). The flies are probably Common Green Bottle Fly (Lucilia sericata).

01 JUN 2016 | Huntley Meadows Park | short-tailed shrew carcass

Another short-tailed shrew carcass was spotted at Accotink Bay Wildlife Refuge, Fairfax County, Virginia USA. This individual is probably a Kirtland’s Short-tailed Shrew too.

A short-tailed shrew carcass spotted at Accotink Bay Wildlife Refuge, Fairfax County, Virginia USA. This individual is probably a Kirtland's Short-tailed Shrew (Blarina brevicauda kirtlandi).

07 AUG 2016 | Accotink Bay Wildlife Refuge | short-tailed shrew carcass

Look closely at the full-size version of the preceding photo. Notice several small insects feeding on the fresh carcass.

Copyright © 2017 Walter Sanford. All rights reserved.

Peter Cottontail

January 2, 2017

Here comes Peter Cottontail, hoppin’ down the bunny trail. Except he (or she, I’m not sure) didn’t hippity-hop away, alarmed by my approach. He just sat there munching on a mid-morning snack, allowing me to move in slowly for several close-up shots.

The photos in this gallery show one of two Eastern Cottontail (Sylvilagus floridanus) rabbits spotted along the same trail at Occoquan Bay National Wildlife Refuge, Prince William County, Virginia USA.

You can see the red-eye effect, caused by my camera flash, in the preceding photos. Red-eye is easy to correct using photo-editing software. In this case, I chose to post the photos “as is” in order to show the size of the rabbit’s pupils.

Notice the piece of grass/twig extending from the rabbit’s mouth. In my sometimes overactive imagination, I think the twig is a toothpick and the rabbit is giving me his best tough guy defiant stare. “You lookin’ at me?” OK, back to reality!

Copyright © 2017 Walter Sanford. All rights reserved.


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