Stylurus sp. exuvia, ongoing work

August 17, 2018

The work to identify an unknown species of odonate exuvia continues. More focus-stacked composite images are in the pipeline to be published in one or more follow-up blog posts.

13 JUL 2018 | Amherst County, VA | Stylurus sp. exuvia (dorsal view)

Tech Tips

The preceding image is a composite of 21 photos taken using the following equipment: 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); Canon MT-26EX-RT Macro Twin Lite set for “Master” mode; and Canon 580 EX- and Canon 580EX II Speedlites in “Slave” mode.

Adobe Photoshop CC 2017 was used to create the composite image.

Related Resource: Stylurus sp. exuvia

Copyright © 2018 Walter Sanford. All rights reserved.

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Stylurus sp. exuvia

August 15, 2018

The following image is a composite of 18 photos taken using the following equipment: 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); Canon MT-26EX-RT Macro Twin Lite set for “Master” mode; and Canon 580 EX- and Canon 580EX II Speedlites in “Slave” mode.

Adobe Photoshop CC 2017 was used to create the composite image.

13 JUL 2018 | Amherst County, VA | Stylurus sp. exuvia (ventral view)

The Backstory

I am collaborating with my good friend Mike Boatwright, administrator of the Virginia Odonata Facebook group, to identify an odonate exuvia that he collected on 13 July 2018 in Amherst County, Virginia USA. We know the exuvia is from the Family Gomphidae (Clubtails) and are fairly certain it is a species from the genus Stylurus. At this point, several species are still in play.

Sincere thanks to Benjamin Coulter for providing guidance and related resources as Mike and I work through several dichotomous keys for identification of Stylurus larvae.

Look for one or more follow-up blog posts as the work progresses.

Related Resource: Stylurus sp. exuvia, ongoing work

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.

What’s yours is mine

August 11, 2018

Dragonflies seem to have no understanding of either personal space or property rights. Of course that’s only part of their appeal!

I stopped for a drink of water during a brief photowalk at Occoquan Bay National Wildlife Refuge, Prince William County, Virginia USA. A Needham’s Skimmer dragonfly (Libellula needhami) landed on the tip of my Sunpak 6700M aluminum monopod, lying on a Coleman camp stool.

10 AUG 2018 | OBNWR | Needham’s Skimmer (mature female)

This individual is a mature female, as indicated by her terminal appendages, muted coloration, and slightly tattered wings.

Copyright © 2018 Walter Sanford. All rights reserved.

Habitat for Tiger Spiketail dragonfly

August 9, 2018

In the world of odonates, there are habitat generalists and habitat specialists. Tiger Spiketail dragonfly (Cordulegaster erronea) is a habitat specialist.

Habitat: Small forest streams and seeps, often with skunk cabbage and interrupted fern. Source Credit: Paulson, Dennis (2011-12-19). Dragonflies and Damselflies of the East (Princeton Field Guides) (Kindle Locations 7028-7029). Princeton University Press. Kindle Edition.

The following video shows ideal habitat for C. erronea: A clean, seep-fed small stream in the forest.

The black rock in the middle of the creek is approximately five feet (~5′) from the place in the stream channel where I was sitting on a Coleman camp stool. The video begins with me looking at a seep that feeds the stream; then I pan left, right, and back to center stage.

Tech Tips: The preceding movie looks better viewed in full-screen mode. The video was recorded in 1080p at 60 fps using a head-mounted GoPro Hero4 Black action camera. The camera was positioned so that it recorded what I saw when looking straight ahead; the scene changed by moving my head. 60 fps was used so that I could edit the video to show smooth slow-motion video of Tiger Spiketail dragonflies in flight. I think one of the bigger take-aways is a Tiger fly-by would have been recorded clearly enough to be able to identify the species. For what it’s worth, the closest focusing distance of the GoPro Hero4 Black is approximately 12 inches (~1′).

GoPro CapCam©

A GoPro QuickClip was used to mount an action camera on the bill of a baseball cap.

GoPro Hero4 Black action camera, plus QuickClip mount.

The GoPro Head Strap + QuickClip is compatible with all GoPro cameras and sells for $19.95 retail.

GoPro Hero4 Black action camera, plus QuickClip mount.

The Backstory

I visited the location shown in the video three times: Several Tiger Spiketail dragonflies were observed at the site on 19- and 26 July 2018; no Tiger Spiketails were spotted on 06 August 2018, the day the video was recorded. It’s worth noting that the adult flight period for C. erronea peaks in July in Northern Virginia (USA). Most of the window of opportunity was missed due to near record setting rainfall for the month of July, including a period of seven consecutive days of rain totaling nearly 10 inches!

Although I saw several Tiger Spiketail dragonflies, every individual was in flight and I was unable to shoot still photos and/or video — they were gone by the time I reached for my camera! The GoPro CapCam© is my solution to this problem.

An Apple iPad mini is used to remotely control the action camera using the GoPro app (formerly known as “Capture”) via Bluetooth. Among many features, the app provides real-time display of the camera field of view. The camera is positioned correctly on the bill of my cap by holding the iPad directly in my line of sight and adjusting the camera mount so the iPad is shown in the middle of the screen, against the background.

Copyright © 2018 Walter Sanford. All rights reserved.

Blue-fronted Dancer damselflies (male, females)

August 7, 2018

Several Blue-fronted Dancer damselflies (Argia apicalis) were photographed along an unnamed small creek in Fairfax County, Virginia USA.

Male

The first individual is a male, as indicated by the pattern of coloration on his thorax and abdomen.

06 AUG 2018 | Fairfax County, VA | Blue-fronted Dancer (male)

Female

Female A. apicalis is polymorphic, including two morphs: tan; and blue.

06 AUG 2018 | Fairfax County, VA | Blue-fronted Dancer (female, tan)

Blue females can be differentiated from blue males by looking for the reproductive anatomy located on the underside of the posterior end of their abdomen.

06 AUG 2018 | Fairfax County, VA | Blue-fronted Dancer (female, blue)

Copyright © 2018 Walter Sanford. All rights reserved.

Stream Bluet damselflies (mating pair, in tandem)

August 5, 2018

A mating pair of Stream Bluet damselflies (Enallagma exsulans) was spotted during a stream-walk along South Fork Quantico Creek in Prince William Forest Park (PWFP), Prince William County, Virginia USA. This pair is in tandem.

After copulation, Stream Bluet engages in a form of guarding behavior known as “contact guarding,” in which the male and female fly “in tandem” to egg-laying sites. Contact guarding is used by some species of odonates to prevent aggressive males from hijacking the female.

26 JUN 2018 | PWFP | Stream Bluet (mating pair, in tandem)

Female E. exsulans is polymorphic, including two morphs: green or blue thorax; abdomen similar to male for both morphs. The female shown in the preceding photo is a green morph.

Look closely at the posterior end of the female’s abdomen. All female damselflies (and some species of dragonflies) use an ovipositor to insert fertilized eggs into vegetation (endophytic oviposition). Notice the white spheroid at the tip of her ovipositor. That’s either a single egg or egg cluster/mass, probably the former.

Now look at the male. He appears to be “recharging” for mating again: Sperm is transferred from the genital opening under abdominal segment nine (S9) to the secondary genitalia located under abdominal segment two (S2). Remember all dragonflies and damselflies have a 10-segmented abdomen.

Editor’s Notes

Thanks to my good friend Mike Boatwright, administrator of the Virginia Odonata Facebook group, for verifying my tentative identification of the species of damselfly. Also thanks to Sue Gregoire, Kestrel Haven Migration Observatory, for sharing her expert opinion that my photo shows a single egg at the tip of the female’s ovipositor.

Copyright © 2018 Walter Sanford. All rights reserved.

You look Familiar

August 3, 2018

A Familiar Bluet damselfly (Enallagma civile) was spotted during a photowalk along one of many trails at Occoquan Regional Park, Fairfax County, Virginia USA.

08 JUN 2018 | Occoquan Regional Park | Familiar Bluet (male)

This individual is a male, as indicated by the pattern of coloration on his abdomen. Female E. civile is polymorphic, including two morphs: tan; and blue. Female blue morphs have a different pattern of black and blue markings on their abdomen than males of the same species.

Editor’s Note

Sincere thanks to my good friend Mike Boatwright, administrator of the Virginia Odonata Facebook group, for verifying my tentative identification.

Related Resource: Familiar Bluet damselfly (female).

Copyright © 2018 Walter Sanford. All rights reserved.

“Lost” photos, redux

August 1, 2018

Another Gray Petaltail dragonfly (Tachopteryx thoreyi) was spotted at the same location in Prince William County, Virginia USA as the one featured in my last blog post.

08 JUN 2018 | Prince William County, VA | Gray Petaltail (male)

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

08 JUN 2018 | Prince William County, VA | Gray Petaltail (male)

The mid-size fallen tree on which the male is perched proved to be a good spot to find Gray Petaltail during every visit to the site.

Related Resource: Gray Petaltail dragonfly (male).

Copyright © 2018 Walter Sanford. All rights reserved.

Gray Petaltail dragonfly (male)

July 30, 2018

Two photo sets of Gray Petaltail dragonfly (Tachopteryx thoreyi), taken on 08 June 2018 at an undisclosed location in Prince William County, Virginia USA, were lost in the excitement of my rediscovery of Sable Clubtail dragonfly (Stenogomphurus rogersi) later the same day in Fairfax County, VA. This gallery is one of two posts featuring some of the “lost” photos.

08 JUN 2018 | Prince William County, VA | Gray Petaltail (male)

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

08 JUN 2018 | Prince William County, VA | Gray Petaltail (male)

The Gray Petaltail ambushed several smaller insects that flew near his perch; he always returned to the same tree after each brief excursion.

08 JUN 2018 | Prince William County, VA | Gray Petaltail (male)

Related Resource: “Lost” photos, redux.

Copyright © 2018 Walter Sanford. All rights reserved.


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