Posts Tagged ‘Family Cordulegastridae (Spiketails)’

Another Arrowhead Spiketail (female)

June 21, 2019

An Arrowhead Spiketail dragonfly (Cordulegaster obliqua) was spotted in a sunny clearing along a small-to-medium size forest stream at an undisclosed location in Prince William County, Virginia USA.

14 JUN 2019 | PNC. William County, VA | Arrowhead Spiketail (female)

This individual is a female, as indicated by her rounded hind wings, terminal appendages, and prominent ovipositor at the tip of her abdomen.

14 JUN 2019 | PNC. William County, VA | Arrowhead Spiketail (female)

Did you recognize the interrupted fern (Osmunda claytoniana) in the background of every photo in this gallery?

14 JUN 2019 | PNC. William County, VA | Arrowhead Spiketail (female)

The Backstory

Mike Powell and I stopped to use GPS to get a fix on our position at the end of a long photowalk that included lots of bushwhacking. We stopped because the small stream we were exploring was getting wider and deeper the farther we walked downstream, and we decided the stream habitat had changed to be less suitable for our target species.

The place where we stopped is a sunny meadow near the confluence of a tiny side stream with the larger stream we were following. As Mike was testing a few GPS apps for his Android cell phone, I noticed a big dragonfly as it flew down the tiny stream, turned left past us, and landed in the sunny meadow. I found the dragonfly after a few minutes of searching the area where I saw it land. I was hoping for a Tiger Spiketail (Cordulegaster erronea) but nonetheless delighted to see a female Arrowhead Spiketail — our second record of this species for the year at the remote location!

Related Resource: Arrowhead Spiketail dragonfly (female)

Copyright © 2019 Walter Sanford. All rights reserved.

Advertisements

Arrowhead Spiketail dragonfly (female)

May 27, 2019

An Arrowhead Spiketail dragonfly (Cordulegaster obliqua) was spotted in a sunny clearing along a small forest stream at an undisclosed location in Prince William County, Virginia USA.

21 MAY 2019 | PNC. William County, VA | Arrowhead Spiketail (female)

This individual is a female, as indicated by her rounded hind wings, terminal appendages, and prominent ovipositor at the tip of her abdomen.

[Females in the Family Cordulegastridae (Spiketails) feature a] …pointed and spikelike (thus the group name) ovipositor, really a “pseudo-ovipositor” formed from the prolonged subgenital plate. Source Credit: Paulson, Dennis (2011-12-19). Dragonflies and Damselflies of the East (Princeton Field Guides) (Kindle Locations 7005-7006). Princeton University Press. Kindle Edition.

21 MAY 2019 | PNC. William County, VA | Arrowhead Spiketail (female)

Although the pattern of arrowhead-shaped markings visible on the dorsal side of her abdomen is unmistakeable, notice that the thorax features two stripes. The latter field mark can be used to differentiate spiketails from cruisers that have one stripe on their thorax.

21 MAY 2019 | PNC. William County, VA | Arrowhead Spiketail (female)

Mike Powell and I have photowalked together so many times that we are comfortable working cooperatively to shoot a subject. I wanted to get a shot of the face of the Arrowhead Spiketail but was concerned it would spook the dragonfly if I were to get “up in her grill.” So I waited until Mike had taken all of the photographs he wanted before approaching the dragonlfy for her “beauty shot.” As it turns out, the model was extraordinarily tolerant and didn’t fly away until sometime after Mike and I moved on to the next site.

21 MAY 2019 | PNC. William County, VA | Arrowhead Spiketail (female)

Notice the interrupted fern (Osmunda claytoniana) that appears in the background of every photo of the Arrowhead Spiketail.

Location, location, location.

Some species of odonates are habitat generalists, meaning they can be found almost anywhere there is water.

Habitat-specific odonates can be found only in specific habitats — for these species, finding them is all about location, location, location. Arrowhead Spiketail dragonflies are habitat-specialists.

Habitat: Small swift streams and soft-bottomed muddy seeps in forest, also streams reduced to series of small pools during drier weather. As in some other spiketails, skunk cabbage often present. Source Credit: Paulson, Dennis (2011-12-19). Dragonflies and Damselflies of the East (Princeton Field Guides) (Kindle Locations 7081-7082). Princeton University Press. Kindle Edition.

Skunk cabbage (Symplocarpus foetidus) and interrupted fern (Osmunda claytoniana) were observed growing in a seep located between a dirt trail and the small stream where the Arrowhead Spiketail was spotted — the perfect place for several species of habitat-specific odonates!

The last photo shows the clearing along a small forest stream where several species of dragonflies were spotted, including the Arrowhead Spiketail featured in this blog post. The stream is no more than a few feet wide and only a few inches deep in most places.

The small stream where several species of dragonflies were spotted.

The backstory

Telephoto lenses can cause a type of distortion called “foreshortening,” as seen in the preceding photo. Mike Powell and I were standing at the edge of the stream bank trying to decide whether we wanted to go down the short, steep slope to explore the clearing when we spotted a large UFO, that is, an “Unidentified Flying Odonate.” Mike and I took “record shots” of the dragonfly; looking at the LCD of our cameras, we identified the UFO as a Gray Petaltail dragonfly (Tachopteryx thoreyi).

Mike and I had seen a Gray Petaltail at another location (near the beginning of our photowalk), but we were unable to photograph it. So down the bank we went! As it turns out, there were at least two Grays in the meadow: a female; and a male. As Mike was photographing one of the Gray Petaltails he noticed another “large dragonfly.” As we slowly moved closer to the new unknown dragonfly, I quickly realized Mike had spotted an Arrowhead Clubtail. Great catch, Mike!

Please see Female Arrowhead Spiketail dragonfly for Mike’s take on our shared experience.

Uncommon

Arrowhead Spiketail is classified as an uncommon species of odonate. The following map shows all official records for Arrowhead Clubtail (C. obliqua) in the United States of America.

DSA Distribution Viewer | Arrowhead Spiketail

Source Credit: Abbott, J.C. 2006-2019. OdonataCentral: An online resource for the distribution and identification of Odonata. Available at http://www.odonatacentral.org. (Accessed: May 27, 2019).

Key: blue dots = Dot Map Project; green dots = Accepted records; yellow dots = Pending records.

Our spotting of Arrowhead Spiketail is a new DSA record for Prince William County, Virginia.

Adult flight period

According to records for the Commonwealth of Virginia maintained by Dr. Steve Roble, Staff Zoologist at the Virginia Department of Conservation and Recreation, Division of Natural Heritage, the adult flight period for C. obliqua is 11 May to 17 July. The species is classified as uncommon. Its habitat is “small streams.”

Bear in mind, Dr. Roble’s records are for the entire state, therefore the adult flight period for C. obliqua seems to be longer than it is in reality. The adult flight period for a single site is probably shorter — more likely around one month. For example, according to records for Northern Virginia maintained by Kevin Munroe, former manager of Huntley Meadows Park, the adult flight period for Arrowhead is 28 May to 27 June (peaks in June).

Copyright © 2019 Walter Sanford. All rights reserved.

 

Brown Spiketail dragonflies

May 6, 2019

Several Brown Spiketail dragonflies (Cordulegaster bilineata) were spotted during a photowalk with my good friend Mike Powell at Occoquan Regional Park, Fairfax County, Virginia USA.

Male

The first individual is a male, as indicated by his “indented” hind wings, and terminal appendages. Notice the epiproct for Brown Spiketail is a wide “plate” that spans both cerci, as shown in the full-size version of the following photo.

The next individual is also male, as indicated by his hamules, located below abdominal segments two and three (S2 and S3).

Female

The last individual is a female, as indicated by her rounded hind wings and terminal appendages.

Credits

Thanks to Michael Boatwright, founder and administrator of the Virginia Odonata Facebook group, for confirming my tentative identification of the gender of the first and last individuals.

Phenology

Phenology (noun) is defined as “the study of cyclic and seasonal natural phenomena, especially in relation to climate and plant and animal life.”

There is an annual cycle of odonate activity that can be subdivided into three broad categories: Early Season (spring); Mid-season (summer); and Late Season (fall).

Brown Spiketail is an “Early Season” species for locations in the Commonwealth of Virginia. I have noticed that the adult flight period for a given species of odonate in Northern Virginia tends to lag behind Amherst County, where my good friend Mike Boatwright (Mike B) lives, by about one-to-two weeks. When Mike B reported his first sighting of Brown Spiketail on 24 April in Amherst County, I knew it wouldn’t be long until Brown Spiketail would be flying in Fairfax County. Eight (8) days later, Mike Powell and I spotted our first-of-season Brown Spiketail dragonflies. Thanks for the heads-up, Mike B!

Related Resources

Copyright © 2019 Walter Sanford. All rights reserved.

Cordulegaster sp. larva (dorsal view)

February 25, 2019

This post features a focus-stacked composite image that shows a dorsal view of an odonate larva/nymph from the Family Cordulegastridae (Spiketails) that was collected and reared by Bob Perkins. The larva died before it metamorphosed into an adult.

Cordulegaster sp. larva (female) | dorsal view

Most larvae go through 10-13 stages of development known as “instars.” The author lacks sufficient experience to identify the instar of this specimen, although it appears to be one of the later stages as indicated by its well-developed wing pads.

Related Resources

Tech Tips

12 photos were used to create the focus stack. A single focus point was positioned over select anatomical features; photos were taken at each point of interest.

The following equipment was used to shoot all of the photographs for the focus-stacked composite image, shown above: 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.

Auto power-off was disabled for the camera and all external flash units.

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

Copyright © 2019 Walter Sanford. All rights reserved.

Cordulegaster sp. larva (ventral view)

February 22, 2019

Bob Perkins collected and reared an odonate larva/nymph from the Family Cordulegastridae (Spiketails). The larva died before it metamorphosed into an adult.

This post features a focus-stacked composite image that shows a ventral view of the preserved larva; a composite image showing the dorsal view will be published in my next blog post.

Cordulegaster sp. larva (female) | ventral view

This individual is a female, as indicated by her rudimentary ovipositor that can be seen on the ventral side of the specimen along the boundary between abdominal segments eight and nine (S8-9). Do you see it?

Related Resources

Tech Tips

Nine (9) photos were used to create the focus stack. A single focus point was positioned over select anatomical features; photos were taken at each point of interest.

The following equipment was used to shoot all of the photographs for the focus-stacked composite image, shown above: 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.

Auto power-off was disabled for the camera and all external flash units.

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

Copyright © 2019 Walter Sanford. All rights reserved.

Test shot: Cordulegaster sp. larva

February 1, 2019

Bob Perkins collected and reared a larva/nymph from the Family Cordulegastridae (Spiketails). The larva died before it metamorphosed into an adult.

Test shots of this beautifully preserved specimen (Cordulegaster sp.) were taken using a relatively small aperture of f/16 for greater depth of field. The following photo is a “one-off,” that is, not a composite image.

Cordulegaster sp. larva (preserved specimen) | face-head

Odonates are aquatic insects. They spend most of their life as larvae that live in water; this stage of their life cycle can last from a few months to a few years. Finally, they emerge from the water and metamorphose into adults in order to reproduce; their offspring return to the water and the cycle begins again.

Most larvae go through 10-13 stages of development known as “instars.” The author lacks sufficient experience to identify the instar of this specimen, although it appears to be one of the later stages.

Related Resources

Tech Tips

The following equipment was used to shoot the preceding photo: Canon EOS 5D Mark II digital camera, in manual mode; Canon MP-E 65mm Macro lens (set for 3x); 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. A Sunpak LED-160 Video Light was used to light the underside of the white plastic posing “stage.”

Auto power-off was disabled for the camera and all external flash units.

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

Copyright © 2019 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.

Twin-spotted Spiketail (male claspers)

May 17, 2018

All 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”).

Male members of the Family Cordulegastridae (Spiketails), including male Twin-spotted Spiketail dragonflies (Cordulegaster maculata), have relatively small cerci (terminal appendages) that can be mistaken for female cerci.

Male dragonfly secondary genitalia, called hamules, are located below abdominal segments two and three (S2 and S3), as shown in the following annotated image. Hamules come in a variety of sizes and shapes, but their function is identical for all species of odonates.

Related Resources

Copyright © 2018 Walter Sanford. All rights reserved.

Brown Spiketail dragonfly (male claspers)

May 15, 2018

Brown Spiketail dragonflies (Cordulegaster bilineata) were spotted on two days during May 2018 at Occoquan Regional Park. Both individuals featured in this post are male, as indicated by their terminal appendages and slightly “indented” hind wings.

All 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”).

Notice the epiproct for Brown Spiketail is a wide “plate” that spans both cerci, as shown in the full-size version of the following annotated image.

Male dragonfly secondary genitalia, called hamules, are located below abdominal segments two and three (S2 and S3), as shown in the preceding annotated image. Hamules come in a variety of sizes and shapes, but their function is identical for all species of odonates. Some species of dragonflies and damselflies — such as Ashy Clubtail versus Lancet Clubtail and Southern Spreadwing versus Sweetflag Spreadwing, to name a few — can be differentiated/identified with certainty only by examining the hamules under magnification.

Copyright © 2018 Walter Sanford. All rights reserved.

More male Brown Spiketails

May 13, 2018

Two more Brown Spiketail dragonflies (Cordulegaster bilineata) were spotted on 11 May 2018 at Occoquan Regional Park. Both individuals are male, as indicated by their terminal appendages and “indented” hind wings.

Male 1

The first photo of Male 1 is the “record shot.”

The next photo shows a dorsal view of the same individual.

Male 2

The first photo of Male 2 is the “record shot.”

The next photo is my favorite in this post. Notice the eye color of this individual is more green than brown. The difference in eye color could be caused by natural variation or it might indicate that Male 2 is more mature than Male 1.

Although Brown Spiketails seem to prefer perching in sunny places, the last photo shows the male hanging in shade rather than direct sunlight.

Copyright © 2018 Walter Sanford. All rights reserved.


%d bloggers like this: