Posts Tagged ‘Cordulegaster bilineata’

Twin-spotted versus Brown Spiketails

February 8, 2022

Four species of genus Cordulegaster are found in the Commonwealth of Virginia: Brown Spiketail (C. bilineata); Tiger Spiketail (C. erronea); Twin-spotted Spiketail (C. maculata); and Arrowhead Spiketail (C. obliqua).

According to the excellent datasets for the Commonwealth of Virginia by Dr. Steve Roble, Staff Zoologist at the Virginia Department of Conservation and Recreation, Division of Natural Heritage, the adult flight periods for spiketail dragonflies are as follows.

MAR 16 – JUL 10 = Twin-spotted

MAR 28 – AUG 08 = Brown

MAY 11 – JUL 17 = Arrowhead

MAY 28 – AUG 22 = Tiger

As you can see, there’s a lot of overlap between the flight periods for Twin-spotted Spiketail and Brown Spiketail. Also notice the overlap between the flight periods for Arrowhead Spiketail and Tiger Spiketail.

I think we can agree the distinctive arrowhead-shaped yellow markings on the abdomen of Arrowhead Spiketail (shown below) are unmistakeable for any other species of spiketail, including Tiger Spiketail.

07 JUL 2014 | Fairfax County, VA | Arrowhead Spiketail (male)

In the opinion of the author it’s more likely a dark-colored Brown Spiketail, such as the one shown below, might be misidentified as a Twin-spotted Spiketail.

02 MAY 2019 | Fairfax County, VA | Brown Spiketail (male)

Differentiating Twin-spotted versus Brown

Twin-spotted and Brown Spiketail dragonflies can be differentiated by looking closely at the yellow markings on abdominal segments one through three (S1-S3).

07 MAY 2018 | Fairfax County, VA | Twin-spotted Spiketail (male)

The pattern of yellow markings on S1-S3 is simpler for Twin-spotted than Brown, as you can see by looking at the full-size versions of these two photos, shown above and below.

11 MAY 2018 | Fairfax County, VA | Brown Spiketail (male)

Female Twin-spotted versus Brown

Female Twin-spotted Spiketails, such as the one shown below, have a much longer subgenital plate (ovipositor) than female Brown Spiketails.

Photo used with written permission from Mike Boatwright.

The subgenital plate for the following female Brown Spiketail is barely visible.

09 MAY 2013 | Fairfax County, VA | Brown Spiketail (female)

It isn’t a lot easier to see the subgenital plate in a close-up view of the same individual shown above.

09 MAY 2013 | Fairfax County, VA | Brown Spiketail (female)

Coach’s Corner

Thanks to Mike Boatwright, founder and administrator of the Virginia Odonata Facebook group, for coaching me up on how to differentiate Twin-spotted Spiketail from Brown Spiketail, including both males and females.

Look for yellow markings on the side of abdominal segments one through three (S1-S3): green arrows show the lack of yellow markings on S1-S3 for Twin-spotted; red arrows show yellow markings on the sides of S1-S3 for Brown.

Set 1

Twin-spotted Spiketail | male (dorsal view)

Photo used with written permission from Mike Boatwright.

Brown Spiketail | male (dorsal view)

Photo used with written permission from Mike Boatwright.

Set 2

Twin-spotted Spiketail | male (dorso-lateral view)

Photo used with written permission from Mike Boatwright.

Brown Spiketail | male (dorso-lateral view)

Photo used with written permission from Mike Boatwright.

What are the take-aways?

Remember the odonate hunter’s credo: Shoot first (photographs, that is); ask questions later. (Repeat it like a mantra.) Get a shot, any shot; refine the shot gradually.

Please don’t waste precious time in the field! You can study the photos when you return home in order to identify the subject(s) you shot as either Twin-spotted Spiketail or Brown Spiketail.

Copyright © 2022 Walter Sanford. All rights reserved.

Hunting spiketail dragonflies in Virginia

January 11, 2022

There are three genera in Family Cordulegastridae (Spiketails) worldwide: Anotogaster; Cordulegaster; and Neallogaster. Only Genus Cordulegaster is found in the United States of America.

Four species of Cordulegaster are found in the Commonwealth of Virginia: Brown Spiketail (C. bilineata); Tiger Spiketail (C. erronea); Twin-spotted Spiketail (C. maculata); and Arrowhead Spiketail (C. obliqua).

It’s all about habitat, habitat, habitat.

In the world of odonates, there are habitat generalists and habitat specialists. Spiketail dragonflies are habitat specialists.

Dennis Paulson’s description of the habitat for each species of spiketail found in Virginia is shown in the following list. Notice the list is generic, meaning, specific names are not given. As you read the descriptions, look for commonalities among the habitats.

1. Cordulegaster sp.

Habitat: Small to midsized rocky streams with good current and muddy pools, typically in forest. Occasionally seen patrolling on larger rivers. Source Credit: Paulson, Dennis (2011-12-19). Dragonflies and Damselflies of the East (Princeton Field Guides) (Kindle Locations 7058-7059). Princeton University Press. Kindle Edition.

2. Cordulegaster sp.

Habitat: Small woodland streams. Source Credit: Paulson, Dennis. Dragonflies and Damselflies of the East (Princeton Field Guides) (Kindle Location 7145). Princeton University Press. Kindle Edition.

3. Cordulegaster sp.

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. Dragonflies and Damselflies of the East (Princeton Field Guides) (Kindle Locations 7081-7082). Princeton University Press. Kindle Edition.

4. Cordulegaster sp.

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

Commonalities

Did you notice the habitats for all four species of spiketails found in Virginia have two characteristics in common?

  • small streams, sometimes seep-fed
  • located in the forest/woodlands

When we say small streams, we mean smallmuch smaller than you might think! Although Twin-spotted Spiketail can be found along mid-size streams (often near the confluence of a smaller stream with a mid-size stream) we think Twin-spotted are more common on small streams.

Answer Key

The following list shows the species of spiketail that matches each of Dennis Paulson’s habitat descriptions.

  1. Twin-spotted Spiketail (Cordulegaster maculata)
  2. Brown Spiketail (Cordulegaster bilineata)
  3. Arrowhead Spiketail (Cordulegaster obliqua)
  4. Tiger Spiketail (Cordulegaster erronea)

The common name for each species is hyperlinked to a page in Walter Sanford’s Photoblog featuring many photographs of that species. The scientific name for each species is linked to Mike Boatwright’s “Spiketails” gallery of photographs on Facebook; click on each photo to see the identity of the spiketail species.

The spiketail species in the preceding lists are shown in chronological order of emergence in Virginia, with Twin-spotted being the earliest and Tiger being the latest. There is some overlap of adult flight periods for some species. Online, interactive Odonate Calendars help you know when to be on the lookout for each species.

I found a small woodland stream. Where should I look for spiketails?

If you’re planning to hunt for spiketails during the 2022 odonate season, the time is now to start scouting small streams in the forest such as the one shown in the following photo.

Photo used with written permission from Mike Boatwright.

Our advice: Focus on finding the right habitat first, rather than finding a particular species of spiketail. Revisit the same small stream(s) periodically throughout the entire odonate season to see which species prefer the stream(s). Be peristent — persistence pays when hunting spiketails!

Twin-spotted Spiketail and Brown Spiketail can be found perching either in fields or along trails located near the small streams from which they emerge. In our experience, Brown Spiketail spends the most time perching of all species of spiketails found in Virginia.

Arrowhead Spiketail and Tiger Spiketail fly long patrols back-and-forth along the stream channel itself, approximately six inches (6″) above the water level. Arrowhead Spiketail stops to perch at the end points of its patrol, often in a sunny clearing or field. On the other hand, we think it’s safe to say Tiger Spiketail perches infrequently.

Do other types of odonates live in the same habitat?

Seeps and small seep-fed streams in the forest are perfect places to look for Gray Petaltail dragonfly (Tachopteryx thoreyi), another habitat specialist found in Virginia, as well as spiketails such as Arrowhead and Tiger.

Photo used with written permission from Mike Boatwright.

Related Resources

Editor’s Note: My good friend and odonate hunting buddy Mike Boatwright and I collaborated to share some of the wisdom gleaned from our experiences hunting spiketail dragonflies in Virginia. Thanks, Mike — couldn’t have done it without you!

Copyright © 2022 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.

New Life List additions in 2018 (odonates)

December 28, 2018

The anticipation of the hunt and the thrill of discovery — the adrenalin rush from finding the target species is ever more elusive as one gains experience and expertise. Accordingly, the number of additions to my Life List is fewer year after year.

Editor’s Note: List items are presented in chronological order, based upon the date of the spotting.

Twin-spotted Spiketail

A Twin-spotted Spiketail dragonfly (Cordulegaster maculata) was spotted at an undisclosed location in Fairfax County, Virginia USA. This individual is a male.

07 MAY 2018 | Fairfax County, VA | Twin-spotted Spiketail (male)

Brown Spiketail (male)

A Brown Spiketail dragonfly (Cordulegaster bilineata) was spotted at an undisclosed location in Fairfax County, Virginia USA. I saw a female Brown Spiketail on 09 May 2013. This individual is one of several males that I spotted on 07 and 11 May 2018.

11 MAY 2018 | Fairfax County, VA | Brown Spiketail (male)

Gray Petaltail

Gray Petaltail dragonfly (Tachopteryx thoreyi) was spotted at a forest seep. This individual is a male with a malformed abdomen that I nicknamed “Bender.”

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

Sable Clubtail

Sable Clubtail dragonfly (Stenogomphurus rogersi) was spotted perched near a small stream located in Fairfax County, Virginia USA. This individual is a male.

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

Citrine Forktail damselfly (male)

Citrine Forktail damselfly (Ischnura hastata) was spotted during a stream-walk along South Fork Quantico Creek in Prince William Forest Park (PWFP), Prince William County, Virginia USA. This individual is a male.


Next post: Recognition in 2018.

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.

Brown Spiketail dragonfly (male)

May 11, 2018

My first Brown Spiketail dragonfly (Cordulegaster bilineata) was a female that I photographed on 01 May 2013 at Meadowood Recreation Area in Fairfax County, Virginia USA. That was the last Brown Spiketail I saw for the next five years. As it turns out, spiketails are relatively uncommon in Northern Virginia. Who knew?

Soon after Mike Powell and I photographed one or two Twin-spotted Spiketail dragonflies (Cordulegaster maculata) on 07 May 2018 at Occoquan Regional Park, we spotted a male Brown Spiketail perched in a sunny place along the same dirt/gravel trail where we had seen the Twin-spotted.

As a wildlife photographer with a focus on insect photography, one of my mantras is: “Get a shot, any shot; refine the shot.” The preceding photo is the “record shot”; the following photos show my efforts to refine the record shot.

There were at least two males competing for the same prime location. It’s possible that all of the photos in this gallery feature the same individual, although I think it’s just as likely more than one male is shown.

Related Resources

Copyright © 2018 Walter Sanford. All rights reserved.

Can I see some eye-dentification?

March 20, 2015

It may seem like all dragonflies look alike when you’re beginning to learn how to identify dragonflies. For example, all dragonflies have large, multifaceted compound eyes. Look closely. Careful observation of the color, shape, and size of eyes should enable you to quickly identify the family (or families) of dragonflies to which a specimen may belong.

The following field markers — used in combination with a good field guide to dragonflies, a species list for your location, and the process of elimination — should enable you to identify unknown specimens more quickly than randomly trying to find a match between your specimen and one of the 316 of species of dragonflies known to occur in the United States!

Clubtail Family (and Petaltail Family)

The eyes of clubtail dragonflies (and petaltails) are widely separated, somewhat similar to the eyes of damselflies. The Clubtail Family is the second largest family of dragonflies, so this field marker should be useful for identifying a lot of dragonflies to the family level — if only clubtails were as easy to identify down to the species level!

Ashy- or Lancet Clubtail dragonfly

09 MAY 2013 | Meadowood Recreation Area | Ashy/Lancet Clubtail (female)

The preceding dragonfly is either an Ashy Clubtail (Gomphus lividus) or Lancet Clubtail (Gomphis exilis). Ashy- and Lancet Clubtail dragonflies are similar in appearance and difficult to differentiate with complete certainty. But one look at those eyes and you know it’s definitely some species of clubtail!

Spiketail Family

Notice the eyes of the following dragonfly nearly touch at a point between its eyes — that’s a distinctive field marker for the Spiketail Family.

Brown Spiketail dragonfly (female)

09 MAY 2013 | Meadowood Recreation Area | Brown Spiketail (female)

Cruiser, Emerald, and Skimmer Families

In a few families of dragonflies, the eyes meet along a short seam near the face.

The Skimmer Family is the largest family of dragonflies. Many species of Skimmers are common and fairly easy to identify.

There are fewer species of dragonflies in the Cruiser Family than the Skimmer Family; no other dragonflies in the United States look similar to cruisers.

Stream Cruiser dragonfly (male)

02 MAY 2013 | Accotink Bay Wildlife Refuge | Stream Cruiser (male)

Many species of the Emerald Family feature distinctive bright green eyes, hence the family name.

Mocha Emerald dragonfly (Somatochlora linearis)

25 JUL 2012 | The Wildlife Sanctuary | Mocha Emerald (male)

Darner Family

The eyes of Darners meet along a long seam from front-to-back.

Common Green Darner dragonflies (mating pair, in tandem)

14 AUG 2012 | Huntley Meadows Park | Common Green Darner (mating pair)

Self-test

OK, let’s apply what you just learned. Looking at the eyes only, can you identify the family for the following dragonfly? If you would like to know whether your answer is correct, then please leave a comment.

Teacher’s Note: In order to avoid revealing the answer to the one-question quiz as soon as the first person comments, I changed the settings for this blog so that comments must be approved manually.

Common Sanddragon dragonfly (male)

26 JUN 2015 | Wickford Park | [Insert family name here.]

Editor’s Notes: This post is adapted from Dragonfly Head & Eyes, one of many excellent guides on the Odes for Beginners Web site. Thanks for the inspiration, Sheryl Chacon!

Copyright © 2015 Walter Sanford. All rights reserved.

Brown Spiketail dragonfly (female)

May 26, 2013

The following photo gallery shows a female Brown Spiketail dragonfly (Cordulegaster bilineata) spotted on 09 May 2013, perching near the ground in an open field along the trail to Hidden Pond, a small lake located at Meadowood Recreation Area in Fairfax County, Virginia USA.

Why are Spiketail dragonflies called “spiketails,” and what field marks can be used to identify this individual as a female? The answer to both questions is illustrated in the following annotated close-up photograph of the posterior end of the Brown Spiketail dragonfly’s abdomen.

Brown-Spiketail_f_anatomy

All female dragonflies have a pair of cerci (superior appendages) that have little or no function. Notice the spike-shaped subgenital plate.

Spiketail dragonflies are so named because the female’s long [subgenital plate], or egg-laying organ, extends beyond the tip of the abdomen. Source Credit: New York State Department of Environmental Conservation.

Thanks to Richard Orr, renowned expert on dragonflies and damselflies of the mid-Atlantic region, for verifying my tentative indentification of both the gender of the dragonfly and some of its anatomical parts.

Related Resources: Odonate Terminal Appendages.

Copyright © 2013 Walter Sanford. All rights reserved.

Brown Spiketail dragonfly (redux)

May 12, 2013

This Brown Spiketail dragonfly (Cordulegaster bilineata) has a face only a mother could love. Happy Mother’s Day!

Brown Spiketail dragonfly (female) Brown Spiketail dragonfly (female)

Copyright © 2013 Walter Sanford. All rights reserved.


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