Posts Tagged ‘terminal appendages’

Dragonfly Curriculum Guide Supplemental Videos

December 16, 2022

One of my photos is featured in a new video entitled Determining Dragonfly Sex: Dragonfly video 15, by Dr. Ami Thompson. See the inset photo in the following video screen capture.

The video is one of 15 Dragonfly Curriculum Guide Supplemental Videos coproduced by Ami Thompson and Peter Xyooj. The Dragonfly Curriculum Guide (PDF) is available for free.

Notice my last name is misspelled in the credits at the end of the video: Stanford is an institution; I should be institutionalized. <Rim shot!> Oh well, at least my name is spelled correctly in the video screen capture shown above.

The inset photo is from “Mocha Emerald dragonfly claspers,” a blog post that I published on 13 July 2017.

09 JUL 2017 | Huntley Meadows Park | Mocha Emerald (male)

Related Resources

Copyright © 2022 Walter Sanford. All rights reserved.

Twin-spotted Spiketail (terminal appendages)

January 25, 2022

Male

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.

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

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.

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

Female

As far as I know I have never seen a female Twin-Spotted Spiketail. (I have seen several individuals that I was unable to photograph.) No problem. Mike Boatwright kindly allowed me to annotate a couple of his photographs.

Photo used with written permission from Mike Boatwright.

These individuals are female, as indicated by their rounded hind wings, terminal appendages, and prominent subgenital plate (ovipositor) at the tip of their abdomen.

Photo used with written permission from Mike Boatwright.

Copyright © 2022 Walter Sanford. All rights reserved.

Arrowhead Spiketail (terminal appendages)

January 21, 2022

Arrowhead Spiketail dragonflies (Cordulegaster obliqua) were spotted along small streams at undisclosed locations in Fairfax County and Prince William County, Virginia USA.

Male and female Arrowhead Spiketails are similar in appearance. They can be differentiated based upon several field marks.

Male

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

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

Arrowhead male and female cerci are similar in appearance, and it can be challenging to see the epiproct clearly from some viewpoints. When in doubt whether an individual is male or female, look for indentations at the base of the hind wings of males.

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

Female

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

21 MAY 2019 | PNC. Wm. County | Arrowhead Spiketail (female)

Although Arrowhead male and female cerci are similar in appearance, there is no mistaking the subgenital plate of female spiketails! It’s easy to see why “Spiketails” is the common name for Family Cordulegastridae.

21 MAY 2019 | PNC. Wm. County | Arrowhead Spiketail (female)

So the take-away is simple: If you see a subgenital plate then the individual is definitely female; if not, then it’s probably a male.

Copyright © 2022 Walter Sanford. All rights reserved.

Yellow-sided Skimmer (terminal appendages)

August 24, 2021

Female and male Yellow-sided Skimmer dragonflies (Libellula flavida) were spotted at a small pond at an undisclosed location in Prince William County, Virginia USA.

Female

The first individual is a female, as indicated by her mostly yellow coloration and terminal appendages.

17 JUN 2021 | PNC. Wm. County | Yellow-sided Skimmer (female)

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

Mature male

The last individual is a mature male, as indicated by his light-blue pruinescence and terminal appendages.

17 JUN 2021 | PNC. Wm. County | Yellow-sided Skimmer (male)

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”).

Immature male Yellow-sided Skimmers look similar to females of the same species. Terminal appendages can be used to differentiate the sex of immature males and mature females.

Related Resource: Yellow-sided Skimmer (male and female) – a blog post by Walter Sanford.

Copyright © 2021 Walter Sanford. All rights reserved.

Black-shouldered Spinyleg (female)

August 13, 2021

A Black-shouldered Spinyleg dragonfly (Dromogomphus spinosus) was spotted by Michael Powell during a photowalk with me along a mid-size stream at an undisclosed location in Prince William County, Virginia USA.

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

05 AUG 2021 | PNC. Wm. County | Black-shouldered Spinyleg (female)

We followed the female from one location…

05 AUG 2021 | PNC. Wm. County | Black-shouldered Spinyleg (female)

to another.

05 AUG 2021 | PNC. Wm. County | Black-shouldered Spinyleg (female)

I was able to take no more than three shots at each perch before she moved on to the next stop.

05 AUG 2021 | PNC. Wm. County | Black-shouldered Spinyleg (female)

Habitat

I’m not sure I’d call Black-shouldered Spinyleg a habitat specialist. I’ve seen and photographed D. spinosus along small streams in the forest, mid-size streams (like the one in this post), and large rivers.

Habitat: Rocky and muddy streams and rivers from small to large, more often in woodland. Also in rocky lakes in northern part of range. Source Credit: Paulson, Dennis (2011-12-19). Dragonflies and Damselflies of the East (Princeton Field Guides) (Kindle Locations 6416-6417). Princeton University Press. Kindle Edition.

Range map

The following map shows all official records for Dromogomphus spinosus in the United States of America. Given the wide range of lotic habitats where Black-shouldered Spinyleg is found, I’m puzzled by the fact that the species isn’t more widespread than it appears to be.

Related Resource: All posts in my blog tagged with the words “Black-shouldered Spinyleg dragonfly.”

Copyright © 2021 Walter Sanford. All rights reserved.

Anatomy of a male Tiger Spiketail

August 10, 2021

The following annotated image shows a Tiger Spiketail dragonfly (Cordulegaster erronea). This individual is a male, as indicated by his hamules, “indented” hind wings, and terminal appendages.

Hamules

Hamules? What are hamules?

hamules: paired structures that project from genital pocket under second segment and hold female abdomen in place during copulation Source Credit: Paulson, Dennis (2011-12-19). Dragonflies and Damselflies of the East (Princeton Field Guides) (Kindle Locations 11618-116198). Princeton University Press. Kindle Edition.

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. 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.

Photo used with written permission from Michael Powell.

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

Indented hind wings

Male members of many families of dragonflies have “indented” hind wings near the body, with some notable exceptions.

Hind wing venation and shape can identify the sex of most dragonflies. Petaltails, darners (except Anax), clubtails, spiketails, cruisers, and some emeralds. Wing shape isn’t helpful to sex baskettails since they are largely the same. They are different in Cordulia, Dorocordulia, Somatochlora and to a lesser degree, Neurocordulia. Source Credit: Ed Lam, author and illustrator of Damselflies of the Northeast.

Terminal appendages

Identifying female versus male dragonflies and damselflies can be challenging but it’s a little easier when you know how to differentiate their terminal appendages.

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 dragonfly terminal appendages don’t look exactly the same for all species of dragonflies, but their function is identical.

Generally speaking, spiketail dragonflies have relatively small terminal appendages. That said, they must get the job done!

Related Resource: Tiger Spiketail dragonfly (male) – a blog post by Walter Sanford.

Copyright © 2021 Walter Sanford. All rights reserved.

 

Tiger Spiketail dragonfly (male)

August 7, 2021

Tiger Spiketail dragonfly (Cordulegaster erronea) was captured along a small stream at an undisclosed location in Prince William County, Virginia USA. The specimen was photographed and released unharmed.

The first few images show Michael Powell, my former friend and photowalking buddy, holding the dragonfly while I shot some photographs.

05 AUG 2021 | Prince William County, VA | Tiger Spiketail (male)

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

05 AUG 2021 | Prince William County, VA | Tiger Spiketail (male)

What a handsome face! Cue “Eye Of The Tiger” by Survivor.

05 AUG 2021 | Prince William County, VA | Tiger Spiketail (male)

The next image shows me holding the dragonfly so that Mike could take some photographs. Hold That Tiger. (Strike up the band!)

Photo used with written permission from Michael Powell.

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

Up, up, and away!

The last photograph shows the Tiger Spiketail “posed” au naturel on the trunk of a fallen tree. Mike and I chose that spot because it was one of only a few sunny places along the small forest stream. The Tiger flew away almost immediately after I released him, headed toward the tree canopy. Mike had time for one clear shot. Good thing, ‘cuz I had no opportunity to get a shot.

Photo used with written permission from Michael Powell.

The backstory

I went on my first Tiger safari during July 2018 when I visited a location in Fairfax County, Virginia that a friend shared with me in strictest confidence. 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!

Every year for the next few years, the story was similar — I saw Tigers but had no photos/videos to verify my sightings. Eventually I came to the conclusion that I would need to capture a specimen with an insect net in order to take photographs.

Let me be perfectly clear — all things being equal I would prefer to photograph dragonflies perching naturally rather than netting them. Sometimes, as in this case, netting is the better way to go.

Rest assured I have great respect for the rare- to uncommon species of odonates. The Tiger Spiketail featured in this post was held in captivity no longer than absolutely necessary, and was handled gently at all times.

Our strategy

Mike and I arrived at the stream site sometime after 10 a.m. While I setup my 18” diameter collapsible insect net, Mike took the point a little farther downstream to look for a Tiger approaching our location. No more than 10 minutes after I was in position alongside the stream, Mike spotted a Tiger flying upstream in our direction.

I waited until the Tiger had almost reached the place where I was standing before I swung my net forward smoothly and was psyched to see the dragonfly go all the way into the net. I said to Mike, “I got it!”

From that point, I worked quickly to gently remove the dragonfly from the net so that Mike and I could take some photographs of this rare species.

Range map

The following map shows all official records for Cordulegaster erronea in the United States of America. Tiger Spiketail is a habitat specialist that is challenging to find.

Related Resources

Copyright © 2021 Walter Sanford. All rights reserved.

Ebony Jewelwing damselfly (male)

July 30, 2021

An Ebony Jewelwing damselfly (Calopteryx maculata) was spotted along a small stream located in Occoquan Regional Park, Fairfax County, Virginia USA.

05 JUN 2021 | Fairfax County, VA | Ebony Jewelwing (male)

This individual is a male, as indicated by his all black wings and terminal appendages.

05 JUN 2021 | Fairfax County, VA | Ebony Jewelwing (male)

Habitat

It’s easy to find Ebony Jewelwing. Look for a small stream in the forest.

Slow-flowing woodland streams, usually associated with herbaceous vegetation. Tend to be more at rapids when that habitat is present. Occur on open banks when trees nearby (trees essential for roosting at night). May be abundant at small streams in woods where very few other species are present. Source Credit: Paulson, Dennis (2011-12-19). Dragonflies and Damselflies of the East (Princeton Field Guides) (Kindle Locations 1249-1251). Princeton University Press. Kindle Edition.

Copyright © 2021 Walter Sanford. All rights reserved.

More Bar-winged Skimmers (males)

July 23, 2021

At least two male Bar-winged Skimmer dragonflies (Libellula axilena) were spotted along the shoreline of a small pond at an undisclosed location in Prince William County, Virginia USA.

It’s possible all of the photos featured in this blog post are of the same mature male that is featured in another recent post, as indicated by a distinctive pattern of spider web strands on the wings of the dragonfly.

Look closely along the leading edge of the wings. Notice the dark bars from which the common name for this species is derived are almost invisible.

17 JUN 2021 | PNC. Wm. County |  Bar-winged Skimmer (mature male)

17 JUN 2021 | PNC. Wm. County |  Bar-winged Skimmer (mature male)

17 JUN 2021 | PNC. Wm. County |  Bar-winged Skimmer (mature male)

17 JUN 2021 | PNC. Wm. County |  Bar-winged Skimmer (mature male)

For what it’s worth, the first and last photos in this set are my favorite.

Related Resource: Bar-winged Skimmer dragonfly (male).

Copyright © 2021 Walter Sanford. All rights reserved.

Gray Petaltail dragonfly (male)

July 13, 2021

A Gray Petaltail dragonfly (Tachopteryx thoreyi) was observed during a photowalk with Michael Powell along the shoreline of a small pond at an undisclosed location in Prince William County, Virginia USA.

Mike spotted the Gray Petaltail first, when we were on opposite sides of the pond. Mike was able to shoot a few photos before the dragonfly flew away and Mike moved on. I thought Mike gave up on the subject too quickly so I decided to use one of my tried and true strategies for finding and photographing odonates: Sit in a good spot and wait for the game to come to me.

I walked around to the other side of the pond and sat down on my small, lightweight camp stool about 12-15 feet from the place where Mike had seen the Gray Petaltail. Sure enough, the dragonfly returned to the same perch soon afterward!

The first photo is the “record shot,” that is, get a shot, any shot.

17 JUN 2021 | PNC. Wm. County | Gray Petaltail (male)

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

17 JUN 2021 | PNC. Wm. County | Gray Petaltail (male)

The dragonfly would perch briefly, then fly away.

17 JUN 2021 | PNC. Wm. County | Gray Petaltail (male)

The male dragonfly did the same thing repeatedly, always returning to a slightly different perch each time. Turns out he was hunting for food.

17 JUN 2021 | PNC. Wm. County | Gray Petaltail (male)

I would describe T. thoreyi as an “ambush predator” — sometimes Gray Petaltail hunts for prey by waiting for other flying insects to pass by and ambushing them aerially when they do. Like the crane fly shown below that the Gray grabbed before landing on my bucket hat.

Photo used with written permission from Michael Powell.

I was happy to provide a white table cloth for a classy dining experience with one of my favorite species of dragonflies.

Habitat

For habitat-specific odonates such as T. thoreyi, it’s all about location, location, location. “Gray Petaltail dragonfly (male)” is another blog post by Walter Sanford that provides actionable intel regarding ideal habitat for Grays.

Range map

The following map shows all official records for Tachopteryx thoreyi in the United States of America. Gray Petaltail is a habitat specialist that is challenging to find.

Related Resources

  • Tachopteryx thoreyi Gray Petaltail on NatureServe Explorer. The conservation status for T. thoreyi in Virginia is “Apparently Secure (S4).” That’s good news. The bad news: That doesn’t mean it’s easy to find.
  • Gray Petaltail dragonfly (male)” – another blog post by Walter Sanford that provides actionable intel regarding ideal habitat for Grays.

Copyright © 2021 Walter Sanford. All rights reserved.