Posts Tagged ‘hamules’

Autumn Meadowhawk dragonflies (mating pairs, in wheel)

January 11, 2018

Several mating pairs of Autumn Meadowhawk dragonflies (Sympetrum vicinum) were spotted during a photowalk around a vernal pool at a remote location in Huntley Meadows Park, Fairfax County, Virginia USA.

22 OCT 2017 | HMP | Autumn Meadowhawk (mating pair, “in wheel“)

Both pairs are “in wheel“: the male is on top; the female is on the bottom.

All odonates (dragonflies and damselflies) have a 10-segmented abdomen, numbered from front to back. Male dragonfly secondary genitalia, called hamules, are located in segments two and three (S2 and S3); female genitalia in segment eight (S8). Dragonflies form the mating wheel in order for their genitalia to connect during copulation.

22 OCT 2017 | HMP | Autumn Meadowhawk (mating pair, “in wheel“)

Editor’s Note: Careful readers may be thinking “Hey, wait a minute — you said you spotted several mating pairs, but the post features photos of just two pairs.” Good catch! The photos of two more mating pairs didn’t make the final cut because the focus was slightly soft in all of those photos.

Copyright © 2018 Walter Sanford. All rights reserved.

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Time to mate (Fall 2017)

October 11, 2017

I speculate Blue-faced Meadowhawk is an arboreal species of dragonfly that returns to the ground/water when it’s time to mate.

A mating pair of Blue-faced Meadowhawk dragonflies (Sympetrum ambiguum) was spotted near a drainage ditch alongside a vernal pool at a remote location in Huntley Meadows Park, Fairfax County, Virginia USA. This pair is “in wheel“: the male is on top; the female on the bottom. The female is a heteromorph, as indicated by her tan coloration.

All dragonflies and damselflies have a 10-segmented abdomen, numbered from front to back: male dragonfly secondary genitalia, called hamules, are located in segments two and three (S2 and S3); female genitalia in segment eight (S8). Dragonflies form the mating wheel in order for their genitalia to connect during copulation.

Copyright © 2017 Walter Sanford. All rights reserved.

Fine-lined Emerald dragonfly redux (Part 2)

September 21, 2017

The same Fine-lined Emerald dragonfly (Somatochlora filosa) was photographed while it perched on grasses located in two shady places along one of the trails at Occoquan Bay National Wildlife Refuge, Prince William County, Virginia USA.

This individual is a male, as indicated by his terminal appendages and prominent hamules.

Set 3

A busy background of thigh-high grasses made it challenging to find a pleasing composition.

Set 4

Photo Set 4 is my favorite, in terms of both quantity and quality. The dragonfly is shown perching on a grass stem that is estimated to be more than six feet high.

The next three photos are uncropped, that is, full-size images (4,000 x 3,000 pixels). This individual has a distinctive eye injury to the top of his left eye (facing forward) that enabled me to recognize the same male dragonfly is the subject in all four photo sets.

Did you notice the male Big Bluet damselfly (Enallagma durum) that photo-bombed the preceding image?

The last photo was cropped lightly in order to improve the composition, and Adobe Photoshop CC 2017 was used to remove a distracting element from the lower-right corner of the image.

Related Resources

Copyright © 2017 Walter Sanford. All rights reserved.

Fine-lined Emerald dragonfly redux (Part 1)

September 19, 2017

Several Fine-lined Emerald dragonflies (Somatochlora filosa) were spotted during a photowalk at Occoquan Bay National Wildlife Refuge, Prince William County, Virginia USA.

The same dragonfly was photographed while it perched in several shady places along one of the trails at the park. In my limited experience, Somatochlora filosa seems to prefer perching on bare tree branches or long stems of wild grass. Part 1 features two photo sets showing Fine-lined Emerald resting on other types of perches; Part 2 will feature two more photo sets showing the dragonfly perching on grasses.

This individual is a male, as indicated by his terminal appendages and prominent hamules.

Set 1

The first photograph is a strong contender for my Odonart Portfolio. I like the way the green vegatation complements the dragonfly’s emerald colored eyes. Can anyone identify the type of plant on which the dragonfly is perching?

Post Update: Sincere thanks to Drew Chaney for identifying the green plant shown in the preceding photo. According to Drew, “It’s common evening-primrose, probably Oenothera biennis.”

Set 2

The second set of photos shows the dragonfly perching on a Common Milkweed (Asclepias syriaca) seed pod.

The next photo was taken a step-or-so closer…

This individual has a distinctive eye injury to the top of his left eye (facing forward).

And after a few side steps, I was able to take a good ventral-lateral shot.

Editor’s Note: Sincere thanks to several members of the Capital Naturalist Facebook group for identifying the species of milkweed plant shown in photo Set 2. “Capital Naturalist” is administered by Alonso Abugattas, Natural Resources Manager, Arlington County Parks, Virginia.

Related Resources

Copyright © 2017 Walter Sanford. All rights reserved.

Fine-lined Emerald dragonflies (males)

September 13, 2017

Three Fine-lined Emerald dragonflies (Somatochlora filosa) were spotted during a long photowalk at Occoquan Bay National Wildlife Refuge. All three individuals are males, as indicated by their terminal appendages and prominent hamules.

If I have seen further it is by standing on the shoulders of giants. Source Credit: Sir Isaac Newton.

Sincere thanks to Jim Waggener, Wildlife Survey Coordinator for The Audubon Society of Northern Virginia, as well as other members of Jim’s survey group for sharing information that enabled me to find this rare to uncommon species of dragonfly. The group has surveyed four sites in Northern Virginia regularly for many years, including Occoquan Bay National Wildlife Refuge.

No. 1

Fine-lined Emerald dragonflies seem to prefer perching on bare tree branches or long stems of wild grass, typically at chest- or head-height although not exclusively. For example, this guy was perched about waist-high on a cluster of fallen tree branches.

10 SEP 2017 | Occoquan Bay NWR | Fine-lined Emerald (male)

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

Fine-lined Emerald seems to prefer perching in sun rather than shade, unlike Mocha Emerald (Somatochlora linearis) — another species from the Family Corduliidae (Emeralds) found in Northern Virginia that prefers shady places.

The following ventral-lateral shot shows the lines on the thorax for which this species is named.

10 SEP 2017 | Occoquan Bay NWR | Fine-lined Emerald (male)

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

No. 2

The male shown in the next photo is perched on a long grass stem, about chest-high. He posed for two shots, patrolled back-and-forth a few times, and then disappeared.

10 SEP 2017 | Occoquan Bay NWR | Fine-lined Emerald (male)

No. 3

The last male was the most cooperative model. The first photo was taken at a distance of approximately six feet.

10 SEP 2017 | Occoquan Bay NWR | Fine-lined Emerald (male)

The next photo was taken a step-or-so closer…

10 SEP 2017 | Occoquan Bay NWR | Fine-lined Emerald (male)

And after a few side steps, I was able to take a good lateral shot.

10 SEP 2017 | Occoquan Bay NWR | Fine-lined Emerald (male)

The Backstory

This might be one of those stories in which the take-away is “persistence pays dividends.”

I made two trips to Occoquan Bay NWR during Fall 2016 when Fine-lined Emerald was my target species. On 21 September 2016, I spotted one or more dragonflies (species unknown) patrolling the treetops along one of the trails at OBNWR. I didn’t see any signs of Fine-lined Emerald on 25 October 2016, consistent with records for late-date maintained by Kevin Munroe (04 October for Northern Virginia) and Dr. Steven Roble (15 October for the Commonwealth of Virginia).

In retrospect, I realized I started searching too late in the year during 2016 so I started earlier in 2017. My first trip to OBNWR was on 30 August 2017; it turned out to be fruitless. I hit the jackpot on 10 September 2017! Fine-lined Emerald is a new species for my life list of dragonflies.

Rare to Uncommon

A distribution map of official records for Fine-lined Emerald helps to illustrate its classification as a rare to uncommon species of odonate.

Source Credit: Abbott, J.C. 2006-2017. OdonataCentral: An online resource for the distribution and identification of Odonata. Available at http://www.odonatacentral.org. (Accessed: September 14, 2017).

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

Related Resources

Copyright © 2017 Walter Sanford. All rights reserved.

Halloween Pennant (young male)

July 25, 2017

Halloween Pennant dragonfly (Celithemis eponina) was spotted during a photowalk at Occoquan Bay National Wildlife Refuge (OBNWR), Prince William County, Virginia USA. This individual is a young male, as indicated by his yellowish-orange coloration, hamules, and terminal appendages.

Both photos in this gallery show the dragonfly perching at the top of Eastern gamagrass (Tripsacum dactyloides). Eastern gamagrass grows to a height of five- to six feet.

Look at the full-size version of the preceding photo. With its jaw open, the head of this pennant reminds me of the skull on a Jolly Roger flag. Argh, matey!

The last photo is my favorite in the set. The clarity, color palette and composition are perfect, he said not too modestly.

Copyright © 2017 Walter Sanford. All rights reserved.

Mocha Emerald dragonfly claspers

July 13, 2017

Mocha Emerald dragonfly (Somatochlora linearis) was spotted along a small creek at a remote location in the forest at Huntley Meadows Park. This individual is a male, as indicated by his terminal appendages and hamules.

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”).

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

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

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

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

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.

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.

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

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

Related Resource: Mocha Emerald terminal appendages (female).

Technique Hint: Did you notice that the “focus” of each photo (not to be confused with the focus point) is shown against a lighter background? That’s no accident — I composed each shot that way. As a result, the terminal appendages (cerci and epiproct) are much easier to see in the first two photos than the last shot, in which the composition highlights the hamules.

Copyright © 2017 Walter Sanford. All rights reserved.

Allegheny River Cruiser dragonfly (male)

June 19, 2017

An Allegheny River Cruiser dragonfly (Macromia alleghaniensis) was netted by Mike Blust at Hardware River Wildlife Management Area, Fluvanna County, Virginia USA.

The complete yellow ring around abdominal segment seven (S7) is a distinctive field marker for this species. This individual is a male, as indicated by his hamules and terminal appendages.

Allegheny River Cruiser is a good candidate for netting, that is, if you want to get a close look at one.

Males fly rapidly up and down streams, mostly but not always near shore, usually quite low… . Cruise up and down roads through woodland, in sun and shade, or fly up higher into forest canopy. Source Credit: Paulson, Dennis (2011-12-19). Dragonflies and Damselflies of the East (Princeton Field Guides) (Kindle Locations 7313-7315). Princeton University Press. Kindle Edition.

The following map shows all official records for Allegheny River Cruiser in the United States of America. Notice the records are roughly coincident with the Allegheny Mountains, from which part of the common name for this species is derived.

Source Credit: Abbott, J.C. 2006-2017. OdonataCentral: An online resource for the distribution and identification of Odonata. Available at http://www.odonatacentral.org. (Accessed: June 13, 2017).

Allegheny River Cruiser is a new species of dragonfly for my life list.

Tech Tips

The photo was taken using a Fujifilm X-T1 digital camera, Fujinon 55-200mm zoom lens, and Fujifilm EF-X500 shoe mount flash.

My camera had a mysterious meltdown when I was trying to photograph the dragonfly in Mike Blust’s hand. Sincere thanks to Mike for his extraordinary patience while I was troubleshooting the problem under extreme pressure.

Editor’s Note

Sincere thanks to Mike Boatwright for taking me to a couple of odonate-hunting localities along the James River, including Hardware River WMA (see map, shown below) and Columbia Boat Landing, Cumberland County, Virginia.

Copyright © 2017 Walter Sanford. All rights reserved.

Cobra Clubtail external reproductive anatomy

May 28, 2017

I liked to make paper- and plastic models when I was a child. Seems like the directions for assembling many models — not that anyone reads the directions — always started by saying something like “Insert Tab A in Slot B.”

Oddly enough, that line reminds me of how odonates copulate, in general, and Cobra Clubtail dragonflies (Gomphurus vastus) in particular.

Male

The hamules are “Tab A.”

Female

The subgenital plate is “Slot B.”

Putting it all together

Insert Tab A in Slot B. That’s the PG-rated version of how Cobra Clubtail dragonflies copulate in order to reproduce.

The Backstory

There is an annual mass emergence of Cobra Clubtails during the first week-or-two of May at Riverbend Park. It’s a spectacular event worth seeing firsthand!

The following photo shows a dead female, one of several Cobra Clubtails that were trampled by groups of elementary school children visiting the park on 09 May 2017. Her premature death saddens me because it was avoidable — the students should have been warned to watch their step because there were lots of Cobra Clubtails perching on the ground almost everywhere.

In the hope the female didn’t die in vein, I reluctantly decided to photograph the corpse in order to illustrate her external reproductive anatomy.

Editor’s Note: Sincere thanks to Dennis Paulson for help in identifying the female parts on the ventral side of abdominal segments eight and nine (S8-9).

Copyright © 2017 Walter Sanford. All rights reserved.

Because it’s fun!

May 16, 2017

Why do I hunt odonates, that is, dragonflies and damselflies? I like being outdoors, visiting beautiful natural places. I like honing my skills as a wildlife photographer. Most importantly, it’s fun! I like the challenge of finding uncommon species, and the thrill of making new discoveries.

A Cobra Clubtail dragonfly (Gomphurus vastus) was spotted along the Potomac River at Riverbend Park, Fairfax County, Virginia USA. This individual is a male, as indicated by his terminal appendages and indented hind wings.

The male was perching on colorful kayaks stored in a wooden rack near the boat ramp. Notice the natural coloration of the dragonfly was affected by light reflected from the kayaks. That’s OK since this photo set is all about fun, right?

09 MAY 2017 | Riverbend Park | Cobra Clubtail (male)

Can you say “hamules?” Males of many species in the Family Gomphidae (Clubtails) have prominent secondary sex organs.

09 MAY 2017 | Riverbend Park | Cobra Clubtail (male)

09 MAY 2017 | Riverbend Park | Cobra Clubtail (male)

09 MAY 2017 | Riverbend Park | Cobra Clubtail (male)

09 MAY 2017 | Riverbend Park | Cobra Clubtail (male)

09 MAY 2017 | Riverbend Park | Cobra Clubtail (male)

Tech Tips: I carried two digital cameras during the trip to Riverbend Park: a Panasonic Lumix DMC-FZ150 superzoom bridge camera plus Canon 580EX Speedlite, my go-to kit for photowalking; as well as my Fujifilm X-T1Fujinon XF55-200mm zoom lens, and Fujifilm EF-X500 shoe mount flash. Since Fujifilm digital cameras are well-known for capturing vivid color, the X-T1 was the camera of choice for this colorful scene.

Editor’s Note: 16 May is the one-year anniversary of my first visit to Riverbend Park to see the annual mass emergence of Cobra Clubtail dragonflies that occurs during the first two weeks in May.

Copyright © 2017 Walter Sanford. All rights reserved.


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