Posts Tagged ‘malformed’

Late-stage emergent baskettail dragonfly

April 18, 2017

Common Baskettail dragonfly (Epitheca cynosura) was spotted at Painted Turtle Pond during a photowalk around Occoquan Bay National Wildlife Refuge (OBNWR), Prince William County, Virginia USA. This individual is a late-stage emergent teneral female.

I photographed the process of emergence from the first sighting to the time when the teneral dragonfly flew away: I shot 23 photos in approximately 16 minutes; time is compressed by showcasing six (6) select photos taken at major milestones during the event.

The following photo is the first image from a time-series documenting the emergence of the teneral female. Elapsed time is expressed in hh:mm:ss format, e.g., 00:00:00 is the time when I spotted the emergent teneral female, and 00:16:08 is the total elapsed time.

13 APR 2016 | 11:38:41 am EDT | Elapsed time: 00:00:00

Notice the drop of fluid at the tip of the abdomen. Emerging dragonflies pump fluid into their wings, causing the wings to expand. Next, the same fluid is withdrawn from the wings and used to expand the abdomen. Excess fluid is expelled afterward.

13 APR 2016 | 11:40:48 am EDT | Elapsed time: 00:02:07

The next photo shows the first time the wings opened.

13 APR 2016 | 11:48:55 am EDT | Elapsed time: 00:10:14

Then the wings closed again and remained closed for a while.

13 APR 2016 | 11:51:02 am EDT | Elapsed time: 00:12:21

The wings reopened a few minutes later. Notice that several wings are malformed slightly.

13 APR 2016 | 11:54:14 am EDT | Elapsed time: 00:15:33

Finally, the wings open up, and very soon the teneral adult flies away. Source Credit: Paulson, Dennis (2011-12-19). Dragonflies and Damselflies of the East (Princeton Field Guides) (Kindle Locations 468). Princeton University Press. Kindle Edition.

The teneral female dragonfly flew away immediately after the last photo in the time-series.

13 APR 2016 | 11:54:46 am EDT | Elapsed time: 00:16:08

This individual is a female, as indicated by her cerci (superior appendages) and thick abdomen. Common Baskettail females have shorter cerci and a thicker abdomen than males of the same species.

Exuviae (in situ)

Several dragonfly exuviae were spotted at Painted Turtle Pond; it’s possible they are cast skins from Common Baskettail. More later after the exuviae are identified using a dichotomous key for dragonfly larvae.

13 APR 2017 | OBNWR | Common Baskettail (exuvia)

These exuviae are not the one from which the teneral female featured in this post emerged.

13 APR 2017 | OBNWR | Common Baskettail (exuvia)

Copyright © 2017 Walter Sanford. All rights reserved.

Malformed Cobra Clubtail dragonflies

February 21, 2017

I took 255 photographs during my first photowalk along the Potomac River at Riverbend Park, Fairfax County, Virginia USA, including lots of photos of Cobra Clubtail dragonflies (Gomphurus vastus). I noticed several malformed individuals when I reviewed the entire photo set recently (in search of look-alike species of clubtail dragonflies). None of the malformations prevented the dragonflies from functioning normally.

The first Cobra Clubtail is a male with a slightly crimped right hind wing, where a small part of the wing failed to fully inflate during emergence.

The next individual is a female. Notice that abdominal segment seven (S7) was crimped during emergence. (All dragonflies and damselflies have a 10-segmented abdomen, numbered from front to back.)

The last individual is a male. Notice his left front leg is missing. The male is either malformed or he lost the leg due to injury.

A Cobra Clubtail dragonfly (Gomphurus vastus) spotted at Riverbend Park, Fairfax County, Virginia USA. This individual is a male; its left front leg is missing. Two dark face bars are field markers that can be used to differentiate Cobra Clubtail from other similar looking species of clubtails.

16 MAY 2016 | Riverbend Park | Cobra Clubtail (male, missing leg)

Two thick dark face bars are field markers that can be used to differentiate Cobra Clubtail from other similar looking species in the Family Gomphidae (Clubtails): Midland Clubtail (Gomphus fraternus) has no face bars; Splendid Clubtail (Gomphus lineatifrons) has thin dark face bars.

Tech Tips:

Shutter Priority mode was used for the first two photographs. Aperture Priority mode was used for the last photo, in order to increase the depth of field. As you can see, the depth of field at f/7.1 was insufficient for the tip of the dragonfly abdomen to be in focus. Typically, I wouldn’t publish the last photo, but I made an exception because it is the only photo I took that shows the face bars clearly.

Copyright © 2017 Walter Sanford. All rights reserved.

Blue-faced Meadowhawk (male, malformed)

February 15, 2017

Blue-faced Meadowhawk dragonfly (Sympetrum ambiguum) was spotted near a vernal pool at Huntley Meadows Park (HMP). This individual is a male, as indicated by his coloration and terminal appendages.

The male’s abdomen is slightly malformed. The malformation is more noticeable in the preceding photo and easy to overlook in the following photo.

Copyright © 2017 Walter Sanford. All rights reserved.

Zebra Swallowtail butterfly

January 12, 2017

A late-season Zebra Swallowtail butterfly (Eurytides marcellus) was spotted during a photowalk along Deephole Point Road at Occoquan Bay National Wildlife Refuge, Prince William County, Virginia USA.

The left hindwing looks like it might be malformed.

Copyright © 2017 Walter Sanford. All rights reserved.

More Black-shouldered Spinyleg dragonflies

August 17, 2016

Another female and male Black-shouldered Spinyleg dragonfly (Dromogomphus spinosus) were spotted during a follow-up photowalk along the Potomac River at Riverbend Park.

Female and male Black-shouldered Spinyleg are somewhat similar in appearance. Terminal appendages, the shape of their hind wings, and the relative size of their club are good field markers to differentiate specimens by gender.

Female

The first individual is a female, as indicated by her terminal appendages. Female dragonflies have a pair of cerci (superior appendages) that have little or no function.

A Black-shouldered Spinyleg dragonfly (Dromogomphus spinosus) spotted along the Potomac River at Riverbend Park, Fairfax County, Virginia USA. This individual is a female.

08 AUG 2016 | Riverbend Park | Black-shouldered Spinyleg (female)

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

The preceding dorsal view of the dragonfly shows its hind wings are rounded near the body, a good field marker for female clubtail dragonflies. In contrast, the hind wings of male clubtails are “indented.” Also notice the female “club” is slightly smaller than the male club, as shown in the following photos.

A Black-shouldered Spinyleg dragonfly (Dromogomphus spinosus) spotted along the Potomac River at Riverbend Park, Fairfax County, Virginia USA. This individual is a female.

08 AUG 2016 | Riverbend Park | Black-shouldered Spinyleg (female)

A Black-shouldered Spinyleg dragonfly (Dromogomphus spinosus) spotted along the Potomac River at Riverbend Park, Fairfax County, Virginia USA. This individual is a female.

08 AUG 2016 | Riverbend Park | Black-shouldered Spinyleg (female)

A Black-shouldered Spinyleg dragonfly (Dromogomphus spinosus) spotted along the Potomac River at Riverbend Park, Fairfax County, Virginia USA. This individual is a female.

08 AUG 2016 | Riverbend Park | Black-shouldered Spinyleg (female)

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”).

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

Although the preceding photo seems to show four terminal appendages, do not be misled! The epiproct for Black-shouldered Spinyleg is essentially a wide plate with two prongs.

Notice the male’s middle leg (on the right side, facing forward) is shorter than either its front- or hind leg. I’m not sure whether the middle leg is malformed, or the result of an injury. Whatever the cause, it might explain why the dragonfly was especially skittish.

Related Resources: Digital Dragonflies, presenting high-resolution digital scans of living dragonflies.

  • Genus Dromogomphus | Dromogomphus spinosus | Black-shouldered Spinyleg | male | top view
  • Genus Dromogomphus | Dromogomphus spinosus | Black-shouldered Spinyleg | male | side view

Copyright © 2016 Walter Sanford. All rights reserved.

Making new friends

July 10, 2016

Swift Setwing dragonfly (Dythemis velox) was discovered recently at Mulligan Pond, Jackson Miles Abbott Wetland Refuge (JMAWR) — the first official record of Swift Setwing in Fairfax County, Virginia USA.

This is the most widespread of the North American setwings and it is apparently continuing to expand its range. Source Credit: Swift Setwing, Odonata Central Field Guide, Dragonfly Society of the Americas.

The following photographs were taken two days later at the same location.

Male 1

A Swift Setwing dragonfly (Dythemis velox) spotted at Mulligan Pond, Jackson Miles Abbott Wetland Refuge, Fairfax County, Virginia USA. This individual is a male.

26 JUN 2016 | JMAWR | Swift Setwing (male)

A Swift Setwing dragonfly (Dythemis velox) spotted at Mulligan Pond, Jackson Miles Abbott Wetland Refuge, Fairfax County, Virginia USA. This individual is a male.

26 JUN 2016 | JMAWR | Swift Setwing (male)

Male 2

A Swift Setwing dragonfly (Dythemis velox) spotted at Mulligan Pond, Jackson Miles Abbott Wetland Refuge, Fairfax County, Virginia USA. This individual is a male.

26 JUN 2016 | JMAWR | Swift Setwing (male)

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

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”).

Female

The last individual is a female, as indicated by her terminal appendages. Female dragonflies have a pair of cerci (superior appendages) that have little or no function.

A Swift Setwing dragonfly (Dythemis velox) spotted at Mulligan Pond, Jackson Miles Abbott Wetland Refuge, Fairfax County, Virginia USA. This individual is a female with a malformed wing.

26 JUN 2016 | JMAWR | Swift Setwing (female)

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

Notice the female has two malformed wings.

A Swift Setwing dragonfly (Dythemis velox) spotted at Mulligan Pond, Jackson Miles Abbott Wetland Refuge, Fairfax County, Virginia USA. This individual is a female with a malformed wings.

26 JUN 2016 | JMAWR | Swift Setwing (female)

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

Copyright © 2016 Walter Sanford. All rights reserved.

Unicorn Clubtail dragonflies (males)

June 10, 2016

During a recent photowalk at Huntley Meadows Park, I was reminded that Unicorn Clubtail (Arigomphus villosipes) is one of my favorite species of dragonflies. C’mon, just look at the color of those eyes — you gotta love that!

I was also reminded Unicorn Clubtails are very skittish. Apparently I’m not the only odonate-hunter who noticed.

It commonly rests on wet pond edges, rock and logs, where it can be extremely difficult to approach. Source Credit: Unicorn Clubtail, Odonata Central.

In my experience, you see more Unicorns by letting them come to you rather than by actively looking for them. Find the right habitat for Unicorn Clubtails, sit down and let the game come to you (to use a sports metaphor). Patience is the key. I shot 16 photos during a two-hour period — far fewer shots than a typical photowalk, but hey, it was a beautiful day to sit under a shade tree and wait for one of my favorite dragonflies to appear!

A Unicorn Clubtail dragonfly (Arigomphus villosipes) spotted at Huntley Meadows Park, Fairfax County, Virginia USA. This individual is a male.

09 JUN 2016 | Huntley Meadows Park | Unicorn Clubtail (male)

The preceding Unicorn Clubtail appears to have a slightly malformed wing and abdomen. Both individuals are males, as indicated by their unique terminal appendages: the epiproct is a large “plate” that spans both cerci.

A Unicorn Clubtail dragonfly (Arigomphus villosipes) spotted at Huntley Meadows Park, Fairfax County, Virginia USA. This individual is a male.

09 JUN 2016 | Huntley Meadows Park | Unicorn Clubtail (male)

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

Related Resource: Kevin Munroe, former manager at Huntley Meadows Park, provides good guidance regarding the right habitat for Unicorn Clubtails at his excellent Web site, Dragonflies of Northern Virginia.

Copyright © 2016 Walter Sanford. All rights reserved.

Previews of coming attractions

June 4, 2016

Two Blue-faced Meadowhawk dragonflies (Sympetrum ambiguum) were spotted at Huntley Meadows Park (HMP). Both individuals are teneral females, as indicated by their coloration and terminal appendages.

No. 1

A Blue-faced Meadowhawk dragonfly (Sympetrum ambiguum) spotted at Huntley Meadows Park, Fairfax County, Virginia USA. This individual is a teneral female.

31 MAY 2016 | HMP | Blue-faced Meadowhawk (teneral female)

No. 2

Although Female No. 2 has a malformed hind wing she was able to fly, albeit weakly.

A Blue-faced Meadowhawk dragonfly (Sympetrum ambiguum) spotted at Huntley Meadows Park, Fairfax County, Virginia USA. This individual is a teneral female with a malformed wing.

31 MAY 2016 | HMP | Blue-faced Meadowhawk (teneral female)

A Blue-faced Meadowhawk dragonfly (Sympetrum ambiguum) spotted at Huntley Meadows Park, Fairfax County, Virginia USA. This individual is a teneral female with a malformed wing.

31 MAY 2016 | HMP | Blue-faced Meadowhawk (teneral female)

Now you see ’em; now you don’t.

Blue-faced Meadowhawk dragonflies are classified as a fall species of odonate. In the mid-Atlantic United States, meadowhawks seem to disappear for several months after they emerge during early summer and reappear during fall. Where do they go? No one knows for sure. I speculate Blue-faced Meadowhawks are an arboreal species of dragonfly that returns to the ground/water when it’s time to mate.

Related Resources:

Copyright © 2016 Walter Sanford. All rights reserved.

Great Spreadwing damselfly claspers (male)

November 1, 2015

All male damselflies have four terminal appendages, collectively called “claspers,” that are used to grab and hold female damselflies during mating: an upper pair of cerci (“superior appendages”); and a lower pair of paraprocts (“inferior appendages”).

All four claspers can be seen in some species of Broad-winged damselflies (Family Calopterygidae) such as Ebony Jewelwing (Calopteryx maculata), and in some species of Spreadwing damselflies  (Family Lestidae) such as Slender Spreadwing (Lestes rectangularis), Southern Spreadwing (Lestes australis), and Sweetflag Spreadwing (Lestes forcipatus).

In contrast, most photos of male Great Spreadwing damselflies (Archilestes grandis) only show the cerci; the paraprocts look like two small nubs that are out of sight, tucked underneath the cerci. The following photo of a male Great Spreadwing, spotted at Huntley Meadows Park (HMP), provides an uncommon peek at the paraprocts from the damselfly’s dorsal side (see photo inset).

A Great Spreadwing damselfly (Archilestes grandis) spotted at Huntley Meadows Park, Fairfax County, Virginia USA. This individual is a male, nicknamed "Bendy Straw."

11 OCT 2015 | HMP | Great Spreadwing (male, nicknamed “Bendy Straw”)

(See full-size versions of the annotated image, as well as the original photo, without annotation.)

I nicknamed this male Great Spreadwing “Bendy Straw” because of his slightly malformed abdomen.

cropped

Graphic image courtesy Mark Jette, created using Adobe Illustrator.

Remember, all male dragonflies have three terminal appendages: an upper pair of cerci (“superior appendages”) and a lower unpaired epiproct (“inferior appendage”).

The last photo provides another peek at the paraprocts from the damselfly’s dorsal side (see photo inset).

A Great Spreadwing damselfly (Archilestes grandis) spotted at Huntley Meadows Park, Fairfax County, Virginia USA. This individual is a male.

21 OCT 2015 | HMP | Great Spreadwing (male)

(See full-size versions of the annotated image, as well as the original photo, without annotation.)

Related Resource: Odonate Terminal Appendages

Copyright © 2015 Walter Sanford. All rights reserved.

“Mr. Magoo” and “Bendy Straw”

October 24, 2015

Some male Great Spreadwing damselflies (Archilestes grandis) have recognizable physical characteristics that distinguish them from other individuals of the same species and give them personality.

Regular readers of my photoblog may recall reading about “Crinkle-cut,” a very aggressive male with distinctive damage to all four of his wingtips, that I followed at Huntley Meadows Park (HMP) during Fall 2014.

This year, I met two new characters at the park: “Mr. Magoo“; and “Bendy Straw,” one of Magoo’s rivals.

Mr. Magoo

The nickname “Mr. Magoo” seems perfect for this male because of the prominent dark spots in his eyes. The eye spots are always in the same place, regardless of viewpoint, therefore it is technically incorrect to refer to them as “pseudopupils.”

A Great Spreadwing damselfly (Archilestes grandis) spotted at Huntley Meadows Park, Fairfax County, Virginia USA. This individual is a male.

08 OCT 2015 | HMP | Great Spreadwing (male, nicknamed “Mr. Magoo”)

A Great Spreadwing damselfly (Archilestes grandis) spotted at Huntley Meadows Park, Fairfax County, Virginia USA. This individual is a male, nicknamed

15 OCT 2015 | HMP | Great Spreadwing (male, nicknamed “Mr. Magoo”)

I spotted “Mr. Magoo” for the first time on 08 October 2015; I have seen him again on the 15th and 21st.

A Great Spreadwing damselfly (Archilestes grandis) spotted at Huntley Meadows Park, Fairfax County, Virginia USA. This individual is a male, nicknamed

15 OCT 2015 | HMP | Great Spreadwing (male, nicknamed “Mr. Magoo”)

Bendy Straw

The nickname “Bendy Straw” seems perfect for the following male because of his slightly malformed abdomen.

A Great Spreadwing damselfly (Archilestes grandis) spotted at Huntley Meadows Park, Fairfax County, Virginia USA. This individual is a male, nicknamed

11 OCT 2015 | HMP | Great Spreadwing (male, nicknamed “Bendy Straw”)

Notice the bend in his abdomen at the boundary between segments seven and eight (S7 and S8). Remember that all dragonflies and damselflies have a 10-segmented abdomen, numbered from front to back.

A Great Spreadwing damselfly (Archilestes grandis) spotted at Huntley Meadows Park, Fairfax County, Virginia USA. This individual is a male, nicknamed

11 OCT 2015 | HMP | Great Spreadwing (male, nicknamed “Bendy Straw”)

I met “Bendy Straw” on 11 October 2015; I haven’t seen “Bendy” again, although Mike Powell photographed him on 16 October.

Editor’s Note: Stay tuned for more photo sets of “Mr. Magoo” and “Bendy Straw,” to be published separately in several upcoming blog posts.

Copyright © 2015 Walter Sanford. All rights reserved.


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