Posts Tagged ‘Painted Turtle Pond’

Unicorn Clubtail dragonflies (males)

July 5, 2017

Unicorn Clubtail dragonflies (Arigomphus villosipes) were spotted at several locations along the shoreline of Painted Turtle Pond, Occoquan Bay National Wildlife Refuge, Prince William County, Virginia USA.

20 JUN 2017 | OBNWR | Unicorn Clubtail (male)

All of these individuals are males, as indicated by their terminal appendages.

20 JUN 2017 | OBNWR | Unicorn Clubtail (male)

The title of the preceding photograph is “The Miracle Shot,” so named because I was able to take one and only one photo of this male before he flew away and the subject is actually in focus!

20 JUN 2017 | OBNWR | Unicorn Clubtail (male)

20 JUN 2017 | OBNWR | Unicorn Clubtail (male)

20 JUN 2017 | OBNWR | Unicorn Clubtail (male)

The last photo shows an especially clear view of the male’s terminal appendages. Zoom-in on the photo and you should notice that the epiproct (“inferior appendage”) for Cobra Clubtail is essentially a wide plate with two prongs.

20 JUN 2017 | OBNWR | Unicorn Clubtail (male)

Copyright © 2017 Walter Sanford. All rights reserved.

Needham’s Skimmer (immature males)

July 3, 2017

Lots of Needham’s Skimmer dragonflies (Libellula needhami) were spotted at Painted Turtle Pond, Occoquan Bay National Wildlife Refuge, Prince William County, Virginia USA.

This individual is an immature male, as indicated by its terminal appendages and yellow-ish coloration. Mature male Needham’s Skimmer dragonflies are red.

Copyright © 2017 Walter Sanford. All rights reserved.

Calico Pennant dragonfly (female)

July 1, 2017

Calico Pennant dragonfly (Celithemis elisa) was spotted during a photowalk at Painted Turtle Pond, Occoquan Bay National Wildlife Refuge, Prince William County, Virginia USA.

20 JUN 2017 | OBNWR | Calico Pennant (mature female)

This individual is a mature female, as evidenced by her terminal appendages and yellow coloration.

20 JUN 2017 | OBNWR | Calico Pennant (mature female)

In my opinion, the coloration of female Calico Pennants is more attractive than male Calicos.

20 JUN 2017 | OBNWR | Calico Pennant (mature female)

Copyright © 2017 Walter Sanford. All rights reserved.

Calico Pennant dragonflies (males)

June 29, 2017

Several Calico Pennant dragonflies (Celithemis elisa) were spotted during a photowalk at Painted Turtle Pond, Occoquan Bay National Wildlife Refuge, Prince William County, Virginia USA.

20 JUN 2017 | OBNWR | Calico Pennant (mature male)

These individuals are mature males, as evidenced by their terminal appendages and red coloration.

20 JUN 2017 | OBNWR | Calico Pennant (mature male)

The next photo is my favorite in this set…

20 JUN 2017 | OBNWR | Calico Pennant (mature male)

And the last photo is a close second-favorite.

20 JUN 2017 | OBNWR | Calico Pennant (mature male)

Copyright © 2017 Walter Sanford. All rights reserved.

Calico making the case for claspers

June 27, 2017

A Calico Pennant dragonfly (Celithemis elisa) was spotted at Painted Turtle Pond, Occoquan Bay National Wildlife Refuge (OBNWR), Prince William County, Virginia USA.

Mature adult female Calico Pennants are yellow; mature adult male Calico Pennants are red. So the following individual must be female, right? Wrong!

20 JUN 2017 | OBNWR | Calico Pennant (immature male)

This individual is an immature male, as indicated by his terminal appendages and yellow coloration.

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”).

20 JUN 2017 | OBNWR | Calico Pennant (immature male)

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

In contrast, female dragonflies have a pair of cerci (superior appendages) that have little or no function.

20 JUN 2017 | OBNWR | Calico Pennant (female)

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

Color can be a deceptive field marker. Immature males appear similar to immature females of the same species (and some mature females) for many types of dragonflies that display sexual dimorphism. This is true for many members of Family Libellulidae (Skimmers), such as Calico Pennant. Terminal appendages may be used to differentiate gender for many species of dragonflies.

20 JUN 2017 | OBNWR | Calico Pennant (immature male)

Related Resource: Odonate Terminal Appendages — single-topic field guides for dragonflies and damselflies featuring both text and annotated photos.

Copyright © 2017 Walter Sanford. All rights reserved.

Epitheca cynosura exuvia

April 26, 2017

On 13 April 2017, a late-stage emergent teneral female Common Baskettail dragonfly (Epitheca cynosura) was observed at Painted Turtle Pond during a photowalk around Occoquan Bay National Wildlife Refuge, Prince William County, Virginia USA.

Several dragonfly exuviae were collected near the same location as the emergent teneral female. All of the exuviae look identical, although there is some variation in size. A two-step process was used to verify the genus and species for one of the larger exuvia.

  • Determine the family.
  • Determine the genus and species.

This specimen is approximately 22 mm (~0.87 in) in length.

Step 1. Family

First, determine the family of the specimen. For reference, watch the excellent Vimeo video, Identifying dragonfly larva to family (8:06). Here’s the decision tree used to identify the exuvia as a member of the Family Corduliidae (Emeralds).

  • The specimen has a mask-like labium that covers the face, characteristic of four families: Cordulegastridae (Spiketails); Corduliidae (Emeralds); Libellulidae (Skimmers); and Macromiidae (Cruisers).
  • There is no horn on top of the face-head, characteristic of Macromiidae, so it’s not a cruiser.
  • Cordulegastridae has jagged crenulations on its labium, so it’s not a spiketail. The crenulations for Corduliidae and Libellulidae look similar.
  • Look at the anal pyramid to differentiate Corduliidae and Libellulidae [See Photo No. 7.]: It’s probably Corduliidae if the cerci are at least half as long as the paraprocts. [Editor’s Note: It’s probably Libellulidae if the cerci are less than half the length of the paraprocts.]

In summary, the exuvia has a mask-like labium with relatively smooth crenulations, no horn on its face-head, and the cerci are more than half as long as the paraprocts, confirming that the specimen is a member of Family Corduliidae (Emeralds).

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

Notice that dorsal hooks are present and well developed on most abdominal segments.

No. 4 | Common Baskettail (Epitheca cynosura) | exuvia (dorso-lateral)

A lateral view of the exuvia provides a good look at the labium, also known as the mentum, a two-segment hinged “jaw” that is used to grab food: the prementum is the segment of the labium closer to the mouth; the postmentum is the segment closer to the base of the head.

The white filaments that extend from the split in the thorax (as shown in Photo No. 1-7) are breathing tubes, artifacts of the unique respiratory system of dragonfly nymphs.

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

A closer view of the head shows two “bumps” that may be a pair of tubercles.

Step 2. Genus and species

Characters from Identification Keys to Northeastern Anisoptera Larvae, dichotomous keys compiled by Ken Soltesz, were used to identify the genus and species for the exuvia. Although palpal/mental setae were not examined, all other characters match Epitheca cynosura.

dichotomous key: a key for the identification of organisms based on a series of choices between alternative characters. Source Credit: Merriam-Webster Dictionary.

Alternate Key to the Genera of the Family Corduliidae, p. 29.

Key to the species of the genus (subgenus) Tetragoneuria, p. 32.

No. 7 | Common Baskettail (Epitheca cynosura) | exuvia (anal pyramid)

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

The last photo shows a ventral view of the exuvia. The vestigial hamuli located between abdominal segments two and three (S2-3) strongly suggests this individual is a male, therefore this specimen probably is not the same exuvia from which the teneral female emerged.

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

Tech Tips:

The following equipment was used to shoot all of the preceding photographs: Canon EOS 5D Mark II digital camera, in manual mode; Canon EF100mm f/2.8L Macro lens (set for manual focus) plus a Kenko 20mm macro automatic extension tube; Canon 580EX II external flash tethered to the camera by a coiled six-foot Vello Off-Camera TTL Flash Cord for Canon Cameras, off-camera, in manual mode; the Canon flash optically triggered a small Nissin i40 external flash (in SF mode) used for backlight; and a Sunpak LED-160 Video Light with a white translucent plastic filter used for side light.

Adobe Photoshop CC 2017 was used to annotate selected images.

Related Resources:

Editor’s Note: Sincere thanks to Sue Gregoire, Kestrel Haven Migration Observatory, for verifying my tentative identification, and for sharing some good odonate nymph knowledge regarding vestigial hamuli!

Copyright © 2017 Walter Sanford. All rights reserved.

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. The exuviae were identified using a dichotomous key for dragonfly larvae; they are cast skins from Common Baskettail.

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.

Common Baskettail dragonfly (male)

April 16, 2017

A Common Baskettail dragonfly (Epitheca cynosura) was spotted near Painted Turtle Pond during a photowalk at Occoquan Bay National Wildlife Refuge (OBNWR). Common Baskettail is a member of Family Corduliidae (Emeralds); this species is seen during early spring in mid-Atlantic United States like Virginia.

I thought this might be a Slender Baskettail dragonfly (Epitheca costalis) due to narrowing of its abdomen. Turns out that was wishful thinking.

13 APR 2017 | OBNWR | Common Baskettail (male)

This individual is a male, as indicated by his terminal appendages. The curved shape of the cerci (superior appendages) is a key field marker for Common Baskettail; in contrast, the cerci for Slender Baskettail tend to be more parallel. Thanks to Mike Boatwright and Paul Guris, members of the Northeast Odonata Facebook group, for reminding me of this pearl of wisdom!

I think baskettail cerci look “rubberized,” like the handles of metal tools made for working with electricity. Whenever I see this distinctive field marker, shown clearly in the following photos, I know the dragonfly is probably a species of baskettail.

13 APR 2017 | OBNWR | Common Baskettail (male)

The last photo shows a dorso-lateral view of the male dragonfly. Notice the epiproct (inferior appendage) is visible clearly in this photo.

13 APR 2017 | OBNWR | Common Baskettail (male)

Also notice the light-colored spots on the hairs covering the body of the dragonfly. The following article by John Abbott suggests the spots may be some type of pollen.

Related Resource: Identification of Male Epitheca (Tetragoneuria) in Texas, by John C. Abbott.

Copyright © 2017 Walter Sanford. All rights reserved.

Slaty Skimmer dragonflies (mating pair)

March 7, 2017

Odonates (dragonflies and damselflies) are aquatic insects that 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, depending upon the species. 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.

A mating pair of Slaty Skimmer dragonflies (Libellula incesta) was spotted at Painted Turtle Pond, Occoquan Bay National Wildlife Refuge (OBNWR), Prince William County, Virginia USA. This pair is “in wheel”: the male is on the upper-left; the female on the lower-right.

A mating pair of Slaty Skimmer dragonflies (Libellula incesta) spotted at Painted Turtle Pond, Occoquan Bay National Wildlife Refuge, Prince William County, Virginia USA. This pair is "in wheel."

18 JUN 2016 | OBNWR | Slaty Skimmer (mating pair, “in wheel“)

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.

More previews of coming attractions

November 5, 2016

Several Autumn Meadowhawk dragonflies (Sympetrum vicinum) were spotted during photowalks at two wildlife watching parks located in Northern Virginia (suburban Washington, D.C.). All specimens are teneral, as indicated by their coloration and the tenuous appearance of their wings.

Occoquan Bay National Wildlife Refuge

During mid-June 2016, a single Autumn Meadowhawk was spotted at Painted Turtle Pond, Occoquan Bay National Wildlife Refuge, Prince William County, Virginia USA. This individual is a teneral female, as indicated by its terminal appendages.

Female abdomens are slightly thicker than those of males and noticeably flared toward both the thorax and tip of the abdomen. The “subgenital plate,” located under the ninth abdominal segment (S9), is a large scoop-like structure used for laying eggs (exophytic oviposition).

An Autumn Meadowhawk dragonfly (Sympetrum vicinum) spotted at Painted Turtle Pond, Occoquan Bay National Wildlife Refuge, Prince William County, Virginia USA. This individual is a teneral female.

18 JUN 2016 | OBNWR | Autumn Meadowhawk (teneral female)

The dragonfly is perching on “soft rush” (Juncus effusus), the common name for the shoreline/emergent plant with a light green round stem and brownish flowers shown in the preceding photo. Soft rush is common in wetland areas. Thanks to Christopher Wicker and Bonne Clark, naturalists at OBNWR, for identifying the plant.

Huntley Meadows Park

About one week later, many teneral Autumn Meadowhawks were spotted at a vernal pool in Huntley Meadows Park, Fairfax County, Virginia USA.

The first individual is a teneral female, perching on soft rush.

An Autumn Meadowhawk dragonfly (Sympetrum vicinum) spotted at Huntley Meadows Park, Fairfax County, Virginia USA. This individual is a teneral female.

24 JUN 2016 | HMP | Autumn Meadowhawk (teneral female)

The next specimen is also a teneral female.

An Autumn Meadowhawk dragonfly (Sympetrum vicinum) spotted at Huntley Meadows Park, Fairfax County, Virginia USA. This individual is a teneral female.

24 JUN 2016 | HMP | Autumn Meadowhawk (teneral female)

The following individual is a teneral male, as indicated by his terminal appendages.

An Autumn Meadowhawk dragonfly (Sympetrum vicinum) spotted at Huntley Meadows Park, Fairfax County, Virginia USA. This individual is a teneral male.

24 JUN 2016 | HMP | Autumn Meadowhawk (teneral male)

The last specimen is another teneral male.

An Autumn Meadowhawk dragonfly (Sympetrum vicinum) spotted at Huntley Meadows Park, Fairfax County, Virginia USA. This individual is a teneral male.

24 JUN 2016 | HMP | Autumn Meadowhawk (teneral male)

Editor’s Notes: This post is a belated companion piece for Previews of coming attractions, published on 04 June 2016, that documented teneral Blue-faced Meadowhawk dragonflies (Sympetrum ambiguum) observed during late-May 2016. About two weeks later, the first teneral Autumn Meadowhawks were observed.

Both Blue-faced Meadowhawks and Autumn Meadowhawks are classified as fall species of odonates. 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 and Autumn Meadowhawks are arboreal species of dragonflies that return to the ground/water when it’s time to mate.

Related Resources:

Copyright © 2016 Walter Sanford. All rights reserved.


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