Posts Tagged ‘Painted Turtle Pond’

Before and After

August 24, 2017

On Saturday, 25 January 2014, I had the honor of co-presenting a program called “Flying Dragons” with Kevin Munroe, former Park Manager, Huntley Meadows Park. Kevin invited me to talk about how to make the transition from a beginner- to intermediate/advanced-intermediate dragonfly hunter. I prepared a photoblog post related to my part of the program, called “Five steps to the next level of dragonfly spotting.” Step 1 is as follows.

Step 1. Be aware the same species of dragonfly may appear differently depending upon gender, age, and natural variation. Some species display sexual dimorphism; in contrast, both genders look virtually identical for some species. Finally, females of some species display polymorphism (also known as polychromatism).

Male Needham’s Skimmer dragonflies (Libellula needhami) look different depending upon age, as shown by the “Before” and “After” photos (below). Further, immature male Needham’s Skimmers look similar to immature/mature females of the same species. Although this might be confusing for a beginner dragonfly hunter, with patience and persistence everything falls into place relatively quickly.

Before

Male Needham’s Skimmers were photographed during photowalks at Painted Turtle Pond, Occoquan Bay National Wildlife Refuge, Prince William County, Virginia USA in late-June and again in late-July. Notice the dramatic difference in appearance of the same species of dragonfly.

After

Copyright © 2017 Walter Sanford. All rights reserved.

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Widow Skimmer dragonfly (female)

August 16, 2017

A Widow Skimmer dragonfly (Libellula luctuosa) was spotted during a photowalk at Occoquan Bay National Wildlife Refuge, Prince William County, Virginia USA. This individual is a female, as indicated by her terminal appendages.

Look for immature- and female dragonflies in fields near water, sometimes far from water. I found this female perching in a large field several hundred yards from Painted Turtle Pond.

As a wildlife photographer with a focus on insect photography, one of my mantras is: “Get a shot, any shot; refine the shot.” In other words, don’t miss the opportunity to document a spotting by trying to get a great shot first.

The preceding photo is the record shot. Next, I worked my way around the subject slowly; several shots later I was able to get a good shot of the dorsal side of the dragonfly.

Copyright © 2017 Walter Sanford. All rights reserved.

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.


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