Happy World Turtle Day!

May 23, 2016

The purpose of World Turtle Day, May 23, sponsored yearly since 2000 by American Tortoise Rescue, is to bring attention to, and increase knowledge of and respect for, turtles and tortoises, and encourage human action to help them survive and thrive. Source Credit: World Turtle Day, Wikipedia.

An Eastern Box Turtle (Terrapene carolina carolina) spotted at West Meadows Trails, Meadowood Recreation Area, Fairfax County, Virginia USA.

An Eastern Box Turtle (Terrapene carolina carolina) was spotted on 14 May 2016 at West Meadows Trails, Meadowood Recreation Area, Fairfax County, Virginia USA.

An Eastern Box Turtle (Terrapene carolina carolina) spotted at West Meadows Trails, Meadowood Recreation Area, Fairfax County, Virginia USA.

A turtle is a good metaphor for the wisdom of slowing the rapid pace of day-to-day existence in order to enjoy some of life’s simpler pleasures.

I visited this location hoping to find several species of uncommon odonates, but I wasn’t so driven that I couldn’t take a few minutes to photograph an animal that I see less frequently than one might expect.

An Eastern Box Turtle (Terrapene carolina carolina) spotted at West Meadows Trails, Meadowood Recreation Area, Fairfax County, Virginia USA.

Copyright © 2016 Walter Sanford. All rights reserved.

Cobra Clubtail dragonflies (females)

May 21, 2016

For those species of dragonflies that do not display sexual dimorphism, males and females are nearly identical in appearance except for their terminal appendages. For example, male and female Cobra Clubtail dragonflies (Gomphus vastus) are similar in appearance.

Two field markers can be used to identify female Cobra Clubtails, as shown in the following annotated images: 1) they have two terminal appendages (cerci) rather than three (males); and 2) their hind wings are rounded rather than “indented” (males).

A Cobra Clubtail dragonfly (Gomphus vastus) spotted at Riverbend Park, Fairfax County, Virginia USA. This individual is a female.

16 MAY 2016 | Riverbend Park | Cobra Clubtail (female)

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

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

A Cobra Clubtail dragonfly (Gomphus vastus) spotted at Riverbend Park, Fairfax County, Virginia USA. This individual is a female.

16 MAY 2016 | Riverbend Park | Cobra Clubtail (female)

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

Related Resource: Cobra Clubtail claspers [males], by Walter Sanford.

Copyright © 2016 Walter Sanford. All rights reserved.

Cobra Clubtail claspers

May 19, 2016

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”).

A Cobra Clubtail dragonfly (Gomphus vastus) was spotted at Riverbend Park, Fairfax County, Virginia USA. Two field markers indicate this individual is a male, as shown in the following annotated image: 1) it has three terminal appendages; and 2) its hind wings are slightly “indented.”

A Cobra Clubtail dragonfly (Gomphus vastus) spotted at Riverbend Park, Fairfax County, Virginia USA. This individual is a male.

16 MAY 2016 | Riverbend Park | Cobra Clubtail (male)

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

All male dragonflies have three terminal appendages, right? Look closely at the preceding annotated image. Notice there are four “prongs” at the posterior end of the abdomen. Cobra Clubtails feature a two-pronged epiproct. Just thought I should clarify any cognitive dissonance that may have been caused by looking at these images!

A Cobra Clubtail dragonfly (Gomphus vastus) spotted at Riverbend Park, Fairfax County, Virginia USA. This individual is a male.

16 MAY 2016 | Riverbend Park | Cobra Clubtail (male)

Notice the male’s abdomen is slightly more elevated in the preceding photo than in the annotated image.

Males perch on shore, or on rocks in rocky rivers, with abdomen elevated, then fly beats up and down. Source Credit: Paulson, Dennis (2011-12-19). Dragonflies and Damselflies of the East (Princeton Field Guides) (Kindle Locations 5952-5953). Princeton University Press. Kindle Edition.

Some species of dragonflies regulate their body temperature by perching in the “obelisk position”: the tip of the dragonfly’s abdomen is pointed toward the Sun, minimizing the surface area of the body exposed to direct heating by the Sun’s rays, thereby avoiding overheating. Given the orientation of Cobra Clubtail relative to the Sun, I’m guessing this type of perching behavior is probably intended to mark territory and attract mates.

Editor’s Note: Female Cobra Clubtail dragonfly terminal appendages will be featured in a follow-up post: Cobra Clubtail dragonflies (females).

Copyright © 2016 Walter Sanford. All rights reserved.

Common Baskettail dragonfly (male, in flight)

May 17, 2016

A Common Baskettail dragonfly (Epitheca cynosura) spotted at Enchanted Pond, Meadowood Recreation Area, Fairfax County, Virginia USA. This individual is a male, in flight.

Common Baskettail (Epitheca cynosura) was spotted on 14 May 2016 at Enchanted Pond, Meadowood Recreation Area, Fairfax County, Virginia USA. This individual is a male, as indicated by its terminal appendages. Notice the male’s bright blue-green eyes in the preceding photo. It’s easy to see why Common Baskettail is a member of the Emerald Family of dragonflies!

Enchanted Pond is relatively small. The shoreline seemed to be subdivided into imaginary segments of valuable real estate; each segment was patrolled by a single male Common Baskettail dragonfly. There were frequent aerial skirmishes when one male strayed into the territory of another. During nearly an hour of observation, I never saw one of the males land. Talk about stamina!

Copyright © 2016 Walter Sanford. All rights reserved.

Aeshnidae exuvia

May 15, 2016

An odonate exuvia was spotted on 14 August 2012 along the boardwalk in the central wetland area at Huntley Meadows Park. The specimen was broken into three pieces when I found it: head and thorax; wing pads; and abdomen.

This individual is a member of the Aeshnidae Family (Darners). Here’s the decision tree I used to tentatively identify the exuvia as a member of the Darner Family.

  • The specimen has a flat labium (not mask-like).
  • Antennae are thin and thread-like (not club-like, as in Gomphidae).

Photo Set 1

Notice the labium is flat and isn’t mask-like, that is, doesn’t cover the face of the larva/exuvia.

An odonate exuviae spotted at Huntley Meadows Park, Fairfax County, Virginia USA. This individual is probably a member of the Aeshnidae Family.

Head and thorax (lateral view).

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

Also notice the antennae are thin and thread-like, as shown in the following annotated image.

An odonate exuviae spotted at Huntley Meadows Park, Fairfax County, Virginia USA. This individual is probably a member of the Aeshnidae Family.

Head and thorax (dorsal side).

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

The shape of the mentum and prementum (especially the rounded palpal blades) indicates this specimen is a Common Green Darner dragonfly (Anax junius), one of the more common species of Aeshnidae found at Huntley Meadows Park.

An odonate exuviae spotted at Huntley Meadows Park, Fairfax County, Virginia USA. This individual is probably a member of the Aeshnidae Family.

Head and thorax (ventral side).

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

Photo Set 2

The next photo shows the wing pads as well as part of abdominal segment one (S1). All odonates have a 10-segmented abdomen. The anterior side is toward the bottom of the photo; posterior toward the top.

An odonate exuviae spotted at Huntley Meadows Park, Fairfax County, Virginia USA. This individual is probably a member of the Aeshnidae Family.

Wing pads (dorsal view).

Abdominal segments two through 10 (S2-10) are shown in the following photo.

An odonate exuviae spotted at Huntley Meadows Park, Fairfax County, Virginia USA. This individual is probably a member of the Aeshnidae Family.

Abdomen (dorsal view).

Lateral spines along abdominal segments seven, eight, and nine (S7-9) verifies the genus and species as Anax junius. Notice the faint feature on segment nine (S9), highlighted by a white circle. This is a “rudimentary ovipositor,” according to SueandJohn KestrelHaven, active members of the “Northeast Odonata” Facebook group. An ovipositor is used for egg-laying by all adult damselflies and some species of adult dragonflies: females have this feature; males do not.

An odonate exuviae spotted at Huntley Meadows Park, Fairfax County, Virginia USA. This individual is probably a member of the Aeshnidae Family.

Abdomen (ventral view).

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

Tech Tips:

The following equipment was used to shoot the preceding photographs:

Adobe Photoshop CC 2015 was used to annotate selected images.

The following photo reveals a behind the scenes look at my low-tech solution for staging specimen parts: a plastic toothpick (tan) from a Swiss Army knife held by a small plastic clothespin (green); both parts were held by an alligator clip (silver) mounted on a short, flexible arm.

An odonate exuviae spotted at Huntley Meadows Park, Fairfax County, Virginia USA. This individual is probably a member of the Aeshnidae Family.

All specimens were staged in front of the same opaque white plastic background. Hard to believe, huh? I own an 18% gray scale card; at some point, I should start using it to adjust the white balance in my macro photos!

Related Resources:

Copyright © 2016 Walter Sanford. All rights reserved.

Common Whitetail dragonfly (teneral female)

May 13, 2016

Common Whitetail dragonfly (Plathemis lydia) was spotted on 15 April 2016 at Huntley Meadows Park. This individual is a teneral female, as indicated by its terminal appendages (cerci) and the pale coloration of her wings.

A Common Whitetail dragonfly spotted at Huntley Meadows Park, Fairfax County, Virginia USA. This individual is a teneral female.

Miraculous metamorphosis, the last post in my photoblog, featured a three-hour time-series of still photos documenting the astounding transformation of a female Common Whitetail dragonfly from a larva to an adult. The teneral female dragonfly in this post emerged recently, probably sometime during the same day these photos were taken.

A Common Whitetail dragonfly spotted at Huntley Meadows Park, Fairfax County, Virginia USA. This individual is a teneral female.

A pattern of dark spots on all four wings, characteristic of female Common Whitetail dragonflies, will develop within a few days to a week-or-so after emergence.

Copyright © 2016 Walter Sanford. All rights reserved.

Miraculous metamorphosis

May 11, 2016

I was sitting on my Coleman camp stool on the earthen dam at Hidden Pond, Meadowood Recreation Area, hoping the sky would clear so I could see some odonates. The sky was almost completely overcast; as a result, I hadn’t seen any dragonflies or damselflies all morning.

My cell phone rang. Matt Ryan, a good friend and part-time naturalist at Huntley Meadows Park, called to tell me about a dragonfly larva he spotted that had just started to transform into an adult. I was conflicted for a few minutes: Meadowood Recreation Area is much farther from my home than Huntley Meadows Park so I was reluctant to leave empty-handed, so to speak, especially since several species of odonates can be seen at Meadowood that aren’t known to occur at Huntley. Fortunately I came to my senses and drove to Huntley as quickly as possible.

The following photo is the first image from a three-hour time-series documenting an emergent female Common Whitetail dragonfly (Plathemis lydia), located within a few feet from the boardwalk in the central wetland area at Huntley Meadows Park. The miraculous metamorphosis was well underway by the time I arrived at the spot. Elapsed time is expressed in hh:mm:ss format.

A Common Whitetail dragonfly spotted at Huntley Meadows Park, Fairfax County, Virginia USA. This individual is an emerging female.

07 MAY 2016 | 11:21 am EDT | Elapsed time: 00:00:00

The wings, folded like accordions, then begin to fill from the base with fluid transferred from the body and fairly soon reach full length. Source Credit: Paulson, Dennis (2011-12-19). Dragonflies and Damselflies of the East (Princeton Field Guides) (Kindle Locations 466-467). Princeton University Press. Kindle Edition.

A Common Whitetail dragonfly spotted at Huntley Meadows Park, Fairfax County, Virginia USA. This individual is an emerging female.

07 MAY 2016 | 11:32 am EDT | Elapsed time: ~00:11:00

A Common Whitetail dragonfly spotted at Huntley Meadows Park, Fairfax County, Virginia USA. This individual is an emerging female.

07 MAY 2016 | 12:20 pm EDT | Elapsed time: ~00:59:00

The fluid is then pumped back into the abdomen, and it expands. Source Credit: Paulson, Dennis (2011-12-19). Dragonflies and Damselflies of the East (Princeton Field Guides) (Kindle Locations 467-468). Princeton University Press. Kindle Edition.

Notice the wings are nearly clear in following photo, indicating the greenish-colored fluid that formerly filled the wings is almost gone. The abdomen is noticeably longer in this photo than in the first image in the time-series, taken at 11:21 EDT.

A Common Whitetail dragonfly spotted at Huntley Meadows Park, Fairfax County, Virginia USA. This individual is an emerging female.

07 MAY 2016 | 12:43 pm EDT | Elapsed time: ~01:22:00

At this point, a pair of terminal appendages (cerci) was clearly visible at the end of the abdomen, indicating this individual is a female.

Notice the wing spots are beginning to darken. A pattern of dark spots on all four wings, characteristic of female Common Whitetail dragonflies, will develop within a few days to a week-or-so after emergence.

A Common Whitetail dragonfly spotted at Huntley Meadows Park, Fairfax County, Virginia USA. This individual is an emerging female.

07 MAY 2016 | 01:23 pm EDT | Elapsed time: ~02:02:00

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 pair of wings on her right side snapped into the resting position approximately two hours and 18 minutes (~02:18:00) after I started this time-series of photos.

A Common Whitetail dragonfly spotted at Huntley Meadows Park, Fairfax County, Virginia USA. This individual is an emerging female.

07 MAY 2016 | 01:38:42 pm EDT | Elapsed time: 02:17:42

The pair of wings on her left side snapped into the resting position one minute and four seconds (00:01:04) later.

A Common Whitetail dragonfly spotted at Huntley Meadows Park, Fairfax County, Virginia USA. This individual is an emerging female.

07 MAY 2016 | 01:39:46 pm EDT | Elapsed time: 02:18:46

Her wings quivered slightly at ~02:24:00 pm and then she flew away.

A Common Whitetail dragonfly spotted at Huntley Meadows Park, Fairfax County, Virginia USA. This individual is an emerging female.

07 MAY 2016 | 02:24 pm EDT | Elapsed time: ~03:03:00

The last photo shows the cast skin from the emergent dragonfly, technically known as an exuvia (singular).

A cast skin from a Common Whitetail dragonfly spotted at Huntley Meadows Park, Fairfax County, Virginia USA. This is the exuvia of an emerging female.

07 MAY 2016 | 02:28 pm EDT | Elapsed time: ~03:07:00

Although I have seen two emerging dragonflies from a different family, albeit briefly, and seen several exuviae (plural) in situ, this was my first opportunity to observe the process carefully for several hours. Sincere thanks to Matt Ryan for kindly thinking of me!

Copyright © 2016 Walter Sanford. All rights reserved.

Another female Stream Cruiser?

May 9, 2016

It’s possible the female Stream Cruiser dragonfly (Didymops transversa) in this gallery — spotted on 20 April 2016 at Accotink Bay Wildlife Refuge — is the same individual featured in a photoblog post published on 23 April 2016.

A Stream Cruiser dragonfly (Didymops transversa) spotted at Accotink Bay Wildlife Refuge, Fairfax County, Virginia USA. This individual is a female.

This is the second photo set that I shot of female Stream Cruisers spotted along the same segment of Beaver Pond Loop Trail. Although the two female dragonflies were perching on opposite sides of the trail, this female could be the same one that I spooked a few minutes earlier when I moved too close for her comfort.

A Stream Cruiser dragonfly (Didymops transversa) spotted at Accotink Bay Wildlife Refuge, Fairfax County, Virginia USA. This individual is a female.

This individual is a female as indicated by the pair of white terminal appendages (cerci) at the end of her abdomen, clearly visible in the following photo.

A Stream Cruiser dragonfly (Didymops transversa) spotted at Accotink Bay Wildlife Refuge, Fairfax County, Virginia USA. This individual is a female.

Stream Cruiser dragonflies have extremely long legs, especially noticeable in the last photo. The abdomen of female Stream Cruisers is thicker than males of the same species, similar to many species of odonates.

A Stream Cruiser dragonfly (Didymops transversa) spotted at Accotink Bay Wildlife Refuge, Fairfax County, Virginia USA. This individual is a female.

Copyright © 2016 Walter Sanford. All rights reserved.

Forest Tent Caterpillar Moth

May 7, 2016

A Forest Tent Caterpillar Moth (Malacosoma disstria) spotted at Huntley Meadows Park, Fairfax County, Virginia USA.

Behold the subtle beauty of a Forest Tent Caterpillar Moth (Malacosoma disstria) caterpillar, spotted on 24 April 2016 in the forest at Huntley Meadows Park. As an adult moth, this species looks relatively plain.

Forest Tent Caterpillar Moth caterpillars look similar to Eastern Tent Caterpillar Moth (Malacosoma americana) caterpillars. As I’m fond of saying, similar is not the same: the “dorsum of each abdominal segment has distinct whitish keyhole or shoeprint-shaped marking” on Forest Tent Caterpillars; Eastern Tent Caterpillars are “distinguished by a solid cream/white line along the dorsum (middle of the back).”

Copyright © 2016 Walter Sanford. All rights reserved.

Spicebush Swallowtail butterfly

May 5, 2016

In my experience, Spicebush Swallowtail butterflies (Papilio troilus) tend to be hyperactive: they flit around randomly, almost non-stop; when they land it is usually only briefly.

A Spicebush Swallowtail butterfly (Papilio troilus) spotted at Huntley Meadows Park, Fairfax County, Virginia USA.

A Spicebush Swallowtail was spotted on 24 April 2016 in the forest at Huntley Meadows Park.

A Spicebush Swallowtail butterfly (Papilio troilus) spotted at Huntley Meadows Park, Fairfax County, Virginia USA.

This one seemed to be a little more sluggish than usual on a cool spring morning, giving me an opportunity to shoot some of the better photos I’ve taken of a Spicebush Swallowtail butterfly.

A Spicebush Swallowtail butterfly (Papilio troilus) spotted at Huntley Meadows Park, Fairfax County, Virginia USA.

Copyright © 2016 Walter Sanford. All rights reserved.


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