Archive for the ‘education’ Category

Great Spreadwing (practice oviposition)

October 15, 2017

This gallery — named “practice oviposition” (egg-laying) — features a six-photo time series of a female Great Spreadwing damselfly (Archilestes grandis).

Female Great Spreadwing damselflies, like all female odonates, have two cerci (sing. cercus), superior appendages that have little or no function. Also notice two styli (sing. stylus), structures that serve as sensors (like “curb feelers“) in egg positioning during oviposition.

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

The female uses her styli to guide the ovipositor into position, as shown in the next two photos.

In this case, I saw no evidence that the ovipositor actually penetrated the tree twig. I think this was a practice run in preparation for the real thing, as the title of this blog post says.

Copyright © 2017 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.

You know it’s fall when…

October 5, 2017

mature adult Autumn Meadowhawk dragonflies (Sympetrum vicinum) are seemingly everywhere there is water. Several Autumn Meadowhawks were spotted recently near a vernal pool at a remote location in Huntley Meadows Park (HMP), Fairfax County, Virginia USA.

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

03 OCT 2017 | HMP | Autumn Meadowhawk (male)

The last individual is a female, as indicated by her terminal appendages, noticeably thicker abdomen, and coloration.

03 OCT 2017 | HMP | Autumn Meadowhawk (female)

Autumn Meadowhawk is 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 Autumn Meadowhawk is an arboreal species of dragonfly that returns to the ground/water when it’s time to mate.

Related Resource: More previews of coming attractions, a blog post by Walter Sanford.

Copyright © 2017 Walter Sanford. All rights reserved.

Mocha Emerald terminal appendages (female)

September 29, 2017

Mocha Emerald dragonfly (Somatochlora linearis) was spotted by Andrew Rapp in Henrico County, Virginia USA. This individual is a female.

Terminal appendages

All female dragonflies have a pair of cerci (superior appendages) that have little or no function. The hind wings of female Mocha Emerald dragonflies are rounded.

21 JUL 2017 | Henrico County, VA | Mocha Emerald (female)

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

21 JUL 2017 | Henrico County, VA | Mocha Emerald (female)

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

Notice the subgenital plate shown in the preceding photo.

subgenital plate: plate below S8 that holds bunches of eggs when enlarged; variable enough in shape to be of value in identification. Source Credit: Paulson, Dennis (2011-12-19). Dragonflies and Damselflies of the East (Princeton Field Guides) (Kindle Locations 11723-11724). Princeton University Press. Kindle Edition.

“S8” refers to abdominal segment eight. Remember that all dragonflies and damselflies have a 10-segmented abdomen, numbered from front to back.

Oviposition (egg-laying)

The following Apple iPhone 3GS “raw” video clip shows a female Mocha Emerald dragonfly laying eggs by the process of oviposition. The process typically lasts a few seconds to a few minutes. This individual was spotted on 16 July 2011 during a photowalk through the “Wildlife Sanctuary,” one of seven small parks in the community of Hollin Hills, Fairfax County, Virginia USA.

Mocha Emerald dragonfly (female, ovipositing) [Ver. 2] (0:23)

Related Resource: Mocha Emerald terminal appendages (male).

Editor’s Note: Sincere thanks to Andrew Rapp for permission to use his still photographs.

Copyright © 2017 Walter Sanford. All rights reserved.

Black Saddlebags (terminal appendages)

September 15, 2017

Male and female Black Saddlebags dragonflies (Tramea lacerata) are somewhat similar in appearance. Terminal appendages can be used to identify gender.

Female

A female Black Saddlebags was spotted along Deephole Point Road at Occoquan Bay National Wildlife Refuge, Prince William County, Virginia USA.

10 SEP 2017 | Occoquan Bay NWR | Black Saddlebags (female)

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

10 SEP 2017 | Occoquan Bay NWR | Black Saddlebags (female)

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

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”).

A male Black Saddlebags was spotted in the central wetland area at Huntley Meadows Park, Fairfax County, Virginia USA.

12 SEP 2014 | Huntley Meadows Park | Black Saddlebags (male)

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

Copyright © 2017 Walter Sanford. All rights reserved.

Springtime Darner (terminal appendages)

September 11, 2017

Male and female Springtime Darner dragonflies (Basiaeschna janata) are colored similarly sometimes. Terminal appendages can be used to identify gender.

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”).

A male Springtime Darner was spotted along a mid-size rocky stream located at Hemlock Overlook Regional Park (HORP), Fairfax County, Virginia USA.

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

Female

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

Female Springtime Darners are polymorphic: the spots on their abdomen are either blue (andromorphic) or green (heteromorphic); this female — spotted at a remote location in Huntley Meadows Park (HMP) — is a blue andromorph.

15 APR 2016 | HMP | Springtime Darner (female, blue andromorph)

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

Copyright © 2017 Walter Sanford. All rights reserved.

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.

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.

Russet-tipped Clubtail (terminal appendages)

August 14, 2017

Male Russet-tipped Clubtail dragonflies (Stylurus plagiatus) have a larger, more colorful club than females of the same species, their hind wings are “indented,” and their terminal appendages are shaped differently. Compare and contrast the appearance of males and females by looking at the following annotated images.

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”).

14 OCT 2016 | JMAWR | Russet-tipped Clubtail (male)

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

Notice the epiproct is a wide “plate” that spans both cerci, as shown in the full-size version of the preceding annotated image.

Female

All female dragonflies have a pair of cerci (superior appendages) that have little or no function. The hind wings of female clubtails are rounded.

21 AUG 2015 | Powhatan County, VA | Russet-tipped Clubtail (female)

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

The female Russet-tipped Clubtail dragonfly shown in the preceding image was spotted along the James River by my good friend Michael Boatwright, founder of the Virginia Odonata Facebook group. Sincere thanks to Mike for permission to use his photographs (background and inset).

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

  • Genus Stylurus | Stylurus plagiatus | Russet-tipped Clubtail | male | top view
  • Genus Stylurus | Stylurus plagiatus | Russet-tipped Clubtail | female | top view
  • Genus Stylurus | Stylurus plagiatus | Russet-tipped Clubtail | female | side view

Copyright © 2017 Walter Sanford. All rights reserved.

Banded Pennants (mating pair, in wheel)

August 8, 2017

“In wheel”

A mating pair of Banded Pennant dragonflies (Celithemis fasciata) was spotted at Mulligan Pond, Jackson Miles Abbott Wetland Refuge (JMAWR), Fairfax County, Virginia USA. This pair is “in wheel.”

02 AUG 2017 | JMAWR | Banded Pennants (mating pair, “in wheel“)

02 AUG 2017 | JMAWR | Banded Pennants (mating pair, “in wheel“)

“Insex”

In a recent blog post, I mentioned that I used to photowalk the boardwalk at Huntley Meadows Park frequently. In deference to the many women and children who visit the park, I coined the term “insex” (sounds like “insects” to the uninitiated) as a family-friendly way to alert my fellow odonate hunters/photowalkers that I heard/saw a mating pair of dragonflies.

More often than not, I hear the clatter of wings before I see a mating pair. When I hear that unique sound, “insex” is the code word I use to give people a heads-up to search for the noisy couple.

In this case, the male Banded Pennant made a silky-smooth, soundless hook-up with the female. I had been watching the female oviposit along the shoreline of the pond while a male was hover guarding her. The fact is, I’m not sure whether he was actually hover guarding or an interloper waiting for an opportunity to grab the female. Either way, I was able to shoot just two photos of the mating pair before they flew in wheel to the top of a nearby tree.

Copyright © 2017 Walter Sanford. All rights reserved.


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