Archive for the ‘education’ Category

Uhler’s Sundragon (female)

April 19, 2019

A Uhler’s Sundragon (Helocordulia uhleri) was spotted during a photowalk along a mid-size stream at an undisclosed location in Northern Virginia USA.

This individual is a female, as indicated by her rounded hind wings and terminal appendages. All female dragonflies have a pair of cerci (superior appendages) that have little or no function. Both cerci are visible clearly in the full-size version of the following photo.

16 APR 2019 | Northern Virginia | Uhler’s Sundragon (female)

Notice the right hind wing is slightly malformed. It appears the wing failed to inflate completely during emergence. The malformation didn’t impair her ability to fly. Pollen (probably tree pollen) is especially noticeable on the darker parts of the body.

Just the facts, ma’am.

According to records for the Commonwealth of Virginia maintained by Dr. Steve Roble, Staff Zoologist at the Virginia Department of Conservation and Recreation, Division of Natural Heritage, the adult flight period for H. uhleri is 29 March to 27 June. The species is classified as common. Its habitat is “streams.”

Bear in mind, Dr. Roble’s records are for the entire state, therefore the adult flight period for H. uhleri seems to be longer than it is in reality. The adult flight period for a single site is probably no more than a month, and more likely around two-to-three weeks. For example, according to records for Northern Virginia maintained by Kevin Munroe, former manager of Huntley Meadows Park, the adult flight period for Uhler’s is 11 April to 05 May.

It’s also worth noting that the window of opportunity to see Uhler’s Sundragon closes rapidly after trees are in full leaf.

Is Uhler’s Sundragon common? I guess the answer to that question depends upon where you live. In Northern Virginia, Kevin Munroe classified H. uhleri as “rare.” In fact, I’m aware of only one location in Northern Virginia where Uhler’s Sundragon can be found with reasonable certainty.

Copyright © 2019 Walter Sanford. All rights reserved.

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Great Blue Skimmer dragonfly (mature male)

April 12, 2019

Great Blue Skimmer dragonfly (Libellula vibrans) was spotted near a vernal pool in the forest at Huntley Meadows Park (HMP), Fairfax County, Virginia USA. This individual is a mature male, as indicated by his terminal appendages, discolored abdomen, and tattered wings.

This male has mated many times, as indicated by the scratches on his abdomen.

Males that have mated often have marks on their abdomen where the female legs have scratched them. This is especially obvious in species in which males develop pruinosity, as the pruinosity on the mid-abdomen is scratched off, and the signs are visible at some distance. Source Credit: Paulson, Dennis (2011-12-19). Dragonflies and Damselflies of the East (Princeton Field Guides) (Kindle Locations 390-392). Princeton University Press. Kindle Edition.

Copyright © 2019 Walter Sanford. All rights reserved.

So close, yet so far!

April 10, 2019

Two Common Whitetail dragonflies (Plathemis lydia) were spotted perching on a wooden fence rail located near the terminus of the Hike-Bike Trail at Huntley Meadows Park (HMP), Fairfax County, Virginia USA.

The individual shown on the left is a mature female; the one on the right is a mature male.

15 SEP 2016 | HMP | Common Whitetail (mature female and male)

Sexing Common Whitetail dragonflies

For many of the common species of odonates found in Northern Virginia, I created a collection of annotated guides that illustrates how to differentiate gender by looking at terminal appendages. The difference in the pattern of wings spots for male and female Common Whitetails is sufficient to identify gender.

Life Cycle of Odonates

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.

I wonder how these two mature adults were able to be so close yet resist the compelling biological urge to hook up!

Copyright © 2019 Walter Sanford. All rights reserved.

Odonate calendars: VA Flight Dates

March 31, 2019

Google Calendar was used to synthesize “CHECKLIST OF THE DRAGONFLIES AND DAMSELFLIES OF VIRGINIA, April 2017 update” — Dr. Steve Roble’s excellent datasets for the Commonwealth of Virginia — into two calendars: Dragonflies (VA Flight Dates); and Damselflies (VA Flight Dates).

The Google Calendar default color palettes were used to color-code both calendars: Dragonflies is Graphite; and Damselflies is Birch. Individual events on each calendar are also color-coded by family.

Dragonflies

Here’s the way the dragonflies calendar looks using the Chrome Web browser on my Apple iMac desktop computer. Notice the Graphite colored vertical bar to the left of each event that indicates it belongs to the dragonflies calendar.

And here’s the way the dragonflies calendar looks using the free Google Calendar app on my Apple iPad mini 2.

Every event features the following information: common name; scientific name; early-date/late-date; abundance; and habitat.

New for 2019

An interactive version of both calendars is available online. The dragonflies calendar is shown below.

Regrettably, the color-coding is lost in the online, interactive version of both calendars. That is, unless you print the calendar.

Color-coding is also lost when the calendar is exported as an “.ics” file. That’s the bad news. The good news is the calendar can be edited after it is imported into Google Calendar and it’s easy to edit the entries to color-code them any way you like.

The colors of the rainbow (ROYGBIV) were used to color-code the seven families of dragonflies; the equivalent colors in the Google Calendar default color palette are shown in brackets.

  • R = Family Aeshnidae (Darners) [Tomato]
  • O = Family Cordulegastridae (Spiketails) [Tangerine]
  • G = Family Corduliidae (Emeralds) [Basil]
  • Y = Family Gomphidae (Clubtails) [Banana]
  • B = Family Libellulidae (Skimmers) [Peacock]
  • I = Family Macromiidae (Cruisers) [Blueberry]
  • V = Family Petaluridae (Petaltails) [Grape]

The colors for Emeralds and Clubtails were flip-flopped because it just makes sense the Emeralds should be color-coded green!

Damselflies

Here’s the way the damselflies calendar looks using the free Google Calendar app on my Apple iPad mini 2.

Like the dragonflies calendar, every event features the following information: common name; scientific name; early-date/late-date; abundance; and habitat.

“FSL” was used to color-code the three families of damselflies common to the mid-Atlantic states (USA); the equivalent colors in the Google Calendar default color palette are shown in brackets.

  • F – Family Calopterygidae (Broad-winged Damselflies) [Flamingo (formerly Tomato)]
  • S – Family Coenagrionidae (Narrow-winged Damselflies) [Sage (formerly Peacock)]
  • L – Family Lestidae (Spreadwings) [Lavendar (formerly Basil)]

For what it’s worth, all of the colors for the damselflies calendar are pastel shades.

New for 2019

An interactive version of the damselflies calendars is available online, as shown below.

Dragonflies and Damselflies

The damselflies calendar was updated for 2019 so that no colors are duplicated from the dragonflies calendar. This should help to eliminate confusion when both calendars are displayed at the same time, as shown below.

Lessons Learned

As I worked on the calendar, patterns began to emerge that I hadn’t noticed before. For example, it’s clear that the serious odonate hunter needs to hit the ground running as soon as early March. Remember that Dr. Roble’s dataset is for the entire state. You may not see a given species on its early-date, but it could be seen on that date and certainly can’t be seen if you don’t look!

Tech Tips

Download the “.ics” file from the Virginia Odonata Facebook group. Launch Google Calendar on a desktop computer. Create a new calendar by clicking on the three vertical dots to the right of “Add calendar” and selecting “Create new calendar”; give the calendar a name such as “Test Calendar” and click on the “Create calendar” button. (You can change the name later.) “Test Calendar” should appear in the list of calendars under “My calendars.”

Mouse-over the name “Test Calendar” and click on the vertical column of three dots, labeled “Options for Test Calendar” then select “Settings and sharing.” In the upper-left sidebar, click on “Import and export”; select the “.ics” file to import and select “Test Calendar” from the drop-down menu labeled “Add to calendar.” There are 143 events in the Dragonflies calendar; 56 events in the Damselflies calendar.

If you decide to color-code individual events like I did, click on an event then click on the pencil icon labeled “Edit event.” Select a color and click the “Save” button, then click the radio button for “All events.” Beware: You can right-click on an individual event and change its color but DON’T GO THERE! That results in an event that doesn’t occur annually using the new color you chose.

Related Resources

Kevin Munroe, former manager of Huntley Meadows Park, created an excellent calendar called Dragonflies of Northern Virginia – Flight Periods. This calendar is a valuable resource for hunting dragonflies in Northern Virginia. I think the value of Kevin Munroe’s calendar is enhanced by using it in combination with my visualization of Steve Roble’s dataset.

Dragonflies & Damselflies of Loudoun County features a flight calendar for dragonflies and damselflies.

Copyright © 2019 Walter Sanford. All rights reserved.

Powdered Dancer damselfly (female)

March 29, 2019

A Powdered Dancer damselfly (Argia moesta) was spotted during a photowalk along a small stream at Hemlock Overlook Regional Park, Fairfax County, Virginia USA.

This individual is a female, as indicated by her coloration. Female Powdered Dancers are polymorphic: this is the tan morph; there is also a blue morph that looks somewhat similar to males of the same species.

10 MAY 2017 | HORP | Powdered Dancer (female)

Also notice the female’s abdomen is thicker near the tip than the tip of a male’s abdomen, due to female egg-laying anatomy.

Credits

Sincere thanks to Michael Boatwright, founder and administrator of the Virginia Odonata Facebook group, for help in identifying this specimen. My tentative identification, recorded in field notes dated 10 May 2017, proved to be incorrect.

I’m comfortable identifying some members of two of the three families of damselflies that occur in the mid-Atlantic states (USA), including Family Calopterygidae (Broad-winged Damselflies) and Family Lestidae (Spreadwings). Most members of the Family Coenagrionidae (Narrow-winged Damselflies), not so much.

I remember clearly the time when I was learning to identify dragonflies. I was more than a little confused at first. With persistence, the puzzle pieces started to fall into place sooner than I expected. Same story when I started learning to identify odonate exuviae. Never happened with damselflies, for whatever reason.

Copyright © 2019 Walter Sanford. All rights reserved.

Blue-fronted Dancers (male, female)

March 22, 2019

Male

A Blue-fronted Dancer damselfly (Argia apicalis) was spotted near Mulligan Pond at Jackson Miles Abbott Wetland Refuge, Fairfax County, Virginia USA.

This individual is a male, as indicated by the pattern of blue coloration on his thorax and abdomen, plus the blue coloration on abdominal segments eight through 10 (S8-10).

25 SEP 2016 | Jackson Miles Abbott WR | Blue-fronted Dancer (male)

Female

Several Blue-fronted Dancers were spotted during a photowalk along Accotink Creek/Great Blue Heron Trail at Accotink Bay Wildlife Refuge (ABWR), Fairfax County, Virginia USA.

The first individual is a female, as indicated by two field marks.

Eyes brown, darker above; lack of blue in eyes in andromorph good distinction from male. Source Credit: Paulson, Dennis (2011-12-19). Dragonflies and Damselflies of the East (Princeton Field Guides) (Kindle Locations 3451-3452). Princeton University Press. Kindle Edition.

Female Blue-fronted Dancers are polymorphicandromorph females are blue like males; heteromorph females are brown-green. Andromorph females tend to be a lighter shade of blue than males of the same species.

This individual is a blue andromorph. Regardless of the color morph…

females never have blue on the last abdominal segments (S8-10). Source Credit: Michael Boatwright, founder and administrator of the Virginia Odonata Facebook group.

02 AUG 2016 | ABWR | Blue-fronted Dancer (female)

More males

Two male Blue-fronted Dancers were spotted at Accotink Bay Wildlife Refuge.

02 AUG 2016 | ABWR | Blue-fronted Dancer (male)

02 AUG 2016 | ABWR | Blue-fronted Dancer (male)

Copyright © 2019 Walter Sanford. All rights reserved.

More composite images: P. obscurus exuvia

February 6, 2019

The following focus-stacked composite images show dorsal- and ventral views of the exuvia from a Common Sanddragon (Progomphus obscuruslarva that was collected and reared by Bob Perkins.

Here are some personal observations after examining the specimen carefully.

The front- and middle legs block the mentum (prementum). This specimen is a good candidate for rehydrating the exuvia and reposing its legs.

Related Resource: Composite image: Progomphus obscurus exuvia.

Tech Tips

Six (6) photos were used to create the first focus stack; seven (7) photos were used for the second. A single focus point was positioned over select anatomical features, working from back-to-front; photos were taken at each point of interest.

The following equipment was used to shoot all of the photographs for the two focus-stacked composite images, shown above: Canon EOS 5D Mark II digital camera, in manual mode; Kenko 20mm macro automatic extension tubeCanon EF100mm f/2.8L Macro lens (set for manual focus); and Canon MT-26EX-RT Macro Twin Lite set for “Master” mode, and several external flashes set for “Slave” mode including Canon 580 EX- and Canon 580EX II Speedlites and a Godox TT685C Thinklite TTL Flash fitted with a Lastolite Ezybox Speed-Lite 2 flash modifier.

Adobe Photoshop CC 2017 was used to create the focus-stacked composite images, as well as spot-heal and sharpen the final output.

Copyright © 2019 Walter Sanford. All rights reserved.

Test shot: Cordulegaster sp. larva

February 1, 2019

Bob Perkins collected and reared a larva/nymph from the Family Cordulegastridae (Spiketails). The larva died before it metamorphosed into an adult.

Test shots of this beautifully preserved specimen (Cordulegaster sp.) were taken using a relatively small aperture of f/16 for greater depth of field. The following photo is a “one-off,” that is, not a composite image.

Cordulegaster sp. larva (preserved specimen) | face-head

Odonates are aquatic insects. They 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. 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.

Most larvae go through 10-13 stages of development known as “instars.” The author lacks sufficient experience to identify the instar of this specimen, although it appears to be one of the later stages.

Related Resources

Tech Tips

The following equipment was used to shoot the preceding photo: Canon EOS 5D Mark II digital camera, in manual mode; Canon MP-E 65mm Macro lens (set for 3x); and Canon MT-26EX-RT Macro Twin Lite set for “Master” mode, and several external flashes set for “Slave” mode including Canon 580 EX- and Canon 580EX II Speedlites and a Godox TT685C Thinklite TTL Flash fitted with a Lastolite Ezybox Speed-Lite 2 flash modifier. A Sunpak LED-160 Video Light was used to light the underside of the white plastic posing “stage.”

Auto power-off was disabled for the camera and all external flash units.

Adobe Photoshop CC 2017 was used to spot-heal and sharpen the final output.

Copyright © 2019 Walter Sanford. All rights reserved.

Recognition in 2018

December 31, 2018

Editor’s Note: Items are presented in reverse-chronological order, based upon the date of the event.

Argia article

Michael Boatwright and I coauthored an article that appeared in the December 2018 issue of Argia, the journal of the Dragonfly Society of the Americas.

Argia 30(4), 2018 (page one of three).

Related Resource: PDF version of the entire article, pp. 14-16.


Signage

Several of my dragonfly photographs are featured on new signage at Melvin L. Newman Wetlands Center, Clayton County, Georgia. The info-graphic, entitled “Mosquito Hawks,” was created by Danielle Bunch, Senior Conservationist for Clayton County Water Authority.

Image used with permission from Danielle Bunch.

Full-size versions of my photographs (featured on the signage) appear in several previous posts on my photoblog.


Next post: Top 10 Photos of 2018.

Copyright © 2018 Walter Sanford. All rights reserved.

Test shots: Stylogomphus albistylus exuvia

December 19, 2018

Bob Perkins collected and reared an Eastern Least Clubtail dragonfly (Stylogomphus albistylus) nymph. This blog post features two focus-stacked composite images of the exuvia from the odonate nymph.

Nine photos were used to create the first focus stack. This small specimen features several easy-to-recognize field marks including large, dish-shaped antennae, distinctive color bands on the legs, lateral spines on abdominal segments eight and nine (S8-9), and terminal appendages tipped with a lighter color.

12 photos were used to create the last focus stack. This individual might be a male, as indicated by what appear to be vestigial hamules on the ventral side of the specimen.

Tech Tips

The following equipment was used to shoot all of the photographs for the two focus-stacked composite images, shown above: Canon EOS 5D Mark II digital camera, in manual mode; Kenko 20mm macro automatic extension tubeCanon EF100mm f/2.8L Macro lens (set for manual focus); and Canon MT-26EX-RT Macro Twin Lite set for “Master” mode, and several external flashes set for “Slave” mode including Canon 580 EX- and Canon 580EX II Speedlites and a Godox TT685C Thinklite TTL Flash fitted with a Lastolite Ezybox Speed-Lite 2 flash modifier.

Adobe Photoshop CC 2017 was used to create the focus-stacked composite images, as well as spot-heal and sharpen the final output.

Copyright © 2018 Walter Sanford. All rights reserved.


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