Cobra Clubtail versus Midland Clubtail

Odonate exuviae from two species in Genus Gomphurus — Cobra Clubtail (Gomphurus vastus) and Midland Clubtail (Gomphurus fraternus) — are nearly perfect body doubles, with the exception of one key field mark that can be used to differentiate the species.

Dorsal views

27 MAY 2017 | Riverbend Park | Cobra Clubtail exuvia (dorsal)

Lateral spines are located on abdominal segments six through nine (S6-S9) for both species.

10 JUN 2019 | Barron County, WI | Midland Clubtail exuvia (dorsal)

Ventral views

27 MAY 2017 | Riverbend Park | Cobra Clubtail exuvia (ventral)

The overall shape of the prementum is similar for both species.

10 JUN 2019 | Barron County, WI | Midland Clubtail exuvia (ventral)

Prementum (ventral view)

The shape of the palpal lobes on the prementum is different for the two species, as shown in the following diagram on p. 15, Key to the species of genus Gomphurus, Identification Keys to Northeastern Anisoptera Larvae, compiled by Ken Soltesz.

Identification Keys to Northeastern Anisoptera Larvae

The following images are magnified approximately three and one-half times life size (~3.5x).

27 MAY 2017 | Riverbend Park | Gomphurus vastus (exuvia)

For both species, focus on the row of teeth along the right palpal lobe. Notice the strongly curved shape of the palpal lobe for Cobra Clubtail (shown above), in contrast with the gently arched shape of the palpal lobe for Midland Clubtail (shown below). Also notice the Cobra palpal lobe has fewer teeth than Midland.

10 JUN 2019 | Barron County, WI | Gomphurus fraternus (exuvia)

Adults

Adult Cobra Clubtail dragonflies are almost identical to Midland Clubtails too. Several field marks can be used to differentiate the two species. In my opinion, one field mark is the easiest to recognize where it really matters — in the field!

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

Notice there aren’t any mid-dorsal marks on abdominal segments eight and nine (S8-S9) for Cobra Clubtail (shown above). In contrast, there is a small yellow triangle on abdominal segment eight (S8) for Midland Clubtail (shown below). This is true for males and females of both species.

Photo used with permission from Freda van den Broek.

Copyright © 2020 Walter Sanford. All rights reserved.

Post update: Aeshna umbrosa exuvia

Male odonates have two sets of sex organs: primary genitalia located on abdominal segment nine (S9); and secondary genitalia located on abdominal segments two-to-three (S2-3).

Closer examination of some test shots of the following Shadow Darner dragonfly (Aeshna umbrosa) exuvia, photographed on 02 December 2018, showed both sets of vestigial genitalia are clearly visible on the ventral side of this specimen.

Shadow Darner (Aeshna umbrosa) | exuvia (lateral-ventral)

Aeshna umbrosa (mating pair)

All odonates (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). Male and female dragonflies form the mating wheel in order for their genitalia to connect during copulation.

A. umbrosa (in wheel). Photo used with permission from Patrick Boez.

Related Resource: Test shots: Aeshna umbrosa exuvia.

Copyright © 2020 Walter Sanford. All rights reserved.

Using Godox TT685F in Optical Slave mode

The Godox TT685F external flash can function as either a radio master or radio slave. True.

According to the B&H Photo Web page for the Godox TT685F, current as of 01 November 2019, the flash can function as either an optical master or optical slave as well. Partly false (as in false advertising); partly true.

Optical master/slave transmission is available for working with other standard flashes. Source Credit: See “Godox TT685F Overview,” B&H Photo.

The Godox TT685F cannot function as an optical master; it can function as an optical slave, in Manual mode only.

How to set the Godox TT685F for Optical Slave mode

Set the flash for Manual mode, one of three “stand-alone” modes (TTL, M, MULTI). Press Function Button 3 <S1/S2> once so the flash is set for S1. This enables an optic sensor so the TT685 will fire synchronously when another flash fires.

Godox TT685F owner’s manual.

Take-aways

Now I can use both my Godox TT685F and Godox TT685O/P with several non-radio external flashes, including: Fujifilm EF-X8, EF-42, and EF-X500; Nissin i40; and Canon Speedlite 580EX, Canon Speedlite 580EX II, and Canon Macro Twin Lite MT-26EX-RT (set for optical mode). In short, the Godox TT685F (and TT685O/P) can be triggered by any other flash, set for any mode, as long as the “master” flash emits, well, a flash of light. In this case, “master” is a relative term that simply means a flash that is triggered directly by the camera.

Related Resource: Setting Up the Godox TT685 Flash, by alex silva photography (12:54). Fast forward to ~5:25. Sincere thanks to Alex for clearly explaining how to set the flash for optical slave mode. I struggled for months to figure out how it works — couldn’t understand the Godox instruction manual!

Copyright © 2019 Walter Sanford. All rights reserved.

Are adult Autumn Meadowhawks arboreal?

Autumn Meadowhawk (Sympetrum vicinum) 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 to mid-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.

Emergence

The first individual — photographed soon after emergence — is a/an teneral/immature male, as indicated by the tenuous appearance of his wings, coloration, and terminal appendages.

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

The next individual is a/an teneral/immature female, as indicated by the tenuous appearance of her wings, coloration, and terminal appendages.

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

Time to mate

Fall is the time to mate for mature adult Autumn Meadowhawk dragonflies (S. vicinum), as you can see in the following photo.

15 NOV 2013 | HMP | Autumn Meadowhawk (mating pair, “in wheel”)

This mating pair is “in wheel”: the male is on the upper-left; the female is on the lower-right. 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.

Forest Canopy Walk at Vermont Institute of Natural Science

Observing dragonflies at the Earth’s surface is fairly easy; observing dragonflies at the treetops, not so much. The new Forest Canopy Walk at the Vermont Institute of Natural Science (VINS) should facilitate the latter.

During 2020, I hope to collaborate with Kelly Stettner, Black River Action Team (BRAT), and Anna Morris, Lead Environmental Educator, VINS, to gather evidence that supports my speculation that adult meadowhawk dragonflies are arboreal. Field observations will be collected on the ground and along the Forest Canopy Walk.

Hosted by Anna Morris, Kelly Stettner and her family scouted the VINS site on 05 October 2019, including the new Forest Canopy Walk and nearby water bodies that provide suitable habitat for Autumn Meadowhawk. Special thanks to Anna for providing a behind the scenes tour a week before the official opening of the Forest Canopy Walk.

Gallery photos used with permission from Kelly Stettner, BRAT.

A week later, Autumn Meadowhawk was observed along the Forest Canopy Walk for the first time. The following photos provide circumstantial evidence that we might be on the right track. I love it when a plan comes together!

Gallery photos used with permission from Anna Morris, VINS.

I’m happy to share that during our public Forest Canopy Walk opening today [12 October 2019], I was stationed at the Eagle platform and got to see two (2) meadowhawks zooming around, then perched on the railing (pictures attached)! This is about 60 feet up, near a Sugar Maple and a Red Oak. [More meadowhawks were seen] the next day at nearly 90 feet up! At this height and as it was so sunny there were at least four individuals zooming around, landing on visitors, etc. Source Credit: Anna Morris, Lead Environmental Educator, VINS.

Related Resources

• Data mining for Autumn Meadowhawk, a follow-on blog post by Walter Sanford.
• Fall Foliage on the Forest Canopy Walk! by VINS YouTube (0:42)

Copyright © 2019 Walter Sanford. All rights reserved.

DMC-FZ150 versus DMC-FZ300

For years, my go-to camera kit for photowalking has been the Panasonic Lumix DMC-FZ150 superzoom digital camera and a Canon 580EX Speedlite. A formula of camera and flash settings that I call “set it and forget it” works most of the time, enabling me to focus on the subject rather than futzing around with camera/flash settings.

My new Panasonic Lumix DMC-FZ300 features some significant upgrades over the DMC-FZ150 such as a touch-screen LCD, built-in WiFi (enabling remote control of the camera using the “Panasonic Image App“), 49 focus points, 4K video, and an intriguing new feature that Panasonic calls “Post Focus.”

The two cameras are similar, but as I say often, similar is not the same. As appealing as the new features of the FZ300 are, the newer camera doesn’t perform like my older FZ150. After limited testing in both the studio and in the field, I have yet to find the new formula for “set it and forget it” using the FZ300. Disappointed and frustrated, I am!

Panasonic Lumix DMC-FZ150

A Springtime Darner dragonfly (Basiaeschna janata) was spotted along Popes Head Creek at Hemlock Overlook Regional Park, Fairfax County, Virginia USA. This individual is a male.

108mm (600mm, 35mm equivalent) | ISO 100 | f/5.2 | 1/800 s | -1 ev

Flash fired, in compulsory flash mode. My external flash unit is set for Manual mode at a power ratio of 1/16, plus or minus one stop. The other settings listed in the photo caption are typical of what I call “set it and forget it,” that is, these settings work for most subjects in most lighting conditions.

The preceding photo was included in my “Top 10 Photos of 2018.” Many, if not most, of the photos in this gallery were taken using the DMC-FZ150 and my “set it and forget it” formula.

Panasonic Lumix DMC-FZ300

A Brown Spiketail dragonfly (Cordulegaster bilineata) was spotted at Occoquan Regional Park, Fairfax County, Virginia USA. This individual is a male.

108mm (600mm, 35mm equivalent) | ISO 100 | f/2.8 | 1/800 s | 1 ev

Flash fired, in compulsory flash mode.

A Common Green Darner dragonfly (Anax junius) was spotted at the North Tract of Patuxent Research Refuge, Anne Arundel County, Maryland USA. This individual is a female.

108mm (600mm, 35mm equivalent) | ISO 100 | f/2.8 | 1/800 s | 0 ev

Flash fired, in compulsory flash mode.

A Harlequin Darner dragonfly (Gomphaeschna furcillata) was spotted at the North Tract of Patuxent Research Refuge, Anne Arundel County, Maryland USA. This individual is a female.

108mm (600mm, 35mm equivalent) | ISO 100 | f/2.8 | 1/800 s | 0 ev

Flash fired, in compulsory flash mode.

What are the take-aways?

I prefer shooting in Shutter Priority mode at relatively fast shutter speeds (using the reciprocal rule) in order to reduce camera shake at longer focal lengths. If the ISO is set for 100 then the exposure triangle tells us that the only variable is aperture (f/stop). Using my “set it and forget it” formula of settings, the FZ150 typically opts for an f/stop of f/5.6 or higher (that is, a smaller lens opening); for some reason the FZ300 always seems to opt for f/2.8.

Problem is, there is too little depth of field at f/2.8! The only way I’m able to shoot serviceable photos using the FZ300 is to compose photos so the entire subject is nearly parallel to the focal plane and to sharpen the images using Adobe Photoshop.

I’m planning to start shooting in Manual mode so that I can set the ISO, aperture, and shutter speed. During limited testing in the studio, it was necessary to use a higher flash power ratio in order to get good exposure. Otherwise, Manual mode is the ultimate in “set it and forget it!”

Related Resources

• Lessons learned: How to use a superzoom camera to shoot insect photos
• The exposure triangle and exposure compensation
• Depth of Field
• Have you ever wondered…? [focal plane, focal plane mark]

Copyright © 2019 Walter Sanford. All rights reserved.

Left on the cutting room floor

Close readers of my blog may have noticed I’ve posted a lot of photos recently that were taken years ago. Why were the photos passed over for publication closer to the time the shots were taken?

Sometimes there are better shots from the same photowalk that I’m eager to share, and sometimes they just don’t make the grade. The former requires no explanation; the following photos help to illustrate the latter.

The following female Slender Spreadwing damselfly (Lestes rectangularis) was spotted during a photowalk around a vernal pool in the forest at Huntley Meadows Park. The damselfly was perched in a hidey-hole in the vegetation at angle that made it impossible to get the entire subject in focus from head-to-tail.

The first photo shows the head and thorax in focus, but the tip of the abdomen and terminal appendages are out of focus.

15 SEP 2016 | HMP | Slender Spreadwing (female)

The last photo shows the tip of the abdomen and terminal appendages in focus, but the head and thorax are in soft focus. Look closely at a full-size version of the photo and you can see both styli (sing. stylus), structures that serve as sensors (like “curb feelers“) in egg positioning during oviposition.

15 SEP 2016 | HMP | Slender Spreadwing (female)

The odd thing is the focus point is nearly the same in both photos, and the aperture is identical. Go figure! Anyway, less than ideal focus is something that will cause me to reject photos every time. And then there’s that “too hot” blade of grass in the lower-right corner — talk about distracting!

Copyright © 2019 Walter Sanford. All rights reserved.

Great Blue Skimmer dragonfly (mature male)

A 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.

15 SEP 2016 | HMP | Great Blue Skimmer (mature male)

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!

Two Common Whitetail dragonflies (Plathemis lydia) were spotted perched 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.

Smeared Dagger Moth caterpillar

A Smeared Dagger Moth caterpillar (Acronicta oblinita), a type of stinging caterpillar, was spotted on 15 September 2016 during a photowalk along the boardwalk that goes through the central wetland area at Huntley Meadows Park (HMP).

Stinging caterpillars use poison-filled bristles to defend themselves from predators. If you touch a stinging caterpillar, you’ll know it by the burning, itching… Source Credit: 13 Stinging Caterpillars. [Smeared Dagger is No. 10.]

15 SEP 2016 | HMP | Smeared Dagger Moth caterpillar

Thanks to Mike Powell, fellow wildlife photographer and blogger, for identifying this unusual caterpillar way back when both of us were less experienced amateur naturalists.

Copyright © 2019 Walter Sanford. All rights reserved.

Blue-faced Meadowhawk dragonflies (males)

Two Blue-faced Meadowhawk dragonflies (Sympetrum ambiguum) were spotted at Old Colchester Park and Preserve (OCPP), Fairfax County, Virginia USA. There is a true vernal pool at the park where Blue-faced Meadowhawks are relatively abundant.

03 OCT 2016 | OCPP | Blue-faced Meadowhawk (male)

Both individuals are male, as indicated by their coloration and terminal appendages.

03 OCT 2016 | OCPP | Blue-faced Meadowhawk (male)

Copyright © 2019 Walter Sanford. All rights reserved.