Posts Tagged ‘female’

Blue-fronted Dancer (male, female)

August 18, 2017

Many Blue-fronted Dancer damselflies (Argia apicalis) were spotted along Bull Run, Hemlock Overlook Regional Park, Fairfax County, Virginia USA.

Male

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

21 JUN 2017 | Fairfax County, VA | Blue-fronted Dancer (male)

There is a blue morph female Blue-fronted Dancer, therefore the male’s blue coloration is insufficient to identify its gender.

21 JUN 2017 | Fairfax County, VA | Blue-fronted Dancer (male)

Female

Female Blue-fronted Dancers are polymorphic, including a blue andromorph and a brown heteromorph, shown below. Thanks to Ken Larsen, member of the Virginia Odonata Facebook group, for help in identifying this individual.

21 JUN 2017 | Fairfax County, VA | Blue-fronted Dancer (heteromorph female)

Related Resources:

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.

Adding an extension tube

August 2, 2017

Optics theory

The net effect of adding an extension tube between a lens and camera body is the “working distance” is decreased, that is, the distance from the front of the lens barrel to the subject is decreased. A smaller working distance means the same lens will focus closer to the subject, thereby increasing magnification.

The effect is greater at shorter focal lengths, as shown by the following table of magnification for the two extension tubes sold by Fujifilm USA.

Table courtesy Fujifilm USA.

Theory into practice

An Eastern Ringtail dragonfly (Erpetogomphus designatus) was spotted along the Potomac River at Riverbend Park, Fairfax County, Virginia USA. This individual is a female, as indicated by her terminal appendages and rounded hind wings.

Both photos in this set were taken using my Fujifilm X-T1 digital camera, Fujinon XF55-200mm zoom lens plus a “Fotasy” brand 16mm extension tube, and Fujifilm EF-X500 shoe mount flash. The lens was set for a focal length of 200mm (~350mm, 35mm equivalent).

At 200mm, the working distance of the lens is 905 mm (90.5 cm, ~35.63 in), or approximately three (3) feet. With a 16mm extension tube mounted between the lens and camera body, the working distance is reduced to 595 mm (59.5 cm, ~23.43 in), or approximately two (2) feet. At a focal length of 55mm, adding the extension tube would result in photos that look more like “macro” photos; at 200mm, adding the extension tube resulted in photos that look like a lens with a longer focal length was used to take the shots.

The first photo is uncropped. I’ve never been able to get a shot like this using a mid-range telephoto zoom lens such as the Fujinon 55-200mm. The 16mm extension tube is the difference-maker.

The last photo is cropped slightly, but not enough to affect the apparent magnification. I look closely at the edges of my photos. In this case, I cropped the photo to remove some distracting elements and leading lines.

Editor’s Notes

I bought a set of two “Fotasy” brand extension tubes (10mm, 16mm) years before Fujifilm released their set of two. The advantage of the Fotasy extension tubes is a set of two costs a little more than half as much as a single Fujifilm extension tube. The disadvantage is compatibility. The Fotasy extension tubes work with my Fujinon XF18-55mm (27-82.5mm, 35mm equivalent) “kit” lens and Fujinon XF55-200mm mid-range telephoto zoom lens; they don’t work with my Fujinon XF100-400mm (152-609mm, 35mm equivalent) telephoto zoom lens. For what it’s worth, the 100-400mm lens was released after the Fotasy extension tubes. Bottom line: I recommend Fujifilm extension tubes, despite the fact that they are significantly more expensive than Fotasy extension tubes.

The Depth of Field is razor thin, in contrast with shooting without an extension tube. I shot the preceding photos at f/11; f/16 or smaller would have been better.

In order to reduce “camera shake,” I almost always shoot in shutter priority mode using the reciprocal rule. Remember, it’s the 35mm equivalent that matters: since my lens is ~350mm, the shutter speed should be set for at least 1/350s; in this case, it was set for 1/1,000s. A monopod was used for added stability.

Copyright © 2017 Walter Sanford. All rights reserved.

Summertime is skimmer time

July 31, 2017

Refer to the Dragonflies of Northern Virginia Calendar of Flight Periods by Kevin Munroe, former manager at Huntley Meadows Park. Notice the flight period for most Skimmers (Family Libellulidae) is centered on June, July, and August. Since meteorological summer is defined as June, July, and August, summertime is skimmer time.

A female Slaty Skimmer dragonfly (Libellula incesta) was spotted during a photowalk at Occoquan Bay National Wildlife Refuge, Prince William County, Virginia USA, as indicated by her mostly black femora, brown face, and terminal appendages.

Female Slaty Skimmers have a pair of flanges beneath their eighth abdominal segment (S8) that are used to scoop water when laying eggs (oviposition), hence the family name “Skimmer.”

Female Slaty Skimmer dragonflies and female Great Blue Skimmer dragonflies (Libellula vibrans) look similar. The following blog post provides guidance regarding key field markers that can be used to differentiate the two species: Great Blue Skimmer dragonfly (young female).

Copyright © 2017 Walter Sanford. All rights reserved.

American Rubyspot damselfly (female)

July 27, 2017

An American Rubyspot damselfly (Hetaerina americana) was spotted during a photowalk along Bull Run in Fairfax County, Virginia USA. As far as I know, this is the first official record for American Rubyspot at this location.

This individual is a female, as indicated by her terminal appendages and ovipositor.

21 JUN 2017 | Fairfax County, VA | American Rubyspot (female)

Notice one of the damselfly’s wings is either malformed or injured. She was able to fly, although it seemed to be a struggle.

The Backstory

The damselfly landed on my thigh a few minutes before the preceding photograph was taken. It was like she was pleading with me to help her, although I admit I tend to project my thoughts onto the odonates I photograph. I would have tried to unfold her wing, but I never had an opportunity. Two teenage girls and a bear-sized dog startled me! (I never heard/saw them approaching. The girls told me their dog is a Long Hair German Shepherd.) When I flinched the damselfly flew to the perch shown above, just beyond my reach.

Copyright © 2017 Walter Sanford. All rights reserved.

Eastern Ringtail dragonfly (female)

July 21, 2017

An Eastern Ringtail dragonfly (Erpetogomphus designatus) was spotted along the Potomac River at Riverbend Park, Fairfax County, Virginia USA. This individual is a female, as indicated by her terminal appendages and rounded hind wings.

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

I saw tens of male Eastern Ringtail, but only one female.

The preceding photograph is my favorite in the set. I like the way the neutral colors in the pavement complement the coloration of the female.

Copyright © 2017 Walter Sanford. All rights reserved.

Black-shouldered Spinyleg (female)

July 9, 2017

Black-shouldered Spinyleg dragonfly (Dromogomphus spinosus) was spotted recently along a rocky stream in Fairfax County, Virginia USA. This individual is a female, as indicated by her terminal appendages and rounded hind wings.

26 JUN 2017 | Fairfax County, VA | Black-shouldered Spinyleg (female)

Notice the spider in front of the dragonfly. Also notice the female is missing part of her left front leg.

26 JUN 2017 | Fairfax County, VA | Black-shouldered Spinyleg (female)

I followed the female to several perches — she was a very cooperative model, unlike the males I photographed later the same day!

26 JUN 2017 | Fairfax County, VA | Black-shouldered Spinyleg (female)

26 JUN 2017 | Fairfax County, VA | Black-shouldered Spinyleg (female)

26 JUN 2017 | Fairfax County, VA | Black-shouldered Spinyleg (female)

26 JUN 2017 | Fairfax County, VA | Black-shouldered Spinyleg (female)

26 JUN 2017 | Fairfax County, VA | Black-shouldered Spinyleg (female)

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.

Another record shot

June 23, 2017

A Black-shouldered Spinyleg dragonfly (Dromogomphus spinosus) was spotted by Mike Boatwright during a photowalk at Columbia Boat Landing, Cumberland County, Virginia USA. This individual is a female, as indicated by her terminal appendages and rounded hind wings.

This photo is a “record shot” of another species of dragonfly spotted during a road trip with Mike to two locations along the James River in central Virginia. Not my best work, but hey, the photo provides documentation of the first Black-shoulder Spinyleg I’ve seen this year. With any luck, it won’t be the last.

Tech Tips

The photo was taken using a Fujifilm X-T1 digital camera, Fujinon 55-200mm zoom lens, and Fujifilm EF-X500 shoe mount flash.

Copyright © 2017 Walter Sanford. All rights reserved.text…


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