Posts Tagged ‘terminal appendages’

Needham’s Skimmer (mature females)

September 25, 2017

In my experience, female Needham’s Skimmer dragonflies (Libellula needhami) seem to be more abundant than males toward the end of the adult flight period for that species.

Two Needham’s Skimmers were photographed during photowalks at Occoquan Bay National Wildlife Refuge, Prince William County, Virginia USA.

Both individuals are mature female, as indicated by their terminal appendages and muted coloration.

Copyright © 2017 Walter Sanford. All rights reserved.

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Up close and personal

September 23, 2017

A single Swift Setwing dragonfly (Dythemis velox) was spotted during a photowalk around Mulligan Pond at Jackson Miles Abbott Wetland Refuge (JMAWR), Fairfax County, Virginia USA. This individual is a male, as indicated by his terminal appendages.

18 SEP 2017 | JMAWR | Swift Setwing (male)

The preceding photograph is the “scene setter” for this gallery. I like to get as close as possible to the subject, and this guy was an extraordinarily cooperative model.

18 SEP 2017 | JMAWR | Swift Setwing (male)

18 SEP 2017 | JMAWR | Swift Setwing (male)

18 SEP 2017 | JMAWR | Swift Setwing (male)

18 SEP 2017 | JMAWR | Swift Setwing (male)

18 SEP 2017 | JMAWR | Swift Setwing (male)

Copyright © 2017 Walter Sanford. All rights reserved.

Fine-lined Emerald dragonfly redux (Part 1)

September 19, 2017

Several Fine-lined Emerald dragonflies (Somatochlora filosa) were spotted during a photowalk at Occoquan Bay National Wildlife Refuge, Prince William County, Virginia USA.

The same dragonfly was photographed while it perched in several shady places along one of the trails at the park. In my limited experience, Somatochlora filosa seems to prefer perching on bare tree branches or long stems of wild grass. Part 1 features two photo sets showing Fine-lined Emerald resting on other types of perches; Part 2 will feature two more photo sets showing the dragonfly perching on grasses.

This individual is a male, as indicated by his terminal appendages and prominent hamules.

Set 1

The first photograph is a strong contender for my Odonart Portfolio. I like the way the green vegatation complements the dragonfly’s emerald colored eyes. Can anyone identify the type of plant on which the dragonfly is perching?

Set 2

The second set of photos shows the dragonfly perching on a Common Milkweed (Asclepias syriaca) seed pod.

The next photo was taken a step-or-so closer…

This individual has a distinctive eye injury to the top of his left eye (facing forward).

And after a few side steps, I was able to take a good ventral-lateral shot.

Editor’s Note: Sincere thanks to several members of the Capital Naturalist Facebook group for identifying the species of milkweed plant shown in photo Set 2. “Capital Naturalist” is administered by Alonso Abugattas, Natural Resources Manager, Arlington County Parks, Virginia.

Related Resources

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.

Fine-lined Emerald dragonflies (males)

September 13, 2017

Three Fine-lined Emerald dragonflies (Somatochlora filosa) were spotted during a long photowalk at Occoquan Bay National Wildlife Refuge. All three individuals are males, as indicated by their terminal appendages and prominent hamules.

If I have seen further it is by standing on the shoulders of giants. Source Credit: Sir Isaac Newton.

Sincere thanks to Jim Waggener, Wildlife Survey Coordinator, as well as other members of Jim’s survey group for sharing information that enabled me to find this rare to uncommon species of dragonfly. The group has surveyed four sites in Northern Virginia regularly for many years, including Occoquan Bay National Wildlife Refuge.

No. 1

Fine-lined Emerald dragonflies seem to prefer perching on bare tree branches or long stems of wild grass, typically at chest- or head-height although not exclusively. For example, this guy was perched about waist-high on a cluster of fallen tree branches.

10 SEP 2017 | Occoquan Bay NWR | Fine-lined Emerald (male)

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

Fine-lined Emerald seems to prefer perching in sun rather than shade, unlike Mocha Emerald (Somatochlora linearis) — another species from the Family Corduliidae (Emeralds) found in Northern Virginia that prefers shady places.

The following ventral-lateral shot shows the lines on the thorax for which this species is named.

10 SEP 2017 | Occoquan Bay NWR | Fine-lined Emerald (male)

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

No. 2

The male shown in the next photo is perched on a long grass stem, about chest-high. He posed for two shots, patrolled back-and-forth a few times, and then disappeared.

10 SEP 2017 | Occoquan Bay NWR | Fine-lined Emerald (male)

No. 3

The last male was the most cooperative model. The first photo was taken at a distance of approximately six feet.

10 SEP 2017 | Occoquan Bay NWR | Fine-lined Emerald (male)

The next photo was taken a step-or-so closer…

10 SEP 2017 | Occoquan Bay NWR | Fine-lined Emerald (male)

And after a few side steps, I was able to take a good lateral shot.

10 SEP 2017 | Occoquan Bay NWR | Fine-lined Emerald (male)

The Backstory

This might be one of those stories in which the take-away is “persistence pays dividends.”

I made two trips to Occoquan Bay NWR during Fall 2016 when Fine-lined Emerald was my target species. On 21 September 2016, I spotted one or more dragonflies (species unknown) patrolling the treetops along one of the trails at OBNWR. I didn’t see any signs of Fine-lined Emerald on 25 October 2016, consistent with records for late-date maintained by Kevin Munroe (04 October for Northern Virginia) and Dr. Steven Roble (15 October for the Commonwealth of Virginia).

In retrospect, I realized I started searching too late in the year during 2016 so I started earlier in 2017. My first trip to OBNWR was on 30 August 2017; it turned out to be fruitless. I hit the jackpot on 10 September 2017! Fine-lined Emerald is a new species for my life list of dragonflies.

Rare to Uncommon

A distribution map of official records for Fine-lined Emerald helps to illustrate its classification as a rare to uncommon species of odonate.

Source Credit: Abbott, J.C. 2006-2017. OdonataCentral: An online resource for the distribution and identification of Odonata. Available at http://www.odonatacentral.org. (Accessed: September 14, 2017).

Key: blue dots = Dot Map Project; green dots = Accepted records; yellow dots = Pending records.

Related Resources

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.

Late-season Swift Setwing dragonflies

September 9, 2017

Several Swift Setwing dragonflies (Dythemis velox) were spotted during a photowalk around Mulligan Pond, Jackson Miles Abbott Wetland Refuge (JMAWR), Fairfax County, Virginia USA.

05 SEP 2017 | JMAWR | Swift Setwing (mature male)

Both individuals featured in this post are mature males, as indicated by their terminal appendages, discolored abdomen, and tattered wings.

05 SEP 2017 | JMAWR | Swift Setwing (mature male)

05 SEP 2017 | JMAWR | Swift Setwing (mature male)

Adult Flight Period for Swift Setwing

Late-season Swift Setwing dragonflies,” the title of this blog post, implies that the adult flight period for this species in Northern Virginia is well known. It isn’t.

The Dragonflies of Northern Virginia Calendar of Flight Periods by Kevin Munroe, former manager at Huntley Meadows Park, doesn’t include Swift Setwing because the species was unknown to occur in Northern Virginia before it was discovered on 24 June 2016 in Fairfax County by my good friend Michael Powell. One year later, we’re still gathering data for this newcomer to the region.

The adult flight period for Swift Setwing in the Commonwealth of Virginia is from 20 June to 02 October, according to records maintained by Steven M. Roble, Ph.D., Staff Zoologist, Virginia Department of Conservation and Recreation, Division of Natural Heritage.

September is in fact late-season for Swift Setwing, based upon state records — a fact underscored by qualitative observations of the appearance of males photographed in early August and early September at the same location.

Post Update

I just realized Mike Powell spotted the First Swift Setwing in 2017 on 19 June 2017 at Mulligan Pond — a new early date for this species in Virginia!

Copyright © 2017 Walter Sanford. All rights reserved.

Adios Mochacho!

September 1, 2017

Mocha Emerald dragonfly (Somatochlora linearis) was spotted along a small creek at a remote location in the forest at Huntley Meadows Park. This individual is a male, as indicated by his terminal appendages and hamules.

The Dragonflies of Northern Virginia Calendar of Flight Periods by Kevin Munroe, former manager at Huntley Meadows Park, shows the adult flight period for Mocha Emerald is from the second week in June through mid-September.

In my experience, July is prime time for Mocha Emerald in Fairfax County, Virginia USA. I spotted many Mochas during a visit to the same location during the second week in July. In contrast, the male featured in this post was the only Mocha Emerald spotted during an intense search along the stream. So it may be time to say “Adios Mocha-cho — see you next year!”

Copyright © 2017 Walter Sanford. All rights reserved.

Another mature female skimmer

August 30, 2017

As I mentioned in my last two blog posts (see Related Resources, below), most of the Skimmer dragonflies (Family Libellulidae) spotted during a recent photowalk at Huntley Meadows Park looked old and tattered.

24 AUG 2017 | HMP | Blue Dasher (mature female)

This individual is a mature female Blue Dasher dragonfly (Pachydiplax longipennis), as indicated by her terminal appendages, discolored abdomen, and tattered wings.

Related Resources

Copyright © 2017 Walter Sanford. All rights reserved.

Aging gracefully, revisited

August 28, 2017

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 female, as indicated by her terminal appendages, discolored abdomen, and tattered wings.

Female Great Blue Skimmers have a pair of flanges beneath their eighth abdominal segment that are used to scoop and hold a few drops of water when laying eggs (oviposition), hence the family name “Skimmer.” Remember that all dragonflies and damselflies have a 10-segmented abdomen, numbered from front to back.

Related Resources

Copyright © 2017 Walter Sanford. All rights reserved.


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