Archive for the ‘damselflies’ Category

Big Bluet damselfly (male)

September 25, 2020

A Big Bluet damselfly (Enallagma durum) was spotted during a photowalk with Michael Powell along Deephole Point Road at Occoquan Bay National Wildlife Refuge, Prince William County, Virginia USA.

This individual — one of hundreds, if not thousands we saw while hunting for a rare to uncommon species of dragonfly — is a male, as indicated by his blue and black coloration and terminal appendages.

15 SEP 2020 | OBNWR | Big Bluet (male)

Ideal habitat for Big Bluet is as follows.

Habitat Large sandy lakes and lower reaches of rivers, even extending into brackish estuaries. Source Credit: Paulson, Dennis (2011-12-19). Dragonflies and Damselflies of the East (Princeton Field Guides) (Kindle Locations 2156-2157). Princeton University Press. Kindle Edition.

Think large, tidal rivers and bays. I have observed E. durum at Dyke Marsh Wildlife Preserve, Accotink Bay Wildlife Refuge, and Occoquan Bay National Wildlife Refuge.

Related Resources: Excellent digital scans created by Gayle and Jeanelle Strickland. Click on the button labeled “Download file” in order to view/save a full-size version of the graphics.

Sidebar: Scientific Classification of Damselflies

The following concise explanation of the scientific classification of damselflies is provided to help the reader understand where the genus Enallagma (American Bluets) fits into the bigger picture of the Order OdonataSuborder Zygoptera (Damselflies).

There are four families of damselflies in the United States of America, although only three families occur in the mid-Atlantic USA: Broad-winged damselflies; Narrow-winged damselflies (a.k.a., Pond Damselflies); and Spreadwing damselflies.

  1. Family Calopterygidae – Broad-winged Damselflies
  2. Family Coenagrionidae – Narrow-winged Damselflies
  3. Family Lestidae – Spreadwings

1. Family Calopterygidae is comprised of two genera.

2. Family Coenagrionidae is comprised of 14 genera. Three genera are common in Northern Virginia: Argia (Dancers); Enallagma (American Bluets); and Ischnura (Forktails).

3. Family Lestidae is comprised of two genera.

  • Archilestes (e.g., Great Spreadwing)
  • Lestes (e.g., Slender Spreadwing, Southern Spreadwing, Swamp Spreadwing)

There are relatively few genera of Broad-winged Damselflies and Spreadwing Damselflies. In contrast, there are many more genera and species of Narrow-winged Damselflies — more species, including many that look similar, makes this family the most challenging to learn!

Related Resource: “The Odonata of North America” is a complete list of both scientific names and common names for damselflies and dragonflies, maintained by the Dragonfly Society of the Americas.

Copyright © 2020 Walter Sanford. All rights reserved.

Blue-fronted Dancer damselfly

August 31, 2020

A Blue-fronted Dancer damselfly (Argia apicalis) was spotted during a photowalk with Michael Powell near Mulligan Pond at Jackson Miles Abbott Wetland Refuge (JMAWR), Fairfax County, Virginia USA.

A. apicalis has “a blue form female and a brown form female.” Since neither the hamules nor terminal appendages can be seen clearly in the preceding photo, I’m unsure whether this individual is male or female.

Post Update

Michael Ready, good friend and fellow member of the Dragonfly Society of the Americas, shared the following comment via e-mail.

That’s an outstanding picture of a Blue-fronted Dancer. You state you are unsure of the individual’s gender. I am confident that it is a male. According to my field guides (Lam and Paulson), the blue-form female lacks the blue eyes and blue S8-10 that are apparent in your picture. Source Credit: Michael Ready.

Thanks for the kind words and helpful information, Michael! As it turns out, the field marks that you described are shown clearly in one of my blog posts: Blue-fronted Dancers (male, female), especially this photo.

Copyright © 2020 Walter Sanford. All rights reserved.

We have a history

August 21, 2020

An Eastern Pondhawk dragonfly (Erythemis simplicicollis) was spotted during a photowalk with Michael Powell near Mulligan Pond at Jackson Miles Abbott Wetland Refuge (JMAWR) in Fairfax County, Virginia USA.

This individual is a female, as indicated by her coloration and terminal appendages. Eastern Pondhawk, especially female E. simplicicollis, are voracious predators.

18 AUG 2020 | JMAWR | Eastern Pondhawk (female)

Regular readers of my blog know I love me some head-tilts, as shown in the preceding photo.

18 AUG 2020 | JMAWR | Eastern Pondhawk (female)

The Backstory

As the title of this blog post suggests, Eastern Pondhawk and I have a history — a negative history. A cohort of Southern Spreadwing damselflies (Lestes australis) was observed for a two-week period during early May 2015 at a vernal pool in the forest at Huntley Meadows Park.

The sudden disappearance of the damselfly cohort seemed to coincide with a population explosion of Eastern Pondhawk in mid-May. After years of heavy predation by Eastern Pondhawk, Southern Spreadwing disappeared completely from the vernal pool.

Related Resource: A Southern Fortnight – Part 1-7.

Copyright © 2020 Walter Sanford. All rights reserved.

Acceptable uncertainty

July 27, 2020

A teneral damselfly was spotted by Michael Powell during a photowalk with me along a mid-size stream in Fairfax County, Virginia USA.

teneral: adult after it has just emerged, soft and not definitively colored. Source Credit: Glossary [of] Some Dragonfly Terms, by Dennis Paulson.

Teneral odonates, especially females, can be challenging at best to identify with certainty. And so it is with this one.

The first photo is the record shot. (Get a shot, any shot.) I think I might have just missed focus on the face.

No. 1 | 15 JUL 2020 | Fairfax County, VA | teneral damselfly

Refine the shot.

No. 2 | 15 JUL 2020 | Fairfax County, VA | teneral damselfly

Although this individual is definitely a member of Family Coenagrionidae (Narrow-winged Damselflies), both the genus/species and gender are somewhat uncertain.

It appears to be an Argia sp. based on long tibial spines. I think it is a male. Source Credit: Mike Boatwright, founder and administrator of the Virginia Odonata Facebook group.

For what it’s worth, Mike Powell and I saw three species of damselflies during our outing: Blue-tipped Dancer (Argia tibialis); Dusky Dancer (Argia translata); and Powdered Dancer (Argia moesta).

I’m not sure of the gender. I see what might be hamules, indicating this individual is male, but also see what looks like a female stylus (plural: styli) near the tip of the abdomen, indicating this might be a female.

Bonus Bugs and More

Look closely at Photo No. 1, the “record shot.” Notice the small orange colored insect perched along the bottom of the same rock on which the damselfly is perched. Can anyone identify Bonus Bug No. 1?

Post Update: “The fly at the [bottom] of this photo may be a black fly (Simuliidae).” Source Credit: John Smith, member “BugGuide” Facebook group.

Now look at Photo No. 2. Notice there is some type of dark insect that’s perched along the same edge of the rock as the damselfly. Can anyone identify Bonus Bug No. 2?

Post Update: “The bug at the bottom of your photo appears to be a caddisfly.” Source Credit: John Smith, member “BugGuide” Facebook group.

Also notice the dark insect is perched near what might be the exuvia from which the damselfly emerged, as shown in Photo No. 2. It’s tannish in coloration.

I didn’t see either the bonus bugs or possible exuvia when we were in the field. Of course!

Related Resource: Newly emerged damselflies, a companion blog post by Michael Powell.

Copyright © 2020 Walter Sanford. All rights reserved.

Blue-tipped Dancer damselfly (male)

July 17, 2020

A Blue-tipped Dancer damselfly (Argia tibialis) was spotted during a photowalk with Michael Powell along a mid-size stream in Fairfax County, Virginia USA. Blue-tipped Dancer is a member of Family Coenagrionidae (Narrow-winged Damselflies).

This individual is a male. I love the gun metal gray color of his upper thorax stripes.

15 JUL 2020 | Fairfax County, VA | Blue-tipped Dancer (male)

Related Resource: A. tibialis male #4 (Blue-tipped Dancer)

Credit

Thanks to Michael Boatwright, founder and administrator of the Virginia Odonata Facebook group, for help in identifying this specimen.

Copyright © 2020 Walter Sanford. All rights reserved.

Odonate Calendars (updated for 2020)

July 15, 2020

Phenology (noun) is defined as “the study of cyclic and seasonal natural phenomena, especially in relation to climate and plant and animal life.”

There is an annual cycle of odonate activity that can be subdivided into three broad categories: Early Season (spring); Mid-season (summer); and Late Season (fall).

A calendar is a good way to visualize odonate phenology. I created a new blog page called “Odonate Calendars” (see right sidebar) that features several calendars showing the adult flight period for all species of dragonflies and damselflies that can be found in the Commonwealth of Virginia.

The page includes two interactive calendars for Dr. Steve Roble’s excellent datasets for the Commonwealth of Virginia: one for dragonflies; another for damselflies. Other calendars are provided under “Related Resources.”

Copyright © 2020 Walter Sanford. All rights reserved.

American Rubyspot damselfly (male)

June 24, 2020

During a photowalk with Michael Powell in Fairfax County, Virginia USA, Mike spotted an American Rubyspot damselfly (Hetaerina americana) perched facing the Potomac River. This individual is a male, as indicated by his red coloration, hamules, and terminal appendages.

All of the photos in the following gallery look similar, although there are subtle differences.

The first photo is the “record shot” for this individual, that is, “get a shot, any shot.” Actually, this one turned out to be a good photo! The camera was set for an aperture of f/5.6 for all shots in the gallery. This viewing angle provided the clearest look at his terminal appendages given the relatively shallow depth-of-field.

08 JUN 2020 | Fairfax County, VA | American Rubyspot (male)

The next photo shows a better look at the damselfly’s metallic ruby red face. Handsome!

08 JUN 2020 | Fairfax County, VA | American Rubyspot (male)

Finally, I just like the look of the “light” in the last photo. Dark and moody.

08 JUN 2020 | Fairfax County, VA | American Rubyspot (male)

Related Resource: American Rubyspot – a blog post by Michael Powell

Copyright © 2020 Walter Sanford. All rights reserved.

Ebony Jewelwing damselfly (female)

June 10, 2020

Two members of Family Calopterygidae (Broad-winged Damselflies) can be found in Fairfax County, Virginia USA: American Rubyspot (Hetaerina americana); and Ebony Jewelwing (Calopteryx maculata). Ebony Jewelwing seems to be more common than American Rubyspot in Fairfax County.

08 JUN 2020 | Fairfax County, VA | Ebony Jewelwing (female)

The preceding photo of an Ebony Jewelwing is one of my “warm-up shots” from a recent photowalk with Michael Powell at a location in Fairfax County, Virginia USA.

This individual is a female. A simple field mark may be used to differentiate female and male Ebony Jewelwing: females feature white pterostigmata; males don’t.

Related Resources

Copyright © 2020 Walter Sanford. All rights reserved.

MYN – Zygoptera exuvia (ventral-lateral view)

March 27, 2020

A Zygoptera exuvia (species unknown) was collected on 21 May 2019 alongside a small pond at an undisclosed location in Prince William County, Virginia USA.

This individual is a member of Family Lestidae (Spreadwings), as indicated by the unique shape of its prementum — it reminds me of a rattle (musical instrument).

The rudimentary ovipositor that is faintly visible on the ventral side of abdominal segment nine (S9) indicates this specimen is a female.

21 MAY 2019 | Zygoptera exuvia (ventrallateral view) | female

My what long antennae you have, Grandma! The better to sense you, my dear.

Related Resources

Tech Tips

This subject was photographed against a pure white background (255, 255, 255) using the “Meet Your Neighbours” (MYN) technique.

Three photos were used to create a composite image: one photo focused on the head; another focused on the wing pads; and a third focused on abdominal segment six (S6).

Copyright © 2020 Walter Sanford. All rights reserved.

Sexing odonate exuviae (Zygoptera)

February 12, 2020

For some (but not all) species of odonate larvae/exuviae, sex is indicated by either a rudimentary ovipositor (female) or vestigial genitalia (male). These sex organs don’t look exactly the same for all species of damselflies, but their function is identical.

The following photo gallery shows relatively clear examples that illustrate how to sex odonate exuvia in Suborder Zygoptera (Damselflies).

Female (rudimentary ovipositor)

Family Calopterygidae (Broad-winged Damselflies)

(none)

Family Coenagrionidae (Narrow-winged Damselflies)

11 MAR 2017 | Argia sp. | exuvia (female)

Family Lestidae (Spreadwings)

(none)

Male (vestigial genitalia)

Family Calopterygidae (Broad-winged Damselflies)

Family Coenagrionidae (Narrow-winged Damselflies)

(none)

Family Lestidae (Spreadwings)

(none)

Related Resources

Copyright © 2020 Walter Sanford. All rights reserved.


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