Posts Tagged ‘pseudopupils’

“Mr. Magoo” and “Bendy Straw”

October 24, 2015

Some male Great Spreadwing damselflies (Archilestes grandis) have recognizable physical characteristics that distinguish them from other individuals of the same species and give them personality.

Regular readers of my photoblog may recall reading about “Crinkle-cut,” a very aggressive male with distinctive damage to all four of his wingtips, that I followed at Huntley Meadows Park (HMP) during Fall 2014.

This year, I met two new characters at the park: “Mr. Magoo“; and “Bendy Straw,” one of Magoo’s rivals.

Mr. Magoo

The nickname “Mr. Magoo” seems perfect for this male because of the prominent dark spots in his eyes. The eye spots are always in the same place, regardless of viewpoint, therefore it is technically incorrect to refer to them as “pseudopupils.”

A Great Spreadwing damselfly (Archilestes grandis) spotted at Huntley Meadows Park, Fairfax County, Virginia USA. This individual is a male.

08 OCT 2015 | HMP | Great Spreadwing (male, nicknamed “Mr. Magoo”)

A Great Spreadwing damselfly (Archilestes grandis) spotted at Huntley Meadows Park, Fairfax County, Virginia USA. This individual is a male, nicknamed

15 OCT 2015 | HMP | Great Spreadwing (male, nicknamed “Mr. Magoo”)

I spotted “Mr. Magoo” for the first time on 08 October 2015; I have seen him again on the 15th and 21st.

A Great Spreadwing damselfly (Archilestes grandis) spotted at Huntley Meadows Park, Fairfax County, Virginia USA. This individual is a male, nicknamed

15 OCT 2015 | HMP | Great Spreadwing (male, nicknamed “Mr. Magoo”)

Bendy Straw

The nickname “Bendy Straw” seems perfect for the following male because of his slightly malformed abdomen.

A Great Spreadwing damselfly (Archilestes grandis) spotted at Huntley Meadows Park, Fairfax County, Virginia USA. This individual is a male, nicknamed

11 OCT 2015 | HMP | Great Spreadwing (male, nicknamed “Bendy Straw”)

Notice the bend in his abdomen at the boundary between segments seven and eight (S7 and S8). Remember that all dragonflies and damselflies have a 10-segmented abdomen, numbered from front to back.

A Great Spreadwing damselfly (Archilestes grandis) spotted at Huntley Meadows Park, Fairfax County, Virginia USA. This individual is a male, nicknamed

11 OCT 2015 | HMP | Great Spreadwing (male, nicknamed “Bendy Straw”)

I met “Bendy Straw” on 11 October 2015; I haven’t seen “Bendy” again, although Mike Powell photographed him on 16 October.

Editor’s Note: Stay tuned for more photo sets of “Mr. Magoo” and “Bendy Straw,” to be published separately in several upcoming blog posts.

Copyright © 2015 Walter Sanford. All rights reserved.

Eye contact

February 24, 2015

I like shots of dragonflies in which the subject strikes an unusual pose. I’m especially fond of head-tilts in which the individual seems to make direct eye contact. I wonder what the dragonfly is thinking when it looks at me through its compound eyes. On one hand, the amateur scientist in me guesses the dragonfly’s only thought is a simple decision tree: Is this thing predator or prey? On the other hand, the romantic in me thinks the two of us make a connection sometimes, and the dragonfly senses I’m a friend rather than a foe. Like the connection between this guy and me …

Eastern Pondhawk dragonfly (male)

The preceding photograph shows an Eastern Pondhawk dragonfly (Erythemis simplicicollis) perching on the boardwalk at Huntley Meadows Park on 10 September 2014. This individual is a male, as indicated by its coloration and terminal appendages.

Eastern Pondhawk is a species of dragonfly with prominent pseudopupils, giving the face a cartoon-like appearance sometimes. In this one-panel cartoon, the speech bubble would read …

Eastern Pondhawk dragonfly (male)

Tech Tip: Apple “Preview” application was used to annotate the preceding photograph.

Copyright © 2015 Walter Sanford. All rights reserved.

Eastern Pondhawk dragonflies (females)

August 10, 2014

Eastern Pondhawk dragonfly (Erythemis simplicicollis) is another species of dragonfly with prominent pseudopupils, as shown by several specimens spotted during a photowalk at Huntley Meadows Park on 22 July 2014.

Eastern Pondhawk dragonfly (female)

These individuals are females, as indicated by their green coloration and white terminal appendages. See Eastern Pondhawk dragonflies, a photo-illustrated guide to the identification of male- and female terminal appendages.

Eastern Pondhawk dragonfly (female)

Look closely at the following photo. Notice the subgenital plate, a black “shark fin” located beneath segment eight of the abdomen.

Underneath Segment 8 there is either an ovipositor or a subgenital plate, depending upon the species [of dragonfly]. Both structures are for laying eggs and extend over Segment 9 and possibly beyond. Source Credit: Dragonflies of the North Woods, by Kurt Mead.

Remember that “Segment 8 and 9″ refers to abdominal segments eight and nine (of 10), numbered from front to back. Digital Dragonflies features a side view of a female Eastern Pondhawk in which the subgenital plate is shown clearly.

Eastern Pondhawk dragonfly (female)

Related Resources: Digital Dragonflies, presenting high-resolution digital scans of living dragonflies.

  • Genus Erythemis |Erythemis simplicicollis | Eastern Pondhawk | female | top view
  • Genus Erythemis |Erythemis simplicicollis | Eastern Pondhawk | female | side view
  • Genus Erythemis |Erythemis simplicicollis | Eastern Pondhawk | male | top view
  • Genus Erythemis |Erythemis simplicicollis | Eastern Pondhawk | male | side view

Copyright © 2014 Walter Sanford. All rights reserved.

“I’m the King of the World!”

August 8, 2014

Well, that’s what I imagine the following Great Blue Skimmer dragonfly (Libellula vibrans) was thinking as it perched atop a dead tree in a remote part of Huntley Meadows Park on 07 July 2014.

Great Blue Skimmer dragonfly (male)

Moving forward on the make-believe bow, he shouted “I’m the King of the World!” For a few moments, he was.

Great Blue Skimmer dragonfly (male)

This individual is a male, as indicated by its coloration, terminal appendages, and the hamules that are visible below the second segment of its abdomen. Remember that all dragonflies and damselflies have a 10-segmented abdomen, numbered from front to back.

Great Blue Skimmer dragonflies are so common at Huntley Meadows it’s easy to overlook the fact that they are handsome/beautiful insects.

Look closely at the dragonfly’s compound eyes. Notice the darker colored areas called “pseudopupils.” According to Richard Orr, renowned expert on dragonflies and damselflies of the mid-Atlantic region, pseudopupils indicate areas of higher visual acuity.

Great Blue Skimmer dragonfly (male)

Related Resources: Digital Dragonflies, presenting high-resolution digital scans of living dragonflies.

  • Genus Libellula | Libellula vibrans | Great Blue Skimmer | male | top view
  • Genus Libellula | Libellula vibrans | Great Blue Skimmer | male | side view
  • Genus Libellula | Libellula vibrans | Great Blue Skimmer | female | top view
  • Genus Libellula | Libellula vibrans | Great Blue Skimmer | female | side view

Copyright © 2014 Walter Sanford. All rights reserved.

Needham’s Skimmer dragonfly (male) redux

September 9, 2012

The following photo shows a Needham’s Skimmer dragonfly (Libellula needhami) perched on a branch of a small tree that had fallen in the Paul Spring stream bed. This individual is a male, as indicated by its coloration and the “claspers” (terminal appendages) at the end of its abdomen.

P1140148-rw2-ver2_aperture
Look closely at the dragonfly’s compound eyes. Notice the darker colored areas called “pseudopupils.” According to Richard Orr, renowned expert on dragonflies and damselflies of the mid-Atlantic region, pseudopupils indicate areas of higher visual acuity.
P1140148-rw2-ver3_aperture
 Habitat: “Paul Spring Park,” one of seven small parks owned and maintained by the Community Association of Hollin Hills, Fairfax County, Virginia USA. Paul Spring is a small year-round stream that flows through Paul Spring Park.

Copyright © 2012 Walter Sanford. All rights reserved. www.wsanford.com


%d bloggers like this: