Posts Tagged ‘hemi-marsh’

Bar-winged Skimmer dragonfly (mature male)

June 20, 2015

Bar-winged Skimmer dragonflies (Libellula axilena) look similar to Great Blue Skimmer dragonflies (Libellula vibrans).

A Bar-winged Skimmer dragonfly (Libellula axilena) spotted at Huntley Meadows Park, Fairfax County, Virginia USA. This individual is a mature male.

10 JUN 2015 | HMP | Bar-winged Skimmer (mature male)

Several key field markers can be used to differentiate the two species of dragonflies, as shown in the following annotated images.

A Bar-winged Skimmer dragonfly (Libellula axilena) spotted at Huntley Meadows Park, Fairfax County, Virginia USA. This individual is a mature male.

10 JUN 2015 | HMP | Bar-winged Skimmer (mature male)

Bar-winged Skimmers have dark reddish-brown eyes and a metallic black face; Great Blue Skimmers have blue eyes and a white face. Also notice the Bar-winged Skimmer has a small black bar along the “costa” (the leading edge of both the fore- and hind wings), located between the nodus and pterostigma — hence its common name, “Bar-winged Skimmer“; the Great Blue Skimmer does not.

A Great Blue Skimmer dragonfly (Libellula vibrans) spotted at Huntley Meadows Park, Fairfax County, Virginia USA. This individual is a male.

31 MAY 2015 | HMP | Great Blue Skimmer (mature male)

Side view of Great Blue Skimmer (shown above); dorsal view (shown below).

A Great Blue Skimmer dragonfly (Libellula vibrans) spotted at Huntley Meadows Park, Fairfax County, Virginia USA. This individual is a young male.

31 MAY 2015 | HMP | Great Blue Skimmer (young male)

The following gallery features several more photos of the same Bar-winged Skimmer spotted at Huntley Meadows Park (HMP) on 10 June 2015.

Copyright © 2015 Walter Sanford. All rights reserved.

Advertisements

Slaty Skimmer dragonfly terminal appendages

June 14, 2015

Slaty Skimmer (Libellula incesta) is a member of the Skimmer Family of dragonflies that is spotted during the summer and fall months at many water bodies in the mid-Atlantic United States, such as the wetlands at Huntley Meadows Park.

Slaty Skimmers display sexual dimorphism. Although mature males and females look different, immature males and females look similar. Terminal appendages may be used to differentiate immature males from females.

A Slaty Skimmer dragonfly (Libellula incesta) spotted at Huntley Meadows Park, Fairfax County, Virginia USA. This individual is a female.

06 JUN 2015 | Huntley Meadows Park | Slaty Skimmer (female)

Female dragonflies have a pair of cerci (superior appendages) that have little or no function. (See a full-size version of the following image, without annotation.)

A Slaty Skimmer dragonfly (Libellula incesta) spotted at Huntley Meadows Park, Fairfax County, Virginia USA. This individual is a female.

06 JUN 2015 | Huntley Meadows Park | Slaty Skimmer (female)

Look closely at the full-size version of the preceding annotated image. 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.” Remember that all dragonflies and damselflies have a 10-segmented abdomen, numbered from front to back.

Immature male Slaty Skimmers and immature/adult female Slaty Skimmers are nearly identical in appearance except for their terminal appendages. (See a full-size version of the following image, without annotation.)

A Slaty Skimmer dragonfly (Libellula incesta) spotted at Little Hunting Creek, Huntley Meadows Park, Fairfax County, Virginia USA. This individual is an immature male.

07 JUL 2014 | Huntley Meadows Park | Slaty Skimmer (immature 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”). (See a full-size version of the following image, without annotation.)

A Slaty Skimmer dragonfly (Libellula incesta) spotted at Huntley Meadows Park, Fairfax County, Virginia USA. This individual is a young male with a slightly malformed wing.

06 JUN 2015 | Huntley Meadows Park | Slaty Skimmer (young male)

This individual is a young male, as indicated by the blue-black partial pruinescence covering his body. He has a slightly malformed wing that is more noticeable in the preceding side view and less noticeable in the following dorsal view.

A Slaty Skimmer dragonfly (Libellula incesta) spotted at Huntley Meadows Park, Fairfax County, Virginia USA. This individual is a young male with a slightly malformed wing.

06 JUN 2015 | Huntley Meadows Park | Slaty Skimmer (young male)

Black pruinescence that completely covers the body of following mature male Slaty Skimmer makes it look quite different from the immature male (shown above), other than its terminal appendages.

A Slaty Skimmer dragonfly (Libellula incesta) spotted at Huntley Meadows Park, Fairfax County, Virginia USA. This individual is a mature male.

10 SEP 2014 | Huntley Meadows Park | Slaty Skimmer (mature male)

Digital scans by G & J Strickland:

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

  • Genus Libellula | Libellula incesta | Slaty Skimmer | male | top view
  • Genus Libellula | Libellula incesta | Slaty Skimmer | male | side view

Related Resources: Odonate Terminal Appendages.

Copyright © 2015 Walter Sanford. All rights reserved.

Spangled Skimmer dragonfly terminal appendages

June 10, 2015

Spangled Skimmer (Libellula cyanea) is a member of the Skimmer Family of dragonflies that is spotted during the summer months at many water bodies in the mid-Atlantic United States, such as the wetlands at Huntley Meadows Park (HMP).

Spangled Skimmers display sexual dimorphism. Although mature males and females look different, immature males and females look similar. Terminal appendages may be used to differentiate immature males from females.

Female dragonflies have a pair of cerci (superior appendages) that have little or no function.

A Spangled Skimmer dragonfly (Libellula cyanea) spotted  at Huntley Meadows Park, Fairfax County, Virginia USA. This individual is a female.

22 MAY 2015 | HMP | Spangled Skimmer (female)

Look closely at the full-size version of the following annotated image. Female Spangled Skimmers have two flanges beneath their eighth abdominal segment (S8) that are used to scoop 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.

Another useful field marker that may be used to differentiate males from females: females have broad dark wing tips; males, not so much.

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 Spangled Skimmer dragonfly (Libellula cyanea) spotted  at Huntley Meadows Park, Fairfax County, Virginia USA. This individual is an immature male.

22 MAY 2015 | HMP | Spangled Skimmer (immature male)

Blue pruinescence that covers the body of following mature male Spangled Skimmer makes it look quite different from the immature male (shown above), other than its terminal appendages and distinctive black-and-white pterostigmata.

A Spangled Skimmer dragonfly (Libellula cyanea) spotted at Huntley Meadows Park, Fairfax County, Virginia USA. This individual is a male.

26 JUN 2012 | HMP | Spangled Skimmer (mature male)

Related Resources: Odonate Terminal Appendages.

Copyright © 2015 Walter Sanford. All rights reserved.

Phishing snakes

May 15, 2015

The following photos show one or more Northern Watersnakes (Nerodia sipedon sipedon) spotted during photowalks along the boardwalk in the hemi-marsh at Huntley Meadows Park in mid-September 2014.

What do you see when you look at the following photos? I think most people would say they see a snake lying on a log, sunning itself. Now look more closely at the full-size versions of each photo — there’s more than meets the eye!

Several fish are visible in the water. Notice most of the fish are located under the log. Like all animals, fish need food and shelter in order to survive. Many species of fish prefer to find a holding place that provides shelter, such as the log, and look for food as it passes their safe spot.

Northern Watersnake (Nerodia sipedon sipedon)

15 September 2014

Over a period lasting several days, I observed one or more snakes hunting fish at the same location. The snake would lie perfectly still on top of the log; as soon as the fish were lulled into a false sense of security, the snake would slip into the water suddenly and snag an unsuspecting fish. The same thing happened again and again, so I’m guessing the snake(s) figured out a good strategy for finding food easily.

Northern Watersnake (Nerodia sipedon sipedon)

15 September 2014

A few days later, there were noticeably fewer fish hiding below the log. Can you say “overfishing?”

Northern Watersnake (Nerodia sipedon sipedon)

19 September 2014

Copyright © 2015 Walter Sanford. All rights reserved.

Blue Dasher dragonflies (mating pair)

April 13, 2015

A mating pair of Blue Dasher dragonflies (Pachydiplax longipennis) was spotted along the boardwalk in the central wetland area hemi-marsh at Huntley Meadows Park on 10 September 2014.

The pair is shown “in wheel.” All odonates (dragonflies and damselflies) have a 10-segmented abdomen, numbered from front to back: male dragonfly secondary genitalia are located in segments two and three (2 and 3); female genitalia in segment eight (8). Therefore, the male dragonfly is on top; the female is on the bottom.

Blue Dasher dragonflies (mating pair, in wheel)

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”).

Blue Dasher dragonflies (mating pair, in wheel)

Copyright © 2015 Walter Sanford. All rights reserved.

Year of the Frog

February 20, 2015

2015 is officially Virginia’s Year of the Frog!

… did you know that frogs are considered by many conservationists to be the most imperiled group of animals in the world? … Frogs are important natural resources that deserve our attention. Because of their aquatic and terrestrial life stages, frogs are excellent indicators of environmental health and water quality. Source Credit: Virginia is for Frogs.

American Bullfrog (Lithobates catesbeianus)

The preceding American Bullfrog (Lithobates catesbeianus) is the unofficial poster girl for the year-long celebration. This frog is probably female, as indicated by the size of her tympanum: the eardrum is about the same size as the eye in females; it is larger than the eye in males.

It’s easy to tell males from females in both the Green Frog and the [American] Bullfrog. Males have a yellow throat, and the tympanum, the visible round external eardrum located behind the eye, is much larger than the eye. Females lack the yellow throat and the tympanum is about the same size as the eye. Source Credit: Ask a Naturalist.

Mid-February is too early for frog-spotting in the mid-Atlantic USA, so I used an image from my archive of unpublished photographs. This individual was observed alongside the boardwalk in the hemi-marsh at Huntley Meadows Park on 12 September 2014.

Editor’s Note: A Tweet by regular reader Charlie Bale inspired me to add a pull quote from Virginia is for Frogs, the featured Web site in this post. Feel free to add comments to my blog anytime, Charlie!

Copyright © 2015 Walter Sanford. All rights reserved.

Purple Loosestrife (Lythrum salicaria)

February 10, 2015

Purple Loosestrife (Lythrum salicaria), shown below, is an invasive plant that was spotted during a photowalk along the boardwalk in the hemi-marsh at Huntley Meadows Park on 29 August 2014.

One mature plant can produce more than 2 million seeds annually. Seeds are easily dispersed by water and in mud adhered to aquatic wildlife, livestock and people. Source Credit: Purple Loosestrife, Ecology and Management of Invasive Plants Program, Cornell University.

Park staff members removed these plants soon after I photographed them. If you see this plant anywhere at the park, then please stop by the Visitor Center in order to notify a staff member of your sighting.

Purple Loosestrife (Lythrum salicaria)

Purple Loosestrife (Lythrum salicaria)

Purple Loosestrife (Lythrum salicaria)

Editor’s Note: Thanks to Kevin Munroe, Manager, Huntley Meadows Park, and Matt Ryan, Naturalist, for identifying the flowering plant shown in my photos. I knew the plant was one I’d never seen at the park; I didn’t know it’s an invasive species that spreads rapidly.

Copyright © 2015 Walter Sanford. All rights reserved.

Droopy

February 8, 2015

A Red Admiral butterfly (Vanessa atalanta) was spotted on 15 September 2014 along the boardwalk in the hemi-marsh at Huntley Meadows Park.

Look closely at the full-size version of the following photo. The marbled pastel colors on the ventral side (underside) of the Red Admiral’s wings are beautifully understated, distinctly different from the high-contrast colors on its dorsal side.

Red Admiral butterfly (Vanessa atalanta)

According to Kevin Munroe, park manager, Red Admiral butterflies prefer to feed on minerals rather than nectar. Salt in sweat and the minerals in animal scat are among the Red Admiral’s favorite foods. In this case, the butterfly was feeding on a faint scat stain on the boardwalk railing.

Red Admiral butterfly (Vanessa atalanta)

Aw, why so sad, Mr. Droopy antennae?

Red Admiral butterfly (Vanessa atalanta)

Copyright © 2015 Walter Sanford. All rights reserved.

Crimsoneyed Rosemallow (Hibiscus moscheutos)

February 6, 2015

Crimsoneyed Rosemallow (Hibiscus moscheutos), shown below, is another flowering plant that is widespread throughout the hemi-marsh at Huntley Meadows Park. More commonly known as either “mallow” or “marsh mallow,” Crimsoneyed Rosemallow is one of ~300 species of plants in the genus Hibiscus.

Marshmallow flowers (Althaea sp.)

The small insect shown in the preceding photo is a Spotted Cucumber Beetle (Diabrotica undecimpunctata), “a major agricultural pest insect of North America.”

Marshmallow flowers (Althaea sp.)

Notice the female katydid hiding deep in the throat of the flower, shown above.

Marshmallow flowers (Althaea sp.)

During “Huntley Meadows Park at Night,” a class/walk-and-talk led by park naturalists P.J. Dunn and Matt Ryan on 19 July 2014, I was surprised to discover Crimsoneyed Rosemallow flowers close at night.

Marshmallow flowers (Althaea sp.)

How many flower parts can you identify? Feel free to use the following reference: Plant Morphology – The Parts of a Flower (diagram courtesy American Museum of Natural History).

The preceding photographs were taken during a photowalk along the boardwalk in the hemi-marsh at Huntley Meadows Park on 17 August 2012.

Editor’s Note: Thanks to Matt Ryan, naturalist at Huntley Meadows Park, for sharing the scientific name of “mallow.”

Copyright © 2015 Walter Sanford. All rights reserved.

Similar is not the same

February 2, 2015

Creeping Water Primrose (Ludwigia peploides), shown below, is a flowering plant that is widespread throughout the hemi-marsh at Huntley Meadows Park.

A former naturalist at the park told me this plant is Creeping Primrose Willow (Ludwigia repens). Turns out she was partly right: right genus; wrong species.

Creeping Water Primrose (Ludwigia peploides)

30 September 2014

Creeping Primrose Willow looks similar to Creeping Water Primrose, although they are not the same: Ludwigia repens flowers have four petals; Ludwigia peploides flowers have either five- or six petals.

I have taken many photographs of this beautiful flowering plant during a period spanning several years beginning in 2011. I reviewed all of those photos and in every case, the little yellow flowers have five petals.

Editor’s Note: Thanks to Matt Ryan, naturalist at Huntley Meadows Park, for help in correctly identifying the species of flowering plant shown in my photo.

Copyright © 2015 Walter Sanford. All rights reserved.


%d bloggers like this: