Archive for March, 2017

Black and Yellow Argiope spiders

March 31, 2017

Two Black and Yellow Argiope (Argiope aurantia) spiders were spotted during a photowalk around Mulligan PondJackson Miles Abbott Wetland Refuge (JMAWR), Fairfax County, Virginia USA.

Larger (female?)

The zig-zag pattern in the center of the web is a characteristic field marker for Black and Yellow Argiope. Females (14-25 mm) are larger than males (5-6 mm), so it’s possible the first spider is a female and the last spider is a male.

Smaller (male?)

Copyright © 2017 Walter Sanford. All rights reserved.

Common Sanddragon dragonfly (male)

March 29, 2017

As you might expect, Common Sanddragon dragonflies (Progomphus obscurus) commonly perch on the sandy banks of small woodland streams. Not this one!

A Common Sanddragon was spotted perching on the vegetation growing alongside a manmade concrete drainage ditch that flows into Dogue Creek, Wickford Park, Fairfax County, Virginia USA.

This individual is a male, as indicated by his terminal appendages. Like all male clubtail dragonflies, the hindwings of male Common Sanddragons are “indented” near the body. This distinctive field marker is shown well by the last photo in this gallery.

Copyright © 2017 Walter Sanford. All rights reserved.

Blue-faced Meadowhawks (mating pair)

March 27, 2017

A mating pair of Blue-faced Meadowhawk dragonflies (Sympetrum ambiguum) was spotted near a vernal pool at Huntley Meadows Park (HMP). This pair is “in wheel“: the male is on the upper-right; the female on the lower-left.

16 OCT 2016 | HMP | Blue-faced Meadowhawk (mating pair, “in wheel“)

The female is a heteromorph, as indicated by her tan coloration.

16 OCT 2016 | HMP | Blue-faced Meadowhawk (mating pair, “in wheel“)

There were noticeably fewer Blue-faced Meadowhawks at this location than in past years. It’s reassuring to see this pair doing their part to ensure perpetuation of the species.

Copyright © 2017 Walter Sanford. All rights reserved.

Slender Spreadwing damselflies (females)

March 25, 2017

Two female Slender Spreadwing damselflies (Lestes rectangularis) were spotted during a photowalk around a vernal pool in the forest at Huntley Meadows Park.

No. 1

No. 2

Notice the second individual is bluer in color. Coloration is variable, so it’s better to look at other field markers when making an identification.

Copyright © 2017 Walter Sanford. All rights reserved.

Arachnids 2, Odonates 0

March 23, 2017

A spider was observed preying upon a teneral damselfly at a vernal pool in Huntley Meadows Park. The genus/species of the spider is uncertain; the damselfly appears to be a female Slender Spreadwing (Lestes rectangularis).

31 MAY 2016 | Huntley Meadows Park | spider preying upon damselfly

According to experts on the BugGuide Facebook group, the spider is probably an unknown species from the Family Araneidae (Orb Weavers).

Post Update: Ashley Bradford, a local arachnid expert and excellent all-around amateur naturalist, identified the spider as an Arabesque Orbweaver (Neoscona arabesca). Thanks, Ashley!

31 MAY 2016 | Huntley Meadows Park | spider preying upon damselfly

Aperture Priority mode was used for the next photo, in order to increase the depth of field. As you can see, the depth of field at f/8.0 was insufficient for both the damselfly and spider to be in focus.

31 MAY 2016 | Huntley Meadows Park | spider preying upon damselfly

A dragonfly was trapped in a spider web at Hidden Pond, Meadowood Recreation Area, Fairfax County, Virginia USA. The dragonfly, possibly an immature male Blue Dasher (Pachydiplax longipennis), is infested with parasitic red water mites.

22 JUN 2016 | Meadowood Recreation Area | dragonfly in spider web

Copyright © 2017 Walter Sanford. All rights reserved.

Scavenger hunt

March 21, 2017

The largest subject shown in the following photo is floating in a vernal pool. What is it? (Ignore the smaller “bonus bugs.”) The answer can be found by scavenging the posts in my photoblog. Need more clues?

31 MAY 2016 | Huntley Meadows Park | Signs of Wildlife

Post Update: The largest subject is one of the forewings from a Polyphemus Silkmoth (Antheraea polyphemus).

Copyright © 2017 Walter Sanford. All rights reserved.

Painted Skimmer dragonfly (teneral female)

March 19, 2017

Painted Skimmer dragonfly (Libellula semifasciata) was spotted at a vernal pool in Huntley Meadows Park (HMP). This individual is a teneral female, as indicated by her terminal appendages and the tenuous appearance of her wings.

No. 1 | 31 MAY 2016 | HMP | Painted Skimmer (teneral female)

Shine on you crazy diamond!

No. 2 | 31 MAY 2016 | HMP | Painted Skimmer (teneral female)

Although Photo No. 1 and 3 look similar, I posted both pictures. Photo No. 1 shows the tenuous appearance of the wings best of all four photos, but I prefer the composition of Photo No. 3. Which one of the two photos do you prefer?

No. 3 | 31 MAY 2016 | HMP | Painted Skimmer (teneral female)

Teneral dragonflies are skittish and prefer to perch in “hidey-holes” that offer protection from predators like paparazzi wildlife photographers. The dragonfly is perching on “soft rush” (Juncus effusus), the common name for the shoreline/emergent plant with light green round stems and brownish flowers that appears in the entire photo set. Soft rush is common in wetland areas.

No. 4 | 31 MAY 2016 | HMP | Painted Skimmer (teneral female)

Painted Skimmer dragonflies do not display sexual dimorphism, that is, adult females and males look similar except for their terminal appendages. Female dragonflies have a pair of cerci (superior appendages) that have little or no function; male dragonflies have three terminal appendages, collectively called “claspers.” The cerci are easy to see in the full-size version of the preceding photo.

Copyright © 2017 Walter Sanford. All rights reserved.

Almost perfect

March 17, 2017

Sometimes I get so focused on the subject of a photo that I don’t see the bigger picture. Although I recognize the problem, I can’t think of a simple solution.

04 OCT 2016 | Huntley Meadows Park | predators and prey

The preceding photo shows a Black and Yellow Argiope (Argiope aurantia) spider spotted at Huntley Meadows Park; a Common Green Darner dragonfly (Anax junius) is trapped in the spider web. I was so focused on getting a shot of the spider in a good position relative to the dragonfly that I never noticed the Chinese Mantid (Tenodera sinensis sinensis) on the right side of the photo. That is, until I returned home.

Notice that I clipped one of the mantid’s legs on the left side of its body (right edge of the photo). That’s the sort of thing that drives me crazy! If I had seen the mantid then I would have recomposed the shot in order to capture all three insects completely. Oh well, another hard lesson learned about wildlife photography.

Copyright © 2017 Walter Sanford. All rights reserved.

Macromia illinoiensis exuvia

March 15, 2017

Post update: Macromiidae exuvia

When this blog post was published on 19 April 2016, I was a novice at identifying odonate exuviae and I was just starting to get serious about studio macro photography. At the time, I was satisfied to be able to identify the dragonfly exuvia as a member of the Family Macromiidae (Cruisers).

What’s new?

I’ve learned a lot since then, including the identity of the specimen to the genus/species level. This is a Swift River Cruiser dragonfly (Macromia illinoiensis) exuvia that was collected along the Potomac River in Fairfax County, Virginia USA.

The first annotated image shows several characters that were used to identify the exuvia to the family level, including a mask-like labium featuring spork-like crenulations and a horn between its pointy eyes.

Swift River Cruiser (Macromia illinoiensis) exuvia (face-head)

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

The following dorsal view of the exuvia provides enough clues to identify the specimen to the genus/species level.

Swift River Cruiser (Macromia illinoiensis) exuvia (dorsal)

The lateral spines of abdominal segment nine (S9) do not reach the tips of the inferior appendages (paraprocts), and if you look closely at the full-size version of the preceding photo then you should see a small mid-dorsal hook on abdominal segment 10 (S10). These characters indicate the genus is Macromia.

Notice the lateral spines of abdominal segments eight and nine (S8-9) are “directed straight to rearward,” indicating the species is illinoiensis.

Where it all began.

The last photo shows a teneral male Swift River Cruiser dragonfly clinging to the exuvia from which it emerged — the same exuvia featured in this post! Matt Ryan collected the exuvia after the adult dragonfly flew away from its perch. When Matt gave the exuvia to me several years later, he was unable to remember where it was collected. As soon as I was able to identify the exuvia to the genus/species level, I remembered seeing the following photo posted in one of Matt’s spottings on Project Noah.

Photo used with permission from Matthew J. Ryan.

With a little detective work, I was able to solve the mystery of the specific identity of the exuvia as well as when and where it was collected. Like I said, I’ve learned a lot since I published the first blog post related to this specimen!

Related Resources:

Editor’s Notes: A funny thing happened on the way to the forum. I rediscovered the “Key to the Genera of the Family Macromiidae” (p. 27, shown above) while paging through the document Identification Keys to Northeastern Anisoptera Larvae in search of the “Key to the Genera of the Family Corduliidae” (page 28). One look at the line drawing at the bottom of p. 27 and I knew the specific identity of the cruiser exuvia.

I need to refresh this blog post with more annotated images of the Macromia illinoiensis exuvia, including one that clearly shows the mid-dorsal hook on S10, but I was so eager to update the old post that I couldn’t wait to shoot and post-process the new images.

Copyright © 2017 Walter Sanford. All rights reserved.

Ichneumon Wasp

March 13, 2017

An Ichneumon Wasp was spotted at Hidden Pond, Meadowood Recreation Area, Fairfax County, Virginia USA.

The genus/species is unknown.

Ichneumonids are notoriously hard to identify: aside from the sheer number of species, there are numerous cases of distant relatives that appear almost identical. Any identification based solely on comparing images should be treated as suspect unless an expert has said there are no lookalikes for the species or group in question. Source Credit: Family Ichneumonidae – Ichneumon Wasps, BugGuide.

Copyright © 2017 Walter Sanford. All rights reserved.


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