Posts Tagged ‘larva’

Cordulegaster sp. larva (dorsal view)

February 25, 2019

This post features a focus-stacked composite image that shows a dorsal view of an odonate larva/nymph from the Family Cordulegastridae (Spiketails) that was collected and reared by Bob Perkins. The larva died before it metamorphosed into an adult.

Cordulegaster sp. larva (female) | dorsal view

Most larvae go through 10-13 stages of development known as “instars.” The author lacks sufficient experience to identify the instar of this specimen, although it appears to be one of the later stages as indicated by its well-developed wing pads.

Related Resources

Tech Tips

12 photos were used to create the focus stack. A single focus point was positioned over select anatomical features; photos were taken at each point of interest.

The following equipment was used to shoot all of the photographs for the focus-stacked composite image, shown above: Canon EOS 5D Mark II digital camera, in manual mode; Kenko 20mm macro automatic extension tubeCanon EF100mm f/2.8L Macro lens (set for manual focus); and Canon MT-26EX-RT Macro Twin Lite set for “Master” mode, and several external flashes set for “Slave” mode including Canon 580 EX- and Canon 580EX II Speedlites and a Godox TT685C Thinklite TTL Flash fitted with a Lastolite Ezybox Speed-Lite 2 flash modifier.

Auto power-off was disabled for the camera and all external flash units.

Adobe Photoshop CC 2017 was used to create the focus-stacked composite image, as well as spot-heal and sharpen the final output.

Copyright © 2019 Walter Sanford. All rights reserved.

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Cordulegaster sp. larva (ventral view)

February 22, 2019

Bob Perkins collected and reared an odonate larva/nymph from the Family Cordulegastridae (Spiketails). The larva died before it metamorphosed into an adult.

This post features a focus-stacked composite image that shows a ventral view of the preserved larva; a composite image showing the dorsal view will be published in my next blog post.

Cordulegaster sp. larva (female) | ventral view

This individual is a female, as indicated by her rudimentary ovipositor that can be seen on the ventral side of the specimen along the boundary between abdominal segments eight and nine (S8-9). Do you see it?

Related Resources

Tech Tips

Nine (9) photos were used to create the focus stack. A single focus point was positioned over select anatomical features; photos were taken at each point of interest.

The following equipment was used to shoot all of the photographs for the focus-stacked composite image, shown above: Canon EOS 5D Mark II digital camera, in manual mode; Kenko 20mm macro automatic extension tubeCanon EF100mm f/2.8L Macro lens (set for manual focus); and Canon MT-26EX-RT Macro Twin Lite set for “Master” mode, and several external flashes set for “Slave” mode including Canon 580 EX- and Canon 580EX II Speedlites and a Godox TT685C Thinklite TTL Flash fitted with a Lastolite Ezybox Speed-Lite 2 flash modifier.

Auto power-off was disabled for the camera and all external flash units.

Adobe Photoshop CC 2017 was used to create the focus-stacked composite image, as well as spot-heal and sharpen the final output.

Copyright © 2019 Walter Sanford. All rights reserved.

“Generic Baskettail” (definitely not a Cruiser)

February 18, 2019

larva/nymph in the Family Corduliidae (Emeralds) was collected by Bob Perkins on 02 December 2017 from a pond in Orange Park, Florida (USA). The larva died before it metamorphosed into an adult.

As you can see by looking at a close-up image of the face-head at 3x magnification, there is no horn on the face of the specimen. Therefore this individual is not a member of Family Macromiidae (Cruisers), as I speculated in my last blog post.

“Generic Baskettail” larva (preserved specimen) | face-head

Knowing the limits of our expertise

Although I still need to key out the specimen carefully, at this point I’m certain Bob is correct — the larva is a member of the Family Corduliidae (Emeralds). The question that remains unanswered is “Which genus/species?” We may never know the answer, as Bob and I have reached the limit of our experience and expertise.

I did a quick scan of Paulson’s [book], looking at the Emerald Family. Here, according to the range maps, are the possibilities for Orange Park [FL]. I believe you can see why I stopped at “generic basketttail.” Source Credit: Bob Perkins.

What do you think the identity is? Most of the items in the preceding species list feature links to photos of odonate larvae/exuviae. See the links to BugGuide from the scientific names in the list.

Related Resource: Test shots: “Generic Baskettail?”

Tech Tips

Four (4) photos were used to create the preceding focus-stacked composite image. A single focus point was positioned over the face, between the antennae. At a magnification ratio of 3:1, it’s difficult to manually focus on a single point — the slightest movement around the macro rig changes focus unintentionally. A simple work-around for this problem is to take several shots of the same focus point and create a composite image of the photos.

The following equipment was used to shoot the preceding composite image: Canon EOS 5D Mark II digital camera, in manual mode; Canon MP-E 65mm Macro lens (set for f/16 at 3x); a Canon MT-26EX-RT Macro Twin Lite set for “Master” mode, and a single external flash set for “Slave” mode — a Godox TT685C Thinklite TTL Flash fitted with a Lastolite Ezybox Speed-Lite 2 flash modifier. A Sunpak LED-160 Video Light was used to add fill light to the top of the subject.

Auto power-off was disabled for the camera and external flash units.

Adobe Photoshop CC 2017 was used to create the focus stack, as well as spot-heal and sharpen the final output.

Copyright © 2019 Walter Sanford. All rights reserved.

Test shots: “Generic Baskettail?”

February 15, 2019

larva/nymph in the Family Corduliidae (Emeralds) was collected by Bob Perkins on 02 December 2017 from a pond in Orange Park, Florida (USA). The larva died before it metamorphosed into an adult.

Test shots of this beautifully preserved specimen were taken using a small-ish aperture of f/11 for greater depth of field. The following photos are “one-offs,” that is, not composite images.

Dorsal

A single focus point — located on the thorax (specifcally, the “shoulder pad” along the right side of the body) — was used to shoot this photo. The specimen has enough “relief” that focus on the wing pads and dorsal hooks is slightly soft. This view of the larva is a good candidate for focus-stacking.

The terminal appendages (cerci, epiproct, paraprocts) are shown clearly in the following photo.

“Generic Baskettail” larva (preserved specimen) | Orange Park, FL USA

Bob’s best guess of the identity of the specimen is Epitheca sp., either Common Baskettail (Epitheca cynosura) or Prince Baskettail (Epitheca princeps).

Whenever I see an odonate larvae/exuviae with long legs, my first thought is Family Macromiidae (Cruisers). Then I check for a horn on top of the head, a key field marker for Cruisers. Look closely at the dorsal view of the larva and I think you’ll agree with me there appears to be a horn on the head. I would like to take close-up photos of the head and key out the specimen in order to determine its identity. In the meantime, my best guess is Stream Cruiser (Didmops transversa) as indicated by the lateral spines on abdominal segment nine (S9) and the absence of a dorsal hook on S10.

Ventral

The ventral side of the specimen has almost no “relief,” so a “one-off” focused on the thorax looks fairly good from head-to-tail.

“Generic Baskettail” larva (preserved specimen) | Orange Park, FL USA

Related Resource: “Generic Baskettail” (definitely not a Cruiser)

Tech Tips

The following equipment (shown below) was used to shoot the preceding photos: Fujifilm X-T1 digital camera; Fujifilm MCEX-16 extension tube; Fujinon XF80mm macro lensGodox XProF TTL Wireless Flash Trigger for Fujifilm camerasGodox TT685F Thinklite TTL Flash for Fujifilm CamerasGodox TT685C Thinklite TTL Flash for Canon Cameras fitted with a Lastolite Ezybox Speed-Lite 2 flash modifier; and a Canon 580EX II Speedlite mounted on a Godox X1R-C TTL Wireless Flash Trigger Receiver for Canon. A new Godox TT685O Thinklite TTL Flash for Olympus/Panasonic Cameras was added to an array of radio-controlled external flash units used to light the specimen. All flashes were set for Manual Mode at 1/128 power.

Adobe Photoshop CC 2017 was used to spot-heal and sharpen the final output.

Copyright © 2019 Walter Sanford. All rights reserved.

More composite images: P. obscurus exuvia

February 6, 2019

The following focus-stacked composite images show dorsal- and ventral views of the exuvia from a Common Sanddragon (Progomphus obscuruslarva that was collected and reared by Bob Perkins.

Here are some personal observations after examining the specimen carefully.

The front- and middle legs block the mentum (prementum). This specimen is a good candidate for rehydrating the exuvia and reposing its legs.

Related Resource: Composite image: Progomphus obscurus exuvia.

Tech Tips

Six (6) photos were used to create the first focus stack; seven (7) photos were used for the second. A single focus point was positioned over select anatomical features, working from back-to-front; photos were taken at each point of interest.

The following equipment was used to shoot all of the photographs for the two focus-stacked composite images, shown above: Canon EOS 5D Mark II digital camera, in manual mode; Kenko 20mm macro automatic extension tubeCanon EF100mm f/2.8L Macro lens (set for manual focus); and Canon MT-26EX-RT Macro Twin Lite set for “Master” mode, and several external flashes set for “Slave” mode including Canon 580 EX- and Canon 580EX II Speedlites and a Godox TT685C Thinklite TTL Flash fitted with a Lastolite Ezybox Speed-Lite 2 flash modifier.

Adobe Photoshop CC 2017 was used to create the focus-stacked composite images, as well as spot-heal and sharpen the final output.

Copyright © 2019 Walter Sanford. All rights reserved.

Composite image: Progomphus obscurus exuvia

February 4, 2019

The following focus-stacked composite image shows the exuvia from a Common Sanddragon (Progomphus obscurus) larva that was collected and reared by Bob Perkins.

I have 10s, maybe 100s, of Common Sanddragon exuviae in my collection, but have never seen one cleaner than this beautiful specimen. I didn’t realize P. obscurus larvae are so hairy!

Related Resource: More composite images: P. obscurus exuvia.

Tech Tips

11 photos were used to create the focus stack. A single focus point was positioned over select anatomical features, working from back-to-front; photos were taken at each point of interest.

The following equipment was used to shoot the preceding composite image: Canon EOS 5D Mark II digital camera, in manual mode; Canon MP-E 65mm Macro lens (set for f/11 at 3x); and Canon MT-26EX-RT Macro Twin Lite set for “Master” mode, and several external flashes set for “Slave” mode including Canon 580 EX- and Canon 580EX II Speedlites and a Godox TT685C Thinklite TTL Flash fitted with a Lastolite Ezybox Speed-Lite 2 flash modifier.

Auto power-off was disabled for the camera and all external flash units.

Adobe Photoshop CC 2017 was used to create the focus stack, as well as spot-heal and sharpen the final output.

Copyright © 2019 Walter Sanford. All rights reserved.

Test shot: Cordulegaster sp. larva

February 1, 2019

Bob Perkins collected and reared a larva/nymph from the Family Cordulegastridae (Spiketails). The larva died before it metamorphosed into an adult.

Test shots of this beautifully preserved specimen (Cordulegaster sp.) were taken using a relatively small aperture of f/16 for greater depth of field. The following photo is a “one-off,” that is, not a composite image.

Cordulegaster sp. larva (preserved specimen) | face-head

Odonates are aquatic insects. They spend most of their life as larvae that live in water; this stage of their life cycle can last from a few months to a few years. Finally, they emerge from the water and metamorphose into adults in order to reproduce; their offspring return to the water and the cycle begins again.

Most larvae go through 10-13 stages of development known as “instars.” The author lacks sufficient experience to identify the instar of this specimen, although it appears to be one of the later stages.

Related Resources

Tech Tips

The following equipment was used to shoot the preceding photo: Canon EOS 5D Mark II digital camera, in manual mode; Canon MP-E 65mm Macro lens (set for 3x); and Canon MT-26EX-RT Macro Twin Lite set for “Master” mode, and several external flashes set for “Slave” mode including Canon 580 EX- and Canon 580EX II Speedlites and a Godox TT685C Thinklite TTL Flash fitted with a Lastolite Ezybox Speed-Lite 2 flash modifier. A Sunpak LED-160 Video Light was used to light the underside of the white plastic posing “stage.”

Auto power-off was disabled for the camera and all external flash units.

Adobe Photoshop CC 2017 was used to spot-heal and sharpen the final output.

Copyright © 2019 Walter Sanford. All rights reserved.

Monarch butterfly chrysalises

February 7, 2017

Let’s continue the Monarch butterfly (Danaus plexippus) theme by flashing back to a time several years ago when my best camera for photowalking was either an Apple iPhone or whatever camera gear I could borrow.

Patuxent Research Refuge

A Monarch butterfly chrysalis was spotted on 02 September 2012 at the Patuxent Research Refuge, Laurel, Maryland USA. The chrysalis was attached to a telephone callbox outside the Visitor Contact Station, North Tract. The chrysalis was located near a bed of milkweed plants. I observed Monarch butterfly caterpillars (larvae) feeding on the same milkweed on 26 August 2012.

The next image is a closer crop of the preceding photo, taken using a loaner Canon EOS Rebel XTi DSLR camera.

Hollin Meadows Elementary School

A Monarch butterfly chrysalis casing was spotted during a photowalk on 09 October 2010 at the Children’s Garden at Hollin Meadows Science and Math Focus School, Fairfax County, Virginia USA. The chrysalis was attached to the outside of a classroom window near a planting of Scarlet milkweed (Asclepias curassavica).

I observed Monarch butterfly caterpillars (larvae) feeding on the Scarlet milkweed plants during late August through early September 2010. Sometime later, during the pupal stage of its life, one of the caterpillars created a chrysalis on a classroom window in order to transform from larva to adult. I discovered the empty casing after the adult Monarch butterfly had emerged from its chrysalis.

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

The photo was taken using an Apple iPhone 3GS and annotated using Adobe Photoshop.

Copyright © 2017 Walter Sanford. All rights reserved.


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