During late-October 2021, I was contacted by Miguel A. Conesa-García, PhD, Profesor Tutor Biología, Diversidad Animal, Ciencias Ambientales, UNED-Málaga.
Miguel was working on finishing the second edition of his book about odonate larvae in the Iberian Peninsula (Spain and Portugal). When Miguel was almost finished, an adult male Wandering Glider dragonfly (Pantala flavescens) was spotted in Spain. P. flavescens is a new species of odonate for the region, so Miguel decided to add the new discovery to the species list in his book.
Cover photo, courtesy Amazon Books.
The following screen capture shows the search string I used to find the book on Amazon.
Screen capture, Amazon Books.
The book is richly illustrated with beautiful photos and diagrams. It’s abundantly evident I could learn a lot from the book — I wish there were an English Edition!
Miguel requested permission to use a photo of a Wandering Glider exuvia in my photoblog, published on 14 November 2018. I was, of course, willing to help.
Page excerpt from Miguel’s book, featuring my photo.
I’m mentioned in the acknowledgements at the end of the book. Regrettably my first name is misspelled and the Web address cited is no longer current. I took the liberty of annotating the page from Miguel’s book to provide the correct information.
The exuvia that I photographed is the “cast skin” from an odonate larva (nymph) that was collected in the field by Andy Davidson, a graduate student at Virginia Commonwealth University in Richmond, Virginia USA. Andy reared the larva in the laboratory as part of a research project entitled “Predator-Prey Interactions in a Changing World.”
Part of the value in rearing odonate larvae in the laboratory is knowing with certainty that an exuvia is from a particular species. This is perhaps the reason that Miguel chose to use my photo.
The following photo shows a tiny spider carcass (~3/16″ long) that was inside an exuvia (~1 3/4” long) from a Common Green Darner dragonfly (Anax junius). The exuvia was collected on 17 June 2021 from a small pond in Prince William County, Virginia USA. I discovered the spider long afterward — too late to save its life.
Thanks to Eva Weiderman and Joseph Girgente — members of the “Odonate Larvae and Exuviae” Facebook group — for their help in identifying the specimen as a jumping spider, Family Saticidae.
Salticidae is one of several families of spiders with eight (8) eyes. My take-away from reading the reference on BugGuide entitled “Spider Eye Arrangements” is identification of this specimen to the genus and species level is challenging at best and impossible at worst.
In contrast, it’s well known that spiders use odonate exuviae for shelter. I wish the jumping spider had come out of its most excellent hidey-hole sooner!
“Raynox DCR-250 close-up filter” is a blog post in which I provide more information about how I use the Raynox with my Panasonic Lumix superzoom bridge cameras.
The following product photos show the bottom of Godox X2T-series wireless flash triggers for Canon, Fujifilm, and Olympus/Panasonic digital cameras. The pin pattern on the flash triggers is the mirror image of the pin pattern on the camera hotshoe.
Notice the pin pattern varies by camera brand. One pin — the power pin — is located in the same place on all types of flash brands. The other pins are used to control functions such as Through The Lens flash metering (TTL) and High-Speed Sync (HSS). This is why almost any relatively new external flash unit can be used in Manual mode with almost any relatively new digital camera, but TTL and HSS are incompatible unless the flash is mounted on the hotshoe of a camera with a matching pin pattern.
Cross-compatibility among Godox TT-685-series external flash units
The beauty of the Godox system of external flash units is it’s truly a system — all units that I own and have tested extensively are cross-compatible.
For example, when a Godox TT685F for Fujifilm cameras is used off-camera it can be fully compatible with a Godox TT685O for Olympus and Panasonic cameras (including TTL and HSS functionality) when it’s fired by a flash trigger such as the Godox X2TO. It’s amazing to watch!
The following quick-and-dirty video is another demonstration of the cross-compatibily among Godox TT685-series external flash units.
A Godox TT685F flash for Fujifilm cameras is featured in the preceding video. The flash was fired remotely using a Godox X2TO wireless flash trigger for Olympus and Panasonic cameras.
An Apple iPad mini 2 was used to shoot a raw video clip that was post-processed using Apple iMovie. The magic wand tool in iMovie was used to automatically enhance the audio and video quality of the clip. Audio quality was improved significantly by the magic wand tool!
The mystery item featured in my last blog post is a Christmas tree ornament hanging above a battery-powered flashlight with a low-power incandescent bulb.
Perhaps the bigger mystery is what makes the gold propeller inside the ornament spin around when the flashlight is powered-on.
Christmas tree ornament hanging above a flashlight.
Energy Transformations
When I taught 8th grade Physical Science classes, “energy transformations” was an overarching theme in one of the lab manuals for the course.
The Rayovac No. H22 Industrial Flashlight (shown above) uses two 1.5 V D-cell batteries to power a 2.4 V incandescent bulb. When the flashlight was powered-on and placed below the Christmas tree ornament, the following energy transformations occured.
potential energy → chemical energy → electrical energy → radiant energy → thermal energy → kinetic energy
Knowing that kinetic energy can be thought of as energy of motion, the question remains: What gives the spinning propeller its kinetic energy?
Heat Rises
How many times have you heard this common misconception? “Heat,” more correctly referred to as “thermal energy,” flows from higher to lower concentration of thermal energy, regardless of directions such as up or down. So what causes the propeller to spin?
Thermal energy from the incandescent flashlight bulb causes the temperature of the air around the flashlight bulb to increase. The warm air around the bulb is less dense than the surrounding air so it rises; the rising air current causes the gold propeller inside the Christmas tree ornament to spin. It’s worth noting I removed the plastic “lens” from the face of the flashlight head so it wouldn’t block airflow from the light bulb to Christmas tree ornament.
The Backstory
The Christmas tree ornament shown above is a treasured memento from my early childhood. My parents bought two similar ornaments: one is blue with a gold propeller; the other is green with a red propeller (not shown).
One of the ornaments was a gift for my sister; the other was for me. I can’t remember which one was given to me. In my defense, that was a long time ago — I might have been as young as three or four years old when we got the ornaments. That said, I remember clearly how fascinated I was with the spinning propeller inside the ornament!
At that time, Christmas tree lights were relatively large colored incandescent bulbs that got uncomfortably warm-to-hot when powered-on. When my Christmas tree ornament was hung above one of those lights, the propeller spun much faster than it did when hanging above the smaller flashlight bulb used for my demonstration.
The mystery item featured in my last blog post is a Beetle Spin® 1/8 oz fishing lure.
Beetle Spin® 1/8 oz fishing lure.
Perhaps the bigger mystery is how the fishing lure ended up where I found it, stuck in the bark of a tree (about head height) quite a distance from a small stream that might be fish-less. There was no fishing line attached to the lure. Anyway, there it was.
Beetle Spin® is one of the classic all-purpose fishing lures that is a nice addition to my tackle box.
One way to differentiate Emerald from Skimmer larvae/exuvia is to look for a “ventromedial groove” in the prementum: it’s probably Corduliidae (Emeralds) if there is a ventromedial groove; it’s probably Libellulidae if there isn’t.
Look closely at a version of the preceding photo that was reformatted, rotated, and cropped to show an enlarged view of the prementum. You should notice a ventromedial groove on the basal half of the prementum, indicating this specimen is a member of Family Corduliidae (Emeralds).
One reason I underexposed the photo is to add definition to the ventromedial groove and avoid overexposing the black background.
I prefer a white background for photographing odonate exuviae. Using a black background proved to be more challenging than I expected. More later in a follow-up blog post.
My last blog post was a “sketch pad” of test shots of an exuvia from a Comet Darner dragonfly (Anax longipes) collected by Stanley Caveney on 19 July 2021 from a pond at MeadowWoods in West Elgin, Ontario, Canada. All of the shots in that post are unedited JPGs straight from my camera. This post features edited versions of the RAF (raw) files from that photo shoot, including some images with value-added annotations.
I used Adobe Photoshop to create a composite image that features the best parts of two photos from the sketch pad.
This specimen is from a male Comet Darner, as indicated by its vestigial primary- and secondary genitalia. The inset photo shows a clear view of the vestigial hamuli (secondary genitalia) that are partially obscured in the background photo.
All of the shots in this post are unedited JPGs straight from my camera, with the exception of the first ventral view (cropped to remove a distracting element from the composition).
Lateral view
I started with a lateral view of an exuvia from a Comet Darner dragonfly (Anax longipes) exuvia collected by Stanley Caveney on 19 July 2021 from a pond at MeadowWoods in West Elgin, Ontario, Canada.
The next two photos show my frustratingly poor attempts to pose the specimen for shots of the ventral side of the exuvia. Every time I positioned the subject the way I wanted, it rolled over before I could take a shot!
The two shots combined show the vestigial primary- and secondary genitalia that indicate this specimen is from a male Comet Darner. Yeah, I know it would help to annotate those parts of its anatomy, but that’s the next step. In the meantime, please follow the embedded hyperlink shown above and you might be able to figure out what I’m saying.
The last photo shows a closer view of the prementum. My goal was to get a better look at the labial palps. Again, annotations would help, but if you know what I’m talking about then you can see the palpal lobes are squared off.
The horn is clearly visible in the last photo. Notice there are three “bumps” located between the eyes of the exuvia: the middle bump is the horn; the antennae bases are located to the left and right of the horn.
walter sanford's photoblog 