Sometimes I’m a content creator; sometimes I share content created by others, especially when the content is better than I could create myself.
Apple iMovie: Magic Movie
The latest version of iMovie includes a new feature called “Magic Movie.” Although I’ve never used “Quik,” the GoPro pay-to-play app that makes it easier for beginner videographers to create movies, I think “Magic Movie” targets the same demographic and does essentially the same thing as “Quik.” Both “Quik” and “Magic Movie” enable the user to quickly combine photos, video clips, and music into a punchy little movies.
How to make a Magic Movie video in iMovie 3, by Roman Loyola, Senior Editor, Macworld explains how to use Magic Movie on iOS devices including iPad and iPhone. The article features detailed, step-by-step directions that are richly illustrated with an embedded video and lots of screenshots.
Apple QuickTime
Don’t sleep on “QuickTime,” a versatile free utility from Apple, that’s capable of doing some of the same things that were covered in my last two blog posts.
For some species of odonate exuviae, sex is indicated by a form of remnant reproductive anatomy. These external structures don’t look exactly the same for all species of dragonflies and damselflies, but their function is identical.
The following photograph shows a ventral view of a femaleCommon Green Darner dragonfly. Notice the external reproductive anatomical structure on abdominal segment nine (S9) is virtually identical to the remnant anatomical structure on S9 of the exuvia, shown above.
Original photo used with permission from Louisa C. Craven.
The Backstory
My dear friend Louisa Craven discovered the lifeless adult dragonfly while on vacation with her family in Nags Head, North Carolina USA. Louisa is an accomplished wildlife photographer who developed an interest in odonates as a result of many photowalks with me.
Thanks to Louisa Craven, my good friend and photowalking buddy, for holding the specimen in the first two photos while I used her Apple iPhone 4S to take photos. This was our first “stream walk” in search of dragonflies and damselflies and both of us were afraid to carry our camera gear as we waded in the river.
I posted these photos in my Project Noah Nature Journal two days after an Audubon Naturalist Society field trip to the North Tract of the Patuxent Research Refuge, led by Richard Orr, renowned expert on odonates of the mid-Atlantic region of the United States.
“Hollin Hills is a development in Fairfax County, Virginia, about 10 miles outside of Washington, D.C. It has about 450 houses. It was designed by Charles Goodman and developed by Robert Davenport.” Source Credit: “Hollin Hills” website (no longer online).
The Civic Association of Hollin Hills (CAHH) owns and maintains seven small parks in the community: the Wildlife Sanctuary; Sutton Potter Park; Brickelmaier Park; Charles Goodman Park; Paul Spring Park; “Mac” McCalley Park; and Voigt Memorial Park.
All of the parks are located along streams except Sutton Potter Park and McCalley Park. The Wildlife Refuge/Sanctuary extends from Woodlawn Trail to the dogleg in the road at Boswell Avenue and Delafield Place. Two parks straddle creeks that are tributaries of Paul Spring, a stream that runs along Paul Spring Road: Brickelmaier Park runs from Popkins Lane to Paul Spring Road; Goodman Park runs from Marthas Road to Paul Spring Road. Paul Spring Park runs along Paul Spring from the intersection of Rebecca Drive and Paul Spring Road to the intersection of Rippon Road and Paul Spring Road, directly across the street from McCalley Park and Voigt Park. The upstream end of Paul Spring Park is near White Oaks Park, a mid-size park maintained by Fairfax County Park Authority.
Sutton Potter Park was featured in an article that appeared in Washingtonian Magazine, “Best of 2004: Sledding Hills.” I shot two photos from a viewpoint about halfway up the long hill: one looking downhill; another looking uphill. Trust me, neither photo provides a sense of the true steepness of the hillslope — a sled ride downhill could be either extremely exhilarating or very terrifying! The park entrance is located at the 7400 block of Range Road; another entrance is located behind the townhouses along Windbreak Drive.
During Fall 2010, I used my Apple iPhone 3G and an app called “EveryTrail” to create an interactive map showing the location of the entrances to the CAHH parks. At some point, I noticed the hyperlink to the interactive map stopped working.
As it turns out, ownership of “EveryTrail” transferred to “TripAdvisor” in 2011; EveryTrail was acquired by “AllTrails” in 2016.
All of the interactive trail maps that I created eight years ago survived two ownership transfers, much to my surprise! Some of the interactivity of the original maps was lost in translation, but hey, all is not lost. “Walking Tour of CAHH Parks” is the current iteration of the interactive map, available from AllTrails. See also “Walking Tour of Huntley Meadows Park (Ver. 2).”
Tech Tips
The “EveryTrail” app was used to record a GPX file that traces the route I walked.
Photos were shot at selected waypoints. All photos featured in both interactive trail maps were taken using the built-in camera of my Apple iPhone 3G; the photos were geotagged automatically by the iPhone’s GPS receiver.
All female dragonflies have a pair of cerci (superior appendages) that have little or no function. The hind wings of female Mocha Emerald dragonflies are rounded.
21 JUL 2017 | Henrico County, VA | Mocha Emerald (female)
(See a full-size version of the original photo, without annotation.)
21 JUL 2017 | Henrico County, VA | Mocha Emerald (female)
(See a full-size version of the original photo, without annotation.)
Notice the subgenital plate shown in the preceding photo.
subgenital plate: plate below S8 that holds bunches of eggs when enlarged; variable enough in shape to be of value in identification. Source Credit: Paulson, Dennis (2011-12-19). Dragonflies and Damselflies of the East (Princeton Field Guides) (Kindle Locations 11723-11724). Princeton University Press. Kindle Edition.
“S8” refers to abdominal segment eight. Remember that all dragonflies and damselflies have a 10-segmented abdomen, numbered from front to back.
Oviposition (egg-laying)
The following Apple iPhone 3GS “raw” video clip shows a female Mocha Emerald dragonfly laying eggs by the process of oviposition. The process typically lasts a few seconds to a few minutes. This individual was spotted on 16 July 2011 during a photowalk through the “Wildlife Sanctuary,” one of seven small parks in the community of Hollin Hills, Fairfax County, Virginia USA.
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.
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.
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!
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.
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.
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.
In Raiders of the Lost Park, a.k.a., “The Wall” — the last post in my photoblog — readers were challenged to guess the location in Huntley Meadows Park where the following photograph was taken.
11 March 2016 | Huntley Meadows Park | Building ruins
After shooting the preceding photograph, I used the Apple “Compass” app (free) for iPhone to determine my exact location. Tech Tip: Capture an image of the iPhone screen by pressing the “Home” and “Power” buttons simultaneously.
“Compass” app icon
Next, open Google Maps in a Web browser; click on the button labeled “Earth” (lower-left corner of window). Enter the following text string (refer to the “Compass” app screen capture, shown above) in the field labeled “Search Google Maps”: 38 46 3 N 77 7 1 W. Press the “return” key; the following satellite image/map should appear.
Pretty cool, huh? Well, now you know my exact location when I photographed the “The Wall.” Notice the “Compass” app also shows I was facing south-southwest when the photo was taken. In other words, I was standing where the red pin appears on the map, facing toward the bottom, a little left of center (relative to the map).
Hiking Directions: From the parking lot at the head-end of the Hike-Bike Trail, walk uphill along S. Kings Hwy. Stop at at the BEGINNING of the guard rail. Look to the right (about 1:30 to 2 o’clock) and you can see the building ruins. Walk a straight line path between the beginning of the guard rail and the ruins; there are fewer thorny vines along this route than I encountered/suffered by following the directions given to me!
Tech Tip: Some of my fellow WordPress bloggers may be wondering, “How did you embed an interactive Google Map in this post?” WordPress “Support” is your friend: Support / Google Maps / Embedding a Google Map.
In Where’s Waldo? — the last post in my photoblog — readers were challenged to guess the location in Huntley Meadows Park where the following photograph was taken.
After shooting the preceding photograph, I used the Apple “Compass” app (free) for iPhone to determine my exact location. Tech Tip: Capture an image of the iPhone screen by pressing the “Home” and “Power” buttons simultaneously.
“Compass” app icon
“Compass” app screen capture
Next, open Google Maps in a Web browser; click on the button labeled “Earth” (lower-left corner of window). Enter the following text string (refer to the “Compass” app screen capture, shown above) in the field labeled “Search Google Maps”: 38 45 8 N 77 6 44 W. Press the “return” key; the following satellite image/map should appear.
Pretty cool, huh? Well, now you know my exact location when I photographed the “Mystery Pool.” Notice the “Compass” app also shows I was facing south-southwest when the photo was taken. In other words, I was standing where the red pin appears on the map, facing toward the bottom, a little left of center (relative to the map).
Tech Tip: Some of my fellow WordPress bloggers may be wondering, “How did you embed an interactive Google Map in this post?” WordPress “Support” is your friend: Support / Google Maps / Embedding a Google Map.
What happens after odonates copulate? There are three possible outcomes:
Nothing, that is, the male and female copulate, separate, and go their own way before the female lays eggs (oviposition) by herself.
“Contact guarding,” in which the male and female fly “in tandem” to egg-laying sites.
“Non-contact guarding,” also known as “hover guarding,” in which the male flies frantically back-and-forth over the female as she lays eggs in an effort to guard the female from other opportunistic males looking for a mate.
Field Observations
The following photos and videos show a few examples of contact guarding and non-contact guarding, recorded during several years of photowalks at Huntley Meadows Park.
The first photo shows a mating pair of Orange Bluet damselflies (Enallagma signatum) spotted on 24 August 2014. The pair is “in tandem”: the male is on the upper-left; the female on the lower-right. Notice the female is partially submerged as she inserts eggs into aquatic vegetation (endophytic ovipostion). Orange Bluet is a member of the “Pond Damsels” family of damselflies.
The next photo shows a mating pair of Common Green Darner dragonflies (Anax junius) spotted on 26 August 2014. The pair is “in tandem”: the male is on the upper-right; the female on the lower-left. The female is laying eggs on the surface of underwater plants (epiphytic ovipostion). The Common Green Darner dragonfly is the only North American darner that usually oviposits in tandem.
The last photo shows a mating pair of Autumn Meadowhawk dragonflies (Sympetrum vicinum) spotted on 06 November 2013. The pair is shown “in tandem,” resting between periods of egg-laying: the male is on top; the female is on the bottom. Autumn Meadowhawk is a member of the Skimmer Family of dragonflies.
The first two movies feature mating pairs of Great Blue Skimmer dragonflies (Libellula vibrans); in both videos, the male is shown hover guarding the female as she lays eggs. The first video was recorded on 06 June 2012; the second video was recorded on 24 July 2011.
The last movie features a mating pair of Common Whitetail dragonflies (Plathemis lydia) spotted on 24 July 2011; the male is shown hover guarding the female. Common Whitetail is a member of the Skimmer Family of dragonflies.
Summary
There are three common families of damselflies in the mid-Atlantic United States: Pond Damsels, also known as the “Narrow-winged Damselflies” (Family Coenagrionidae); Broad-winged Damselflies (Family Calopterygidae); and Spreadwings (Family Lestidae).
And there are seven families of dragonflies: Clubtails (Family Gomphidae); Cruisers (Family Macromiidae); Darners (Family Aeshnidae); Emeralds (Family Corduliidae); Petaltails (Family Petaluridae); Skimmers (Family Libellulidae); and Spiketails (Family Cordulegastridae).
I consulted the members of two odonate-related Facebook groups in preparation for writing this post: Northeastern Odonata; and Southeastern Odes. I posed a couple of questions related to odonate reproduction, with the goal of answering one over-arching question: Which families of damselflies and dragonflies engage in some form of post-copulatory guarding?
Is there a common species of dragonfly in which the male abandons the female immediately after mating? No contact guarding, no non-contact guarding, just “Adios muchacha!”
Do all damselfly females lay eggs in tandem with males? If not, then please cite at least one example.
My sincere thanks to two renowned odonate experts who kindly replied to my questions!
Not sure about the first question. I’ve seen plenty of females of many different species arriving alone at a water body to lay eggs but without seeing a mating pair break tandem, it’s hard to say when they separated. Females can store sperm so will often lay eggs without the company of a mate. As for damselflies, off the top of my head, Eastern- and Fragile Forktails typically oviposit alone. Slender Spreadwings too. Source Credit: Ed Lam, author and illustrator of Damselflies of the Northeast.
Skimmers are the only dragonflies in which guarding is common. It doesn’t happen in clubtails, cruisers, darners (except of course in a few kinds of green darners that oviposit in tandem), emeralds, petaltails, and spiketails. Among skimmers, stream breeders such as clubskimmers and sylphs don’t have any kind of guarding. In genera such as Pantala gliders and Tramea saddlebags, if they’re not in tandem then the female oviposits by herself. Forktails are among the few pond damsels that don’t oviposit in tandem (a couple of western species are an exception to the exception). Source Credit: Dennis Paulson, author of Dragonflies and Damselflies of the East.
Coming full circle to the title of this post, most dragonfly males do not engage in post-copulatory guarding; most damselfly males do.
walter sanford's photoblog 