Archive for the ‘iMovie’ Category

Great Spreadwing damselflies (males, gymnasts)

November 9, 2015

The following photos show a Great Spreadwing damselfly (Archilestes grandis) spotted on 08 October 2015, two days after the first Great Spreadwing was observed at a small permanent pond in a remote location at Huntley Meadows Park (HMP). This individual is a male, nicknamed “Mr. Magoo” because of the prominent dark spots in his eyes.

A Great Spreadwing damselfly (Archilestes grandis) spotted at Huntley Meadows Park, Fairfax County, Virginia USA. This individual is a male, nicknamed "Mr. Magoo."

08 OCT 2015 | HMP | Great Spreadwing (male, nicknamed “Mr. Magoo”)

I’m not sure what “Mr. Magoo” was doing in the preceding photo. A novice odonate hunter might be fooled into thinking the damselfly is a female, ovipositing in the grass stem (endophytic oviposition). I speculate the young male was “test-driving” his terminal appendages, with the grass stem serving as a simulation of the neck of a female.

A Great Spreadwing damselfly (Archilestes grandis) spotted at Huntley Meadows Park, Fairfax County, Virginia USA. This individual is a male, nicknamed "Mr. Magoo."

08 OCT 2015 | HMP | Great Spreadwing (male, nicknamed “Mr. Magoo”)

After two seasons of field observation of Great Spreadwing damselflies, I have noticed several males flexing their abdomen like gymnasts. Are they simply stretching, or is this behavior related to a pre-/post-mating ritual? It’s impossible to know for certain, but I’m sure it’s amusing to watch! In particular, notice the unusual “two-step dance” performed by the male featured in the following video.

04 NOV 2015 | HMP | Great Spreadwing (male)

I’m a fairly accomplished photographer, he said, not too modestly. In contrast, my skills as a videographer are relatively rudimentary as evidenced by the preceding video. My movies usually turn out better when I plan the shoot and use a tripod; in this case, the video clips were shot spontaneously (therefore hand-held) when an opportunity presented itself.

One of my mantras of wildlife photography/videography is “get a shot, any shot; refine the shot.” I wish the preceding video had turned out better. Although I was able to shoot a couple of video clips of this unusual gymnastic routine, there was no opportunity to refine the shots. Oh well, maybe next year!

Related Resources:

Editor’s Note: According to Ed Lam, author and illustrator of Damselflies of the Northeast, the damselfly featured in the video is grooming itself.

He appears to be grooming in the video. They can’t reach down to knock off debris, spiderwebs, etc. but they can rub their legs together or against an object. Similarly, the abdomen seems to be contacting the wings. Sometimes you see this behavior after they have been handled and released if they don’t immediately fly away. Source Credit: Ed Lam, Northeast Odonata Facebook group.

Copyright © 2015 Walter Sanford. All rights reserved.

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Slaty Skimmer dragonfly (female, laying eggs)

June 28, 2015

Slaty Skimmer (Libellula incesta) is a member of the Skimmer Family of dragonflies. Females lay eggs (oviposition) by skimming the water surface repeatedly, hence the family name “Skimmer“; two flanges beneath their eighth abdominal segment (S8) scoop water that is used to flick fertilized eggs toward shore, as illustrated in the following annotated image. Remember that all dragonflies and damselflies have a 10-segmented abdomen, numbered from front to back.

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

10 JUN 2015 | Huntley Meadows Park | Slaty Skimmer (mature female)

The preceding still photo shows a mature female Slaty Skimmer dragonfly resting immediately after copulation.

The following movie shows the same female laying eggs in a large pool of water downstream from the central wetland area at Huntley Meadows Park on 10 June 2015.

Tech Tip: The preceding movie looks better viewed in full-screen mode.

Copyright © 2015 Walter Sanford. All rights reserved.

Painted Skimmer dragonfly (female, laying eggs)

June 6, 2015

Painted Skimmer (Libellula semifasciata) is a member of the Skimmer Family of dragonflies. Females lay eggs (oviposition) by skimming the water surface repeatedly, hence the family name “Skimmer“; two flanges beneath their eighth abdominal segment (S8) scoop water that is used to flick fertilized eggs toward the shore, as illustrated in the following annotated image. Remember that all dragonflies and damselflies have a 10-segmented abdomen, numbered from front to back.

The following movie shows a female Painted Skimmer dragonfly laying eggs in a vernal pool at Huntley Meadows Park on 20 May 2015. (Same day, different time. Same park, different location. Same species, different female.)

Editor’s Note: Copulation between male and female Painted Skimmers occurs in-flight and is very brief, lasting just a few seconds. In my experience, oviposition is brief too. My camera was set up for shooting still photographs when I spotted the mating pair; by the time I moved into position, the pair had separated and the female was laying eggs. Fortunately I had the presence of mind to shoot video rather than stills. The video quality isn’t great, buy hey, at least I captured the moment, albeit brief!

Copyright © 2015 Walter Sanford. All rights reserved.

Painted Skimmer dragonfly (female, breathing and grooming)

June 2, 2015

The following movie features a Painted Skimmer dragonfly (Libellula semifasciata) spotted on 20 May 2015 during a photowalk alongside the wetlands at Huntley Meadows Park. This individual is a female, as indicated by its terminal appendages.

Dragonflies breathe through small holes in the underside of their thorax and abdomen called “spiracles.” Notice the dragonfly’s thorax and abdomen expanding and contracting as she inhales and exhales.

The female appears to be grooming while perching on vegetation, using her front legs to wipe her eyes and face. The author has observed many species of dragonflies engaged in similar behavior.

Tech Tips: The preceding movie looks better viewed in full-screen mode.

The video clips used to create this movie were shot on a very windy day. I used a tripod for my camera and centered the subject in each clip, but the wind caused the dragonfly to drift off-center at times. Not that I’m a perfectionist or anything.

Related Rescources:

Copyright © 2015 Walter Sanford. All rights reserved.

Green Frog (male, calling)

January 11, 2015

I spotted a Green Frog (Lithobates clamitans) along the boardwalk in the hemi-marsh at Huntley Meadows Park on 25 May 2014. This individual is a male, as indicated by the size of its tympanum (eardrum).

Females and males can be differentiated by the size of the tympanum (the eardrum, located behind the eye and below the dorsolateral ridge). In females, it is about the same size as the eye and in males it is much larger than the eye. Source Credit: Northern green frog, a Project Noah spotting by Kara Curtain/Jones, graduate student and teaching assistant at George Mason University, Department of Environmental Science and Policy.

Tech Tip: The preceding video looks better viewed in full-screen mode.

Related Resources: Some species of amphibians, such as Spring Peeper (Pseudacris crucifer), are heard more often than seen. In 2014, I resolved to learn the calls of many of the amphibians that are common at Huntley Meadows Park. The following alphabetical list provides quick links to audio recordings of several species of frogs and toads of Virginia, courtesy Virginia Herpetological Society.

Test your skill in identifying frog calls by visiting the USGS Frog Quizzes Web page. Be forewarned: The quizzes are challenging! Refer to Virginia is for Frogs for more frog-related resources including Teacher’s Corner, featuring ideas for lesson plans and activities.

Copyright © 2015 Walter Sanford. All rights reserved.

Autumn Meadowhawk dragonfly (female, breathing and grooming)

December 28, 2014

The following video features an Autumn Meadowhawk dragonfly (Sympetrum vicinum) spotted on 15 November 2013 during a photowalk along the boardwalk in the hemi-marsh at Huntley Meadows Park. This individual is a female, as indicated by its coloration and terminal appendages.

Dragonflies breathe through small holes in the underside of their thorax and abdomen called “spiracles.” Notice the dragonfly’s thorax and abdomen expanding and contracting as she inhales and exhales.

The female appears to be grooming while perching on the warm surface of the boardwalk, using her front legs to wipe her eyes and face. The author has observed many species of dragonflies engaged in similar behavior.

Tech Tip: The preceding video looks better viewed in full-screen mode.

Related Rescources:

Copyright © 2015 Walter Sanford. All rights reserved.

Insex | Part 2: Pas de deux

December 26, 2014

What happens after odonates copulateAutumn Meadowhawk dragonflies (Sympetrum vicinum) engage in a form of guarding behavior known as “contact guarding,” in which the male and female fly “in tandem” to egg-laying sites. Contact guarding is used by some species of odonates to prevent aggressive males from hijacking the female.

The following video shows several mating pairs of Autumn Meadowhawks spotted on 27 October 2014 at a vernal pool in the forest at Huntley Meadows Park. Each pair is in tandem: the male is in front; the female in back. Autumn Meadowhawk is a member of the Skimmer Family of dragonflies: the female dragonfly is laying eggs by the process of oviposition; guided by the male, she skims the water repeatedly, picking up drops of water that are used to flick fertilized eggs toward the shore.

Tech Tip: The preceding video looks better viewed in full-screen mode.

In ballet, a pas de deux (French, literally “step of two”) is a dance duet in which two dancers, typically a male and a female, perform ballet steps together. Source Credit: Pas de deux, Wikipedia.

Copyright © 2014 Walter Sanford. All rights reserved.

What happens after, well, you know?

September 9, 2014

Guarding Behavior in Some Odonates

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.

Orange Bluet damselflies (mating pair, in tandem)

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.

Common Green Darner dragonflies (mating pair, 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.

Autumn Meadowhawk dragonflies (mating pair, in tandem)

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?

  1. 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!”
  2. 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 clubtailscruisers, 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.

Related Resources

Copyright © 2014 Walter Sanford. All rights reserved.

Toad-ally in love! (Part 1)

April 20, 2014

The wetlands are alive, with the sound of trilling! Yep, either I’m channeling Julie Andrews from The Sound of Music or it’s mating season for toads in the mid-Atlantic region of the United States of America.

The mating process begins when male toads, such as the following Eastern American Toad (Anaxyrus americanus), go to a body of water and begin calling females. This individual was spotted on 12 April 2014 in a large vernal pool located near the terminus of the Hike-Bike Trail at Huntley Meadows Park.

American Toad (Anaxyrus americanus)

The following movie shows a male toad calling several times. The mating calls of other male toads can be heard in the background, as well as wind noise (the video clip was recorded on a windy day).

Editor’s Note: This is Part 1 in a five-part series of posts featuring two types of toads commonly seen at Huntley Meadows Park: Eastern American Toads (Anaxyrus americanus); and Fowler’s Toads (Anaxyrus fowleri).

Related Resources:

Copyright © 2014 Walter Sanford. All rights reserved.

Common Whitetail dragonfly (male, breathing)

June 11, 2013

The following video features a Common Whitetail dragonfly (Plathemis lydia) spotted on 31 May 2013 during a photowalk along the boardwalk in the hemi-marsh at Huntley Meadows Park. This individual is a male, as indicated by its coloration and terminal appendages.

Dragonflies breathe through small holes in the underside of their thorax and abdomen called “spiracles.” Notice the dragonfly’s thorax and abdomen expanding and contracting as he inhales and exhales.

Related Resource: Autumn Meadowhawk dragonfly (female, breathing and grooming), featuring an embedded YouTube video (0:30).

Copyright © 2013 Walter Sanford. All rights reserved.


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