The real monsters of Huntley Meadows

September 19, 2014

Longtime residents of eastern Fairfax County, Virginia USA may recall reading about the “Mount Vernon Monster” that reportedly roamed the region during the late 1970s. Although I have neither seen nor heard the monster, I jokingly reply “Bigfoot” whenever people pass me at Huntley Meadows Park and ask whether I shot any good photographs. But seriously, folks — there are real monsters at the park, including horse flies and robber flies.

The following photos show two horse flies, possibly Tabanus calens, spotted during recent photowalks along the boardwalk in the central wetland area. Both individuals are females. Male horse flies don’t bite; females bite, painfully!

Adult horse flies feed on nectar and sometimes pollen. Females of most species are anautogenous, meaning they require a blood meal before they are able to reproduce effectively, if at all. Much like male mosquitoes, male Tabanidae are not ectoparasitic and lack the mouth parts (mandibles) that the females use in drawing the blood on which they feed. Most female horse flies feed on mammalian blood, but some species are known to feed on birds or reptiles. Some are said to attack amphibians as well. Source Credit: Horse-fly, from Wikipedia.

Horse fly (female)

17 September 2014. Photo 1. Horse fly (female).

Males have eyes that meet along a seam down the middle of the head (holoptic eyes); females have eyes that are well-separated. Source Credit: Benjamin A. Coulter, member of the BugGuide group on Facebook.

Horse fly (female)

17 September 2014. Photo 2. Horse fly (female).

The next gallery shows another female horse fly spotted along the boardwalk on 15 September 2014.

The last photo shows a Red-footed Cannibalfly (Promachus rufipes), a species of robber fly spotted near the beginning of the boardwalk.

Red-footed Cannibalfly (Promachus rufipes)

10 September 2014. Red-footed Cannibalfly.

Robber flies feed mainly on other insects. (Whew, that’s a relief!)

The fly attacks its prey by stabbing it with its short, strong proboscis injecting the victim with saliva containing neurotoxic and proteolytic enzymes which very rapidly paralyze the victim and soon digest the insides; the fly then sucks the liquefied material through the proboscis. Source Credit: Asilidae, from Wikipedia.

There are “approximately 1,040 species of robber flies in approximately 100 genera in our area.” Source Credit: Family Asilidae – Robber Flies, from BugGuide. Thanks to Mike Powell, fellow wildlife photographer and blogger, for identifying the species of robber fly shown above!

Copyright © 2014 Walter Sanford. All rights reserved.

Slaty Skimmer dragonfly (mature male)

September 17, 2014

Another photograph from my “Simply Slaty” series …

Slaty Skimmer dragonfly (mature male)

The preceding photo shows a Slaty Skimmer dragonfly (Libellula incesta) spotted in the hemi-marsh at Huntley Meadows Park on 10 September 2014. This individual is a mature male, as indicated by its coloration, terminal appendages, and tattered wings.

Copyright © 2014 Walter Sanford. All rights reserved.

The Bronze Age

September 15, 2014

The following photograph shows a Great Blue Skimmer dragonfly (Libellula vibrans) spotted during a photowalk along the boardwalk in the central wetland area at Huntley Meadows Park on 12 September 2014. This individual is an old female, as indicated by its coloration, terminal appendages, and tattered wings.

Female Great Blue Skimmers have a pair of flanges beneath their eighth abdominal segment that are used to scoop and hold a few drops of water when laying eggs (oviposition), hence the family name “Skimmer.” Remember that all dragonflies and damselflies have a 10-segmented abdomen, numbered from front to back.

Great Blue Skimmer dragonfly (mature adult female)

Contrast the coloration of the old female (above) with a young female (below), shown in flight as she is laying eggs (oviposition) in a vernal pool in the forest. The photo was taken on 17 July 2014.

Great Blue Skimmer dragonfly (female, oviposition)

No wonder the first step in “Five steps to the next level of dragonfly spotting” says …

Step 1. Be aware the same species of dragonfly may appear differently depending upon gender, age, and natural variation. Some species display sexual dimorphism; in contrast, both genders look virtually identical for some species. Source Credit: Walter Sanford. Educator, Naturalist, and Photographer.

Copyright © 2014 Walter Sanford. All rights reserved.

Handsome Meadow Katydids (mating pair)

September 13, 2014

Handsome Meadow Katydids (mating pair)

The preceding photograph shows a mating pair of Handsome Meadow Katydids (Orchelimum pulchellum) spotted during a a photowalk along the boardwalk in the central wetland area at Huntley Meadows Park on 10 September 2014.

Can you tell which member of the mating pair is the male and which one is the female? Hint: There is at least one obvious difference between the two individuals.

Handsome Meadow Katydid (female)

Look closely at the preceding photo, taken at Huntley Meadows on 12 September 2014. Did you notice the long, curved, reddish-colored structure extending from the posterior end of the abdomen? It’s an ovipositor that female katydids …

… use to insert eggs into hiding places (which can be in crevices on plants or even inside plant tissues). Source Credit: Matt Pelikan, BugGuide group on Facebook.

The following photo was shot at Huntley Meadows on 10 September 2014. This individual is a male, as indicated by the absence of an ovipositor.

The wings pretty much obscure the most visible male parts, but these also have distinctive shapes in katydids and are useful for ID. Source Credit: Matt Pelikan, BugGuide group on Facebook.

Handsome Meadow Katydid (male)

Coming full circle to the mating pair of Handsome Meadow Katydids shown in the first photo, the female is on top and the male is on the bottom.

Copyright © 2014 Walter Sanford. All rights reserved.

Blue Dasher dragonfly (adult female, oviposition, in flight)

September 11, 2014

Blue Dasher dragonfly (female, oviposition, in flight)

The photographs in this post show a Blue Dasher dragonfly (Pachydiplax longipennis) spotted during a photowalk along the boardwalk in the central wetland area at Huntley Meadows Park on 24 August 2014. This individual is an adult female, as indicated by its coloration and terminal appendages, shown in flight as she is laying eggs (oviposition) in the hemi-marsh.

Blue Dasher dragonfly (female, oviposition, in flight)

Editor’s Note: I used a Canon 580EX II Speedlite mounted on my Panasonic Lumix DMC-FZ150 superzoom digital camera — it works much better than the built-in pop-up flash! The external flash unit works in manual mode only. For more information, see Lessons Learned: How to use a superzoom camera to shoot insect photos.

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.

Twelve-spotted Skimmer dragonfly (adult male)

September 7, 2014

Twelve-spotted Skimmer dragonfly (adult male)

The preceding photo shows a Twelve-spotted Skimmer dragonfly (Libellula pulchella) perching alongside the boardwalk in the central wetland area at Huntley Meadows Park on 04 September 2014. This individual is an adult male, as indicated by its coloration and terminal appendages.

The soft pastel colors in the background are a mirror image of the blue sky and white clouds overhead, reflected from the hemi-marsh. Look closely at a full-size version of the photo and you can see the sky reflected from the dragonfly’s left eye!

The next photo seems to evoke a different mood, despite the fact that it’s the same dragonfly perching in nearly the same spot.

Twelve-spotted Skimmer dragonfly (adult male)

Related Resources: Digital Dragonflies, presenting high-resolution digital scans of living dragonflies.

  • Genus Libellula | Libellula pulchella | Twelve-spotted Skimmer | male | top view
  • Genus Libellula | Libellula pulchella | Twelve-spotted Skimmer | male | side view

Editor’s Note: I used a Canon 580EX Speedlite mounted on my Panasonic Lumix DMC-FZ150 superzoom digital camera to shoot this photograph. The 580EX seems to “play nicer” with the Panasonic than my 580EX II. In particular, the 580EX always “wakes up” automatically whenever the camera exits power-saver mode; the 580EX II has to be forced to wake up sometimes (by pressing the “Pilot” button). For more information, see Lessons Learned: How to use a superzoom camera to shoot insect photos.

Copyright © 2014 Walter Sanford. All rights reserved.

Eastern Amberwing dragonfly (male)

September 5, 2014

Another photograph from the “simpler is better” school of thought …

Eastern Amberwing dragonfly (male)

The preceding photo shows an Eastern Amberwing dragonfly (Perithemis tenera) perching alongside the boardwalk in the central wetland area hemi-marsh at Huntley Meadows Park on 20 August 2014. This individual is a male, as indicated by its coloration and terminal appendages.

Eastern Amberwing is the smallest of 37 species of dragonflies on the “Dragonflies and Damselflies of Huntley Meadows Park” species list. Elfin Skimmer (Nannothemis bella) is the smallest species of dragonfly in North America, measuring approximately one inch (1″) in length!

Editor’s Note: This photo was taken using my new Fujifilm X-T1 digital camera and 55-200mm zoom lens (88-320mm, 35mm equivalent). I used the Fujifilm Shoe Mount Flash EF-42 in TTL mode with a shutter speed of 1/250s.

Copyright © 2014 Walter Sanford. All rights reserved.

Black Saddlebags dragonfly (male)

September 3, 2014

The following photos show a Black Saddlebags dragonfly (Tramea lacerata), spotted during a photowalk at Huntley Meadows Park on 29 August 2014. This individual is a male, as indicated by its coloration and terminal appendages.

It is uncommon to see the broad-winged skimmers from the genus Tramea perching. Dragonflies are classified as either “fliers” or “perchers,” based upon their feeding habits. Black Saddlebags are fliers.

Black Saddlebags dragonfly (male)

Black Saddlebags is one of at least five major species of dragonflies known to be migratory in North America. See interactive three-dimensional (3-D) virtual imagery of the five migratory dragonflies, including Black Saddlebags, provided by the Migratory Dragonfly Partnership. Very cool!

Black Saddlebags dragonfly (male)

Near the end of the boardwalk in the central wetland area at Huntley Meadows Park, part of the forest is “drowned” as a result of the wetland restoration project. Some trees thrive in standing water; others not so much and they are dying slowly, causing their leaves to display the colors of autumn a month-or-so earlier than usual. I was able to compose several shots so the dragonfly was framed against a soft background of fall colors reflected from the surface of the hemi-marsh.

Black Saddlebags dragonfly (male)

In the next photo, the male dragonfly appears to be grooming while perching on a twig, using his front legs to wipe its eyes and face.

Black Saddlebags dragonfly (male)

Late afternoon sunlight reflected from the dragonfly’s wings caused spectacular highlights in some poses, as shown below.

Black Saddlebags dragonfly (male)

All male dragonflies have three terminal appendages, collectively called “claspers,” that are used to grab and hold female dragonflies during mating: an upper pair of cerci (“superior appendages”); and an epiproct (unpaired “inferior appendage”).

Cerci very long (more than twice as long as epiproct) and black. Source Credit: Paulson, Dennis (2011-12-19). Dragonflies and Damselflies of the East (Princeton Field Guides) (Kindle Locations 11241-11242). Princeton University Press. Kindle Edition.

Both the cerci and epiproct are shown clearly in the following photograph.

Black Saddlebags dragonfly (male)

Related Resources: Digital Dragonflies, presenting high-resolution digital scans of living dragonflies.

  • Genus Tramea | Tramea lacerata | Black Saddlebags | male | top view
  • Genus Tramea | Tramea lacerata | Black Saddlebags | male | side view

See also Dragonfly grooming (2:26), a YouTube video featuring a male Blue Dasher dragonfly (Pachydiplax longipennis).

Editor’s Note: The preceding photos were taken using my new Fujifilm X-T1 digital camera and 55-200mm zoom lens (88-320mm, 35mm equivalent). I used the Fujifilm Shoe Mount Flash EF-42 in TTL mode with a shutter speed of 1/250s rather than the X-T1’s 180x default sync speed.

Copyright © 2014 Walter Sanford. All rights reserved.

“The A-Team”

September 1, 2014

Handsome subject, simple composition, pleasing combination of rich colors (especially the eyes), good exposure, and sharp focus — I love it when a plan comes together!

Blue Dasher dragonfly (male)

The preceding photograph shows a Blue Dasher dragonfly (Pachydiplax longipennis) spotted during a photowalk along the boardwalk in the central wetland area at Huntley Meadows Park on 24 August 2014. This individual is a male, as indicated by its coloration and terminal appendages.

Editor’s Note: I used a Canon 580EX II Speedlite mounted on my Panasonic Lumix DMC-FZ150 superzoom digital camera — it works much better than the built-in pop-up flash! The external flash unit works in manual mode only, but hey, it works well when set properly. For more information, see Lessons Learned: How to use a superzoom camera to shoot insect photos.

Copyright © 2014 Walter Sanford. All rights reserved.


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