Posts Tagged ‘heteromorph’

Post update

November 15, 2016

The first official record of Blue-faced Meadowhawk dragonfly (Sympetrum ambiguum) at Jackson Miles Abbott Wetland Refuge was observed at Mulligan Pond on 15 September 2016. 10 days later, another Blue-faced Meadowhawk was spotted near the same location.

A female Blue-faced Meadowhawk dragonfly (Sympetrum ambiguum) spotted at Jackson Miles Abbott Wetland Refuge, Fairfax County, Virginia USA. This individual is an heteromorph.

25 SEP 2016 | JMAWR | Blue-faced Meadowhawk (female heteromorph)

This individual is a female heteromorph, as indicated by her tan coloration and terminal appendages.

As it turns out, the female spotted on the 15th and this one spotted on the 25th were the only Blue-faced Meadowhawks seen during many photowalks around Mulligan Pond during Fall 2016.

Copyright © 2016 Walter Sanford. All rights reserved.

Advertisements

Shadow Darner dragonfly (female)

October 18, 2016

A Shadow Darner dragonfly (Aeshna umbrosa) was spotted during a photowalk at Mulligan PondJackson Miles Abbott Wetland Refuge (JMAWR).

A Shadow Darner dragonfly (Aeshna umbrosa) spotted at Mulligan Pond, Jackson Miles Abbott Wetland Refuge, Fairfax County, Virginia USA. This individual is a female heteromorph.

14 OCT 2016 | JMAWR | Shadow Darner (female heteromorph)

This individual is a mature female, as indicated by her coloration, rounded hindwings (near abdomen), and terminal appendages. Female Shadow Darners are polymorphic; this one is a female heteromorph, as indicated by her brown eyes and duller coloration than males of the same species.

A Shadow Darner dragonfly (Aeshna umbrosa) spotted at Mulligan Pond, Jackson Miles Abbott Wetland Refuge, Fairfax County, Virginia USA. This individual is a female heteromorph.

14 OCT 2016 | JMAWR | Shadow Darner (female heteromorph)

The following annotated image illustrates some parts of the reproductive anatomy of a female Shadow Darner dragonfly, including an ovipositor for egg-laying and two styli (sing. stylus), structures that serve as sensors in egg positioning.

A Shadow Darner dragonfly (Aeshna umbrosa) spotted at Mulligan Pond, Jackson Miles Abbott Wetland Refuge, Fairfax County, Virginia USA. This individual is a female heteromorph. [Good view of ovipositor/styli.]

14 OCT 2016 | JMAWR | Shadow Darner (female heteromorph)

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

Both female and male Shadow Darners have two long, petal-like cerci (sing. cercus). Notice the female (shown above) is missing both cerci.

[Female] Cerci rounded at tip, longer than S9–10, usually broken off at maturitySource Credit: Paulson, Dennis (2011-12-19). Dragonflies and Damselflies of the East (Princeton Field Guides) (Kindle Location 4604). Princeton University Press. Kindle Edition.

In contrast, the following male has both cerci and an epiproct; the three terminal appendages are collectively called “claspers.” Claspers are used to grab and hold female damselflies during mating.

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

Related Resources: Scanned digital images from Western Odonata Scans in Life.

  • Shadow Darner | Aeshna umbrosaheteromorph female
  • Shadow Darner | Aeshna umbrosaheteromorph female (note very tattered wings of this old individual)
  • Shadow Darner | Aeshna umbrosaandromorph female
  • Shadow Darner | Aeshna umbrosamale (typical “A. u. umbrosa” with small green abdominal spots but nowhere near the range of that subspecies!)

Copyright © 2016 Walter Sanford. All rights reserved.

Time to mate

September 18, 2016

A mating pair of Blue-faced Meadowhawk dragonflies (Sympetrum ambiguum) was spotted at a vernal pool in Huntley Meadows Park (HMP). The vernal pool, currently dry, is the same one where teneral Blue-faced Meadowhawks were observed during late-May and early-June 2016.

This mating pair is “in wheel.” All dragonflies and damselflies have a 10-segmented abdomen, numbered from front to back: male dragonfly secondary genitalia, called hamules, are located in segments two and three (S2 and S3); female genitalia in segment eight (S8). Dragonflies form the mating wheel in order for their genitalia to connect during copulation.

A mating pair of Blue-faced Meadowhawk dragonflies (Sympetrum ambiguum) spotted at Huntley Meadows Park, Fairfax County, Virginia USA. This pair is "in wheel." The female is an andromorph.

15 SEP 2016 | HMP | Blue-faced Meadowhawks (mating pair, “in wheel“)

Some species of dragonflies display sexual dimorphism; females are polymorphic for a smaller subset of those species. Andromorph females are male-like in color; heteromorph females are duller in color than males.

Notice the female in this mating pair is an andromorph. Female andromorphs are less common than heteromorphs.

A mating pair of Blue-faced Meadowhawk dragonflies (Sympetrum ambiguum) spotted at Huntley Meadows Park, Fairfax County, Virginia USA. This pair is "in wheel." The female is an andromorph.

15 SEP 2016 | HMP | Blue-faced Meadowhawks (mating pair, “in wheel“)

Copyright © 2016 Walter Sanford. All rights reserved.

Blue-faced Meadowhawk dragonfly (female)

November 19, 2015

The following photo gallery shows a Blue-faced Meadowhawk dragonfly (Sympetrum ambiguum), perching on the ground near a vernal pool/small permanent pond at Huntley Meadows Park (HMP).

A Blue-faced Meadowhawk dragonfly (Sympetrum ambiguum) spotted at Huntley Meadows Park, Fairfax County, Virginia USA. This individual is a heteromorph female.

15 OCT 2015 | HMP | Blue-faced Meadowhawk (female)

This individual is a heteromorph female, as indicated by its coloration and terminal appendages.

A Blue-faced Meadowhawk dragonfly (Sympetrum ambiguum) spotted at Huntley Meadows Park, Fairfax County, Virginia USA. This individual is a heteromorph female.

15 OCT 2015 | HMP | Blue-faced Meadowhawk (female)

There were noticeably fewer Blue-faced Meadowhawks at this location during Fall 2015 than in the past, perhaps a consequence of two consecutive colder than average winters. Just two females were spotted this year, both heteromorphs; no andromorph females were observed. No mating pairs were seen in 2015.

A Blue-faced Meadowhawk dragonfly (Sympetrum ambiguum) spotted at Huntley Meadows Park, Fairfax County, Virginia USA. This individual is a heteromorph female.

15 OCT 2015 | HMP | Blue-faced Meadowhawk (female)

The reddish-brown leaves in the background remind me of marbled paper.

A Blue-faced Meadowhawk dragonfly (Sympetrum ambiguum) spotted at Huntley Meadows Park, Fairfax County, Virginia USA. This individual is a heteromorph female.

15 OCT 2015 | HMP | Blue-faced Meadowhawk (female)

Notice the terminal appendages are flared in the last photo. The author has observed several species of odonates that exhibit this odd behavior, both male and female.

A Blue-faced Meadowhawk dragonfly (Sympetrum ambiguum) spotted at Huntley Meadows Park, Fairfax County, Virginia USA. This individual is a heteromorph female.

15 OCT 2015 | HMP | Blue-faced Meadowhawk (female)

Copyright © 2015 Walter Sanford. All rights reserved.

Blue-faced Meadowhawk dragonfly (female)

October 16, 2015

The following photos show a Blue-faced Meadowhawk dragonfly (Sympetrum ambiguum), perching in a drainage ditch near a vernal pool at Huntley Meadows Park (HMP).

A Blue-faced Meadowhawk dragonfly (Sympetrum ambiguum) spotted at Huntley Meadows Park, Fairfax County, Virginia USA. This individual is a heteromorph female.

11 OCT 2015 | HMP | Blue-faced Meadowhawk (female)

This individual is a heteromorph female, as indicated by its coloration and terminal appendages.

A Blue-faced Meadowhawk dragonfly (Sympetrum ambiguum) spotted at Huntley Meadows Park, Fairfax County, Virginia USA. This individual is a heteromorph female.

11 OCT 2015 | HMP | Blue-faced Meadowhawk (female)

Copyright © 2015 Walter Sanford. All rights reserved.

Things are not always what they seem

October 6, 2015

Male Eastern Amberwing dragonflies (Perithemis tenera) are so distinctive in appearance that you can identify them with just a quick glance, right? Maybe; maybe not.

Things are not always what they seem: the first appearance deceives many; the intelligence of a few perceives what has been carefully hidden. Source Credit: Phaedrus.

When I spotted the following Eastern Amberwing dragonfly along Barnyard Run at Huntley Meadows Park, I misidentified it as a male. Truth be told, I always thought its terminal appendages look more female than male, but I allowed myself to be fooled by the reddish-orange coloration of its wings. Turns out this individual is either an andromorph or gynandromorph female.

An Eastern Amberwing dragonfly (Perithemis tenera) spotted at Huntley Meadows Park, Fairfax County, Virginia USA. This individual is an andromorph female.

29 JUN 2015 | HMP | Eastern Amberwing (female, gynandromorph)

heteromorph is a female that looks different than a male. An andromorph is a female that resembles a male. A gynandromorph combines both male and female characteristics.

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 a lower unpaired epiproct (“inferior appendage”). Female dragonflies have a pair of cerci (superior appendages) that have little or no function.

Look closely at the full-size version of the preceding annotated image. Notice this individual appears to have three cerci. For this reason, Dr. Dennis Paulson hypothesizes this individual may be a gynandromorph.

In contrast, heteromorph female Eastern Amberwings, such as the one shown below, feature two and only two cerci plus mostly clear wings with a variable pattern of wing spots.

An Eastern Amberwing dragonfly (Perithemis tenera) spotted at Huntley Meadows Park, Fairfax County, Virginia USA. This individual is a female.

05 AUG 2015 | HMP | Eastern Amberwing (female, heteromorph)

After a second look at my photo library, I discovered another possible andromorph/gynandromorph female spotted at Mulligan Pond, Jackson Miles Abbott Wetland Refuge.

An Eastern Amberwing dragonfly (Perithemis tenera) spotted at Jackson Miles Abbott Wetland Refuge, Fairfax County, Virginia USA. This individual is an andromorph female.

24 JUL 2015 | JMAWR | Eastern Amberwing (female, gynandromorph)

Several males were spotted at the same location. Look closely at the full-size version of the preceding and following photos. Notice the difference in appearance between the terminal appendages of the andromorph/gynandromorph female (shown above) and male (shown below).

An Eastern Amberwing dragonfly (Perithemis tenera) spotted at Jackson Miles Abbott Wetland Refuge, Fairfax County, Virginia USA. This individual is a male.

24 JUL 2015 | JMAWR | Eastern Amberwing (male)

See? There’s a reason I’m fixated on odonate terminal appendages! Dr. Paulson and I are curious to know whether other naturalists have spotted andromorph/gynandromorph female Eastern Amberwing dragonflies.

Since this post began with a quote from Phaedrus, somehow it seems appropriate it should end with another quote.

The only problem with seeing too much is that it makes you insane. Source Credit: Phaedrus.

Editor’s Note: Sincere thanks to Dennis Paulson for verifying my tentative identification of the andromorph/gyandromorph female Eastern Amberwing dragonfly spotted on 29 June 2015. I was motivated to double-check my initial identification after recently noticing the following quote from one of Dennis’ excellent books.

Very rare andromorph females may have entirely yellow-orange wings as males, with some dark smudging. Source Credit: Paulson, Dennis (2011-12-19). Dragonflies and Damselflies of the East (Princeton Field Guides) (Kindle Locations 9406-9407). Princeton University Press. Kindle Edition.

Copyright © 2015 Walter Sanford. All rights reserved.

More dragonfly terminal appendages

March 14, 2015

Some species of dragonflies display sexual dimorphism; females are polymorphic for a smaller subset of those species. Andromorph females are male-like in color; heteromorph females are duller in color than males.

Terminal appendages are important field markers that may be used to differentiate adult males and adult andromorph females of the same species.

Blue-faced Meadowhawk dragonfly (male)

08 OCT 2013 | Huntley Meadows Park | Blue-faced Meadowhawk (male)

Andromorph female Blue-faced Meadowhawk dragonflies (Sympetrum ambiguum), like the one shown below, are less common than heteromorph females. Andromorphs have a red abdomen with black rings, like male Blue-faced Meadowhawks; unlike males, most female faces are tan and their terminal appendages look different than male appendages.

Blue-faced Meadowhawk dragonfly (female)

08 OCT 2013 | Huntley Meadows Park | Blue-faced Meadowhawk (female)

The following photo shows a heteromorph female Blue-faced Meadowhawk dragonfly. Heteromorphs have a tan abdomen with black rings.

Blue-faced Meadowhawk dragonfly (female)

27 SEP 2013 | Huntley Meadows Park | Blue-faced Meadowhawk (female)

Editor’s Note: Some odonate experts favor the term “polychromatism” rather than “polymorphism.”

Polychromatism has often (inappropriately) been termed polymorphism. I follow the terminology recommended by Don Hilton (1987), in which the female coloration is termed gynochromatypic and that of the male androchromatypic. Source Credit: Corbet, Phillip S (2004). Dragonflies: Behaviour and Ecology of Odonata. [The 1962 edition of the book is available online: A Biology of Dragonflies.]

Related Resources:

Copyright © 2015 Walter Sanford. All rights reserved.

One-off

March 4, 2015

Sometimes, one picture tells the whole story …

Blue-faced Meadowhawk dragonflies (mating pair, in wheel)

The preceding photograph shows a mating pair of Blue-faced Meadowhawk dragonflies (Sympetrum ambiguum) spotted on 27 October 2014 near a vernal pool in the forest at Huntley Meadows Park.

The pair is “in wheel”: the male is on top; the female is on the bottom. The female is a heteromorph, as indicated by her coloration.

Copyright © 2015 Walter Sanford. All rights reserved.

Blue-faced Meadowhawk dragonflies (mating pairs, in wheel)

January 17, 2015

The following photographs show two mating pairs of Blue-faced Meadowhawk dragonflies (Sympetrum ambiguum) spotted on 17 October 2014 near a vernal pool in the forest at Huntley Meadows Park.

Both pairs are “in wheel”: the males are on top; the females are on the bottom. Both females are heteromorphs, as indicated by their coloration.

Blue-faced Meadowhawk dragonflies (mating pair, in wheel)

Mating Pair No. 1

Copulation between the male (S2-3) and female (S8) abdominal segments is shown clearly in preceding uncropped photo.

Blue-faced Meadowhawk dragonflies (mating pair, in wheel)

Mating Pair No. 2

Copyright © 2015 Walter Sanford. All rights reserved.

To All The Girls I’ve Loved Before (Part 3)

December 22, 2014

This is the third installment in a three-part series featuring some of my favorite photos of female dragonflies spotted while photowalking Huntley Meadows Park during Fall 2014.

The following photos show a Blue-faced Meadowhawk dragonfly (Sympetrum ambiguum) spotted on 12 October 2014, perching near the base of the berm that was built as part of the wetland restoration project. This individual is a heteromorph female, as indicated by its coloration and terminal appendages.

Blue-faced Meadowhawk dragonfly (female, heteromorph)

Notice the insect (I presume) perching in front of the dragonfly, as shown in the next two photos. A couple of members of the BugGuide Facebook group think this may be a grasshopper nymph, possibly a species of Short-horned Grasshopper (Family Acrididae).

Blue-faced Meadowhawk dragonfly (female, heteromorph)

Why didn’t the dragonfly eat the insect?

Blue-faced Meadowhawk dragonfly (female, heteromorph)

The Backstory: I wandered along the berm looking for dragonflies until I reached the small observation platform located above the new water control structure that is used to manage water levels in the central wetland. I discovered an unknown plant near the edge of the forest, to the left of the platform. What appear to be beautiful crimson red flowers are in fact the seed pods of Virginia marsh St. Johnswort (Triadenum virginicum). The seed pods remind me of tiny rosebuds. But I digress.

Virginia marsh St. Johnswort (Triadenum virginicum)

When I returned to berm, fellow odonate enthusiast Lova Brown Freeman pointed out the female Blue-faced Meadowhawk dragonfly shown in the preceding photos. At first, the dragonfly was perching on jute used to protect post-construction ground cover plantings. The coloration of the dragonfly and jute were an almost perfect match, making the dragonfly difficult to see through the viewfinder of my camera. Fortunately for me, the dragonfly moved to a piece of bark, making it easier to find and photograph. Good find, and thanks for sharing, Lova!

Lova is a talented craftsperson who specializes in crocheting. Many of Lova’s craft items are nature-themed. Visit Lova’s Crafty Caboodle for more information.

Editor’s Note: Credit Dr. Edward Eder and Mr. Alonso Abugattas for independently identifying the unknown plant, shown above.

On re-examining the photo I noticed that the “flowers” were not flowers at all but rather seed pods. Saint Johnswort has red seed pods that look a lot like this picture. Source Credit: Personal communication, Dr. Edward Eder.

Cool, is that Marsh St. Johnswort, Triadenum virginicum (sometimes called Hypericum virginicum)? What a great find! I don’t think that’s supposed to be found around here, not in Fairfax or Arlington anyway. That might be a new county record if the park decides to get a voucher and report it to the state. Source Credit: Alonso Abugattas Jr., Capital Naturalist Facebook group.

Copyright © 2014 Walter Sanford. All rights reserved.


%d bloggers like this: