Posts Tagged ‘Southern Spreadwing damselfly’

Pop quiz answer key

June 9, 2017

Perhaps the simplest way to provide answers to the recent pop quiz — in which readers were challenged to identify the gender of two Southern Spreadwing damselflies (Lestes australis) — is to show what the teneral/immature male (shown in my last post) will look like when he’s a little older.

The following photos show Southern Spreadwings spotted at Mason Neck West Park, Fairfax County, Virginia USA. Both individuals are male, as indicated by their terminal appendages and blue coloration.

Both photographs of the male Southern Spreadwings were taken at an angle that shows their terminal appendages clearly.

All male damselflies have four terminal appendages, collectively called “claspers.” Male damselfly terminal appendages don’t look exactly the same for all species of damselflies, but their function is identical. Claspers are used to grab and hold female damselflies during mating: an upper pair of cerci (“superior appendages”) and a lower pair of paraprocts (“inferior appendages”).

In contrast, female damselflies have two cerci (sing. cercus), superior appendages that have little or no function. Notice the two “nubs” at the tip of the abdomen, as shown in the photo of the female Southern Spreadwing that was featured in the pop quiz.

Editor’s Notes: There are five families of damselflies (Suborder Zygoptera) in the United States of America, although only three families occur in the mid-Atlantic region: Family Calopterygidae (Broad-winged Damselflies)Family Coenagrionidae (Narrow-winged Damselflies); and Family Lestidae (Spreadwings).

Male Broad-winged Damselflies and Spreadwing Damselflies have terminal appendages that are large enough to see with the unaided eye. Generally speaking, both male and female Narrow-winged Damselflies are too small to see their terminal appendages clearly in most photographs.

Copyright © 2017 Walter Sanford. All rights reserved.

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Pop quiz

June 7, 2017

OK, it’s time to assess what you’ve learned about damselflies by following my blog.

Two Southern Spreadwing damselflies (Lestes australis) were photographed on the same day at the same location. Both damselflies are teneral/immature, that is, they are relatively young. One is a female; one is a male. Can you identify the gender of the damselflies shown in the following photos?

I’ll give you a hint: Examine their terminal appendages by looking at the full-size version of both photos.

No. 1

No. 2

Editor’s Note: The answer key will be published in my next post.

Copyright © 2017 Walter Sanford. All rights reserved.

Voltinism, revisited

April 30, 2017

Voltinism is a term used in biology to indicate the number of broods or generations of an organism in a year. Source Credit: Wikipedia.

Some species of odonates, such as Southern Spreadwing damselfly (Lestes australis), can be multivoltine.

Huntley Meadows Park

Long-term monitoring of a vernal pool at Huntley Meadows Park has shown Southern Spreadwing is multivoltine at that site.

Mason Neck West Park

Males and females from a single brood of Southern Spreadwing were observed during Fall 2016 at Mason Neck West Park; males from another brood were spotted at the same location on 05 April 2017 and again on 18 April 2017. This evidence suggests Southern Spreadwing is multivoltine at Mason Neck West Park (MNWP). Further field observations are necessary to determine whether more than two broods occur at this location.

This individual is a male, as indicated by his coloration and terminal appendages.

Please look at the full-size versions of the preceding photos in order to appreciate the “fresh” coloration that seems to be a noticeable characteristic for many species of recently-emerged odonates.

Copyright © 2017 Walter Sanford. All rights reserved.

How to Identify Damselfly Exuviae to Family

March 11, 2017

There are five families of damselflies (Suborder Zygoptera) in the United States of America, although only three families occur in the mid-Atlantic region: Family Calopterygidae (Broad-winged Damselflies)Family Coenagrionidae (Narrow-winged Damselflies); and Family Lestidae (Spreadwings).

Pattern recognition can be used to tentatively identify damselfly larvae/exuviae to the family level: the shape of the prementum is characteristic for each of the three families; mnemonics can be used to remember each distinctive shape.

Family Calopterygidae (Broad-winged Damselflies)

Family Calopterygidae features a prementum with a shape that looks somewhat similar to Family Coenagrionidae. Look for an embedded raindrop shape, located toward the upper-center of the prementum.

An Ebony Jewelwing damselfly (Calopteryx maculata) exuvia was collected along a small stream located in eastern Fairfax County, Virginia USA.

Family Calopterygidae (Broad-winged Damselflies) | prementum

Family Coenagrionidae (Narrow-winged Damselflies)

The shape of the prementum for Family Coenagrionidae reminds me of a keystone.

A Narrow-winged Damselfly exuvia — probably Argia sp. (it’s a work in progress) — was collected along the Potomac River in Fairfax County, Virginia USA. This individual is a female, as indicated by the rudimentary ovipositor located on the ventral side of her abdomen.

Family Coenagrionidae (Narrow-winged Damselflies) | ventral

The lamellae, also known as caudal lamellae, are external structures used by damselfly larvae for both respiration and locomotion. In contrast, the respiratory system for dragonfly larvae is internal. Characteristics of the caudal lamellae (including shape of/patterns on) are some of the clues that can be used to identify damselflies to the genus/species level.

Family Lestidae (Spreadwings)

The unique shape of the prementum for Family Lestidae reminds me of a rattle (musical instrument).

A damselfly exuvia from the Family Lestidae (Spreadwings) was collected from a small vernal pool located in eastern Fairfax County, Virginia USA. Although the genus/species is unknown (again, it’s a work in progress), both Slender Spreadwing (Lestes rectangularis) adults and Southern Spreadwing (Lestes australis) adults were observed at the vernal pool on the same day this specimen was collected.

Family Lestidae (Spreadwings) | prementum

Related Resources: The first step is the hardest, as the saying goes. In this case, it’s easier to identify damselfly larvae/exuviae to the family level than it is to identify specimens to the genus/species level. There are relatively few resources, especially online resources. The following links to two dichotomous keys and a pattern-matching guide for caudal lamellae should help you get started. Many of the same species of damselflies that are known to occur in Michigan, Florida, and the Carolinas can be found in the mid-Atlantic region.

Copyright © 2017 Walter Sanford. All rights reserved.

Southern Spreadwing at MNWP

November 19, 2016

Many Southern Spreadwing damselflies (Lestes australis) were observed around the stormwater management pond located at Mason Neck West Park (MNWP) during Fall 2016. The following gallery, presented in chronological order, showcases select specimens spotted during several photowalks at the park.

The first individual is a female, as indicated by her coloration and terminal appendages.

A Southern Spreadwing damselfly (Lestes australis) spotted at Mason Neck West Park, Fairfax County, Virginia USA. This individual is a female.

27 SEP 2016 | MNWP | Southern Spreadwing (female)

The next two photos show a couple of males, as indicated by their coloration and terminal appendages.

A Southern Spreadwing damselfly (Lestes australis) spotted at Mason Neck West Park, Fairfax County, Virginia USA. This individual is a male.

27 SEP 2016 | MNWP | Southern Spreadwing (male)

A Southern Spreadwing damselfly (Lestes australis) spotted at Mason Neck West Park, Fairfax County, Virginia USA. This individual is a male.

27 SEP 2016 | MNWP | Southern Spreadwing (male)

The following photo shows a mating pair “in tandem,” the post-copulatory phase when the male guides the female to egg-laying sites. The male is on top; the female on the bottom.

A mating pair of Southern Spreadwing damselflies (Lestes australis) spotted at Mason Neck West Park, Fairfax County, Virginia USA. This pair is in tandem.

27 SEP 2016 | MNWP | Southern Spreadwing (mating pair, in tandem)

The female uses her ovipositor to insert eggs into vegetation (endophytic oviposition).

A mating pair of Southern Spreadwing damselflies (Lestes australis) spotted at Mason Neck West Park, Fairfax County, Virginia USA. This pair is in tandem; the female is laying eggs (oviposition).

27 SEP 2016 | MNWP | Southern Spreadwing (mating pair, in tandem)

More males were spotted on consecutive days in early-October.

A Southern Spreadwing damselfly (Lestes australis) spotted at Mason Neck West Park, Fairfax County, Virginia USA. This individual is a male.

03 OCT 2016 | MNWP | Southern Spreadwing (male)

A Southern Spreadwing damselfly (Lestes australis) spotted at Mason Neck West Park, Fairfax County, Virginia USA. This individual is a male.

04 OCT 2016 | MNWP | Southern Spreadwing (male)

The last individual is a female that I found resting/roosting in a field of grasses, quite a distance from the water. As it turns out, this female — spotted on 14 October 2016 — is also the last Southern Spreadwing observed at Mason Neck West Park during 2016. It’s worth noting the late-date for Southern Spreadwing at MNWP is consistent with the late-date of 15 October 2015 for the same species at Huntley Meadows Park.

A Southern Spreadwing damselfly (Lestes australis) spotted at Mason Neck West Park, Fairfax County, Virginia USA. This individual is a female.

14 OCT 2016 | MNWP | Southern Spreadwing (female)

A Southern Spreadwing damselfly (Lestes australis) spotted at Mason Neck West Park, Fairfax County, Virginia USA. This individual is a female.

14 OCT 2016 | MNWP | Southern Spreadwing (female)

Copyright © 2016 Walter Sanford. All rights reserved.

Voltinism

November 17, 2016

Voltinism is a term used in biology to indicate the number of broods or generations of an organism in a year. Source Credit: Wikipedia.

Some species of odonates, such as Southern Spreadwing damselfly (Lestes australis), can be multivoltine.

Since the first official record of Southern Spreadwing damselfly at Huntley Meadows Park — a male spotted on 23 May 2014 in a drainage ditch near a vernal pool in the forest — the author has carefully monitored this location for the past two years. Henceforth, this location shall be referred to as the “study site.”

Field observations have shown one brood of Southern Spreadwing during Spring 2014 and Spring 2015; an individual from another probable brood of Southern Spreadwing was spotted during Fall 2015. Individuals from two broods of Southern Spreadwing were observed during Spring and Fall 2016.

Males

The following photo shows the only Southern Spreadwing observed at the study site during Spring 2016. This individual is a male, as indicated by his coloration and terminal appendages.

There are two vernal pools at the study site: the larger one is more like a small permanent pond that was formerly fishless; the smaller one is a true vernal pool and appears to be fishless. This individual was observed in a drainage ditch near the true vernal pool: the ditch is wet during spring/early-summer; dry in late-summer/fall.

Territorial Expansion

There is another vernal pool at Huntley Meadows Park that the naturalists refer to as the “Accidental Vernal Pool” because it was created by accident during the construction phase of the wetland restoration project. As it turns out, this pool is a good habitat for many species of odonates, including some species that prefer fishless water.

A male Southern Spreadwing was spotted at the “accidental vernal pool” on 26 May 2016; this is the first time this species has been observed in that location. It’s good to see the expansion of Southern Spreadwing territory, especially since it appears the habitat at the “study site” has been degraded by the introduction of fish to the larger pond.

One or more males were spotted the following day at the accidental vernal pool.

Female

A single Southern Spreadwing was observed at the study site during Fall 2016.

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

I thought I had discovered a male Sweetflag Spreadwing damselfly (Lestes forcipatus) on 15 October 2015 at the study site. I made my speculative identification before I knew that Southern Spreadwings can be multivoltine. The observation and positive identification of a female Southern Spreadwing during the same month (in consecutive years) at the same location almost certainly means the species of the male I saw in 2015 was misidentified.

Editor’s Notes: Southern Spreadwing damselflies have been observed at two other locations in Northern Virginia: males from a single brood were observed during Spring 2016 at Meadowood Recreation Area; males and females from a single brood were observed during Fall 2016 at Mason Neck West Park. Further field observations are necessary to determine whether Southern Spreadwing is multivoltine at these sites.

Related Resource: Southern Spreadwing at MNWP, by Walter Sanford.

Copyright © 2016 Walter Sanford. All rights reserved.

Southern- or Sweetflag Spreadwing?

May 27, 2016

I spotted a skittish spreadwing damselfly on 14 May 2016 during a photowalk around Enchanted Pond, Meadowood Recreation Area. I was able to shoot some photos of the spreadwing during a follow-up visit on 20 May 2016.

A male member of the Family Lestidae of damselflies (Spreadwings) spotted at Enchanted Pond, Meadowood Recreation Area, Fairfax County, Virginia USA. This individual is either a Southern Spreadwing damselfly (Lestes australis) or Sweetflag Spreadwing damselfly (Lestes forcipatus).

This individual is a member of the Family Lestidae of damselflies (Spreadwings): it is either a Southern Spreadwing damselfly (Lestes australis) or Sweetflag Spreadwing damselfly (Lestes forcipatus). It is a male, as indicated by its terminal appendages: Southern Spreadwing; Sweetflag Spreadwing.

A male member of the Family Lestidae of damselflies (Spreadwings) spotted at Enchanted Pond, Meadowood Recreation Area, Fairfax County, Virginia USA. This individual is either a Southern Spreadwing damselfly (Lestes australis) or Sweetflag Spreadwing damselfly (Lestes forcipatus).

According to Ed Lam, author and illustrator of Damselflies of the Northeast, “Male Southern and Sweetflag cannot be separated in the field.”

In my experience at Huntley Meadows Park, Southern Spreadwing is an early season (spring) species; Sweetflag Spreadwing is a late season (fall) species. In deference to Ed Lam’s expertise, I’ll go with the either/or classification rather than a somewhat speculative single species identification.

Copyright © 2016 Walter Sanford. All rights reserved.

New discoveries in 2015

December 27, 2015

As the story is told, a reporter asked Willie Sutton “Why do you rob banks?” “Because that’s where the money is,” Willie answered. So when people ask me why I go to the remote locations in Huntley Meadows Park, I answer “Because that’s where the undiscovered species of odonates are.”

There are undiscovered species of odonates at the remote places in the park, in part, because fewer people go to the more difficult to reach locations. Also, the remote locations are often where the “habitat specialists” are found, in contrast with the “habitat generalists” that inhabit the central wetland area.

Springtime Darner dragonfly

Teamwork, and some take-aways

Springtime Darner dragonfly (female)

18 April 2015 | Photograph used with permission from Michael Powell.

Southern Spreadwing damselfly

A Southern Fortnight, Part 1 – Year-long mystery solved!

A mating pair of Southern Spreadwing damselflies (Lestes australis) spotted at Huntley Meadows Park, Fairfax County, Virginia USA. This pair is in tandem.

03 MAY 2015 | HMP | Southern Spreadwing (mating pair, in tandem)

Roseate Skimmer dragonfly

Roseate Skimmer dragonfly (male)

A Roseate Skimmer dragonfly (Orthemis ferruginea) spotted at Huntley Meadows Park, Fairfax County, Virginia USA. This individual is a male.

23 SEP 2015 | Huntley Meadows Park | Roseate Skimmer (male)

Sweetflag Spreadwing damselfly

Another new species of spreadwing damselfly?

A Sweetflag Spreadwing damselfly (Lestes forcipatus) spotted at Huntley Meadows Park, Fairfax County, Virginia USA. This individual is a male.

15 OCT 2015 | HMP | Sweetflag Spreadwing (male)

Copyright © 2015 Walter Sanford. All rights reserved.

A Southern Fortnight, Part 7 – “Arty”

September 14, 2015

The Backstory: A Southern Fortnight

For the first two weeks during May 2015, Southern Spreadwing damselflies (Lestes australis) were observed at a vernal pool and nearby drainage ditch in the forest at Huntley Meadows Park. I spotted approximately six males and several females during the fortnight. Their sudden disappearance seemed to coincide with a population explosion of Eastern Pondhawk dragonflies (Erythemis simplicicollis) in mid-May. Eastern Pondhawks, especially females, are voracious predators with a penchant for preying upon damselflies.


Alas, all good things must come to an end. This is the last post in what turned out to be a seven-part series called “A Southern Fortnight.” But don’t be sad because I saved some of the better photos for last! The male Southern Spreadwing featured in this post had a preference for perching in front of colorful vegetation that enabled me to capture shots of the damselfly sharply-focused against beautiful bokeh backgrounds, while he waited patiently for a mating partner to join him.

In order to avoid “camera shake” when using my Panasonic Lumix DMC-FZ150 superzoom bridge camera, I prefer to shoot in shutter priority auto-exposure mode. The rule-of-thumb for tack-sharp photos recommends a shutter speed that is equal to or greater than the reciprocal of the lens focal length (actual focal length for full-frame sensor cameras or 35mm equivalent for crop sensor cameras), in my case, no less than 1/800s for a 600mm equivalent telephoto lens. The following photo was shot in shutter priority mode: ISO 100 | 108mm/600mm | f/5.2 | 1/1000s | 0 ev.

A Southern Spreadwing damselfly (Lestes australis) spotted at Huntley Meadows Park, Fairfax County, Virginia USA. This individual is a male.

08 MAY 2015 | HMP | Southern Spreadwing (male)

Whenever the subject is as cooperative as this one and I have the luxury of time, I will shoot some photos in aperture priority auto-exposure mode in order to get greater depth-of-field. At a smaller aperture, the camera will often select a relatively slow shutter speed so it is essential to hold the camera rock-steady and that usually means using a tripod. In this case, I was sitting on my Coleman camp stool with my elbows resting on my knees. The following photo was shot in aperture priority mode: ISO 100 | 108mm/600mm | f/7.1 | 1/160s | 0 ev.

A Southern Spreadwing damselfly (Lestes australis) spotted at Huntley Meadows Park, Fairfax County, Virginia USA. This individual is a male.

08 MAY 2015 | HMP | Southern Spreadwing (male)

Notice the terminal appendages are out of focus in the following photo. Usually I wouldn’t publish a photo like this one, but decided to make an exception since it’s the only photo in this set that shows both the damselfly’s light-blue face and his hamules. The male’s claspers are clearly in focus in the four other photos.

A Southern Spreadwing damselfly (Lestes australis) spotted at Huntley Meadows Park, Fairfax County, Virginia USA. This individual is a male.

08 MAY 2015 | HMP | Southern Spreadwing (male)

Although the last two photos show the damselfly in nearly the same pose, I chose to use both images due to subtle variations in the coloration of the background.

A Southern Spreadwing damselfly (Lestes australis) spotted at Huntley Meadows Park, Fairfax County, Virginia USA. This individual is a male.

08 MAY 2015 | HMP | Southern Spreadwing (male)

A Southern Spreadwing damselfly (Lestes australis) spotted at Huntley Meadows Park, Fairfax County, Virginia USA. This individual is a male.

08 MAY 2015 | HMP | Southern Spreadwing (male)

Related Resources:

Copyright © 2015 Walter Sanford. All rights reserved.

A Southern Fortnight, Part 6 – Damselfly reproductive anatomy

August 19, 2015

The Backstory: A Southern Fortnight

For the first two weeks during May 2015, Southern Spreadwing damselflies (Lestes australis) were observed at a vernal pool and nearby drainage ditch in the forest at Huntley Meadows Park. I spotted approximately six males and several females during the fortnight. Their sudden disappearance seemed to coincide with a population explosion of Eastern Pondhawk dragonflies (Erythemis simplicicollis) in mid-May. Eastern Pondhawks, especially females, are voracious predators with a penchant for preying upon damselflies.


The following annotated image illustrates some of the reproductive anatomy of male and female Southern Spreadwing damselflies.

A mating pair of Southern Spreadwing damselflies (Lestes australis) spotted at Huntley Meadows Park, Fairfax County, Virginia USA. This pair is in tandem; the female is laying eggs (oviposition).

08 MAY 2015 | HMP | Southern Spreadwing (mating pair, in tandem)

The following annotated image illustrates some of the reproductive anatomy of a female Southern Spreadwing: two cerci (sing. cercus), superior appendages that have little or no function; two styli (sing. stylus), structures that serve as sensors in egg positioning; and an ovipositor  (shown above) that is used to insert eggs into vegetation (endophytic oviposition).

A Southern Spreadwing damselfly (Lestes australis) spotted at Huntley Meadows Park, Fairfax County, Virginia USA. This is the female member of a mating pair, resting after laying eggs (oviposition).

07 MAY 2015 | HMP | Southern Spreadwing (adult female)

According to Ed Lam, author and illustrator of Damselflies of the Northeast, “male Southern and Sweetflag cannot be separated in the field.” It is possible to reverse-engineer a positive identification based upon a single key field marker for female specimens of the two species: Southern Spreadwing females have a much smaller ovipositor than Sweetflag Spreadwing females, as illustrated in the following references.

Sidebar: Damselfly Hook-up and Copulation

After a male damselfly grabs a female with his claspers, he transfers sperm from the genital opening under the ninth abdominal segment (S9) to his hamules, shown above, located beneath the second abdominal segment (S2). Next the pair forms the mating wheel, then the male transfers sperm from his hamules to the female through her genital pore under the eighth abdominal segment (S8). The beginning-to-end process is shown in the following still photos and two-part series of videos.

Digital Scans:

Copyright © 2015 Walter Sanford. All rights reserved.


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