Posts Tagged ‘Family Lestidae (Spreadwings)’

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.

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.

Slender Spreadwing damselflies (females)

March 25, 2017

Two female Slender Spreadwing damselflies (Lestes rectangularis) were spotted during a photowalk around a vernal pool in the forest at Huntley Meadows Park.

No. 1

No. 2

Notice the second individual is bluer in color. Coloration is variable, so it’s better to look at other field markers when making an identification.

Copyright © 2017 Walter Sanford. All rights reserved.

Arachnids 2, Odonates 0

March 23, 2017

A spider was observed preying upon a teneral damselfly at a vernal pool in Huntley Meadows Park. The genus/species of the spider is uncertain; the damselfly appears to be a female Slender Spreadwing (Lestes rectangularis).

31 MAY 2016 | Huntley Meadows Park | spider preying upon damselfly

According to experts on the BugGuide Facebook group, the spider is probably an unknown species from the Family Araneidae (Orb Weavers).

Post Update: Ashley Bradford, a local arachnid expert and excellent all-around amateur naturalist, identified the spider as an Arabesque Orbweaver (Neoscona arabesca). Thanks, Ashley!

31 MAY 2016 | Huntley Meadows Park | spider preying upon damselfly

Aperture Priority mode was used for the next photo, in order to increase the depth of field. As you can see, the depth of field at f/8.0 was insufficient for both the damselfly and spider to be in focus.

31 MAY 2016 | Huntley Meadows Park | spider preying upon damselfly

A dragonfly was trapped in a spider web at Hidden Pond, Meadowood Recreation Area, Fairfax County, Virginia USA. The dragonfly, possibly an immature male Blue Dasher (Pachydiplax longipennis), is infested with parasitic red water mites.

22 JUN 2016 | Meadowood Recreation Area | dragonfly in spider web

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.

Great Spreadwing damselfly (male, grooming)

December 20, 2016

Great Spreadwing damselfly (Archilestes grandis) was spotted in the forest near a vernal pool at Huntley Meadows Park. This individual is the same male featured in my last blog post.

Before grooming

Look closely at the full-size version of the following photo. Notice the schmutz on the male damselfly’s abdomen, located near the right cercus of his terminal appendages.

11:09:41 a.m. EST

Grooming

A while later the male damselfly contorted himself into a position that looked like he was doing gymnastics. As it turns out, he was rubbing the tip of his abdomen against his thorax and legs in order to remove the schmutz.

11:31:09 a.m. EST

11:31:13 a.m. EST

11:31:18 a.m. EST

After grooming

Look closely at the full-size version of the following photo. Notice the schmutz on the male damselfly’s abdomen is gone. Soon afterward, the male flew in the direction of the vernal pool, presumably to look for female mates.

11:32:54 a.m. EST

Related Resource: Great Spreadwing damselflies (males, gymnasts) is a blog post by Walter Sanford that includes an embedded video showing similar grooming behaviors. The video features two segments: segment one shows the male damselfly grooming his legs; segment two shows the male grooming his wings by rubbing his abdomen against them.

Editor’s Note: If you check the EXIF for all five photos, then you will see the time stamp is one hour later than the times shown above. 06 November was the first time I used my camera since the end of Daylight Saving Time (at 2:00 a.m. the same day) — I forgot to reset the time in-camera!

Copyright © 2016 Walter Sanford. All rights reserved.

Great Spreadwing damselfly (male, eating)

December 18, 2016

Great Spreadwing damselfly (Archilestes grandis) was spotted in the forest near a vernal pool at Huntley Meadows Park. This individual is a male, as indicated by his deep blue eyes, familiar yellow racing stripe on the side of its thorax, bluish-white coloration on abdominal segments 9-10 (S9-10), and distinctive terminal appendages (claspers).

While I was sitting on my Coleman camp stool watching the male damselfly, suddenly he flew up and around head and landed near the same spot where he had been perching. I know from experience this type of behavior suggests the damselfly probably grabbed something to eat.

The following brief time-series of photos shows the damselfly eating an unknown species of winged insect.

11:19:52 a.m. EST

11:19:58 a.m. EST

11:20:14 a.m. EST

Editor’s Note: If you check the EXIF for all three photos, then you will see the time stamp is one hour later than the times shown above. 06 November was the first time I used my camera since the end of Daylight Saving Time (at 2:00 a.m. the same day) — I forgot to reset the time in-camera!

Copyright © 2016 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.


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