Posts Tagged ‘Enallagma signatum’

Blues for “Bluets”

July 12, 2015

Regular readers of my photoblog know I love me some odonates! Mostly, that is. Many American Bluets, members of the Pond Damsels Family of damselflies, can be difficult to identify, especially in the field. There are many species of bluets, most of them are blue, and many of them look similar. Yes, sometimes I get the blues when trying to identify bluets — no wonder I lovingly refer to them as “damnselflies!”

Five species of bluets are listed on the Friends of Huntley Meadows Park Odonata species list of damselflies: Familiar Bluet (Enallagma civile); Big Bluet (Enallagma durum); Stream Bluet (Enallagma exsulans); Skimming Bluet (Enallagma geminatum); and Orange Bluet (Enallagma signatum).

Orange Bluets, named for their orange-and-black coloration, are easy to identify and relatively common in the central wetland area at the park.

The fact of the matter is you’re unlikely to see more than one or two of the blue bluets on the species list, so there should be no need to curse my little friends in frustration because you’re unable to identify them. Look closely at the pattern of blue-and-black markings on the abdomen of males and you should be able to easily differentiate the three species of bluets featured in this post. Identifying females can be a lot more challenging.

Familiar Bluet

In my experience, the only blue bluet you’re likely to see in the central wetland area at Huntley Meadows Park (HMP) is Familiar Bluet (Enallagma civile).

Familiar Bluet damselfly (male, in flight)

15 SEP 2014 | HMP | Familiar Bluet (male, in flight)

Stream Bluet

Stream Bluets (Enallagma exsulans) are relatively common along some of the streams that flow through Huntley Meadows Park, such as Barnyard Run.

A Stream Bluet damselfly (Enallagma exsulans) spotted at Huntley Meadows Park, Fairfax County, Virginia USA. This individual is a male.

24 JUN 2015 | HMP | Stream Bluet (male)

It’s helpful to get shots of mating pairs in tandem, since males and females of the same species can look quite different.

A mating pair of Stream Bluet damselflies (Enallagma exsulans) spotted at Huntley Meadows Park, Fairfax County, Virginia USA. This pair is in tandem.

10 JUL 2015 | HMP | Stream Bluets (mating pair, in tandem)

Female Stream Bluets are polymorphic, displaying either green or blue on the thorax. The green morph appears in the two photos of a mating pair of Stream Bluets featured in this post.

A mating pair of Stream Bluet damselflies (Enallagma exsulans) spotted at Huntley Meadows Park, Fairfax County, Virginia USA. This pair is in tandem.

10 JUL 2015 | HMP | Stream Bluets (mating pair, in tandem)

Big Bluet

The author has never seen a Big Bluet damselfly (Enallagma durum) at Huntley Meadows Park. My theory is the wetlands at the park are the wrong habitat for Big Bluets.

Habitat Large sandy lakes and lower reaches of rivers, even extending into brackish estuaries. Source Credit: Paulson, Dennis (2011-12-19). Dragonflies and Damselflies of the East (Princeton Field Guides) (Kindle Locations 2156-2157). Princeton University Press. Kindle Edition.

It’s noteworthy that the only location where I have seen Big Bluets is Accotink Bay Wildlife Refuge (ABWR), and Ken Larsen’s photo of a Big Bluet (linked from the FoHMP Odonata species list) is from Occoquan Bay National Wildlife Refuge. Are you seeing the same pattern I see? The common keyword between our Big Bluet spottings is “bay.” Unless someone can show me a photograph of a Big Bluet spotted at Huntley Meadows Park, I feel strongly it should be deleted from the FoHMP Odonata species list.

A Big Bluet damselfly (Enallagma durum) spotted at Accotink Bay Wildlife Refuge, Fairfax County, Virginia USA. This individual is a male, shown eating an unknown insect.

17 SEP 2012 | ABWR | Big Bluet (male, eating prey)

The following poor quality photo is used to provide another illustration of the idea that it’s helpful to get shots of mating pairs in tandem, since males and females of the same species can look quite different. Female Big Bluets are polymorphic, displaying either brown or blue coloration. The brown morph is shown below.

A mating pair of Big Bluet damselflies (Enallagma durum) spotted at Accotink Bay Wildlife Refuge, Fairfax County, Virginia USA. This pair is in tandem.

10 SEP 2012 | ABWR | Big Bluet (mating pair, in tandem)

Related Resource: Dragonflies of Loudoun features a flight calendar for dragonflies and damselflies. Familiar Bluets are on the wing from July through September; Stream Bluets from May through August. Big Bluets aren’t listed. Hmmm, could it be because there aren’t any bays located in Loudoun County, Virginia?

Editor’s Note: The environment at Huntley Meadows Park may not be the ideal habitat for Skimming Bluet damselflies (Enallagma geminatum). The author has never seen a Skimming Bluet at the park, and the species isn’t linked from the FoHMP Odonata species list, suggesting Ken Larsen has never photographed one. If you have a photo of a Skimming Bluet at Huntley Meadows, then please contact me.

Copyright © 2015 Walter Sanford. All rights reserved.

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Orange Bluet damselflies (males)

February 26, 2015

What’s orange and black but actually called a “bluet?” The Orange Bluet damselfly (Enallagma signatum), of course!

Orange Bluet damselfly (male)

The word “bluet” refers to a type of damselfly rather than the color blue, specifically species of damselflies in the Genus Enallagma (American Bluets). Most bluets are primarily blue in color, as you might expect; three other smaller groups of bluets are mostly black, yellow-to-red, and mostly violet.

Orange Bluet damselfly (male)

There are five families of damselflies in the United States of America. Three of five damselfly families occur in the mid-Atlantic region: Broad-wings; Spreadwings; and Pond Damsels. Pond Damsels is the largest family, including bluets, dancers, forktails, sprites, etc.

An Orange Bluet, shown above, was spotted alongside the boardwalk at Huntley Meadows Park on 12 September 2014. This individual is a male, as indicated by its coloration and terminal appendages. Females are green, adding to the color conundrum that is Orange Bluet!

Another male was spotted on 15 August 2014. The photo was taken using my Fujifilm X-T1 digital camera and 55-200mm zoom lens (88-320mm, 35mm equivalent).

Orange Bluet damselfly (male)

Copyright © 2015 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.

I heart you!

August 16, 2014

I was looking for mating pairs of Eastern Pondhawk dragonflies (Erythemis simplicicollis) during a photowalk at Huntley Meadows Park on 10 August 2014. Meanwhile my friend Mark Jette spotted a mating pair of damselflies.

The Orange Bluet damselflies (Enallagma signatum) shown in the following photographs are “in wheel,” in which the male uses “claspers” (terminal appendages) at the end of his abdomen to hold the female by her neck/thorax while they are joined at their abdomens. The male, orange and black in color, is on top; the female, green and black in color, is on the bottom.

The copulatory, or wheel, position is unique to the Odonata, as is the distant separation of the male’s genital opening and copulatory organs. Source Credit: Paulson, Dennis (2011-12-19). Dragonflies and Damselflies of the East (Princeton Field Guides) (Kindle Locations 377-378). Princeton University Press. Kindle Edition.

The wheel position is sometimes referred to as “in heart” when damselflies mate.

Orange Bluet damselflies (mating pair, in wheel)

The preceding photograph was edited to highlight the heart shape formed by the mating pair of damselflies.

Orange Bluet damselflies (mating pair, in wheel)

The classic heart shape became deformed as time passed.

Orange Bluet damselflies (mating pair, in wheel)

In case you’re wondering, I spotted four- to five pairs of mating Eastern Pondhawk dragonflies but wasn’t fast enough to shoot a single photograph! Eastern Pondhawks mate quickly, often for just a few seconds and sometimes entirely in mid-air. Usually by the time you spot a mating pair and reach for your camera, the peep show is over: the pair separates when copulation is complete and the female starts laying eggs (oviposition) while the male hover-guards the female from other aggressive males.

Related Resources:

Copyright © 2014 Walter Sanford. All rights reserved.

Color conundrum

March 12, 2014

What’s orange and black but actually called a “bluet?” The Orange Bluet damselfly (Enallagma signatum), of course!

The word “bluet” refers to a type of damselfly rather than the color blue, specifically species of damselflies in the Genus Enallagma (American Bluets). Most bluets are primarily blue in color, as you might expect; three other smaller groups of bluets are mostly black, yellow-to-red, and mostly violet.

In the mid-Atlantic [USA] and for most of the United States, there are only three families of damselflies: Broad-winged (Calopterygidae), Spreadwings (Lestidae), and Pond Damsels (Coenagrionidae). Only out west along the extreme southern border you might encounter something from the two other recorded families. Everyone should start by learning the families.

Broad-wings include the showy and relatively large jewelwings and rubyspots who indeed have broad, densely-veined wings that are often obviously marked with black, brown, amber, or red.
Spreadwings perch with their wings slightly spread, the bases of the wings are narrow and look stalk-like and spreadwing stigmas are longer than they are wide.
Pond Damsels are our largest family and include the bluets [American Bluets], dancers, forktails, sprites, etc., in other words, practically everything else. They also have wings that are narrowly stalked at the base but the stigmas are short, about equal in width and length.

Source Credit: Personal communication from Ed Lam, author and illustrator of Damselflies of the Northeast.

The following photo shows an Orange Bluet damselfly spotted during a photowalk around Mulligan Pond at Jackson Miles Abbott Wetland Refuge, Fairfax County, Virginia USA on 23 August 2013. This individual is a male, as indicated by its coloration and terminal appendages.

Orange Bluet damselfly (male)

I visited the bay side of Accotink Bay Wildlife Refuge on 16 August 2013. There were zillions of damselflies on the wing but almost no dragonflies. Very odd.

Thanks to Mr. Chris Hobson, Natural Areas Zoologist with the Virginia Natural Heritage Program, Virginia Department of Conservation and Recreation, for identifying the following orange-form female Orange Bluet damselfly that I spotted along the shore of Accotink Bay.

Orange Bluet damselfly (female)

I read somewhere that it’s possible to catch damselflies without a net, using only your thumb and index finger to grab them by their wings. Louisa Craven, my good friend and photowalking buddy, and I decided to test the technique during a photowalk at Accotink Bay Wildlife Refuge on 24 September 2012. After a few misses, Louisa proved it can be done by catching a male Orange Bluet damselfly!

Orange Bluet damselfly (male)

The following photos show the same individual perching on Louisa’s hand and my index finger, respectively.

Orange Bluet damselfly (male)

Orange Bluet damselfly (male)

Copyright © 2014 Walter Sanford. All rights reserved.

Eastern Pondhawk dragonfly (male, predator-prey)

September 26, 2012

A male Eastern Pondhawk dragonfly (Erythemis simplicicollis) spotted along the shore of Accotink Bay. Notice the abdomen of a male Orange Bluet damselfly (Enallagma signatum) lying on the leaf to the right of the dragonfly. The Eastern Pondhawk probably ate the head and thorax of the Orange Bluet, although I didn’t actually witness the event.

510-cr2-ver2_aperture

The Eastern Pondhawk dragonfly is a …

Voracious predator, especially females, eating odonates of all kinds their own size and smaller… Source Credit: Paulson, Dennis (2011-12-19). Dragonflies and Damselflies of the East (Princeton Field Guides) (Kindle Locations 10223-10224). Princeton University Press. Kindle Edition.

Habitat: Accotink Bay Wildlife Refuge, a 1,200 acre preserve located at Army Garrison Fort Belvoir, Fairfax County, Virginia USA.

Copyright © 2012 Walter Sanford. All rights reserved. www.wsanford.com


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