Posts Tagged ‘Stream Bluet damselfly’

Stream Bluet damselflies (mating pair, in tandem)

August 5, 2018

A mating pair of Stream Bluet damselflies (Enallagma exsulans) was spotted during a stream-walk along South Fork Quantico Creek in Prince William Forest Park (PWFP), Prince William County, Virginia USA. This pair is in tandem.

After copulation, Stream Bluet engages in a form of guarding behavior known as “contact guarding,” in which the male and female fly “in tandem” to egg-laying sites. Contact guarding is used by some species of odonates to prevent aggressive males from hijacking the female.

26 JUN 2018 | PWFP | Stream Bluet (mating pair, in tandem)

Female E. exsulans is polymorphic, including two morphs: green or blue thorax; abdomen similar to male for both morphs. The female shown in the preceding photo is a green morph.

Look closely at the posterior end of the female’s abdomen. All female damselflies (and some species of dragonflies) use an ovipositor to insert fertilized eggs into vegetation (endophytic oviposition). Notice the white spheroid at the tip of her ovipositor. That’s either a single egg or egg cluster/mass, probably the former.

Now look at the male. He appears to be “recharging” for mating again: Sperm is transferred from the genital opening under abdominal segment nine (S9) to the secondary genitalia located under abdominal segment two (S2). Remember all dragonflies and damselflies have a 10-segmented abdomen.

Editor’s Notes

Thanks to my good friend Mike Boatwright, administrator of the Virginia Odonata Facebook group, for verifying my tentative identification of the species of damselfly. Also thanks to Sue Gregoire, Kestrel Haven Migration Observatory, for sharing her expert opinion that my photo shows a single egg at the tip of the female’s ovipositor.

Copyright © 2018 Walter Sanford. All rights reserved.

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You look Familiar.

October 4, 2015

Do I know you? You look familiar. Like a Familiar Bluet damselfly (Enallagma civile), that is.

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

23 SEP 2015 | Huntley Meadows Park | Familiar Bluet (male)

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

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

23 SEP 2015 | Huntley Meadows Park | Familiar Bluet (male)

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. That being said, identification of bluet damselflies is relatively simple at Huntley Meadows Park. (Yay, another reason to love the park!)

The fact of the matter is you’re unlikely to see more than one or two of the blue bluets on the Friends of Huntley Meadows Park Odonata species list of damselflies, especially if you never venture beyond the boardwalk: Familiar Bluet (Enallagma civile); and Stream Bluet (Enallagma exsulans).

The two species look somewhat similar, but similar is not the same, as illustrated by the following composite image: Stream Bluet damselfly (spotted on 24 June 2015); Familiar Bluet damselfly (spotted on 23 September 2015). How many differences can you see?

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

Composite image: Stream Bluet (male) versus Familiar Bluet (male).

Both species tend to be habitat specialists rather than habitat generalists: Familiar Bluet is the only blue bluet you’re likely to see in the central wetland area at Huntley Meadows Park; Stream Bluet is more likely to be found along some of the streams that flow through the park, such as Barnyard Run.

And then there’s the matter of timing, as shown by the Dragonflies of Loudoun calendar of adult flight periods for damselflies: 23 September is still prime time for Familiar Bluets; prime time for Stream Bluets ends in August. So if you see a beautiful blue damselfly at Huntley Meadows during September/October, then it’s almost certainly a male Familiar Bluet.

Now that you’re familiar with the who, what, where, and when of Familiar Bluets, why don’t you go find one before they’re gone? Look for them on aquatic vegetation close to the water.

Copyright © 2015 Walter Sanford. All rights reserved.

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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