Posts Tagged ‘phenology’

Brown Spiketail dragonflies

May 6, 2019

Several Brown Spiketail dragonflies (Cordulegaster bilineata) were spotted during a photowalk with my good friend Mike Powell at Occoquan Regional Park, Fairfax County, Virginia USA.

Male

The first individual is a male, as indicated by his “indented” hind wings, and terminal appendages. Notice the epiproct for Brown Spiketail is a wide “plate” that spans both cerci, as shown in the full-size version of the following photo.

The next individual is also male, as indicated by his hamules, located below abdominal segments two and three (S2 and S3).

Female

The last individual is a female, as indicated by her rounded hind wings and terminal appendages.

Credits

Thanks to Michael Boatwright, founder and administrator of the Virginia Odonata Facebook group, for confirming my tentative identification of the gender of the first and last individuals.

Phenology

Phenology (noun) is defined as “the study of cyclic and seasonal natural phenomena, especially in relation to climate and plant and animal life.”

There is an annual cycle of odonate activity that can be subdivided into three broad categories: Early Season (spring); Mid-season (summer); and Late Season (fall).

Brown Spiketail is an “Early Season” species for locations in the Commonwealth of Virginia. I have noticed that the adult flight period for a given species of odonate in Northern Virginia tends to lag behind Amherst County, where my good friend Mike Boatwright (Mike B) lives, by about one-to-two weeks. When Mike B reported his first sighting of Brown Spiketail on 24 April in Amherst County, I knew it wouldn’t be long until Brown Spiketail would be flying in Fairfax County. Eight (8) days later, Mike Powell and I spotted our first-of-season Brown Spiketail dragonflies. Thanks for the heads-up, Mike B!

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Copyright © 2019 Walter Sanford. All rights reserved.

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The party’s over

May 22, 2017

Several Eastern Pondhawk dragonflies (Erythemis simplicicollis) were spotted during a photowalk along a mid-size stream in Fairfax County, Virginia USA.

10 MAY 2017 | Fairfax County, VA | Eastern Pondhawk (immature male)

For some types of dragonflies, immature males have the same coloration as females of the same species. This is true for many members of the Family Libellulidae (Skimmers) such as Eastern Pondhawk. Terminal appendages can be used to identify gender.

10 MAY 2017 | Fairfax County, VA | Eastern Pondhawk (female)

The Backstory

I visited a new location in Fairfax County, Virginia on 03 May 2017, following my hunch that the spot might be a good place to find some of the more uncommon species of odonates. Turns out my hunch was right!

I revisited the same location a week later. Let’s just say lightning didn’t strike the same place twice. I saw several Eastern Pondhawks but none of the uncommon species of odonates that I saw a week earlier. I don’t know whether it’s phenology or the fact that Eastern Pondhawks are voracious predators, but it seems like whenever they show up it’s game over for the uncommon species of dragonflies and damselflies that emerge during spring. By the way, that explains the title of this post.

When I see the first-of-season Eastern Pondhawks, I start singing “The Party’s Over” like Don Meredith used to at the end of Monday Night Football games on ABC-TV. Yes, I’m old enough to remember Dandy Don!

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Copyright © 2017 Walter Sanford. All rights reserved.

Phenology

May 25, 2016

Phenology (noun) is defined as “the study of cyclic and seasonal natural phenomena, especially in relation to climate and plant and animal life.”

There is an annual cycle of odonate activity that can be subdivided into three broad categories: Early Season (spring); Mid-season (summer); and Late Season (fall).

It appears the time has passed for many of the early season species of dragonflies, such as Blue Corporal (Ladona deplanta). I spotted one Blue Corporal during a photowalk on 14 May 2016 at Hidden Pond, Meadowood Recreation Area; no Blue Corporals were seen during a follow-up visit on 20 May 2016.

A Blue Corporal dragonfly (Ladona deplanata) spotted at Hidden Pond, Meadowood Recreation Area, Fairfax County, Virginia USA. This individual is a female.

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

A Blue Corporal dragonfly (Ladona deplanata) spotted at Hidden Pond, Meadowood Recreation Area, Fairfax County, Virginia USA. This individual is a female.

I prefer to photograph dragonflies on simple, uncluttered backgrounds such as the piece of heavy lumber shown above. In my opinion, it is easier to see key field markers when the background isn’t a distraction.

A Blue Corporal dragonfly (Ladona deplanata) spotted at Hidden Pond, Meadowood Recreation Area, Fairfax County, Virginia USA. This individual is a female.

In contrast, Michael Powell — a good friend and photowalking buddy — prefers photos of dragonflies in more natural settings. Here’s to you, Mike!

A Blue Corporal dragonfly (Ladona deplanata) spotted at Hidden Pond, Meadowood Recreation Area, Fairfax County, Virginia USA. This individual is a female.

Related Resources:

Copyright © 2016 Walter Sanford. All rights reserved.


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