Posts Tagged ‘Tiger Spiketail dragonfly’

Habitat for Tiger Spiketail dragonfly

August 9, 2019

Millions of readers have acquired the secrets of success through The Magic of Thinking Big. Source Credit: Amazon.

One of the secrets of success when scouting good habitat for Tiger Spiketail (Cordulegaster erronea) is “the magic of thinking small,” as in small seep-fed streams in the forest.

What does the right habitat look like?

The following photos were taken during a Tiger hunt with Michael Powell along a small stream in the forest at an undisclosed location in Prince William County, Virginia USA. The photos are shown in sequence as we worked our way downstream from the headwaters. Mike and I have seen a single Tiger Spiketail patrolling this stream on two days during 2019: 01 July; and 06 August.

The first photo shows a seep in the forest at the headwaters of a small stream located along a segment of a marked trail in Prince William County, Virginia. Notice that skunk cabbage (Symplocarpus foetidus) and interrupted fern (Osmunda claytoniana) aren’t associated with this seep.

06 AUG 2019 | PNC. William County, VA | Tiger Spiketail habitat

The next photo is located a short distance downstream from the headwaters, looking back upstream. The stream channel is ~2-3 feet wide and no more than a few inches deep.

06 AUG 2019 | PNC. William County, VA | Tiger Spiketail habitat

A smaller “side seep” (upper-right) is a tributary of the same stream (foreground).

06 AUG 2019 | PNC. William County, VA | Tiger Spiketail habitat

The last photo shows the view looking downstream from a point just below the small side seep. Although the stream seems to disappear near the bright sunlit patch on the forest floor, in fact the stream flows over the first in a series of mini-“waterfalls” that get progressively higher going downstream.

06 AUG 2019 | PNC. William County, VA | Tiger Spiketail habitat

What time of day is best for Tiger hunting?

Based upon field observations by Kevin Munroe, Michael Boatwright, and Mike Powell and me, Tiger Spiketail seems to have two time periods of increased activity that might be site-dependent: 10 a.m. to 12 noon; and 2 p.m. to 4 p.m. Mike Boatwright and I speculate increased activity might be associated with the time of day when a given site receives more sunlight. The Tiger at the site Mike Powell and I visited seems to be a “morning person.”

Do other odonates live in the same habitat?

Mike Powell photographed a Gray Petaltail dragonfly (Tachopteryx thoreyi) along the same stream on 10 July 2019. Now we know with reasonable certainty that Gray Petaltail and Tiger Spiketail can coexist in the same seep(s).

Mike also photographed a Twin-spotted Spiketail dragonfly (Cordulegaster maculata) on 16 April 2019 in a field near the mouth of the stream. Twin-spotted Spiketail larvae probably live in the stream itself, rather than the seeps that feed the stream.

Related Resource: Habitat for Tiger Spiketail dragonfly, featuring GoPro video showing another small stream where Tiger Spiketail has been observed in Northern Virginia.

Copyright © 2019 Walter Sanford. All rights reserved.

Habitat for Tiger Spiketail dragonfly

August 9, 2018

In the world of odonates, there are habitat generalists and habitat specialists. Tiger Spiketail dragonfly (Cordulegaster erronea) is a habitat specialist.

Habitat: Small forest streams and seeps, often with skunk cabbage and interrupted fern. Source Credit: Paulson, Dennis (2011-12-19). Dragonflies and Damselflies of the East (Princeton Field Guides) (Kindle Locations 7028-7029). Princeton University Press. Kindle Edition.

The following video shows ideal habitat for C. erronea: A clean, seep-fed small stream in the forest.

The black rock in the middle of the creek is approximately five feet (~5′) from the place in the stream channel where I was sitting on a Coleman camp stool. The video begins with me looking at a seep that feeds the stream; then I pan left, right, and back to center stage.

Tech Tips: The preceding movie looks better viewed in full-screen mode. The video was recorded in 1080p at 60 fps using a head-mounted GoPro Hero4 Black action camera. The camera was positioned so that it recorded what I saw when looking straight ahead; the scene changed by moving my head. 60 fps was used so that I could edit the video to show smooth slow-motion video of Tiger Spiketail dragonflies in flight. I think one of the bigger take-aways is a Tiger fly-by would have been recorded clearly enough to be able to identify the species. For what it’s worth, the closest focusing distance of the GoPro Hero4 Black is approximately 12 inches (~1′).

GoPro CapCam©

A GoPro QuickClip was used to mount an action camera on the bill of a baseball cap.

GoPro Hero4 Black action camera, plus QuickClip mount.

The GoPro Head Strap + QuickClip is compatible with all GoPro cameras and sells for $19.95 retail.

GoPro Hero4 Black action camera, plus QuickClip mount.

The Backstory

I visited the location shown in the video three times: Several Tiger Spiketail dragonflies were observed at the site on 19- and 26 July 2018; no Tiger Spiketails were spotted on 06 August 2018, the day the video was recorded. It’s worth noting that the adult flight period for C. erronea peaks in July in Northern Virginia (USA). Most of the window of opportunity was missed due to near record setting rainfall for the month of July, including a period of seven consecutive days of rain totaling nearly 10 inches!

Although I saw several Tiger Spiketail dragonflies, every individual was in flight and I was unable to shoot still photos and/or video — they were gone by the time I reached for my camera! The GoPro CapCam© is my solution to this problem.

An Apple iPad mini is used to remotely control the action camera using the GoPro app (formerly known as “Capture”) via Bluetooth. Among many features, the app provides real-time display of the camera field of view. The camera is positioned correctly on the bill of my cap by holding the iPad directly in my line of sight and adjusting the camera mount so the iPad is shown in the middle of the screen, against the background.

Copyright © 2018 Walter Sanford. All rights reserved.

Post update: Cordulegastridae exuvia

February 16, 2018

In a recent blog post entitled Cordulegastridae exuvia, I was able to identify the specimen to the family level. Since then, I was able to identify the genus and species.

The dichotomous key for Cordulegastridae larvae that appears on p. 330 in Dragonflies of North America, Third Edition by Needham et al. was used to identify the exuvia.

dichotomous key: a key for the identification of organisms based on a series of choices between alternative characters. Source Credit: Merriam-Webster Dictionary.

The first couplet [1, 1′] is as follows.

1. No lateral spines on abdominal segments 8-9; western [2]
1’. Lateral spines present on segments 8-9; eastern [3]

No. 1 | Cordulegaster sp. | exuvia (ventral)

(See a full-size version of the original photo, without annotation.)

Since the preceding annotated image shows lateral spines on abdominal segments eight and nine (S8, S9), proceed to the third couplet [3, 3′].

3(1’). Palpal setae 4; usually 5 large and 5 small premental setae present; some setae on margin of frontal shelf spatulate (Fig. 391e) [erronea]
3’. Palpal setae 5-7; 5-9 large and 3-5 small premental setae present; all setae on frontal shelf slender, not spatulate (Fig. 391f) [4]

(See a full-size version of the original photo, without annotation.)

The preceding annotated image shows the inner side of the prementum. Four (4) palpal setae are present, plus five (5) large- and five (5) small premental setae. The premental setae on the lower-right side of the prementum seem to be more intact than the ones on the upper-left: the large premental setae are labeled using white numerals; the small premental setae are labeled using red numerals.

The setae on the frontal shelf are mostly missing, as shown below. It’s possible they were broken off either when the larva burrowed in stream sediment (personal correspondence, Sue Gregoire) or when I cleaned the specimen.

No. 3 | Cordulegaster sp. | exuvia (frontal shelf)

(See a full-size version of the original photo, without annotation.)

Genus and species

The number of palpal setae strongly indicates the specimen is an exuvia from a Tiger Spiketail dragonfly (Cordulegaster erronea). Further, the rudimentary ovipositor shown in Photo No. 1 indicates this individual is a female.

The face behind the mask

Do you remember the way the female exuvia looked with its mask-like labium in place? In my opinion, she looked exotically beautiful!

No. 4 | Cordulegaster sp. | exuvia (face-head)

(See a full-size version of the original photo, without annotation.)

Well, that was then and this now. The following photo shows the face and mouth of the exuvia after the face mask was pulled away from the face in order to count the setae on the inner side of the prementum. Look closely at the full-size version of the photo. Yikes, that’s the stuff of nightmares!

No. 5 | Cordulegaster sp. | exuvia (face and mouth)

Related Resource: Cordulegastridae exuvia, a blog post by Walter Sanford featuring an exuvia collected by Mike Boatwright.

Tech Tips

The following equipment was used to shoot macro Photo No. 2, 3 and 5: Canon EOS 5D Mark II digital camera, in manual mode; Canon MP-E 65mm Macro lens (set for 2x); and Canon MT-26EX-RT Macro Twin Lite. A Sunpak LED-160 Video Light (with a white translucent plastic filter) was used for some photos.

The following equipment was used to shoot macro Photo No. 1 and 4Fujifilm X-T1 digital camera; Fujifilm MCEX-11 extension tube; and Fujinon XF80mm macro lens. An off-camera Fujifilm EF-X500 external flash unit and Sunpak LED-160 Video Light (with a white translucent plastic filter) were used for Photo No. 4. A Raynox DCR-250 close-up filter and Canon MT-26EX-RT Macro Twin Lite was used for Photo No. 1.

Adobe Photoshop CC 2017 was used to annotate selected images.

Copyright © 2018 Walter Sanford. All rights reserved.


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