Archive for the ‘Panasonic DMC-ZS7’ Category

Advanced Dragonfly Studies

November 26, 2014

During June 2014, I attended an adult class and field trip offered by the Audubon Naturalist Society called “Advanced Dragonfly Studies: Common Darners, Spiketails, Cruisers, and Clubtails of the Mid-Atlantic.” The class instructor was Richard Orr, renowned expert on odonates of the mid-Atlantic region of the United States. The field trip to the Patuxent Research Refuge was led by Mr. Orr and Stephanie Mason, Senior Naturalist, Audubon Naturalist Society.

As I was writing a recent blog post entitled Year in Review: New finds in 2014 (odonates), I decided against including odonates spotted during during the ANS field trip. My rationale was simple: I didn’t find most of the specimens. 42 species of odonates were observed in one day, including many new species for my “life list.” I was able to photograph only a few of the odonates seen by the group due to the fast pace of the advanced class.

Widow Skimmer dragonfly

While waiting for all participants to arrive for the field trip, Bonnie Ott spotted a Widow Skimmer dragonfly (Libellula luctuosa) perching in a flower bed beside the North Tract Visitor Contact Station. This individual is an immature male, as indicated by its coloration and terminal appendages.

Widow Skimmer dragonfly (immature male)

Elegant Spreadwing damselfly

An Elegant Spreadwing damselfly (Lestes inaequalis) was netted at Rieve’s Pond. This individual is a female, as indicated by its coloration. Notice the ovipositor visible on the underside of its abdomen, near the tip. “Usually not very common,” according to Dennis Paulson, author of Dragonflies and Damselflies of the East. [New species for my “life list.”]

Elegant Spreadwing damselfly (female)

Double-ringed Pennant dragonfly

A Double-ringed Pennant dragonfly (Celithemis verna) was spotted at New Marsh. This individual is an immature male, as indicated by its coloration and terminal appendages. [New species for my “life list.”]

Double-ringed Pennant dragonfly (immature male)

Another Double-ringed Pennant was spotted at Sundew Bog in the Central Tract. This individual is a mature male. Stephanie Mason is shown in the background, referring to Stokes Beginner’s Guide to DragonfliesEditor’s Note: “The Central Tract of the refuge is closed to public visitation due to the sensitive nature of much of the scientific work.” Source Credit: Patuxent Research Refuge brochure.

Double-ringed Pennant dragonfly (mature male)

Elfin Skimmer dragonfly

Tiny Elfin Skimmer dragonflies (Nannothemis bella) can be found at Sundew Bog. This individual is either a female or immature male, based upon its coloration. [New species for my “life list.”]

Elfin Skimmer dragonfly (Nannothemis bella)

Bar-winged Skimmer dragonfly

A Bar-winged Skimmer dragonfly (Libellula axilena) was netted at Sundew Bog. This individual is a male, as indicated by its coloration and terminal appendages.

Bar-winged Skimmer dragonfly (male)

Golden-winged Skimmer dragonfly

A Golden-winged Skimmer dragonfly (Libellula auripennis) was netted at Sundew Bog. This individual is a male, as indicated by its coloration and terminal appendages. Golden-winged Skimmer dragonflies and Needham’s Skimmer dragonflies (Libellula needhami) are similar in appearance. [New species for my “life list.”]

Golden-winged Skimmer dragonfly (male)

The distinguished gentleman holding the dragonfly is Peter Munroe, Kevin Munroe’s father. Kevin is the manager of Huntley Meadows Park.

Golden-winged Skimmer dragonfly (male)

Clubtail dragonfly

The following specimen, spotted at Sundew Bog, is either an Ashy Clubtail (Gomphus lividus) or Lancet Clubtail (Gomphus exilis) dragonfly. Ashy- and Lancet Clubtail dragonflies are similar in appearance and difficult to differentiate with complete certainty. Both species were spotted at this location. This individual is a female, as indicated by its terminal appendages and the rounded shape of its hind wings (near the abdomen).

Clubtail dragonfly (female)

Emerging Common Sanddragon dragonflies

The last stop on the field trip was a walk/wade in the Little Patuxent River, southeast of Bailey Bridge, where we spotted several Common Sanddragon dragonflies, including a few individuals metamorphosing from larvae to adults. [New species for my “life list.”]

Tech Tips: All of the preceding photos were taken using a Panasonic LUMIX DMC-ZS7 digital camera. The camera is no longer available. The ZS7 was one of the first digital cameras that featured GPS geotagging. Good idea; bad implementation. After extensive field-testing, I discovered the ZS7’s built-in GPS didn’t work as well as Apple iPhone’s “A-GPS” for geotagging photos, and stopped using the camera. I decided to bring the camera with me on the field trip because it is small, lightweight, and relatively inexpensive in contrast with several other digital cameras I own. Turns out “lightweight” is the operative word. After a long hiatus, I’d forgotten how poorly the camera performs — regrettably, the photos featured in this post are an unpleasant reminder!

Copyright © 2014 Walter Sanford. All rights reserved.

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Emerging Common Sanddragons

June 29, 2014

Two emerging Common Sanddragon dragonflies (Progomphus obscurus) were spotted on 15 June 2014 during the “Advanced Dragonfly Studies” adult class and field trip to the Patuxent Research Refuge. The field trip was led by Richard Orr, renowned expert on odonates of the mid-Atlantic region, and Stephanie Mason, Senior Naturalist, Audubon Naturalist Society.

emerge: to leave water and undergo metamorphosis into an adult; emergence is thus both from water and from exuvia Source Credit: Paulson, Dennis (2011-12-19). Dragonflies and Damselflies of the East (Princeton Field Guides) (Kindle Locations 11593-11594). Princeton University Press. Kindle Edition.

The first two photos show a sanddragon emerging from its exuvia (plural exuviae), also known as a “cast skin.” Notice that its wings have not started expanding.

Common Sanddragon dragonfly (emerging, teneral, exuvia)

Common Sanddragon dragonfly (teneral, exuvia)

The wings, folded like accordions, then begin to fill from the base with fluid transferred from the body and fairly soon reach full length. The fluid is then pumped back into the abdomen, and it expands. Finally, the wings open up, and very soon the teneral adult flies away. Source Credit: Paulson, Dennis (2011-12-19). Dragonflies and Damselflies of the East (Princeton Field Guides) (Kindle Locations 466-468). Princeton University Press. Kindle Edition.

The last photo shows a teneral adult (upper right) and its exuvia (lower left). Since it takes approximately 30 minutes for dragonfly wings to expand, we can infer this sanddragon emerged before the other one.

Common Sanddragon dragonfly (teneral, exuvia)

Copyright © 2014 Walter Sanford. All rights reserved.


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