17 September 2011

Green-striped Darners

We saw our first Green-striped Darner (Aeshna verticalis) in October of 2003 at the hawkwatch (formerly SMRR, now the Detroit River Hawkwatch) at Lake Erie Metropark.

Years have gone by without seeing others and now, in the past week, we have found multiple individuals at two more locations in Wayne County.

On August 28th, we visited Crosswinds Marsh in an attempt to confirm Canada Darner (A. canadensis). At one point in the NW area of phase I, a mosaic darner flew across the trail and perched in a small tree. This turned out to be a female Green-striped Darner (A. verticalis). This shot shows the obtuse angle of the anterior lateral thoracic stripe:

This shot shows the dorsal patterning:

This shot shows the frons and the face:

Several days later on September 3rd we visited Maybury State Park. In the northwest area of the park, we found several darners working an open area. We captured a pair of Green-striped Darners (A. verticalis).

Side view of the male:

Dorsal view patterning:

Another good feature for confirming ID of A. verticalis is the lack of "teeth" on the dorsal surface of the cerci. I'm not sure one could see "teeth", or bumps, in this photo even if it was a Canada (A. canadensis), but in the hand and under a microscope the "teeth" were absent:

The female lateral view:

It has been fun gaining more experience with the Green-striped Darners (A. verticalis), but we still need to find that elusive Canada Darner (A. canadensis) in Wayne County. In the coming days, we'll add more information about how to differentiate A. verticalis from A. canadensis.

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