29 May 2007

New yard ode

Stylurus here!

It's always nice to be surprised by a dragonfly.

While tinkering on the patio, I heard some pitter-patter on top of our open garage door. The door is hinged at the top and when open it is horizontal to the ground. I did a couple of vertical jumps to see what was making the noise and a female House Sparrow flew off to the adjacent conifer. Just as I made my second jump, a friend came around the corner of the house and asked, "What are you doing?" I'm sure I looked silly jumping in place by the garage. "I'm looking at the House Sparrow," and then I thought nothing more of the bird.

Thirty minutes later I went to close the garage door since Nannothemis and I were going to head out for some urban dragon hunting. However, at the top of the door was a clubtail. I quickly snatched her up while noticing her deformed wingtips. This bug must have been the sparrow's interest.

Our "expedition" was put on hold as this wasn't a typical yard ode. After analysis with a hand lens and microscope, we determined the specimen to be a female Unicorn Clubtail (Arigomphus villosipes). There are only a dozen or so specimens for Michigan.

Although identification of villosipes is fairly straightfoward, this female had a subgenital plate and ovipositer that actually looked more like the diagrams of A. pallidus (Gray-green Clubtail, not found in our area) in Needham, Westfall, and May than villosipes, although in all other respects it was typical villosipes. Nannothemis took some pix through the microscope, and may get around to posting them here.

03 May 2007

Stream Cruiser: One for the books

One ode I did not note in my previous post about Kentucky was a brown-and-yellow, medium-sized dragonfly we saw in several places while at Berheim Forest. They were patrolling the margins of two lakes, one a large (32 acre) lake, the other lake about a third that size. They were in constant motion, never perching, and hard to get on with binoculars. We could see the cerci were pale. This had us stumped. Unicorn Clubtail (Arigomphus villosipes) patrols like this and has pale cerci, but it was early for them, and they also frequently perch on flat surfaces.

Sylurus thought these could be Stream Cruisers (Didymops transversa). That's what they looked like, but according to our references, the habitat and behavior were not quite right:
We returned the next day and asked permission to try to net one and identify it. They were out again, and Stylurus positioned himself in the flight path of one of the insects. Time passed. And some more time. Eventually, I walked away to photograph some other bugs. Shortly thereafter, Stylurus came happily up the path with the subject dangling from this fingers.

It was a Stream Cruiser after all. I can't remember which book I read this in, but one description noted the "long spidery legs" of this species. This photo sure shows that!

We placed the cruiser on a shrub near the lake, where it obligingly hung around for a few more photos.

When we reported our findings to Ellis Laudermilk, the invertebrate biologist for Kentucky, he said he could not recall Stream Cruisers cruising lakes. This was a lifer for both of us.