Marsh Bluet

Yesterday we revisted a nice wetland recently made accessible by the development of a new municipal park. The park is essentially a lot of ball fields, but if you walk beyond them, through an extensive old field community, you reach a short rise that overlooks a large grassy wetland. This is just across the street from the previously mentioned retention ponds that have such interesting boggy species of mysterious origin. On the other side of the wetland, new development is also taking place, in what used to be an old peat mine. Ah-hah! This must be where our Nannothemis, Amphiagrion, and Nehalennia are coming from. We were hopeful that we might find emeralds there, too.

Alas, we didn't find Jack Schitt there. It was fairly dry, since it's been so hot, and maybe the density of the vegetation, with no open spots, makes it less ideal than we had hoped. We wandered around -- still lots of interesting land and birds -- and ended up at two retention ponds behind a new megachurch of enigmatic denomination. The ponds looked a year old. There was a lot of activity by the usual species: pondhawks and dashers, whitetails and Widow Skimmers, etc. There were several Carolina Saddlebags (Tramea carolina) in the mix, a species we only located in the county last year. Stylurus set about trying to nab one, while I scanned the grass for damsels.

I have been on the lookout five years for any of the suite of similar bluets that have not been found in the county at all or for many years: Boreal (Enallagma boreale), Northern (E. cyathigerum), Hagen's (E. hageni), or Marsh (E. ebrium). I have looked at Familiar Bluets until I'm, uh, blue in the face. Today was no exception. Familiar, familiar, familiar. All those cerci with the funny little pale tubercule. Finally my persistance paid off, and I found one with forked superior cerci (left). Marsh Bluet! I went on to find that about a third of the bluets at the pond were Marsh, the rest Familiar. After awhile, I could see the Marsh were a little smaller and paler blue, but the patterns were pretty much alike. The only previous specimen of Marsh Bluet in the county is from 1904.

As we were getting ready to leave, what should appear over one of the ponds. You guessed it: Comet Darner. It flew only briefly, then perched about 17 feet up in a tree in the shade. It was too distant and the lighting too poor for a decent photo, but it offered us long looks through binoculars. Stylurus put both our sets of net poles together and still couldn't reach it. It flew off deeper into the trees, and although we sat there in the 94F heat for another 45 minutes, it never reappeared.


Today we went to Lenawee Co., back to Indian Trails Crossing Park. It is pleasant to walk along, or in, the River Raisin looking for gomphids and Macromia. It is mostly shallow, sandy or gravelly, and clean (or at least it seems pretty clean. I'll let you know if any of the scratches, scrapes, or fly bites on my legs become hideously infected.). Although we saw a couple Macromia, and some Black-shouldered Spinylegs, it was unproductive overall. But scenic.

Here's looking at you

Blue-fronted Dancer, Argia apicalis

Go visit the Friday Ark!

More on the Painted Skimmer

Due to my fixation with the Comet Darner, Anax longipes, I have given short shrift to the significance of the record of the Painted Skimmer, Libellula semifasciata, that I obtained on June 16. I'd do well to dwell on my successes rather than my failures.


Mark O'Brien's L. quadrimaculata praenubila

There are only four specimen records of L. semifasciata for Michigan; the dates are 1892, two from 1908, and one "recent" record from 1936. Sight records have been noted (Kielb 1996), but without verification. In 2001, O'Brien (2002) photographed what he thought was L. semifasciata, albeit a slightly strange one (above), and later found out that it was actually a rare form of the Four-spotted Skimmer, Libellula quadrimacula (O'Brien 2003). L. quadrimaculata is a very widespread species, known in the Europe as the Four-spotted Chaser, and is more common in Michigan (although there has not been a Wayne Co. record since 1917). The form Mark saw was L. q. praenubila, a form with more highly colored wingtips that is found in Europe, with only one reference to a North American sighting, from Maine (Harvey 1901). A typical female L. quadrimaculata can be seen here, and compared to the praenubila form here.

I've examined my female specimen and verified that it is indeed L. semifasciata and not L. q. praenubila. Among the diagnotic features are a yellow stigma bordered in black, rather than all brown in L. quadrimaculata; fewer bridge crossveins on the forewing than in L. quadrimaculata; and, in females, a widened flange on abdominal segment 8, not present in L. quadrimaculata. Photos of these features in the June 16 specimen are below, taken through a dissecting microscope and adjusted for the resulting lousy exposure.

L. semifasciata: pterostigma yellow bordered in black.

L. semifasciata: s8 is slightly widened

L. semifasciata: enhanced photo showing details of forewing veination. Click for larger image.

Photos of L. semifasciata -- the whole bug, alive in living color -- can be seen here, here, and here. The last image is a biggy, but shows the pterostigma and wing veination especially well.

The Painted Skimmer is considered rare in Ontario, with only three sighting records in Essex Co. in the Ontario Odonata Atlas. Thus, this Wayne Co. record is a smashingly good find.

And, as an addendum, today we found ANOTHER Painted Skimmer about ten miles northwest from Humbug, at a great site where we have found many other interesting odes -- a marsh and wooded wetland complex slated for development. It quickly flew over a fence, so we were unable to photograph it or examine it. Perhaps this species is more common than previously believed; we'll certainly be looking for it in earnest in the coming weeks to clarify the situation.

References:

• Harvey, F.L. 1901. Contributions to the Odonata of Maine -- IV. Ento. News 12:269-277.
• Kielb, M.A. 1996. The occurrence of Libellulid dragonflies in southeastern Michigan and adjacent Ontario. Great Lakes Entom. 29:1-9.
• O'Brien, M. F. 2002. The Painted Skimmer, Libellula semifasciata, in Michigan: rare or not? Mich. Birds & Nat. Hist. 9:17-18.
• O'Brien, M.F. 2003. A rare form of Libellula quadrimaculata -- "praenubila" in Michigan. Williamsonia 7(2):1-2.

Humbug, indeed!

I have been doing survey work for the Detroit River International Wildlife Refuge at their Humbug Marsh Unit, the last bit of natural shoreline on the U.S. side of the river. It was recently acquired from developers, after a long fight, and will be the gateway to the refuge. This property is not currently open to the public, and baseline flora and fauna surveys are being undertaken to prepare for site planning and restoration.

I didn't have high hopes for odonata here. Wetlands are severely impacted by Phragmites, there are no permanent ponds or streams, water quality is mediocre, and I didn't think the characteristics of the Detroit River at this location were really conducive to a variety of odes. Yesterday was the first day I have been there since our hot spell, and what a surprise!

I was initially joined by USFWS employee Emily D. (I have no idea if she wants fan mail, so I won't give her whole name) in the southern portion of the unit, which is the most disturbed. A single Calico Pennant (Celithemis elisa) and the pedestrian Familiar Bluet (Enallagma civile) were all we initially saw. I had just finished explaning how amazing it was to me that I'd been able to find over 40 new species for the county when Emily, using my crappy spare binoculars, asked "What's this one?" I looked where she was pointing and told her "Oh! That's a county record!" After several tries I was able to catch a nice Painted Skimmer (Libellua semifasciata). There is a sight/literature record for Wayne Co., but this is the first specimen.
The all-too Familiar Bluet

We were able to find a few other common species, such as Black Saddlebags, and an early Ruby Meadowhawk (Sympetrum rubicundulum). After Emily departed, I was able to secure a Spot-winged Glider (Pantala hymenaea), a difficult bug to catch.


Spot-winged Glider

Brimming with overconfidence, I was standing and patiently trying to see if I could observe nesting behavior in a catbird, and whoosh! a large ode zooms by at knee height, pivots, approaches me, feints, hovers near me wondering about that huge cave, formed by my mouth hanging open (did I hear laughing?), and takes off over my head. Once again, my nemesis, the Comet Darner (Anax longipes). Oh, yes, I encountered this thing four more times over the next couple of hours, cruising the trail or perching just out of reach. My last look at it was it taking off over a canal that empties into the Detroit River. This species remains a sight record only for Wayne Co.

Comet Darners typically inhabit fishless ponds, and I don't think there is appropriate habitat nearby, although there are a lot industrial properties in the vicinity, some of which have ponds. So perhaps I won't have another swing at this ode...but who knows. I ended up the day with 18 odonate species (as well as 17 butterfly and 33 bird species), and strong motivation to return to find more.

Photo du jour: Pronghorn Clubtail

Male Pronghorn Clubtail, with detail of last abdominal segments and cerci.