29 September 2005

Great Spreadwing: New for Michigan

Remember back in July, when I said one of our goals was to find Great Spreadwing, Archilestes grandis, in Michigan? On 27 September, we did.

We've been looking for this brawny bug for a couple of years; it's a southwestern species that has been expanding its range since the 1920s. It was first found in southwest Ontario in 2002, although it has been present in Ohio since 1925. The other day, Stylurus and I met in northwestern Wayne Co. for dinner. It was a fairly new restaurant, part of a ~35 ac (~15 ha), as-yet unfinished development. A small creek emerged from a metal culvert under the busy road out front and went right between the restaurant and the parking lot, heading off to the rear of the development. The creek is perhaps 1 meter across, and the "protected natural wet land" (according to the sign; sic, and sick) is about 4 meters wide, full of weeds, trash, etc.

It was a beautiful day, the last really warm day of summer. We crossed over the decorative little bridge, and a flash of substantial odonata wings caught our attention. I literally skidded to a stop, thinking it might be a late ovipositing Aeshna working the creek. But no, perched on a poorly planted (and therefore mostly dead) shrub was an enormous female spreadwing.

"Wow," I said...I think out loud, "that has to be Archilestes grandis!"

"There's another!" Stylurus pointed out a male.

This was a little too unlikely, I thought. "They must be Amber-wings," I said, referring to the next-largest spreadwing, Lestes eurinus, still staring dreamily at the perched female. I knew as I said it this was not true.

Of course, we both had nets in the car, and I went ahead and caught the female. No doubt, here it was: Michigan's first Great Spreadwing.

Dinner abandoned for the time being, we walked along the creek for about a quarter-mile. The swath of green was never more than 5 meters or so wide, bordered by erosion cloth and then denuded ground with a covering of opportunistic weeds. The creek itself was rarely visible. Along most of the length were piles of twisted brush, thick growths of thistles, burdocks, buckthorn, and pioneering patches of Purple Loosestrife: an excellent example of Michigan's fantastic wetland protection and mitigation laws in action. There were five or so places where bridges leading to nowhere (but soon, office buildings) had been built over the creek, offering glimpses on either side of various types of garbage, and about five or six other Great Spreadwings. We caught a male for a second voucher. The sun was waning and we went back to the restaurant for a celebratory meal.

Yesterday afternoon it was still fairly warm but a strong cold front was approaching. I returned to try to census the population along the creek and take some photos. By the time I arrived it was cloudy with a strong wind. Hunkering low in the vegetation I located two pairs of Archilestes in tandem, and another six solo males. I would say that there are probably at least two or three dozen individuals along the creek, and that this is likely an established population. How long it will persist as the area becomes more degraded is anybody's guess. This species is tolerant of disturbed areas, but if the creek gets completely overgrown, polluted from runoff from the parking lots, full of algae from fertilizer or other nutrients such as abundant goose poop from the retention basin feeding it, or the flow gets obstructed from all the trash, then it may not longer be suitable habitat for this very grand Great Spreadwing.

(images clickable)

19 September 2005

11 September 2005

Supersize it

I've seen pondhawks eating other dragonflies and big gomphids taking down large butterflies, but I usually see bluets eating gnats. I was surprised to see this Familiar Bluet (Enallagma civile) hauling around a moth which probably weighed nearly as much as the damsel itself. I didn't see the initial capture, but the moth was alive when I first started taking pictures. At this point, the bluet had already dined on the moth's head.

Thistle or plant down that had gotten stuck on the bluet's thoracic hairs is silhouetted in the late afternoon sun.

08 September 2005

Tramea party

Black Saddlebags (Tramea lacerata) are one of the species of North American odonata thought to be at least partially migratory. They are common here, and although I can't say I've observered anything that appeared to be migration, I have seen large congregations of them.

At a large, scrubby open area near the Detroit River on Labor Day, Stylurus and I saw hundreds of Black Saddlebags. They were both in the air hunting, and many were perched in the vegetation, like this one. There were a couple of Carolina Saddlebags with them (we were hoping for the rarer Red Saddlebags, T. onusta, but the one we caught was T. carolina), and many Pantalas. Normally, Wandering Glider (P. flavescens) is the more common species, but in this group Spot-winged Glider (P. hymenaea) outnumbered them; it's been a bumper year here for that species.

Update on dragonfly migration: A nifty paper was published in 2006. The abstract is here and a summary appears at Science Daily.

It's also been a decent year here for southern butterflies. Nectaring on Eupatorium (mostly tall boneset) were at least a half-dozen Fiery Skippers (Hylephila phyleus). This is a species just at or beyond the northern limit of its range in Michigan. Some years it's fairly common, while it is absent in others.

It must be autumn.

01 September 2005


I can't say that I can tell you much about the tropical genus Uracis, except that they are a lot like dragonlets (Erythrodiplax) and also libellulids. The male above is Uracis fastigiata. In central Panama, we found them in sun-dappled shady areas near water, but they weren't common. The extent of the black on the wings of this species varies; this is as extensive as it gets. The wings actually appeared stiff and plastic-like, and they flew with a fluttery, butterfly-like flight. It must be the end of their flight season, because most we saw were worn, if not battered.

In sunny, open areas we found the related Uracis imbuta (below). They were a little smaller, and more typically dragonlet-like, without the thick-winged appearance. Do you see what that individual is perched on? That's right -- Uracis grass.