centuryplant: Close-up of the head and thorax of a Dragonhunter dragonfly (Dragonhunter dragonfly)

This photo comes from the Jay C. Hormel Nature Center in Austin, Minnesota (home of the Hormel Foods Corporation). I'd never have bothered to visit this place, except that it happens to be in Mower County, one of the two counties in Minnesota that had no Odonata records whatsoever. Actually, it's nice. I didn't see any particularly exciting species, but the fields were full of meadowhawks, and I've never seen so many spreadwing damselflies in one place. They may be the main ingredient in Spam.

I thought this was a Spotted Spreadwing (Lestes congener), but the experts at Odonatacentral.org have neither accepted nor rejected the record so far. Maybe I was too optimistic -- young adult spreadwings are hard to identify. This one must have climbed out of his larval casing pretty recently, since he's not holding his wings out at an angle the way spreadwings usually do. He still looks shiny and new, as if he's made of bronze; he'll develop more dark markings later.

If you look at the full size photo, notice the spines on his legs. Those are for catching bugs out of the air. Damselflies look so delicate that it's easy to forget what effective predators they are.

centuryplant: A Halloween Pennant dragonfly (Default)

Last July I took a drive through McLeod and Meeker counties, just west of the Twin Cities metro area, to look for dragonflies and damselflies. I chose the route after finding out from the Odonatacentral website that these counties' species lists were almost empty -- eight dragonfly records between them, and no damselflies at all. That's not so unusual for Minnesota. It's hard to understand: this state has tons of fresh water for odonates to breed in, and it should be an interesting place to study them because it's a crossroads -- lots of species' western, eastern, southern, or northern borders pass somewhere through the state. Yet for some reason we're way behind on filling out our county lists. On the range maps for some damselfly species, Minnesota looks like a hole -- as if they heard a bridge fell down and they're afraid to come here. So sometimes, instead of hiking in areas that are relatively well-studied, I drive around and look for new species in counties where, apparently, nobody has been paying much attention. There aren't always parks, but there are boat docks everywhere.

My last stop of the day was the Marion Lake Shorefishing Area, which is really nothing more than a few benches. The lake at that point has a steep shore with a lot of riprap to stabilize it, and above that is a wide mowed path, then another slope with tall grass going up to the highway. This is a good place to be at the end of the day because there aren't any trees nearby to shade it out, and you have light right up until the sun sets across the lake. Even so, it was getting pretty dim by the time I made it there, and most of the damselflies I found were perching on flowers and grass seedheads that blew around wildly in the wind. I wasn't sure any of the pictures I'd taken would be usable at all. I was happy to get home and find this:

I think those are aphids clustered upside-down on the stem. The large insect is a bluet, a very common kind of damselfly throughout the U.S. Most species are sky-blue and black, in a banded pattern that always reminds me of resistors. These are the sparrows of damselflies -- there are a lot of species that are very hard to tell apart. Most females can only be identified with a microscope. Males are a little easier: if you look at their abdomens from above, some of them are mostly black, and those species can, in theory, be identified through binoculars. Others are mostly blue, and can only be identified by examining the cerci at the end of the abdomen. This one is just about half-and-half on the middle segments, which means it's probably a Tule Bluet.

But what really interests me about this damselfly is that the blue bits aren't all blue. Young adult bluets are brown -- usually a pale brown with a drop of purple in it; the warmer tone here is probably produced by the sunset light. This one is just getting his adult coloration, and it's coming in in patches. I think it looks like turquoise in matrix -- as if the brown is being gradually polished away.

7 more photos )


centuryplant: A Halloween Pennant dragonfly (Default)

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