Of Damsels and Dragons

Spotted a couple of nice critters today:

Blue Dasher (Pachydiplax longipennis),
Illinois Beach SP, Lake Co, IL 6/6/2014

This is a Blue Dasher (Pachydiplax longipennis). It's a common dragonfly around here. (Over most of the country, actually.)

Painted Skimmer (Libellula semifasciata),
Illinois Beach SP, Lake Co, IL 6/6/2014

This one's a Painted Skimmer (Libellula semifasciata). This one's not uncommon in the eastern US, but here in Lake County we're at the very western edge of their range, and this is only the second one I've seen in the county. (The third one showed up at Lyons Woods FP a couple of hours later!)

Dragonflies are serious predators -- they eat other arthropods that they mostly catch in flight, with some of the larger species specializing on tiny gnats and midges. Their large sizes (up to 4.5 inches long in the Giant Darner (Anax walsinghami)), fearless behavior, and incredible flying ability have created legends of all sorts about them, but in fact they're perfectly harmless as long as you don't actually manage to catch one. If you do, you'll likely find out that they've got a pretty strong bite, more than capable of drawing blood from a careless thumb.

If you have dragons, there should be damsels, so here's a couple of beauties:

Slender Spreadwing (Lestes rectangularis),
Spring Bluff FP, Lake Co, IL 6/3/2012

This one's a Slender Spreadwing (Lestes rectangularis).

Rainbow Bluet (Enallagma antennatum),
Raven's Glen FP, Lake Co, IL 6/9/2012

This stunner is a Rainbow Bluet (Enallagma antennatum) from Raven's Glen FP, the only place I've seen them.

Despite the dragon/damsel dynamic that the names suggest, these guys are predators as well. They prey on smaller arthropods (and they're awfully small themselves), while trying not to be dragon food.

As you might expect, dragons are generally larger than damsels, but there is overlap. (Surprisingly, the longest wingspan in the order belongs to a South American damsel (7.5 inches!) (Megaloprepus caerulatus) that preys on spiders.) Better ways to distinguish them involve the eyes and the wings -- most damsels hold their wings back over the body when resting, while dragons hold them straight out from the body. Spreadwing damsels usually hold their wings out, but in a very distinctive V-shape.

The eyes of most dragons touch at the top of the head. In some species, that's only at a point, but in others there's actually a seam running down much of the crown, where the eyes meet. Damsels always have their eyes separated by a distinct crown. Often, there are blue spots on the eyes and crown, sometimes forming a blue bar across the head.

If we have dragons and damsels, we need a knight. Here's the next best thing:

Dragonhunter (Hagenius brevistylus), Nicolet NF, Oconto Co, WI 8/11/2013

This is a Dragonhunter (Hagenius brevistylus), so named because it preys on dragonflies. It is, of course, itself a large dragonfly. It's in the clubtail family, Gomphidae, so named because many of them have broadened segments at the rear of the abdomen forming a club.

If you look closely at this one, you'll see that the eyes don't in fact touch -- they are separated in a manner similar to the damselflies. They do hold the wings out like other dragonflies, and they're stocky like other dragons rather than slender like the damsels, but still... They're a worthwhile reminder, I think, that for all the categorizing we like to do, we're responding to what the critters are doing -- they could care less what we call them, or how we go about figuring out what they are and who they're related to.