Its been a while. I’ve been derailed into some rather unpleasant personal matters for several years but hopefully I can get this blog back on the tracks one step at a time.

I was driving through southern New Mexico the other day and stopped for a lunch break along a watery ditch. A few darners were flying about so I decided to grab my trusty net, which has laid dormant for several years, and see if I could catch anything.

It didn’t take long before one of the patrolling males flew up over the culvert on which I stood and into my waiting net. I have done very little dragonfly hunting in the west so I could hardly wait to what exciting new species I had caught!

The hypnotic blue eyes tell the tale. It was a blue-eyed darner, Rhionaeschna multicolor.

The male terminal appendages in profile are also diagnostic of the species.

And small differences in the lateral thoracic stripes can also help distinguish it from certain species of darners in the genus Aeshna and the arroyo darner, Rhionaeschna dugesi.

This was not entirely new to me, but was exciting nonetheless. I’ve also collected R. multicolor in the driftless area of southeastern Minnesota, where it is a rare treat at the edge of its range. Or at least it used to be the edge, the species seems to be expanding its range in the upper Midwest.

Hopefully I’ll soon be posting about some new-to-me species in the western US, now that I’ve got that nasty case of blogger’s block out of the way.

I wandered up to the sandy outwash moraines north of my home a few days ago, to see what’s happening on small to medium streams. Last week Hagenius brevistylus (dragonhunter) was star of the show. I glimpsed a brief aerial melee where 4-5 hags were aggressively engaged with each other over the stream before scattering. I only caught the tail end of the brouhaha, so I’m not sure exactly what transpired. Perhaps it was several amorous males competing for the attention of a female, or just a brief border war between territories.

I looked down and found additional evidence suggestive of violent aerial disputes. Floating near shore was a dead male Hagenius (there’s only one species in the genus). I can’t be sure what happened but I do know males are very aggressive; it may have been knocked out of the sky by another male.

Hags were in evidence on other small streams too. I found them patroliing up and down streams, their large size and characteristic J-shaped abdomens giving them away. I found them perched on culverts overlooking pools and riffles, and perched in their typical awkward-looking fashion on tiny twigs overlooking the water.

But that was last week; this week they are scarce. Things are in flux now, transitioning from early summer species to late summer species. They are clearly on the wane now so I decide to head up the railroad track and visit a stream I’ve never sampled before. The lure of the unknown is always irresistible.

As soon as I arrive at the stream, I spot something resting on a rock below the trestle. I enlarge a blurry camera image that I shot from the bridge above and can make out a dark clubtail with abdominal rings and a very large club. Its Stylurus scudderi, or zebra clubtail, a fairly uncommon find. This one is particularly wary though. I scramble down the slope and spend an hour trying to net it but  it never lets me get close. The footing is rocky and awkward, and my stumbling, lurching approach scares it off each time.

I finally concede defeat and move downstream, wading into the soft mushy shore near a small bed of cattails. I quickly spot something else that piques my interest even more: a Somatochlora flying along the shoreline then circling back downstream along a brushpile in the middle of the stream.It repeats this several times as I try to decide what it might be. It looks too large for Somatochlora minor, and it looks too small to be the S. williamsonia  I was hoping for. I creep further downstream into softer and weaker layers of cattail detritus, until I risk breaking through. I position my net hoop in the vegetation at stream’s edge, the camouflaged opening pointed downstream, and wait.

I don’t have to wait long until it returns to its beat. It flies upstream, low along the shore, and with a quick flip of my wrists its in the net. It turns out to be something even better than I expected. Its S. elongata, the ski-tailed emerald!  I’ve spent most of my years surveying dragonflies in bogs or collecting larvae in streams, and much lot less time surveying adults of small streams. This is one of a very few times I’ve encountered elongata adults. Its a more than ample reward for my efforts chasing the uncooperative Stylurus scudderi.

Somatochlora elongata, the ski-tailed emerald

 

 

Ever felt as if something was eating you up inside? Ever had a gnawing feeling in your gut that something was wrong but weren’t sure exactly what it was? Ever wish you were a dragonfly and could just fly away from it all? You might want to reconsider that wish. For some helpful perspective on life’s troubles let me introduce the abdominal ailments of Macromia illinoisensis and Didymops transversa, aka the Swift River Cruiser and Stream Cruiser.

In 2013, dragonfly experts Ken Tennessen and Bill Smith were out north of Boulder Junction, Wisconsin looking for nymphs of Somatochlora cingulata (lake emerald) when they noticed something unusual. The M. illinoisensis nymphs they collected had something long and white coiled inside their abdomens. Although both Ken and Bill each had decades of experience collecting cruiser nymphs in Wisconsin and elsewhere, they had never seen anything like this before.

What Ken and Bill observed: Macromia nymph with ropy white coils inside. Photo © Dr. Ken Tennessen

They dissected some of the nymphs and confirmed their suspicions. The nymphs were being parasitized by some sort of nematode (round worm). Nematode parasites of dragonflies had rarely been reported before, and the two went on to confirm that the closely related Didymops transversa is also being parasitized in some Wisconsin lakes. The culprit is apparently a nematode in the family Mermithidae, and it does not seem to be hosted by any other type of dragonfly in the area. It may prove to be specific to the Macromiidae.

Macromia illinoisensis nymph dissected to show the nematodes within. Photo © Dennis Johnson

Mermethidae are a taxonomically difficult and poorly known group, as are most nematodes. They are somewhat infamous though because of Mermis nigrescens, a mermithid that parasitizes grasshoppers. That species lays its eggs on vegetation, and the grasshopper ingests the eggs which hatch and grow to great lengths internally. The parasite can grow to at least 6 inches in the body cavity, feeding on the hemolymph (blood) of the grasshopper. They then exit the body of the unfortunate dead..or living…grasshopper, and complete their life cycle in the soil.

This find opens an exciting new area of discovery in regional dragonfly biology, and is just one of several major dragonfly discoveries that Ken and Bill have been involved in. Their research team now includes Marla Garrison and Dennis Johnson, and I expect more interesting news from this group in the future.

Tennessen, K., W.A. Smith, M. Garrison and D. johnson. 2015. Nematode Parasites in Nymphs of Macromia illinoiensis in Northern Wisconsin Lakes.  Argia: 27 (1) p. 24-25. 

©2017 Wayne P. Steffens

A rare (for this year) sunny Monday, and another dragonfly safari in northern Lake County Minnesota. I headed back north to where I collected Somatochlora brevicincta (Quebec emerald) for the first time about 10 years ago, hoping I might have similar luck. It was a pretty unexpected place for brevicincta, a rather wide and open channel with lilypads and such, the kind of place where I’d expect to see Libellula quadrimaculata (4-spotted skimmer) and Leuchorrhinia frigida (frosted whiteface) rather than brevicincta. But today I only found the former 2 species. I know the real breeding habitat for brevicincta is the peatland to the north, but I don’t have time to trek through the woods today. I’m more curious to find out how often they use this road. I don’t find any today.

However, just across the road I saw a small dark form flying low and secretively over the narrow trickle flowing through the ditch. Somatochlora minor! The channel it was patrolling was barely a foot wide. Although one of our more common emeralds, I never tire of the green eyes, brilliant yellow spots, and the places they inhabit.

Somatochlora minor male (ocellated emerald)

 

Farther up the road I stopped to try and catch an Aeshna feeding over the roadbed. I haven’t seen many Aeshna yet this summer, but as summer wears on they will soon be almost everywhere.  This one turns out to be the ubiquitous Aeshna canadensis (Canada darner) but several other species should appear here soon. Identifying some of the Aeshna (mosaic darners) can be tricky; if you’re still learning or want to learn to identify them the Wisconsin Dragonfly Society has a useful identification guide here.

I find some Somatocholora walshii a bit further up the road, and then head for home.I’ll come back looking for the rare A. subarctica  (subarctic darner) in August or early September. By then, most of the Somatochlora will be gone.

I follow a hunch. On my way home I stop near a swampy area that has always intrigued me but I’ve never sampled. It just has “the look” of someplace that might harbor interesting species, although I can’t quite put my finger on or elucidate exactly what that look is. Its just a mix of some black ash, white cedar, and black spruce. I stop the car when I see a medium-sized dragonfly feeding back and forth over the road. It evades me several times, but as it flies overhead I see the clear silhouette of a Somatochlora-dark, slender, steady and deliberate in its flight. Rather than fly up and down the road as I often see them do, this one zigs back and forth across the road, tacking gradually east. Then it reverses course and zig-zags back and forth heading west. After several maddening cycles and about 20 minutes of this game where it always senses my interest and avoids me, it finally makes a mistake. It comes down to waist level to grab an insect, then cuts across the road into my waiting net.

My patience paid off. Its another new location for Somatochlora forcipata (forcipate emerald), the third site that I’ve found them this year including my back yard, and without too much effort. As I said last week, they are there to be found by the patient and the lucky. I’ll have to come back and investigate where the breeding habitat is.

©2017 Wayne P. Steffens

Today we headed out toward the bogs and rivers of northern Lake County, MN not far from where I live. The goal, as it often is, was to find some Somatochlora and see what other dragonflies we could scare up. It didn’t take long.

Just a few miles up the road we stopped near a small river. I found one Somatochlora minor (ocellated emerald) dead in the road.  I have become pretty good at spotting roadkilled dragonflies, even when driving.  I once found a new Somatochlora hineana (Hine’s emerald) site near St Ignace, Michigan by finding a roadkill. With a little practice, dragonfly wings can be seen sparkling and flopping about in the wind as other cars pass.  I also saw some more emeralds flying overhead but couldn’t get my net on them.

Up past the Cloquet River is the real Somatochlora Country, where the wilder country that emeralds love really begins.  In the space of a few miles I found Somatochlora walshii (brush-tipped emerald), Somatochlora kennedyi, (Kennedy’s emerald), and the prize of the day, a female Somatochlora forcipata (forcipate emerald).

This is one of the least commonly seen emeralds and is considered rare by some. I believe they are merely more difficult to find. They are certainly uncommon, but not rare. This one was captured as it oviposited in a small roadside ditch puddle that was quite unremarkable. The primary breeding habitat might be sphagnum pools in nearby bogs, but I’ve also seen them repeatedly in areas where sphagnum is scarce or entirely absent, like my backyard at houses in both Minnesota and Wisconsin.

©2017 Wayne P. Steffens