Delta-spotted Spiketail (Cordulegaster diastatops)

Spiketails are particular about their habitat requirements, making them elusive and uncommon, and it's always a treat to stumble across one of these eye-catching dragonflies. It's unfortunate that this Delta-spotted Spiketail was unable to elude a vehicle.

At about 60 mm in length the Delta-spotted Spiketail is a large dragonfly, and although the tip of the abdomen with its characteristic ovipositor – the "spike" – is missing there are no secondary genitalia so we know this is a female.

Basing a dragonfly's distribution on roadkill is chancy as the insect could have been transported from a thousand kilometers away, but this one is fresh, pliable and still has its striking black and yellow colors (odonates tend to fade rather quickly after death). Delta-spotted Spiketails breed in beaver meadows so there's plenty of perfectly good habitat available in the area and no reason to suspect it isn't indigenous to south-central Hastings County.

Too bad my first encounter was with a dead dragonfly but accidents happen. An adult insect is near the end of its life cycle in any event so hopefully she's already mated and oviposited, producing a brood to carry on the species for the future.

Male Arrowhead Spiketail – trans-Canada Trail

East of Tweed along the trans-Canada Trail are three sand-bottomed woodland streams that are known to support Spiketails. There's a fourth habitat that looks eminently suitable but it hasn't been investigated as yet.

In early June of 2011 a female Arrowhead Spiketail was photographed near Alexander Street. Last August, Cordulegaster naiads – and plenty of them! – were discovered inhabiting another stream (they were still doing all right in mid-January). And earlier this spring naiads were found in a creek near the intersection of Sulphide Road and the trans-Canada Trail.

Studies of the larvae proved inconclusive as to whether they might be Arrowhead Spiketails (Cordulegaster obliqua) or Twin-spotted Spiketail (Cordulegaster maculata) but a couple of days ago Mother Nature gave a hint as to which species it might be ...

Of course, this doesn't rule out the possibilty that Twin-spotted Spiketails might be co-habiting with their cousins.

Another Stream full of Spiketails!

It seems like in another month to six weeks I'm going to have to be in two places at once. Just west of the intersection of the Sulphide Road and the trans-Canada Trail is a woodland steam with a sandy bottom.

Ideal Spiketail breeding habitat, it definitely looked like it was worth checking out, and sure enough there was a female Spiketail naiad in my second handful sand. She's about 40 mm in length and should emerge for her final molt to adulthood in a few weeks.

Needless to say these naiads they are impossible to spot when they are in full stealth mode, buried with only their eyes exposed.

The Spiketails are also doing well in the stream where I first encountered them. There's a lot more happening now than back in the middle of January.

It didn't take much effort to dredge up a couple more female naiads, one about 25 mm long and the other 45 mm.

Late last autumn my efforts to ascertain the species proved inconclusive, though I was able to narrow the possibilities down to either the Arrowhead Spiketail (Cordulegaster obliqua) or the Twin-spotted Spiketail (Cordulegaster maculata), with what little data I had weighted in favor the latter. Rather than trying to monitor two streams separated by almost two kilometers, in another couple of weeks or so I'm going to capture a couple or three larvae and try to raise them.

It's been ten months since I first discovering the naiads, with some luck and a little more patience I'm going to find out what they are soon ...

Close Encounters with Dragonflies in mid-January

The New Year started off with some serious winter weather, but Mother Nature has given us a break for the past three days, with the temperatures hovering around a more bearable 5°C, plus or minus a degree or two. As good a time as any to take advantage of the moderate meteorologic conditions and search for whatever dragonflies might be out and about.

The woodland stream depicted in the next photos is along the trans-Canada Trail, roughly half a kilometer east of Tweed. This is the view looking north of the trail.

And it didn't take long to find a dragonfly. She is 30 mm in length, and it definitely is a girl – the tiny ovipositor can be seen peeking out between abdominal segments eight and nine.

A photo of the stream to the south of the trail, and again, a few scoops of sand and silt from the stream bed produced a pair young males. The larger of the two is 25 mm long, the other little guy is 18 mm in length.

This is the same site where I found the Spiketail naiads last August, and I know there are lots of them lurking in the bottom of the stream. The real purpose of this excursion was not to look for dragonfly naiads, it was to satisfy my curiosity as to what they might be eating. Are any of these insect species food for Cordulegaster larvae? I don't know for certain, but given what I've read about odonate larvae in general, they are voracious eaters and will take whatever they can capture and overpower.

There are some mayfly naiads inhabiting the stream but they are not common. Caddisflies are a bit better represented, I found two species, a small one that makes its protective casing out of grains of sand, and the larva in the following photo. (Incidentally, the insect was pulled from its case by accident, I didn't tear it out for the sake of a few pictures.)

I think the caddisfly larva is probaly genus Triaenodes, at any rate both the insect and its casing strongly resemble the one in the next photos (taken during the much warmer days of a summer long past).

There were also some stonefly naiads hiding in the leaf debris along the steam's edge. Like the mayflies, they are not common, and they are tiny, almost translucent, only about 5 mm long. Not much of a meal for the naiads that I dredged up, but good enough to feed a hatchling.

The most likely source of nourishment for the growing young Spiketails are the large, maggot-like critters in the following images. Based on their aforesaid "maggot-like" aspect, I surmised (as it turned out, correctly) that they might be cranefly larvae, indeed, I think they are the larvae of the Giant Crane Fly (Tipula abdominalis). The stream bed is teeming with these detritivores and one scoop of muck can yield half a dozen. They are large, normally chunky, oval shaped and grub-like in appearance and about 25 mm long, but can extend themselves to 40 mm or 60 mm.

The insects didn't like being out of their element and weren't co-operating, so this is best macro I could obtain of the spiracular lobes. Here's a link to some much better images at BugGuide.Net.

This is an old photo from a few years ago of the adult fly, not an uncommon species, and aptly named too.

The air was warm enough to permit some active insect life outside the insulating confines of the water and there were a few small black midges flying around. And before I left for home I saw this on the snow ...

A little Long-jawed Orbweaver spiderling, no longer than 3 mm. No matter how tough the circumstances or adverse the conditions, life goes on ...

A Few Notes on Water Nymphs

It's inevitable that the "bugs" which generally pique the interest of most people are the adult form of the insect. The colorfully patterned wings of a butterfly or the iridescent elytra of a beetle that catch our eyes do so because in many cases insects are flying around trying to attract attention – that of a potential mate. The colors might be aposematic, bright, bold and arranged in striking patterns, a warning saying "don't mess with me". Or as often as not, an insect gets noticed because it's just plain weird and bizarre, it's so different that it almost qualifies as an alien form of life.

Ditto for dragonflies and damselflies – they're generally large or colorful, and pretty hard to miss on a visit to a river, lake or wetland. But the reality is that the odonates we see flying around are actually near the ends of their lives, on average lasting for only a couple of weeks before succumbing to predation or bad weather. Larger dragonflies such as darners can spend two or three years in their larval state, and by focusing only on the adult insects one is missing out on understanding most of their life cycles and roles in nature.

The following notes and photographs, not to mention the rest of this blog, are the work of a beginner who has taken only the first few steps down the long and never-ending road of learning. If you've had a close encounter with a cool naiad that's new to you and you're looking for a definitive answer as to species you've come to the wrong place, instead, try one of the links to the keys for identifying odonate larva further down this page.

Damselfly naiads are generally smaller than dragonfly larvae and have three external gills at the tips of their longer, slimmer abdomens. This is the larva of a Pond Damselfly, family Coenagrionidae.

The naiads of family Lestidae tend to be larger. Based on the habitat where it was found – a vegetated marsh – this could be a Northern Spreadwing (Lestes disjunctus), Sweetflag Spreadwing (Lestes forcipatus), Slender Spreadwing (Lestes rectangularis) or Amber-winged Spreadwing (Lestes eurinus).

The riparian habitat and very long basal segments of this naiad's antennae indicate family Calopterygidae. There are two possibilities locally – the Ebony Jewelwing (Calopteryx maculata) and the less commonly encountered River Jewelwing (Calopteryx aequabilis). According to Odonata Larvae of Michigan – Key to the Calopteryx Larvae of Michigan ~ "... tubercles behind eyes prominent and acute ..." ~ looking at the oblique views the spine behind the eye is clearly prominent and acute. This is the aquatic avatar of Calopteryx maculata.

Dragonfly naiads are stouter and more robust than their damselfly cousins, and their gills are internal (in other words, they breathe through their asses). This is a typical dragonfly larva, and based the adults of the species observed at the heavily vegetated lakeshore habitat and the naiad's profile it's a Skimmer, family Libellulidae.

Dozens of exuviae can be found during the summer months at the same lakeshore habitat. It's often advantageous to study exuviae as opposed to larvae since they can be examined and photographed without fear of hurting or killing the insect. Based on their general outlines these are Libellulidae exuviae, probably one of the common larger species such as the Widow Skimmer (Libellula luctuosa), Halloween Pennant (Celithemis eponina), Eastern Pondhawk (Erythemis simplicicollis) or Blue Dasher (Pachydiplax longipennis).

Celithemis eponina ~ can be ruled out, its eyes taper to conical points.
Pachydiplax longipennis ~ lacks the prominent dorsal spines.
Erythemis simplicicollis ~ "... lateral spines absent ..."
Libellula luctuosa ~ best guess, but most of the information needed for an exact ID is not in the photo. Next year I'll try to keep an eye out for emerging adult dragonflies, and it shouldn't be too difficult to capture the exuviae.

Identification to the species level might be difficult, but dragonfly naiads and exuviae can be narrowed down to as to family based on their general shape. This relatively stout exuviae is another example of family Libellulidae, and according to the Odonata Larvae of Michigan – Meadowhawks it keys out as a Ruby Meadowhawk (Sympetrum rubicundulum).

The best means of being certain as to the identity of an exuviae is to observe the eclosion or emergence of the adult dragonfly. This exuviae was left ehind by a Whitface – Leucorrhinia spp. – probably a Frosted Whiteface (L. frigida) as it's by far the most common of the Leucorrhinia species observed at the marsh where the exuviae was collected.

And about an hour and twenty minutes before it was photographed, this cast-off exoskeleton was worn by a female Four-spotted Skimmer (Libellula quadrimaculata).

Early last month I posted images of some family Cordulegastridae naiads. The shape of the naiads is distinctive and unmistakeable, but I have yet to encounter adults of this species (whichever one it may be!) and without having discovered the naiads would have no idea they were in the area – a great example of why the study of the naiads and exuviae is worthwhile.

And three years ago I uploaded a sequence of photos (taken by Pauline Campbell) of a Dragonhunter making its final molt to adulthood. In this case the profile of the exuviae is not typical of most Gomphidae, the burrowing larvae of Clubtails tend to be somewhat slender rather than broad and leaf-like.

Cruiser naiads are long-legged and spidery in appearance. There are two possibilities in this area – the Swift River Cruiser (Macromia illinoiensis), and the more commonly encountered Stream Cruiser (Didymops transversa). Due to the limits of the camera's macro (Canon PowerShot A530) and lack of experience in knowing what characteristics to photograph and/or observe when in the field I was unable to resolve the identity of the naiad to the species level ~ Aquatic Insects of Michigan – Macromiidae - Cruisers.

However, the experts at BugGuide.Net identified this Cruiser naiad right down to the sub-species level (perhaps based on the length of the lateral spines on S9?). Depending on which book or authority you want to follow, it's a Swift River Cruiser a.k.a. Illinois River Cruiser.

You've got to love that cute little frog-like face ...

After the photo session the naiad was released. The insect's colors are much more vibrant in its natural setting, however, underwater photography introduces greens and blues reflected from the sky and water.

Darner naiads and exuviae have relatively large eyes, and long but robust abdomens. By studying the images of the prementum, labial palps and blades posted at BugGuide.Net, I was able to ID this exuviae as belonging to a Canada Darner (Aeshna canadensis).

There were about a dozen of these dark exuviae clinging to a bridge over the fast moving water of the Moira River. Three of the images below are of an exuviae that belonged to a female – note the ovipositor.

BugGuide.Net to the rescue again ... the cast-off exoskeletons were left behind by Fawn Darners (Boyeria vinosa). I should have figured, both by the general aspect of the exuviae and because I was starting to see adults flying.

Thus endeth this lesson in how little I know ... and there's still a long way to go ...