A Late Season Common Whitetail

Encountered west of Tweed near a marsh bordering the trans-Canada Trail (44.46889°, -77.31528°) – a surprising find as the final few surviving Common Whitetails (Plathemis lydia) were flying nearly a month ago, and no others have been sighted until now. The last sighting in this area was a male on August 18, 2014 near the intersection of River St. and the trans-Canada Trail (44.473668°, -77.312911°).

The dulled colors aside, this female is in really good condition with no wear and tear on the wings, it was extremely wary and alert and it sure could fly. Half an hour of patient stalking were required to capture the agile odonate.

As of today – September 17th, 2104 – the dragonfly is still alive and well. Sad to say, her days are numbered. Even if she manages to evade the Darners patrolling the marsh (six species currently known – and lots of them!) the first frost of autumn lies in the not too distant future ...

Adult dragonflies can live for a few weeks if they don't fall victim to predators or the elements. Looking at the lackluster colors of the eyes and thorax and the frayed wings of this male Common Green Darner (Anax junius), one can only wonder how old it might be.

An superannuated female Lance-tipped Darner (Aeshna constricta). Again, the coloration and patterning – originally a beautiful yellow-green – is obscured, the cerci are broken, and the wings have obviously seen their fair share of use and abuse.

The colors of this male Canada Darner's (Aeshna canadensis) are fairly bright and only the whitish discoloration and ragged edges of the wings suggest its age.

The dragonfly's face, however, was something of a shock – the brown clypeus is hardly typical of this species. Discoloration of the exoskeleton due to old age? Or an aberrantly colored individual?

Lake Darner (Aeshna eremita)

At first glance the Lake Darner looks very similar to the Canada Darner. The main distinguishing characteristics are the distinct dark cross-stripe on the face, the very deeply notched anterior thoracic stripe and a second thoracic stripe that is relatively broad compared to other Aeshna species.

On the average Lake Darners are larger than Canada Darners; this male measured 75 mm in length. In addition the cerci of Aeshna eremita are strongly bent upward and bear prominent bumps on the upper surface, but without a Canada Darner handy to compare these features to the differences were not obvious in the field.

A female Lake Darner, at 72 mm almost as long as the male encountered on September 15th. The field marks are right on the money and identical to those of the male, with a notched (the notch being nearly semi-circular) first thoracic stripe and wide second thoracic stripe ...

... a central line on S2 joining the band on S1, and fused blue spots on S10 (the male deviated on this feature, his were touching, but just barely).

A closeup of the face depicting the cross-stripe.

The terminal appendages (cerci) are rounded at their tips and similar to those of the female Canada Darner. Again, note the fused blue spots on S10.

Details of the genital plate and styli, however, these features aren't useful for separating this darner from other related species (at any rate, they are not mentioned in field guides).

The Lake Darners encountered thus far have been unbelievably tame. The female had captured an insect and, looking for a place to sit and eat it in peace, tried perching on my face twice. A male (perhaps attracted to the female?) stopped to perch in the tall grass within arm's reach as the female was being photographed.

Easily identified Aeshna

In contrast to the difficult to distinguish females of the Lance-tipped Darner and Black-tipped Darner, the following two dragonflies are distinctive and can often be identified in flight if seen at close range. The females of both species are colored and patterned pretty much like the the males.

Shadow Darner (Aeshna umbrosa), male – photographed in early September

Habitat – Tweed, Ontario: a marsh west of town, bordering the Eastern Ontario Trail (44.46889°, -77.31528°). Typical local wetland with rushes, Cattails, Arrowheads and other emergent vegetation, the predominant shrubs are Speckled Alders and various species of Willow
Behavior – prefers to fly over small open areas of water among the alders and willows

– the narrow yellowish-green thoracic stripes are recurved at the top (underneath the wings), resembling walking canes
– relatively small greenish abdominal spots, giving the dragonfly a darker aspect than other local Aeshna spp
– the spatulate cerci appear similar to those of the Lance-tipped Darner when viewed laterally, but are wider and look very different in dorsal view
– no cross-stripe on the face, or a very thin brown line at most

A green form female Shadow Darner encountered in late September.

Mottled Darner (Aeshna clepsydra), male – photographed in early September

Habitat – Tweed, Ontario: Stoco Lake, east of the boat pier (44.474563°, -77.306227°). Sand and mud bottom, relatively shallow stagnant water, emergent plants such as rushes, White Water Lilies, Wapato and Pickerelweed
Behavior – forages low amidst the rushes and other emergent vegetation along the lake shoreline

– the lateral sides of the thorax are mottled in yellow, green and blue
– relatively large light blue abdominal spots, giving the dragonfly a much paler aspect than other local Aeshna spp
– the cerci are straight and unadorned, with a small spine at the tip
– the face has a dark cross-stripe

The Mottled Darner might be easy to identify, but it is a difficult dragonfly to find, an uncommonly encountered odonate at best. It was a real privilege to watch three of these dazzling darners foraging only a half a meter away, flitting just above the water among the emergent rushes near the boat pier (there were others flying further east among the rushes and Pickerelweed, but not close enough to be absolutely certain they were indeed Mottled Darners). The last known encounter in the Tweed area was on September 24th, 2009.

Difficult to distinguish Darners

Yes, even after seven years of "dragonhunting" there are some species that prove to be my nemesis (or should that be nemeses?) when it comes to separating them in the field, namely, the females of Black-tipped and Lance-tipped Darners.

Male dragonflies are never a problem, they are easily distinguished by their terminalia, such as, for example, this male Black-tipped Darner (Aeshna tuberculifera). The inset shows the claspers and the "black-tip" – the all black S10, although in some individuals this segment may bear tiny blue spots.

The female Black-tipped Darner (Aeshna tuberculifera) is very similar to the male in terms of color and patterning. So far so good ...

Lance-tipped Darner (Aeshna constricta), male ... the inset illustrates the "lance-tipped" cerci, also note the blue spots on the upper surface of S10.

Now let's look at a couple of Lance-tipped Darner (Aeshna constricta) blue form females – as noted in field guides the styli are long and quite visible, but the styli of the Black-tipped Darner are noticeable as well, and lengths can be difficult to judge in the field. Unlike the male's last abdominal segment, the female Lance-tipped Darner's S10 doesn't bear any blue spots, so that doesn't help.

With a length of 71 mm to 78 mm the Black-tipped Darner is theoretically larger than the Lance-tipped Darner, which weighs in at 65 mm to 72 mm. But length is also tough to guesstimate in the great outdoors, and who bothers to cart a ruler around with them on a nature hike?

Lance-tipped Darner female #1

Lance-tipped Darner female #2

The following study of the differences between the females of these two species is based both on the material found in field guides and my own observations. Markings can vary according to the individual insect and by region so I'm not sure how reliable my observations are in the context of the big picture, but they work for me.

Lance-tipped Darner (Aeshna constricta), female:
– The lateral thoracic stripes are relatively narrow and notched.
– The dark lines separating the lateral blue abdominal spots are very straight and quite narrow.
– The blue line on S2 is continuous, and there is generally more blue than dark in this area.
The last two factors conspire to give the Lance-tipped Darner's abdomen a bluer overall aspect than the abdomen of the Black-tipped Darner.

Comparing the female Black-tipped Darner (Aeshna tuberculifera):
– The lateral thoracic stripes are broad and pale, sometimes almost white, and when the dragonfly is perched in a shady place they almost seem to glow.
– The dark lines separating the lateral blue abdominal spots are somewhat irregular, and larger than in the Lance-tipped Darner.
– The blue line on S2 is broken, there is more dark than blue on this part of the dragonfly.
– The face usually bears a thin brown cross-stripe.

Although not common, green and yellow form females occur more frequently among Lance-tipped Darners than Black-tipped Darners. There were a total of about fifty of these striking insects foraging high in the air and perching on the shrubs and this was the only green female encountered.

Note that although the colors are different in the next two examples, the patterning is still consistent with the blue form Lance-tipped Darner females studied above.

Two yellow form females were flying but I was only able to capture one of them.

Before sending this beauty on her way I had to capture an image of those awesome eyes ...

A green form female Lance-tipped Darner in a more natural pose, hiding in plain sight despite its size and eye-catching markings. The complex patterning breaks up the dragonfly's profile and makes it difficult to espy when it's perching among the tangle of background vegetation.

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 ...