Trying to make sense of Teneral Spreadwings

These immature spreadwings, photographed at the marsh bordering the Eastern Ontario Trail about one kilometer west of town, lack the colors and patterns of adults. Virtually tenerals, they are about the length of an Emerald Spreadwing, about 40 mm, but much less robust. Distinguishing the Northern (or Common) Spreadwing (Lestes disjunctus) and the Sweetflag Spreadwing (Lestes forcipatus) can confound even experts and lacking experience I'm finding it difficult to determine the species. To add to the chaos, although they can usually be differentiated in the field there are teneral and immature Emerald and Slender Spreadwings competing in this same habitat, all within the same few square yards. Pairs of adults will be studied in future to determine if both species are extant in this area.

Although the dorsal colors of the thorax and shoulder stripes don't agree with the illustrations for an adult Northern Spreadwing (Lestes disjunctus), the sides of this immature male are pale yellow. The teeth on the cerci, shape of the paraprocts and narrow profile of the apical hood also look correct for this species.

Lateral view of another male; note the pale yellow sides of the thorax and claspers similar to those of the other male above.

Dorsal view of a third immature male's claspers.

Lateral and ventral views of a fourth male's claspers.

Oblique and lateral view of an immature female, possibly Lestes disjunctus. The sides of this individual are pale yellow. The backs of the heads of both males and females depicted thus far are dark.

The ovipositor looks correct for Lestes disjunctus.

Now things get confusing. Unfortunately I was unable to acquire of photo of the entire damselfly as a view of the postocular area would be helpful. The claspers are different than the three featured above. While the paraprocts appear to be the same the profile of the apical hood looks wider and the teeth on the cerci are subtly different. Is this a normal variation of Lestes disjunctus? An effect of the camera angle and lighting? Or are we looking at the terminal abdominal segments of an immature male Sweetflag Spreadwing (Lestes forcipatus)?

Views of an immature female; the postocular area appears pale. The pattern of the darker areas on the dorsal surface of the abdomen agree with those for Lestes forcipatus (but is this significant in the case of a teneral?).

Detail of the terminal abdominal segments. In the images above it's obvious that the large ovipositor extends well past the end of the abdomen. Although the Emerald Spreadwing has a long ovipositor, it is nowhere near this size in any individuals that I have seen, and the Emerald Spreadwing is much chunkier in appearance in any event. A darker lower rim would be desirable to help nail the identity down, however, the other criteria strongly suggest this is an immature female Sweetflag Spreadwing (Lestes forcipatus).

A teneral male Slender Spreadwing (Lestes rectangularis). In addition to the length of the abdomen this spreadwing can be identified in the field by the pale veins on the outer margins of the wings.

A Few Photos of some Common Damselflies

Most of the damselflies and dragonflies in this blog were identified with the help of the Field Guide to The Dragonflies and Damselflies of Algonquin Provincial Park and the Surrounding Area. This book is a must have reference for the serious naturalist. It covers the Odonata apt to be found in southern Ontario and the illustrations and species accounts are excellent.

The first group of pictures are Pond Damselflies, family (Coenagrionidae).

Violet Dancer (Argia fumipennis violacea), males and female. It's impossible to mistake the males for any other local species.

Powdered Dancer (Argia moesta), male

Stream Bluet (Enallagma exsulans), male, and a mating pair

Skimming Bluet (Enallagma geminatum), males and females

A couple of shots of a male Tule Bluet (Enallagma carunculatum) ...

... and a female Tule Bluet

Tule Bluets mating, in the second photo the pair are just disengaging from the "wheel" or "heart" position.

... and a male Familiar Bluet (Enallagma civile)

The ubiquitous Eastern Forktail (Ischnura verticalis) ... male, immature female, mature female and a mating pair

Fragile Forktail (Ischnura posita), male

A male Slender Spreadwing (Lestes rectangularis); the long, thin abdomen and lack of pruinosity on the last segments are diagnostic. This damselfly is a member of the family Lestidae, the Spread-wing damselflies, which typically hold their wings at about 45° to their body rather than folded together in the manner of pond damsels.

Without a clear photo or study of the male's claspers I stuck my neck out and originally misidentified the following specimen as a Northern Spreadwing (Lestes disjunctus).

The male above is an older specimen with a considerable amount of pruinosity hiding any identifying marks. Moreover, the final arbiter of damselfly species are the male's claspers or female's mesostigmal plates and/or the structure of the ovipositor. It seemed like a good idea to go back and take a closer look. The photo below is another male spreadwing (yes, I'm assuming the same species as above on the basis of appearance but I think it's reasonable to do so). Closeups of this damselfly's claspers are depicted in the succeeding two images. Note how the bottom claspers are very thin; this suggests a Swamp Spreadwing (Lestes vigilax), as per the Field Guide to The Dragonflies and Damselflies of Algonquin Provincial Park and the Surrounding Area. And if I zoom in on the upper claspers, the teeth match the drawings shown in the book for this species.

It seemed like an even better idea to follow correct scientific procedure, capture a specimen, and examine the claspers in more detail in the field. I think the damselfly below is young Swamp Spreadwing male: the colors on the thorax and abdomen are visible and match those in the color drawing in the field guide. More importantly, note the claspers ... I took closeups from several different angles. The upper and lower claspers are the same as on the spreadwings in the images above and as depicted in the book. So despite the fact that the two damselflies look quite different, I can only conclude they are the same species.

The next three photos depict a female (note the ovipositor) Spotted Spreadwing (Lestes congener). This time it's safer to go by general appearances, this is the only spreadwing species with two spots on the side of the thorax.

Three views of a male Spotted Spreadwing (Lestes congener). This damselfly had a few preferred perches on the shoreline grasses and despite its relatively small size (about 35 mm) it was surprisingly aggressive with regard to defending its turf. It took on all comers, not only damselflies of other species larger than itself but even intercepting and chasing a White-faced Meadowhawk that had the temerity to approach too closely.

Dorsal and ventral views of the Spotted Spreadwing's claspers.