An anomalous male Eastern Forktail, and how to distinguish a disorderly disarray of damselflies

By far the most common local species, I've likely seen thousands of these small damselflies but to date this is the only Ischnura verticalis I've observed exhibiting a discontinuous antehumeral stripe.

Two days later I stumbled across another Eastern Forktail with a pinched or reduced shoulder stripe.

An imposter that might be mistaken for an Eastern Forktail: there were about a dozen of these small damselflies (about 30 mm long) in the tall grasses just under the dam shortly before sunset.

Note the vulvar spine on S8 ... definitely an Enallagma female.

The dorsal view is not the best due to the poor lighting. But the central blue oval spot on S9 is diagnostic, as are the small blue ocular spots, the narrow yellowish antehumeral stripe and heavy black humeral stripe, the pale yellow on the legs and the orange pterostigmata. This damselfly is a female Rainbow Bluet (Enallagma antennatum). I'm looking forward to photographing the males ... but where are they? Only the females were out and about ...

This damselfly is a teneral male Eastern Forktail ...

... and the next two images depict a teneral male Eastern Forktail with a broken (virtually nonexistent) shoulder stripe. Now have a look at the lateral view of a male Rainbow Bluet (Enallagma antennatum). The red tinted eyes of the teneral Eastern Forktail may be deceptive but (aside from the shoulder stripes) the ocular spots and the patterns on the terminal abdominal segments are quite different.

A male Fragile Forktail (Ischnura posita) has an "exclamtion mark" shaped shoulder stripe. This damselfly is also generally smaller than the Eastern Forktail and the last abdominal segments of this species are never blue.

Although they look similar at first glance mature female Fragile Forktails and Eastern Forktails can also be distinguished by their shoulder stripes. The shoulder stripe is broken in the mature female Fragile Forktail shown below, but solid in the mature female Eastern Forktail.

The following two immature female Ischnura posita haven't developed the pruinosity typical of the older females. Note the pale blue of the broken shoulder stripes and the sides of the thorax.

Thus far I have only encountered blue Fragile Forktail females in this area but according to the books they can be tan or grey. The females below were photographed at the marsh bordering the Eastern Ontario Trail, where this insect is abundant and not likely to be added to the endangered species list any time soon. Another good habitat to seek out these tiny damselflies are the placid pools of water hedged by low, dense vegetation along the Moira River. Now and again I've found the odd stray foraging in flower gardens a fair distance from the nearest water.

What's for Lunch?

Depends on what you are. Butterflies imbibe their nutrients through a straw-like proboscis.

While they are generally thought of as insects that sip nectar from flowers, butterflies can often be observed drinking from ... in fact, having a preference for ... mud, sap, bird droppings, manure, urine, rotting fruit or well aged carcasses. This is how they obtain vital salts, minerals and amino acids.

These Eastern Tiger Swallowtails (Papilio glaucus) were feeding at freshly watered compost on the garden. The two butterflies were frequently jockeying for position to get at the same morsel.

A White Admiral (Limenitis arthemis arthemis) stopping to sip at a damp spot on the Eastern Ontario Trail. Having one for the road, so to speak?

A Baltimore Checkerspot (Euphydryas phaeton) engaging in the same behaviour a short distance further up the trail.

Ventral view of the Baltimore Checkerspot

This hapless Hobomok Skipper (Poanes hobomok) stopped to nectar at a Purple Vetch, placed its proboscis where it shouldn't have, and has itself become dinner for a Flower Crab Spider (Misumena vatia). These spiders are able to change their color to yellow or white in order to blend into the background of the flower on which they are lurking.

As often happens the hunter becomes the hunted. Things were moving fast so I couldn't get good closeups of this wasp dragging a paralysed orb weaver to its burrow, where the spider will provide nourishment for the wasp's larva. As yet I haven't been able to identify the wasp, but I should be able to narrow it down in time. There are many different species of spider wasp and they don't prey indiscriminately on any spider, each has its own host species. This wasp would be adapted to instinctively avoid getting entagled in an orb weaver's web.

I found the orb weaver itself interesting, as there aren't that many green spiders around and I couldn't recall having seen one quite like this. I did some Googling and it looks like this spider is a Giant Lichen Orbweaver (Araneus bicentenarius). The spider in my photo would easily fit on the nail of my pinky finger but according to the author linked to above the adult female is the size of a golf ball.

Lunch for the larva of a Beewolf (Philanthus sp.) is the bee in the female's grasp. The Beewolf settled on a stepping stone in the garden for a few seconds to oviposit on the unfortunate host bee.

For a damselfly lunch is a smaller insect. There isn't enough left over to tell what the Stream Bluet (Enallagma exsulans) is eating ...

... but this Marsh Bluet (Enallagma ebrium) is chowing down on a seed bug. The bug wasn't captured on the wing, the bluet pounced on it while it was resting on the blade of grass seen in the photo.

This takes first prize: how to get a perfect meal and simultaneously eliminate a potential younger competitor from the gene pool. A mature female Eastern Forktail (Ischnura verticalis) consuming an immature female of her own species. You are what you eat ...

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.