Friday, August 1, 2014

Eastern Least Clubtail (Stylogomphus albistylus)

Yesterday while counting dragonflies and damselflies along the shoreline of the Moira River, south of the dam, I spied an odonate the size of a Powdered Dancer – about 40 mm long – come in for a landing. Much to my surprise the "Powdered Dancer" proved to be a tiny Gomphid. It was extremely wary and flew off when I approached it to take a picture, and the following photo, a far cry from being the acme of digital art, was all I managed to get. I sighted the little dragonfly a few minutes later but again couldn't get close enough for a decent photo or a really good look at its markings.

I was fairly certain my mystery dragonfly was a female Eastern Least Clubtail and one of the experts at Ont-Odes was of the same opinion. I resolved, weather permitting, to return the following day armed with a net and binoculars and see if I could acquire better evidence toward a positive ID.

Not long after arriving I spotted one of the diminutive dragonflies perching on some rocks not far from the shoreline. The pale terminalia clearly contrasted with the dark background of the water, and I think this may have been a male (I doubt if the tiny nubs that constitute a female's cerci would have been visible looking through the binoculars). However, I couldn't really tell for certain if I was looking at claspers and when I approached with the net the insect took flight.

After another half an hour of patiently waiting a female landed right at the spot of yesterday's encounter (no doubt the same individual). She wasn't quite so alert today and I managed to capture her. She's on the older side, past middle age, and although not seriously worn her wings show a little bit of fraying at the edges. The dragonfly's length is 40 mm dead on (I used a straw on site and measured it at home later).

The Eastern Least Clubtail (Stylogomphus albistylus) is gracile dragonfly, and the tip of the abdomen is not prominently clubbed, even less so in females than males. The abdominal segments are boldly ringed with greenish-yellow.

A look at the beautiful – almost luminous – green eyes and prominent markings on upper surface of the thorax.

A mug shot – don't mistake that "grin" for a smile, she was not a happy camper and constantly kept trying to bite me.

Although the female's cerci are nothing like the intricately sculpted structures of the male, the terminalia are pale – almost white – in both sexes.

After the photo session the little lady was free to go her way in peace, or whatever little peace there may be in the odonate world. There was a Black-shouldered Spinyleg perching on the rocks in the same area, and though none were about today there are usually a few Dragonhunters patrolling the river. Both species are fast, powerful fliers and should one of these much larger clubtail cousins espy the Eastern Least Clubtail there's no doubt as to the outcome ...

So many things come down to nothing more than luck. Considering this dragonfly's habit of perching on emergent rocks in the middle of the river it's no wonder I've overlooked it despite surveying this spot fairly thoroughly for several years, and had it not been for yesterday's chance encounter I would still be ignorant of this gem's presence so close to home, practically in my back yard.

The barren, rocky river shoreline at the Vanderwater Conservation Area seemed like another promising place to search for the Eastern Least Clubtail, as the odonate species there are much the same as closer to home. On June 15th friend and I visited a location (44.38019°, -77.31537°) where in addition to the aforementioned shoreline there is also a forest, a woodland stream and a seep along the side of the road, and a dry meadow, all within tens of meters of one another, making for an interesting juxtaposition of habitats. And at a bridge not far from the Vanderwater Conservation Area (44.421932°, -77.306281°) he encountered and photographed a Rusty Snaketail (Ophiogomphus rupinsulensis).

August 08 was warm and sunny, it seemed like a perfect day to check out the Vanderwater Conservation Area and – jackpot! – at about 2:00 PM in the afternoon I sighted a male Eastern Least Clubtail. He was extremely wary and with good reason, as a Black-shouldered Spinyleg and a Dragonhunter were active in the area.

However, I waited patiently and sure enough he kept returning to his favourite spot. The dragonfly seemed to become accustomed to my presence and decided I wasn't a threat, and I was eventually able to get close enough to capture some images of this uncommon but beautiful little dragonfly.