Thursday, October 30, 2014

An Autumnal Atteva aurea

Often mistaken for a beetle, an Ailanthus Webworm Moth nectaring at a Bull Thistle provides a little splash of color among the surrounding dried grasses and wildflowers gone to seed. The boldly contrasting patterning and colors are thought to be aposematic, a warning that the moth is distasteful or toxic.

The Ailanthus Webworm Moth has a wingspan of from 20 mm to 30 mm, and as its name implies the larvae feed on the leaves of Tree of Heaven (Ailanthus altissima).

Tuesday, October 28, 2014

A Belated Butterfly

Three Monarchs were reported in Toronto on October 27th so this male is not exceptionally behind schedule on the long journey to its wintering grounds in Mexico. But October 28th is definitely the latest I have seen one in my area (south-central Hastings County, Ontario).

The butterfly was generally southbound but flying into the prevailing breeze, stopping frequently to fuel up at some late blooming Bull Thistles. As a rule I wouldn't bother with capturing such an easily identifiable insect but I thought it might be worth checking if it was tagged (no, it was not).

Although it rained this morning the sun peeked out for a couple of hours and the temperature hovered near 20°C. It felt a lot warmer due to the humidity and a few Cabbage Whites and Clouded Sulphurs were also out and about, mostly nectaring at Dandelions or "puddling" at moist soil. Within the past week a Painted Lady, a Mourning Cloak and a some Eastern Commas have also been sighted.

One thing that certainly is exceptional, considering the time of year, is the awesome weather! After all, we could be looking at snow flying rather than butterflies ...

Thursday, October 16, 2014

October Odes

It's mid-October and the end of odonate season is drawing nigh. As a rule the only species apt to be flying this late are Autumn Meadowhawks, with the odd White-faced Meadowhawk and Spotted Spreadwing for variety. There haven't been any hard frosts as yet and October 14th proved to be sunny with unseasonably warm temperatures near 25°C; a visit to a local field and marsh produced a few surprises.

West of Tweed (44.46667°, -77.31972°) is a dry field which supports short grasses, Staghorn Sumac, Sweetfern, Rubus spp and Hawkweeds, with a scattering of Eastern Red Cedars that are home to a small colony of Juniper Hairstreaks. At approporiate times of the year it's a good place to find odonates that like to forage far from water such as Four-spotted Skimmers, Halloween Pennants and Mosaic Darners (Aeshna spp). Of course the ubiquitous Autumn Meadowhawks (Sympetrum vicinum) are still present at this habitat, this is a male ...

... and a female with its distinctive triangular ovipositor.

The three female Common Green Darners (Anax junius), however, were unexpected as most of their kind packed up and departed for more temperate climes two or three weeks ago. Shortly after the photo of the female in flight was taken the dragonfly angled sharply upward in pursuit of an Asian Lady Beetle, but on the verge of grasping it veered off and let it be. Ladybirds secrete a defensive chemical, an alkaloid called coccinellin, and the dragonfly seemed to recognize the beetle was potentially distasteful or toxic.

An even better find was a large (about 35 mm long) female Enallagma spp. This damselfly emerged fairly recently, its colors are bright and the black markings on its abdomen still have the glossy metallic sheen of youth. Study of the mesostigmal plates verified that this is a Familiar Bluet (Enallagma civile). A late flier indeed, the last local bluet (E. carunculatum) was encountered on September 24th. According to the Field Guide to The Dragonflies and Damselflies of Algonquin Provincial Park and the Surrounding Area, Enallagma civile is known to fly in early October, but this is the latest I have seen this damselfly in my area.

The habitat at 44.46889°, -77.31528° is a typical local wetland with Cattails and a variety of rushes and sedges, with the taller vegetation consisting of a few Tamarack and various small willows and alders. Two male White-faced Meadowhawks (Sympetrum obtrusum) were encountered here, they might well be the last for this year as their numbers have slowly but surely been declining with the passage of autumn. The Autumn Meadowhawks are still out in full force; about sixty were estimated to be flying with roughly equal numbers of males and females. Of course most were engaged in a frenzied last minute orgy of mating and oviposition, doing all they can to ensure their genes make it into the next generation before the onset of cold weather puts an end to their little lives ...

No female Spotted Spreadwings (Lestes congener) have been seen at this marsh during the last couple of surveys. It appears that the males can't find any either and in desperation are taking whatever they can get. Yes, that's two males in tandem in the second out-of-focus photo. The other male wasn't compliant and they separated ... some relationships are doomed to failure from the very start ...

There are still some Aeshna spp flying, not unknown in October but not common either. I didn't have a net to capture the two darners for closeup shots but they both obligingly perched or hovered long enough to be identified. One was a beautiful green form female Canada Darner (Aeshna canadensis), it could well be the same individual captured and photographed at this habitat on October 1st. An old male Lance-tipped Darner (Aeshna constricta), its colors somewhat obscured and wings whitened and frayed by age, was also doing its rounds.

All in all, not a bad count considering the location and time of year. No doubt there are a couple or three other species still hanging in there, if so photos or accounts will be posted, stay tuned ...

October 22nd – time, as it has a way of doing, has passed and is now moving toward late October. Today was sunny and breezy with the temperature hovering around 10°C, and there were over twenty male and seven female Autumn Meadowhawks (all seven females were in tandem) and a lone female White-faced Meadowhawk flying at the marsh. As might be expected the White-faced Meadowhawk was an old girl with dulled colors and frayed wings.

Despite not having observed any for the past couple of weeks, there are still some female Spotted Spreadwings around, in fact three of them, as well as four males.

Last but not least, one Aeshna spp was hawking insects along the trail but it was too far away for me to make out any details and ascertain the species. And it seems that the late flying dragonflies and damselflies may be with us a little bit longer. There's no frost in the forecast for at least a week and next Tuesday the temperature will be a balmy 17°C.

October 23rd – sunny with a light breeze blowing and the temperature close to 16°C. About twenty Autumn Meadowhawks were foraging amidst the tall vegetation bordering the Tweed Fairgrounds and the soccer field. Two female Green Darners and a male Lance-tipped Darner were also sighted in this area.

October 25th – generally overcast, windy, temperature about 15°C. A male Lance-tipped Darner was observed patrolling along the trail near the marsh west of town, an old (or perhaps just cold) individual with dulled colors.

October 27th – still at the marsh, a sunny day but on the cool side with the mercury (a figure of speech, actually there's red alcohol in the competitively priced thermometer I'm using) hovering near 13°C. Despite the less than congenial temperature there were about fifty Autumn Meadowhawks flying with twenty being in tandem pairs. The Spotted Spreadwings are still with us and three males and a female were perching on the shrubs and grasses. As might be expected these little damselflies are staring to show their age, with advance of autumn the brassy luster of their youth has turned to a more muted gray-brown.

October 28th – sunny, and Mother Nature has turned up the thermostat to near 20°C. Three tandem pairs of Autumn Meadowhawks were spotted east of Tweed along the shore of the Moira River – are these to be the last odonates of 2014? As of this writing (October 31st) it's only a few degrees above the freezing point of water, some snow flurries are in the air and over the next two or three days the mercury will enter the realms of negativity and dip below the dreaded zero mark at night ...

Thursday, September 25, 2014

An Equinoctial Odonate

Perhaps post-equinoctial would be more appropriate, as this immature male Twelve-spotted Skimmer (Libellula pulchella) was encountered on September 24th, 2014 at the Tweed Fairgrounds (south-central Hastings County, Ontario).

The Twelve-spotted Skimmer is a summer dragonfly, the first local fliers were observed at the Vanderwater Conservation Area in mid-June, a couple of very old males on their last legs were sighted as recently as ten days ago. But this is a young dragonfly, as yet lacking the pruinescence on the abdomen typical of fully mature males, and to see one flying this late in the year – the second day of autumn – is unusual to say the least.

Striking Spiders

Striking – arresting the attention and producing a vivid impression on the sight or the mind, attracting attention by reason of being unusual, extreme, or prominent, conspicuously attractive or impressive.

A dazzling Dark Fishing Spider, arresting the attention of an observer by virtue of her size, from the cephalothorax to the tip of the abdomen she is a mere 20 mm in length. Dolomedes tenebrosus can attain a body size of up to 26 mm with the legs spanning 90 mm but this one is deflated after laying her eggs. Like most Pisauridae (a.k.a. Nursery Web Spiders) she stands guard over her brood until they a bit older and better able to fend for themselves.

The spiderlings have already been through one molt and the pale exuviae can be seen littering the nursery.

A couple of closeups of the female, with one of her offspring clinging to her abdomen in the second photo.

A friend brought this wondrous Wolf Spider to me for identification, but unfortunately for the spider it was DOA when it arrived. The body length of this particular female Tigrosa aspersa was 23 mm and the legs measured 70 mm across, however, these "wolfies" can reach a respectable 30 mm.

The spider did indeed produce a vivid impression on the sight and the mind – the person who killed it woke up in the night and found the spider crawling on them; I wasn't informed what part of their anatomy. They immediately dispatched it (this was not the intent or one of the definitions of "striking" in the title), but under the circumstances it's pretty hard to fault a person for being startled ...

The arrangements spider's eyes are unique to each family, and this one's eye pattern is typical of the family Lycosidae.

A marvelous Marbled Orbweaver, in my opinion this is by far the most beautifully colored and patterned spider I have ever encountered. Araneus marmoreus is small compared to the foregoing two spiders, the body measures about 20 mm and the legs are relatively short, but it makes up visually what it lacks in sheer bulk – conspicuously attractive or impressive indeed!

The Marbled Orbweaver featured above is a female, and she's gravid and ready to lay her eggs any day to start the life cycle of her kind anew. On the other hand the female Longjawed Orbweaver (Tetragnatha spp) in the following photo won't likely get her chance to pass her genes on to the next generation, that opportunity now belongs to the small wasp, only about 3 mm in length, that's clinging to the underside of the spider.

The image was acquired under poor lighting conditions and is a bit out of focus but the wasp's ovipositor, ready to deliver its egg (or eggs?), is clearly visible in the photo. It's interesting to note that the wasp is in a "safe zone" and the hapless spider cannot reach it with its jaws.

The picture has been uploaded to BugGuide.Net where hopefully someone can identify the wasp. As of now I have no idea as to the wasp's species (Ichneumon, perhaps?) or life cycle – does it lay one egg per spider, or more? Will the spider be paralyzed by the hymenopteran's venom, or will it continue to go through the motions as the wasp larva (or larvae?) consume it from within? Whatever the story may be, like everything else in the world of nature we can be certain it's fascinating and compelling, possibly even (from our human viewpoint) bizarre ... which are all synonyms for the word "striking".

Wednesday, September 24, 2014

A female Saffron-winged Meadowhawk

East of Tweed, near a patch of wildflowers along Lakeview Lane (44.478429°, -77.301881°) – my third sighting of a Saffron-winged Meadowhawk this year (the other two were at Dry Lake, south of Marlbank). Sympetrum costiferum is larger – this individual measured 38 mm – and darker than the average Sympetrum apt to be encountered in our area, and it has a habit of perching on the ground.

As with other Sympetrum, the female Saffron-winged Meadowhawks is orange (compare to the red abdomen and brown thorax of the male).

The veins along the leading edges of the wings are saffron colored and the pterostigmata are long and pale orange.

Closeups of the face ...

... and its genital plate, a part of the dragonfly's anatomy that is unique and distinctive for each species.

Saturday, September 20, 2014

Amethyst Aster (Aster x amethystinus)

A hybrid between two very different looking species, the New England Aster (Symphyotrichum novae-angliae) and the Heath Aster (Symphyotrichum ericoides), the Amethyst Aster (Aster x amethystinus) exhibits characteristics of both parent plants which, not surprisingly, were abundant in the high and dry field where the Amethyst Asters were encountered.

The following groups of three photos illustrate the features of the Amethyst Aster, New England Aster and the Heath Aster respectively.

The overall aspects of the plants.

The blossoms resemble those of the New England Aster but are only about half as large and bear fewer ligulate flowers.

Even the involucral bracts or phyllaries are intermediate between those of the progenitor species.

More studies of the Amethyst Aster – the relatively small leaves are crowded and clasp the stem.

The main stem of the plant is hairy.