The First Spiders of the Year

A bit of snow and ice doesn't seem to discourage this young female Dolomedes striatus from getting off to an early start on the season. About 10 mm in length, if she survives long enough she will double her size, attaining a length of 20 mm or a bit more. The clearly defined bands on the abdomen and distinctly striped femora distinguish this Fishing Spider from its relatives.

A female Shore Spider (Pardosa milvina) was also active nearby, hunting for any insects bold or hardy enough to venture forth. The spiders were encountered along the shoreline of a marsh, the ambient temperature was a seasonable 15°C.

They haven't topped the record this tiny Long-jawed Orbweaver (Tetragnatha sp) moving around on the snow on January 13th, with the thermometer hovering around 5°C.

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".

Close Encounters with Dragonflies in mid-January

The New Year started off with some serious winter weather, but Mother Nature has given us a break for the past three days, with the temperatures hovering around a more bearable 5°C, plus or minus a degree or two. As good a time as any to take advantage of the moderate meteorologic conditions and search for whatever dragonflies might be out and about.

The woodland stream depicted in the next photos is along the trans-Canada Trail, roughly half a kilometer east of Tweed. This is the view looking north of the trail.

And it didn't take long to find a dragonfly. She is 30 mm in length, and it definitely is a girl – the tiny ovipositor can be seen peeking out between abdominal segments eight and nine.

A photo of the stream to the south of the trail, and again, a few scoops of sand and silt from the stream bed produced a pair young males. The larger of the two is 25 mm long, the other little guy is 18 mm in length.

This is the same site where I found the Spiketail naiads last August, and I know there are lots of them lurking in the bottom of the stream. The real purpose of this excursion was not to look for dragonfly naiads, it was to satisfy my curiosity as to what they might be eating. Are any of these insect species food for Cordulegaster larvae? I don't know for certain, but given what I've read about odonate larvae in general, they are voracious eaters and will take whatever they can capture and overpower.

There are some mayfly naiads inhabiting the stream but they are not common. Caddisflies are a bit better represented, I found two species, a small one that makes its protective casing out of grains of sand, and the larva in the following photo. (Incidentally, the insect was pulled from its case by accident, I didn't tear it out for the sake of a few pictures.)

I think the caddisfly larva is probaly genus Triaenodes, at any rate both the insect and its casing strongly resemble the one in the next photos (taken during the much warmer days of a summer long past).

There were also some stonefly naiads hiding in the leaf debris along the steam's edge. Like the mayflies, they are not common, and they are tiny, almost translucent, only about 5 mm long. Not much of a meal for the naiads that I dredged up, but good enough to feed a hatchling.

The most likely source of nourishment for the growing young Spiketails are the large, maggot-like critters in the following images. Based on their aforesaid "maggot-like" aspect, I surmised (as it turned out, correctly) that they might be cranefly larvae, indeed, I think they are the larvae of the Giant Crane Fly (Tipula abdominalis). The stream bed is teeming with these detritivores and one scoop of muck can yield half a dozen. They are large, normally chunky, oval shaped and grub-like in appearance and about 25 mm long, but can extend themselves to 40 mm or 60 mm.

The insects didn't like being out of their element and weren't co-operating, so this is best macro I could obtain of the spiracular lobes. Here's a link to some much better images at BugGuide.Net.

This is an old photo from a few years ago of the adult fly, not an uncommon species, and aptly named too.

The air was warm enough to permit some active insect life outside the insulating confines of the water and there were a few small black midges flying around. And before I left for home I saw this on the snow ...

A little Long-jawed Orbweaver spiderling, no longer than 3 mm. No matter how tough the circumstances or adverse the conditions, life goes on ...

A Cave Orbweaver and a forgotten Fishing Spider

Probably not an uncommon spider but seldom encountered, as its name suggests the Cave Orbweaver (Meta ovalis) prefers to "hang out" near the entrances of caves or in rock piles. Of course man-made habitats such as cellars will serve just as well, and that's how this male came to be on the side of a building downtown. And quite a hardy spider this is, because the photos were taken on a windy, rainy November 11th, 2013, with the temperature hovering only a few degrees above the freezing point.

Cave Orbweavers belong to the family Tetragnathidae – commonly called Long-jawed Orb Weavers – but they lack the huge, serrated jaws and elongated bodies and legs of their nearest relatives.

At a length of about 12 mm this spider is a heavyweight for a male; in many spider species the males are considerably smaller than the females. The enlarged palps, modified to carry sperm packets, are easily seen in the following three images.

The female spider depicted in the next two photos was encountered at a marsh east of Tweed on August 32rd, 2011. It was fairly large, a good 25 mm in length, and although I was unable to acquire an image of the eye arrangement its general aspect was that of a Nursery Web Spider, family Pisauridae. However, this individual was much darker, and the relatively dull, straight abdominal stripes contrasted sharply when compared with the undulating white lines of the ubiquitous Pisaurina mira. I thought it might be P. brevipes, and the photos ended up being filed in my Pisaurina folder and forgotten ...

Over two years later – November 13th, 2013 – I stumbled across the photos while reorganizing some files and decided to upload them to BugGuide.Net for a positive ID. My guess as to family was correct, but the species – P. brevipes – was wrong. This spider is actually Dolomedes striatus, and it's the fourth species of Fishing Spider I've found in this neck of the woods.

Hanging by a Thread

Identifying a spider to the species level based on its colors and markings from just a photograph can be difficult or impossible, even for an expert. It's pretty safe to say this glossy female, about 15 mm long, is a Foliate Orbweaver (Larinioides cornutus). She looks like she's gravid and ready to lay eggs any time soon.

There's enough detail in the next image to see the eye pattern and determine that the spider is a Ground Crab Spider, genus Xysticus. And it looks like she's bagged another Ground Crab Spider, perhaps a different species, or maybe a younger version of her own kind.

This female is about 8 mm in length. Size and the patterning on the abdomen suggest Xysticus punctatus, but without having captured the spider and examined its anatomy in detail, its impossible to say for sure.

The best we can say for certain as to the identity of this tiny spider, only a few millimeters long, is subfamily Erigoninae (Dwarf Spiders). The webs these little spiders were weaving looked more like something an Orb Weaver would make rather than the typical sheetweb. This is strictly guesswork because there are a few look-alikes in this group – the closest match in terms of species seems to be Hypselistes florens. Finding a mating pair would go a long way toward confirming this hypothesis because the males are very distinctive ... photo of Hypselistes florens by Tom Murray at BugGuide.Net.

A mug shot of a male Long-jawed Orb Weaver, genus Tetragnatha. The name "long-jawed" sort of fits, doesn't it?

A pair of mating Long-jawed Orb Weavers – the male and female have locked those impressively toothed jaws. Presumably the purpose of this to restrain the female, as spiders are born predators and her hair-trigger killer instincts impel her to eat her prospective mate.

The same two spiders after they've separated. This is the male, and he was in a hurry to disengage after mating but having difficulty doing so. Was this due to the spider's teeth and jaws being entangled, or because the female was trying to attack the male?

The more robust female.

Sexual dimporphism in spiders can be pretty dramatic, as demonstrated by these female and male Flower Crab Spiders (Misumena vatia), the much larger female is eating a Soldier Fly. When I first encountered these two, the male was on top of the flower. When he moved underneath to avoid me, this happened ...

There might be a mating in the offing but the female sure didn't seem to like what was happening and she was trying to brush the male off of her backside with her hind legs. Considering the difference in size it's lucky for the diminutive male that his prospective mate was preoccupied with her dinner, because otherwise his life might indeed be hanging by a thread.