Showing posts with label Dark Fishing Spider. Show all posts
Showing posts with label Dark Fishing Spider. Show all posts

Thursday, September 25, 2014

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".

Thursday, May 19, 2011

Ginormous Spider

Rain for the past week has made outdoor photography difficult to impossible and today when the sun finally peeked out it seemed like well past time to take a walk on the trail. About a kilometer east of town I came across a standing dead tree with the bark falling off and thought I'd peel it back some more to see what strange and weird critters might be lurking underneath, smiling and waiting to get their pictures taken. Well, I certainly got what I was looking for: I almost grabbed hold of the biggest spider I have ever encountered in my life! Despite its size it's almost invisible against the background of bark.

Based on the pattern of the eyes (zoom in on the next two images) and general appearance I think this a female Dark Fishing Spider (Dolomedes tenebrosus).

The spider was scurrying for cover so this lateral view is a bit out of focus but the photo serves to give an idea of how robust this arthropod is. It was in no way aggressive and once it got accustomed to my prescence I likely could have let it climb on my hand without fear of being bitten.

Just how large was this arachnid? The acorn cupule, the quarter (24 mm in diameter) and my thumb (the nail is 15 mm long) in the following images will give an idea of scale. With its legs extended the spider would have measured about three inches from front to back and easily spanned the palm of my hand.