The Challenge of Identifying Spiders

Recently, as I have begun investigating what little life forms live around me, I have come across a great number of spiders.  While these little eight legged friends freak my wife out tremendously, I find them fascinating and I have strived to learn more about them.  To help with this, I have begun consulting web sites and I have been reading more about spiders.  What has become immediately obvious is spiders are extremely complicated creatures.  Just in Washington State there exist 700 species of spiders!

Really, I have no hope to get every spider I find to the species level, but I would like to get a general idea for each one.  Here is a shot of a spider I took by my office recently.

At the time I took this shot, I thought that for sure someone familiar with spiders should be able to identify this one.  I could not have been further from wrong.

This was a good sized (at least an inch) spider that I found under a loose piece of tree bark.  It was not happy to let me take photos, but I managed to convince it to stay still for long enough to get some shots.  Here is a closeup I got of its eyes.

After poring through my different guides, I decided to post this spider at bugguide.net.  Other than guessing that it is some kind of wolf spider, I was not able to get much help.  Recently I have expanded my literature in spiders, so I further consulted what I have.

The Spider, by John Crompton

This book is more about the life and habits of spiders than it is any kind of identification guide.  I have not finished it yet, but what I have read is fascinating - such as how spiders make their webs and how complicated the silk that each spider creates is.  While I doubt reading this book will improve my spider identification skills, it will certainly improve my understanding of these fascinating creatures.

The Common Spiders of the United States, by James H. Emerton

This book has a wealth of information and identification material for spiders in the United States.  Unfortunately it hasn’t helped me too much yet as the book is more geared towards those very familiar with spider anatomy.  If I killed the spiders and then examined them with a microscope, I’m sure this book would be greatly helpful.  However, I do not wish to harm any of the spiders I find but just take their picture.

National Audubon Society Field Guide to North American Insects & Spiders

As I have begun seeing more and more spiders, this book has become rather useless.  I still use it to identify insects, but it hasn’t helped much recently with spiders.

Spiders and Their Kin, by Levi and Levi

I just bought this book recently and I am amazed by the wealth of information in such a small book.  It is clearly the best guide I have right now for identifying spiders.

Based on the material, I realize that very often I will not be able to tell the exact species in the wild, but there are some things I can do to improve my chances of making an identification.

1) Take a picture from the front that clearly displays the pattern of the eyes.

2) Take a picture of the abdomen such that I can clearly see any markings.

3) Take a picture of the spinnerets (back of the spider)

As with the pictures above, I often get shots of the front of the spider, but very often I do not get a good shot of the adbomen (the case here) and I almost never get shots of the spinnerets (as no one would find the shot very interesting).

Unfortunately, in the absence of these shots, and because the front of this spider is quite dirty - preventing a good look at the eyes, I still have no idea what type of spider it is and I may never truly find out.  Here’s another example of how tricky identification can be.  I took this shot recently of a spider on the shingles of my house.  Here is a closeup of the eyes.

Keep in mind this spider is turned on its side.  I then consulted both Spiders and Their Kin and this handy guide to spider eyes.  The two closest matches are a type of crab spider and the sac spider.  Here’s a better view of the entire spider.

The formation of the legs certainly does not imply that this is a crab spider.  Therefore for now I think this is a sac spider, of family Anyphaenidae, but I am nowhere near 100% on it.  In particular this spider looks to be a little too hairy to be a sac spider.  Here’s another spider I took of building 30.  Unfortunately I only got one shot off and my flash heads were partially blocked, making the image too dark.  I lightened it in Photoshop at the expense of some image quality.

The eye arrangement would seem to point to either a Dysderid or an orb weaver spider.  I am currently unsure whether it is one, or neither of these.  Here’s one of the few ones that I think I may have figured out.

I believe that this is a cybaeus as the colors and eye formations match.  Also, this spider looks very similar to the one in the link and both spiders were found in the same general area (the counties are actually neighbors).  Here’s another link to this kind of spider.  As this link also mentions Washington State, I suspect the chances are much higher that I have a positive ID.  Interestingly, the site mentions that almost nothing is known about them.  Here’s an egg sac that I believe belongs to this spider.

The spider was found in a rotted log that I broke open.  There are many other shots that I could show, but with hope now that I know some tricks to improve identification, future shots will enable me to do a better job identifying.

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Tags: identification, macro, photography, spider