Pitfalls in spider identification

So I’ve found another thing I’m not particularly good at . . . spider identification. And, since we have 2000 plus species in South Africa, I’m not even trying to identify down to species level.

Species identification was never my strong suit. Not birds (at least not the ones that fall into the Big/Little Brown Bird category), not flowers. When asked by my Botany professor (during a Plant Taxonomy practical) which plant family a flower he was waving in front of me belonged to, I answered correctly. When he asked why, I replied that the flower was the exact shade of blue as another flower in the same family. Not the answer he was hoping for! I was supposed to recite the number and arrangement of various anatomical features. So why I expected spider identification to be any different, I don’t know.

My method of spider identification is rather laborious. When I’ve taken a photo of the spider in question, I usually compare it to the photos available online. It is a process of identification by elimination. Obviously, I know all the big and very well known spiders by name, it’s the little, often brownish ones that are the problem. So after excluding the very obvious non-starters (baboon spiders, rain spiders, tarantulas . . .), I start examining the maybes. Not that one, definitely not that one, not that one, not that one, maybe that one, not that one, very possibly that one . . .  and so on. Often without any success.

I have also been reading up about spider identification online, and my research is not encouraging.

1) Although there are often beautiful photos of spiders online, there is hardly ever any indication of scale.  Wikipedia has great information regarding the size, markings etc of spider species, but you have to know what to look up first.

Note to spider photographers: I know it’s impossible to carry around (and use) a little ruler with you all the time, but maybe it would be possible to provide additional information with the photograph?

2) The photos are often enlarged. Which makes them very interesting and artistic, but not a good indication of what the spider would look like in your home or garden. What would be good is for photographers to post “zoomed out” photos of the spiders too.

Crab spider (Image source: Wikipedia)

3) One has to get really close to be able to see some of the distinguishing features . . . or have a really good zoom lens.   For example, one source on how to identify wolf spiders says “One of the easiest ways to identify the wolf spider is from the position of its eyes (if you get close enough to see them). Wolf spiders generally have two rows of four eyes, and then two on top of these rows. This one of a handful of markers unique to the Wolf spider.” In the same article it says that “The Wolf Spider is often mistaken for its more deadly cousin the Brown-Recluse spider”. Great. So how close is close? This close:

Brown Recluse (Violin) Spider (Image source: Wikipedia)

Wolf Spider (Image source: Wikipedia)

4) There may be exceptions to the rule due to, for example, regional variations.

According to an article on the Spider Club of South Africa siteViolin Spiders [also known as the Brown Recluse Spider], Loxosceles sp, are normally brown to reddish brown in colour with dark markings on their bodies, and a characteristic violin-shaped marking on the cephalthorax, although this violin shaped marking is not as distinct on our South African species.” As noted in the previous point, the eyes of the Violin spider are distinctive but you have to get pretty close to see them.  This is an important issue . . . Violin spiders are poisonous.

Another example is the Brown Button (or Brown Widow) spider. According the Spider Club source “Brown Button Spiders have varied colouring from creamy white, through brown to black, with a variety of markings on the dorsal (upper) side of the abdomen and they always have red or orange hourglass shaped markings on the ventral (under) side of the abdomen.” So if it’s black, I might mistake it for a Black Button (Widow) spider which is far more dangerous than a brown one. Or, I could completely misidentify it, unless I turn it upside down to check out the hourglass marking. Mmmh . . . maybe not. Maybe I’ll just assume the worst and make a run for it!

Searching for online spider photos, I have come to realize that quite a few of the very good spider photographers, are not spider experts. They just run across interesting spiders in the course of their general nature photography. Some don’t even bother trying to identify the spiders. Instead they make friends with a spider expert, and work on a barter system along the lines of “one positive identification for one very interesting spider photo you can use on your spider site”.  Maybe, unless you really want to do an in-depth study of spiders, that’s the way to go?


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Categories: Nature/Environment


I live on the Southern coast of South Africa, and write about the things that interest, amuse or inspire me. You can find me at https://notesfromafrica.wordpress.com and http://southerncape.wordpress.com (my photoblog)


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8 Comments on “Pitfalls in spider identification”

  1. December 19, 2010 at 4:19 pm #

    I really like the personal story you incorporate into the first paragraph–quite funny, actually! Also, that Wolf Spider is fascinating–weird with all of thos eyes.

    You inspired me to take a photo of a moth on our kitchen window in Haiti–wing span of 5 and 1/4 inches–maybe 13 and 1/2 mm–not a very good photo–but I was following your good example when I took it. I might include it in a post anyway–we’ll see if it fits somewhere. (Note: I won’t even begin trying to identify it–my description would be “big and brown.”)

    • December 19, 2010 at 8:04 pm #

      Yes, doesn’t that Wolf Spider look weird? Reminded me of a muppet-like character.

      I found a website yesterday which you might find interesting. You can submit a photo and they will try and identify the bug for you. Go to: http://www.whatsthatbug.com/

  2. December 19, 2010 at 6:23 pm #

    Thanks for the thoughtful suggestions, they make very good sense!
    Wishing you all the best for the holiday.

    • December 19, 2010 at 8:09 pm #

      I really love all your bug and spider photographs. Maybe one day I’ll be able to match your standards . . .

      The photos I’ve seen on your site have always been very easy to figure out, and relate to the real thing. I have more of a problem when a photographer tries to be too “creative”. That’s fine if it’s just for the sake of an interesting photo, but doesn’t work on a spider identification site.

  3. December 19, 2010 at 7:52 pm #

    LOL! I like the common sense answer you gave the professor.

    As for the spider id-thing, that sounds like a daunting task, and totally confusing. Although, it might be fun watching a lot of ruler carrying photographers 😉 I think you will hear a lot of interesting attempts at interspecies communications.

    • December 19, 2010 at 8:14 pm #

      And the professor never let me forgot it! “Now Lisa, what kind of flower does this colour remind you of?”! He was a nice old guy though. Wasn’t being mean about it – think he found the whole thing very amusing.

      Yeah, I’m not sure that I would want to measure spiders, or hold up the ruler near them while I took a photo.

  4. December 20, 2010 at 2:54 pm #

    All I can say, Lisa, is thank the Lord for macro settings on the camera! Imagine having to go that close to a spider to identify it? That would be another kind of challenge all together 🙂
    Sunshine xx

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