Biology Lesson of the Week

Strangely, this question has been posed to me several times in the last couple of weeks. Not quite sure why there has been so much interest recently, but it's probably because of the onset of fall. I think the subject was even brought up briefly at a recent "girl's night" (but I don't remember why and it wasn't a question directed at me). Anyway, on to the question...several people have asked me recently if a "daddy-long-legs spider" really is the most poisonous spider out there.

I usually reply with, "Why are you asking me? I never took any entomology courses! I hate bugs!" But never the less, I do have an answer for them. I remember briefly discussing it in a biology class long ago, and then several years ago, my curiosity got the better of me and I did some research. Now, some of you may already be saying to yourselves "Gee, Tracie, we knew this wasn't true! What do you take us for, a bunch of morons?" To those of you that are having these thoughts I reply, "Yes, but do you know why it isn't true?". If so, than please go about your business, you're dismissed from class...you're apparently smarter than I was. ;)

Anyway, for those of you still with me, this is what I found:
First of all, what most people refer to as a "daddy-long-legs spider" is not really a spider! The brown-bodied "spiders" we see crawling around on wood piles, in gardens, and occasionally in our houses are of a completely different Order. (Remember "King Phillip Called Out For Good Soup"? Ok, I'm a biology nerd, but you guys did have to learn Kingdom, Phylum, Class, Order, Family, Genus, Species right??) Anyway, even though these little guys ARE arachnids (Class Arachnida), they aren't spiders and don't have some of the classic spider characteristics. They only have two eyes (look close and you can see them), don't spin a web, and have one main body segment (instead of two like spiders). They also don't have any venom at all. Yep, that's what I said. No venom.

Ok, here is where I had to jump back into some research. I knew there was an actual spider that some people also call "daddy-long-legs", but couldn't remember what kind of spider it was . Yep, there is an actual spider that has the same common name. I know! Confusing. "So," I thought, "maybe whoever started this myth, was actually referring to the 'real' spider!" They are in the Order Araneae and are occasionally called cellar spiders. They do have silk, and two body segments, and I guess they look a little like the other "daddy-long-legs".

Now these little guys actually do have venom. It is apparently a neurotoxin, from what I could find, which leads me to believe that someone read that somewhere and went "Oh my! A neurotoxin! That must be deadly to humans!" They probably then proceeded to tell friends, family, and whoever would listen, that the "daddy-long-legs" was a highly venomous spider. So, I'm sure someone eventually countered that with, "Well, then why has no one ever died from a bite from a daddy-long-legs?" Now, this fictional person that I have made up probably didn't want to look like a fool, so they replied with, "Well, because their mouths are too small to bite humans with!" or "Well, because their fangs aren't strong enough to penetrate skin!". And so the myth begins...

Let's think about this myth a little more. What I want to know is, how in the world we could possibly know that a daddy-long-legs has "the most deadly venom, but can't bite humans because its mouth is too small/fangs too weak"? Think about it...if the mouth was too small to bite...how would we know the venom (assuming there is venom) was harmful to humans? Did someone milk a daddy-long-legs and inject the venom into some innocent victim and hope for the best? (visualize for me how they milk venom from snakes...now imagine trying to do that to a spider...did you laugh out loud?...yes, I know that is not how they would actually do it, but I thought it was a funny visual)

"So", you might ask, "what about the actual spider? The one that does have venom?" Well, from what I gathered, there has been no research done on what this venom would do to a mammalian system. But I did find mentioned that someone had done research on its effects on other insects, and that it was a pretty unremarkable venom. While you can't believe everything you read, I'm sure that if this venom was actually harmful, it would not only be better researched, but also documented more thoroughly.

Wow, are you still with me? I'm impressed! Careful, you may become a Biology nerd too! Anyway, now you know...even if you never cared. You have nothing to fear from our long legged friends. And, when someone repeats that myth to you, you can scoff at them and use your superior knowledge to make them feel small. Ok, on second thought...don't do that. You won't make many friends that way!

So the moral of this entry is "Don't believe everything you hear/read". It could end up making you look very silly...