31 August 2010

A spidery dilemma

I have a patio. It's on that patio where I grow my orchids and other plants. It's covered and one of my favorite things in the world is to stand out there while a thunderstorm rolls in. I have a dining table out there and my second favorite thing in the world to do is to have people over for dinner al fresco --my Christmas Eve dinners are legendary. I spend a lot of time on that patio and I do what I can to encourage geckos to hang out, they keep the mosquitoes at bay. Similarly, insects like paper wasps eat the caterpillars that crop up on my ferns and spiders keep the rest of the undesirables in check.

I don't have any prejudices against pesticides and I'll use them if the situation warrants it, but I prefer to have something resembling a functioning eco-system out there. Watching the cycles of life and death play out, and observing the dynamics of predator and prey is fascinating. I like to imagine myself to be a passive observer and so I tend to let the system out there regulate itself.

Well all of that changed on Sunday. I was watering my plants and I noticed something in the base of the pot I have a tangerine growing in. By base, I mean the drainage hole. The pot has side drainage (that allows the roots to air out between waterings --citrus trees love to have aired out roots). Anyhow, here's the the drainage hole.


I don't have a decent lens so the rest of the photos I'll use here are ones I found around the internet.

What I saw lurking around was this spider.

via Picasa

As a rule, spiders don't freak me out in the least. They are absolutely fascinating creatures and despite the fact that they are everywhere, how much we know about them doesn't amount to much. Most of them aren't too tough to identify but beyond that, nobody seems to know a whole lot about them.

The spider I saw was pretty small, about an eighth of an inch long, but I've been around enough to know what it was. I suspected from its body shape that it was a juvenile black widow and sure enough, I got a positive ID from The Bug Guide. The Bug Guide and its companion website What's That Bug? Are fantastic resources for IDing these sorts of things.

It's too small to be able to tell if it's a male or a female but based on my location , it's a safe bet to call it  Latrodectus mactans, the Southern Widow Spider. L. mactans ranges as far north as New York State by the way, and there are members of the genus Latrodectus found all over the world.

Here's a photo of a mature Latrodectus mactans. Note that the hourglass shape is on its underside, not on its back as is commonly believed.

via Appalachian Light

That marking by the way, varies greatly from spider to spider and many of them do have red markings on their dorsal sides. Here's another photo of a mature female.

via Wikimedia Commons

Florida's also home (as are a lot of other places around the world) to another widow spider, Latrodectus geometricus. No one seems to know where L. geometricus originated but its range is spreading rapidly.

via Wikimedia Commons

Anyhow, widow spiders have a job to do and they're particularly good at it. While it's true that they can bite and that bite is not very pleasant, they aren't an aggressive species. Few spiders are. The only way that the L. mactans on my patio will ever bite me is if I pick it up once its an adult. Even if it did bite me, I have an intact immune system and no underlying health problems. Though it would hurt like crazy and not look real pretty as it healed, it wouldn't kill me.

When it's mature, it'll be nearly an inch long. That's big enough to take down a palmetto bug and that's makes L. mactans OK in my book.

At the same time though, it could also do a number on me. Though I'd never pick up an L. mactans, I could grab it accidentally while I'm puttering around out there some day.

So what to do? Do I mete out the terrible, swift justice of a can of Raid or do I let it go about its life in the base of my tangerine? On one hand, it's a beautiful creature. It's perfectly evolved for the life it leads. On the other hand, it's my patio and my interests trump the spider's.

What would you do?

30 comments:

  1. KILL the little b*ggar! Okay, I confess I dislike most insects ... particularly flies.
    -Brenda-

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  2. Of course I'd leave it alone. We found one when we lived in North Carolina and Gene killed it. I was furious.

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  3. Duly noted, both of you. I find brown widows on my front porch all the time --they are less prone than their black cousins-- and they don't bug me. But then again, I don't hang out on my front porch.

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  4. Found myself in a similar dilemma with a large orb-weaving spider that was insistent on creating a web in the arched entry way to my front patio. Can't blame him (or her), the arch provided geometry for the lovely web. The problem was that I, guests or the postman was always running into the web and then coming face-to-face with this harmless spider and it's lunch, dinner or breakfast (some hapless insect). I let the critter be and invited folks to use the side entrance.

    In your case, I would have to say it's time for the spider to move-on since he does pose a slight (albeit small) risk. Do you remember that cocktail party and Paul's where Alex was bit by the black widow?

    If you don't want to Raid it, consider scooping it up in a glass and letting it do it's thing in some neglected open lot.

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  5. Squash the hell out of it!

    (Oh my, how Republican of me.)

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  6. Bill: Widow spiders are territorial and dropping it off somewhere will still result in a dead spider. Kind of like "human" moustraps which are just a passive/ aggressive way to kill a mouse.

    Raina: As my brothers and I used to say, "Kill it before it multiplies!"

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  7. I did not know that about Widow spiders. As you can tell, I've always opted to Raid the Widows I've found; but, with some reluctance.

    Thanks for the Widow 411!

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  8. The pesticide in Raid is pyrethrin. It's essentially chrysanthemum oil. It's bad news for wee beasties but harmless to people.

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  9. My wife would have me out there with a GALLON of Raid because spiders bite her all the time, so she doesn’t want them around. They don’t bother me, so I’m fine with them, but it takes two to tango, so I bow to her wishes. But as for yourself, given how you already feel about leaving that sort of thing alone, that’s what I would continue to do, just leave that animal alone. She’s not likely to make much of a pet, but you’re right. She won’t be an enemy either. You leave her alone, and she’ll return the favor.

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  10. It's the knowing that it's there that bothers me. I'm sure there are plenty more where the one I know about came from. In fact, based on my location it's impossible for there not to be. But still...

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  11. Ugh, you weren't kidding about this post giving me the creeps. Though, the story isn't the issue, it's the pictures. Personally, I get my husband to deal with spiders at my house because I get the heebiegeebies if I have to deal with them. And my darling husband refuses to catch and release them to the great outdoors, so they get squashed.

    For your particular spider, I'd say that if you can't move it, kill it. While *you* might not have any issues with a black widow bite, you might have company who isn't as resilient as you are.

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  12. Nim, you'd probably go into cardiac arrest in my sewing room. We live in an old house and my workshop is in the basement. It's painted and fairly clean, but no matter how clean it's kept, there are dozens, if not hundreds, of spiders down there. Fortunately, I am very fond of arachnids, so they're welcome to share the space!

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  13. Lisa: I was going to run this post next weekend but your comment yesterday compelled me to move it up to today. The concern you voiced today is actually my primary problem with this guy.

    Melody: Spiders mean no ants, cockroaches or the rest. You're a woman after my own heart.

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  14. Thanks Paul, I'm glad my neuroses are so influential :P

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  15. I'm so impressed you're considering keeping him around. I'm with Nim - spiders give me the creeps! Probably a little irrational, but oh well. Just the other day there was a HUGE spider egg sac right outside my bedroom window. Yes, it was outside but I don't trust my window to be so well-sealed that hundreds of baby spiders born right beside it couldn't get in.

    I felt a little guilty but I knocked it off the balcony - not sure if the babies could've survived the fall. I admire you for being so spider-friendly! I say leave him be if it really doesn't bother you.

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  16. Don't you dare harm that little beastie, Paul. Don't you know that she is good luck? http://www.luckymojo.com/spider.html

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  17. It is a tough one - I'd say don't kill it since it is where it is supposed to be (outside). Spiders don't bother me and I have worked hard at not allowing my daughter to become scared of bugs or spiders.

    That having been said, I wouldn't want a poisonous spider in an area where my daughter would be. Sorry to post a link here but I wrote a post outlining the rules someone should follow in just this very circumstance - thought it might be appropriate - Bob

    http://bit.ly/91SWDR

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  18. Emily: There's nothing to be impressed about. I dislike palmetto bugs more than I dislike Black Widows. If I keep the Balck Widow around it will grow up to eat palmetto bugs. It's just self-interest. However...

    JoAnn: Is that all spiders or is it just orb weavers? Black widows aren't orb weavers if that makes a difference.

    Bob: You have carte blanche to leave links around here when ever you want to. Kudos to you for raising your daughter not to fear spiders and insects. I like your rules. Mine are similar but tempered with just enough natural history to make them seem arbitrary to anybody other than me.

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  19. EEEWWWW! I'm on the side of the those that say "squish the little bugger." I was surprised by your research to see that they are not all black but wome come in different colors and with striped patterns too. Now I'm back to being terrified of all the little beasties! Usually I'm not bothered by garden spiders and some of them and their webs are quite lovely.

    We have tarantulas here. I don't stomp them of course and they don't come in the house -we have an unspoken truce: "You con't come into my domain and I won't kill you." Actually, the only time I've ever seen them is during their mating seasons when they treck out onto the roadways searching for mates. They are really fascinating to watch and come in all sorts of colors from light grey to brown and black.

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  20. We have no tarantulas here. I'm envious. It's just as well though. If we had tarantulas here I'd never get any work done, I'd be too preoccupied watching them. Though we have no tarantulas, we do get the occasional visit from a scorpion and they're even more fascinating than tarantulas.

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  21. Don't you have a doggie? How do dogs fare when bitten by these spiders? If it's not a threat, then I'd let the little guy hang out.

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  22. From what I understand, dogs are immune from most spider venoms. Correct me if I'm wrong dog people.

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  23. Not sure on the last question Paul, we need Rufus here for that one. On the spider I may vote the "shoe" method. It's fine if the little cutie lives outside but argh, I'd hate to get there one morning, find she's not there and then have to wonder where she chose her new abode for herself and her offspring...as it gets colder outside.
    And I will also say that i really like spiders, but this is a bit of a dangeriffic one.

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  24. Only orb-weavers? Oh, Paul, you have become entirely too web-centric.

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  25. V: We do need Rufus on this spider venom question. I wonder where he is...

    JoAnn: There's a world of difference between the orb weavers and their non-orb-weaving kin.

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  26. Uhmm no... G'bye Charlotte, or whatever that spider's name is.

    :-D

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  27. No names. Ever. Anthropomorphizing isn't my bag.

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  28. We have a related species that likes nice quiet dry places like the underside of patio furniture. The bite, while not dangerous to healthy adults, is agonising -- for days (my BIL was bitten a few years ago). I do kill redbacks when I find them, as I have children and child visitors, who would be more likely to be bitten than I am. If you don't have little kids visiting, at least you know where this particular spider is. Of course it's the one you don't see who will bite you!

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  29. Chookie: Are Sydney Funnel Web spiders as common as they appear to be on the nature documentaries I watch? They seem to have the right combo of venom and aggression to make life complicated.

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  30. I really wanted to know the answer to the question about the Sydney Funnel Web, which seeks out and attacks humans with fangs as long and sharper than thumbtacks, who will kill a fully grown human in as little as 8 minutes. Paul, you're going to contact Chookie directly. Please.

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