Saturday, July 12, 2008

Support Of A Different Sort

This week's theme for PhotoHunt is 'support'. Luckily I could think of several potential subjects, but one in particular kept coming back to me. I've always been amazed by the ability of some insects and spiders to walk on water. This recent photo of a water spider came to mind. Actually I think it is more accurately called a fishing spider, but the photo is not detailed enough for me to make a good determination. If I'm not mistaken the true water spiders actually live in the water and can swim underwater. Regardless, this spider uses the surface tension of water to 'support' itself on the water. It's legs are 'hydrophobic' meaning they resist being wetted by water. It's somewhat like wax on a car making the water bead into droplets.

I don't normally go looking for spiders to take photo's of, but sometimes they are just too obvious to pass up. I do watch them from time to time as they scurry across the water. They are amazingly fast. Some insects/spiders can move across the water at a rate of up to 30 body lengths per second. That's maybe 4 inches per second. Perhaps that doesn't sound that fast, but compared to the fastest sprinters who can run about 5 body lengths per second it rates pretty good.

A few days ago I witnessed an unusual maneuver by one of the large spiders. He was easing along when all of a sudden - sproing - he made a vertical leap straight up in the air as though he had been shocked. When he hit the water again he was off in a flash. Presumably this is an evasive action when the spider is startled or senses a predator such as a trout or bass approaching from underneath.

There are not a lot of these spiders at the pond, at least not the size of these. Most often they are not actually on the water, but resting on twigs, grass, or leaves at the edge of the pond. Evidently it takes a lot of energy to walk on the water as the spider has to remain tensed to distribute its weight effectively.

Of course, where you find big spiders you usually find baby spiders. (I presume these are spiders but they may be some type of water insect. It's hard to tell in the photo.)

Oddly most of the readily visible spiders are found along the northern bank of the pond. I'm presume that has something to do with the type of vegetation in or near the water and the amount of sun the area gets throughout the year. Also, more of the floating debris such as leaves, pollen, and such tends to wind up on the northern bank.

When you think about it, walking on water is a pretty neat trick. It's not just the issue of remaining out of the water, but also how do you move. Movement is all about action and reaction. Most walking creatures require friction to move themselves from one place to another. Your foot is held to the surface you are on by friction and your muscles propel you forward. Imagine standing on slick ice and trying to start running and you can see what I mean.

Well, since the spiders legs are hydrophobic and just barely actually 'touch' the water, how do they move without the tip of the leg slipping? The way I understand it the water spider does not exactly use that same type of action that we do. It uses an action similar to rowing. It actually pushes the slight dimple its legs produce in the surface tension of the water backwards which moves its body forward like an oar pushes the water back and the boat forward. For faster movement, such as moving to escape a potential predator, the legs actually penetrate the surface tension slightly, but the spider is so light its forward motion keeps its legs from sinking too deeply.


For you PhotoHunt visitors I have a little post script. I'm sure many of you may have experienced this same type thing frequently. Last week's theme was 'pointed'. Just after I had made my theme photo post I happened to take a photo that would have been great for pointed. The photo is not of the best quality as the subject was about 10 feet up in a tree and it was getting late in the day, but I'm sure you will appreciate the 'pointed' aspect it displays. If anyone has an idea what this is I would like to know.

Weekly Theme - Support


  1. Wow, what a great take on this week's theme! It was also very informative as I didn't know how the spider could walk across the water. Nice photos too! Thanks for visiting mine today.

  2. Nice shot. I have tried for one, but haven't gotten it yet. Thanks for stopping by my blog.

  3. Glad to say I never such spiders here in the water. Thanks for sharing. Great picture.

  4. Thanks for stopping by leaving such a nice comment on my blog.

    I think you have a great take on this week's theme too!

    Have a great rest of the weekend.

  5. What a beautiful photograph and how interesting, you are teaching me so much. I have never seen a spider on water.
    Support.....yes perfect Baker....

  6. Nice picture great entry for this weeks theme..

  7. This is a fun entry... informative too! And I agree, that last one would've been great for pointed, but that last PH post was perfect hehe

  8. Another amazing example of nature's miracles!

  9. sammawow - thanks for the visit and the kind words

    ellen - Thanks for dropping by and the comment

    carin - Thanks for the memory with the grape vine supports - And thanks for the visit

    j.c. montgomery - I appreciate the comment - I liked your theme presentation - nice and simple - 'this supports this'

  10. Cheryl - It is always a pleasure to have you visit - I really appreciate it - I do like to try to throw in a little info on the theme photo when I can, lol

    mimi 11460 - Hi there - I checked out your yellow flowers - Nice - Thanks for the visit

  11. philos - Thank you for dropping by and the comments - funny thing about that 'pointed' photo, I had no idea it was pointed until I saw the photo - I just saw it flitting around and took the shot on a whim - I was quite surprised when I downloaded the photo

    moziesme - Thanks for dropping by again and the kind comments - nature is indeed full of miracles

  12. Great shot and take on the theme. "Support" has lent itself to such a broad array of ideas this week, so it's been fun seeing everyone's perspective. While I don't care for spiders, it is fascinating to see them floating on top of the water.

    Thanks for dropping by. :D

  13. Hey bunny trails - yes, it is always interesting to see the different takes on a theme - thanks for the comments

    I really liked your take - instant identification, lol - didn't need any long explanation

  14. Loved your comment on my salt water story. I'm very gullible -- is that a true story? I wouldn't doubt it except it's almost too delicious to be true.

  15. feefifoto - If I recall correctly I read that in Reader's Digest several years ago. Perhaps it was in the 'Life In Uniform' feature because I believe it was a police officer investigating a collision that she was talking to.

    I've probably remembered it all these years because I considered it to be true. Whatever the source I took it to be legitimate and it was not presented as a joke.

    BTW - I love feefifoto - Very cute name.

  16. I have seen spider on water... still creep me out. Must...resist... urge... to....squish...them!!

  17. LOL irishkat

    I'm not a great fan of spiders myself. If you try to squish these, though, I hope you can walk on water.

    You need more coffee, lol. (Inside joke, folks)

  18. I'm not a great fan of spiders either, but I think this was a great take on this weeks theme. :)

  19. kewl pic:D i wish i had photo ops like that.

  20. That is an excellent pick of pic for the photo hunt theme!! :)

  21. Great shot of that spider gliding on the water.

  22. LOL Rose - Seems like a lot of people have an aversion to spiders. Don't worry, he's not trained as an attack spider.

    Thanks cating. The bridge pic was great. Just keep looking around for those photo ops.

    Hey urban buddha - Loved that photo of the ornamental tree support. Very nice.

    Thanks for the visit rachel - I saw that photo of the chopsticks being used for support - Cool

  23. Very informative entry! Amazing! Thanks for visiting my blog & the nice comment. You are more than welcome to "steal" my idea of using the definition. It only made sense for me to use it, because when I read the theme my thought was what would the "true" definition be. It was neat to see the different definitions for support. Many blessings!

  24. Thanks for the visit and kind words, ourhomeschool. I can see by your blog you are a real animal lover. We once had a bunny, too. I was amazed how well it played with our cat. They were real buddies.


Thanks for stopping by to visit our little pond. We would love to see you again real soon.