Last night I met this lovely young lady at the motel where I'm staying in Lovelock, NV. The one there on the left, with the long, hairy legs and red hourglass. A baby black widow spider (Latrodectus hesperus), about an inch long. Still young and cute enough to be not too scary, don't you think?This evening I was talking with arachnologist Dr. Kelly Kissane, who teaches at the University of Nevada, Reno. She told me that black widows are called "combfoot" spiders, and have tiny hooks at the end of their legs with which they hang onto their webs. She said the hooks are so small that I'd need a microscope to see them. Well, here was a challenge - a chance to test the Super Macro capability of my new Canon PowerShot S5 IS digital camera. I went back to the base of the lally post by the gazebo where I'd seen this spider last night. She was still there, waiting for some tasty insect to fly into her tangleweb. She wasn't at all camera shy, just stayed put and ignored me as I experimented with focus and flash.
The trick I needed to master was using manual focus, handheld, at such a close distance that the depth of field was only one millimeter. Anything out of that small window would be out of focus. This is where my rifle team training at Boston College served me well. I set up in a pretty stable sitting position, bracing the camera with both arms and legs, to minimize any shake. Using the manual focus while working in the dark took practice. But I finally got this shot. Look real close at the hook on the end of the leg and you can see the filament of web that the spider is hanging from.
I'm pretty pleased with the macro capability of the new 8MP Canon Powershot. I do a lot of microscope work, so I'm used to seeing the fine details of things. This camera seems to have the capability of capturing microscopic levels of detail on the fly. Cool!
4 comments:
Hi, Ed
Very impressive! But to clarify, you have a picture of the tarsal claws. The "comb" is the serrated hairs at the end of the tarsi on the 4th pair of legs, and you need a pretty good quality compound scope to see them. The comb is used to stroke the spider silk to make it fluffy and sticky (think of it as being the fuzzy part of velcro, and the insect being the hooked part...)
But tarsal claws are also much easier to see under a scope, so your picture is still very impressive!
Kelly - thanks for that clarification. So the hairs themselves are serrated; wow, that's definitely going to take a high-powered scope to see. I don't think this little cutie would stand still long enough on my field microscope to look for that.
the spider is indeed young, but that is not why her abdomen is sunken in like that. She's starving, all spiders have that shrivelled abdomen appearance if they haven't eaten in a very long time. Must not be many insects where she's hanging out.
Kelly, you'll be glad to know, then, that she had a nice lady-bug feast the night before last. But alas, she was no longer there when I checked tonight. I suspect it has to do with the leaf-blower incident.
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