Crab Spider Tent

A crab spider and silk webbing at our family last weekend.

A few of us took a short trip out to our family prairie last weekend.  My daughter was back from college for the weekend and wanted to see what was happening in the prairie, so we did a little canoeing (tight circles in the small pond), hiking, and exploring.  Later, I found myself photographing dotted gayfeather seeds, and while I was looking for more of those plants, I stumbled upon a grass leaf that was bent funny with some kind of white silk holding it in that position.  I had actually walked past the grass leaf before my brain finally registered the fact that I should go back and examine it.

Looking more closely, I could see enough of the creature inside to identify it as a crab spider.  It had been raining quite a bit during the previous couple weeks, so my first thought was that the crab spider had made itself a little rain shelter.  (Crab spiders don’t make webs, but like all spiders, do make silk and use it for various purposes.).  However, my better guess was that it was a nest and that it might contain a bunch of spider eggs.  I photographed it for a few minutes, taking lots of photos, since the breeze was making it hard to keep the spider in focus.

A tiny spiderling, accidentally photographed.

Later, when I was looking through images at home, I was culling all the photos of the spider that weren’t in focus (dang that wind) when I happened to spot something that confirmed my guess.  Right above an unfocused crab spider face, a tiny spiderling appeared – just in one photo, not in any others.  Apparently, this was indeed a crab spider nest, and at least one egg had already hatched.  

The crab spider eventually shifted around and showed its face.

Crab spiders aren’t the only group of spiders that take care of their kids.  Frequent readers of this blog will, of course, remember a previous post of mine showing a mother wolf spider carrying her brood around on her body, and even if you don’t, you may have heard that wolf spiders lug both their egg sacs and newly hatched babies around with them.  Wolf spiders aren’t alone, though, and we’re still learning more about how well various spider species care for their young.  If you’re interested, you can read more in this nice blog post from Biome Ecology.  Otherwise, you can just join me in wishing this particular crab spider’s brood good luck as they disperse and try to find safe places to overwinter.

Photo of the Week – October 5, 2018

Bison are pretty tough.  At our Niobrara Valley Preserve, and at many other sites in the upper Great Plains, bison make it through the winter without any supplementary feed. They just eat cured grasses, grow a thick coat, and plow through snow and ice as needed.  Bison don’t need humans to help with calving, and they protect their babies very effectively from predators.  It shouldn’t be surprising, then, that animals like that would be completely unfazed by a little rain.

Yesterday, some of our Nebraska staff took a trip up to The Nature Conservancy’s Broken Kettle Grasslands in the northern Loess Hills of Iowa.  Land steward James Baker led us on a very scenic hike before a band of cold rainy weather moved in.  We then piled into some trucks with James and Director of Stewardship Scott Moats and went to visit the resident bison herd.  The bison were peacefully grazing as we drove up, despite the pouring rain.  When we stopped, a small group came over to check us out. Here are a few photos of those rugged bison, who didn’t need to huddle in dry and heated pickups to stay comfortable.

P.S. In case you had any doubt about my nerd qualifications, here’s one more piece of evidence.  As I was working up these photos (in the backseat of a truck heading back to Nebraska) yesterday, I was looking closely at the streaks of rain captured by my camera.  Based on the size of a bison calf’s eye and the length of the rain streaks closest to those eyes, I estimated that my camera captured about an inch of raindrop fall during the 1/250 of a second the camera’s shutter was open.  Now, I’d want to do some actual measuring of bison calves’ eyes to check this, but based on that rough estimation, those raindrops were falling about 250 inches per second.  Now, if I convert that number to miles per hour, I get 14.2 mph.  A quick online search found that raindrops are estimated to fall at about 20 mph.  I was pretty close!!  I mean, given that I don’t really know how big a bison eye is or how close those raindrop streaks were to that eye…  (NERD)