February 21st, 2006
watchful spiders
A couple of days ago, Chris Clarke posted The cursorial life, a fine essay having to do with spiders, David Quammen, and writing, on his Creek Running North blog. His description of a spider found lurking about his desk . . .
It stared me down, eight eyes to my mere two. For a full minute it waved its forelegs at me. Spiders use a small set of modified legs, pedipalps, to “chew” their food and examine small objects, and the males of many species, including jumping spiders, use these pedipalps in often-elaborate sexual display. This spider vehemently waved its pedipalps at me, gesticulating as though cursing me roundly. It was close enough that I could see the individual light brown hairs on each palp, which moved up and down with some vigor. . .
. . . caused me to smile (for it seemed so familiar), but also set me thinking about some of my own encounters with spiders — of which there have been many due to my photographic work. I looked up some notes on “watchful spiders” written a couple of years ago, and decided to post them here on Burning Silo, as they might be of interest to others:
Watchful Spiders:
While walking through the oldfield pastures here at my farm, I often see spiders and insects disappearing for cover under a leaf or behind a stem. Small creatures can be very observant — and who wouldn’t be, when confronted by a monstrous-sized being stomping through their homeland? One of the more watchful inhabitants is the Oblong Running Crab spider (Tibellus oblongus), a soft gray to tan-coloured spider which looks rather like a tiny squid stretched out atop milkweed or goldrenrod leaves, or on the blades of tall grasses.
When I spot one of these spiders, it’s usually flitting sideways to hide on the underside of a leaf. The action is so quick, that it’s the arachnid equivalent to sleight-of-hand. Now you see it, now you don’t. However, this spider rarely stays hidden for more than a few seconds before it flips back onto the topside of the leaf — no doubt, overcome by curiousity as it returns to see if the intruder has departed. As soon as it discovers that I’m still hovering over its leaf, it flips back below for a few more seconds. In the space of a minute, it may repeat its performance half a dozen times. That is, unless it’s a female guarding a nest of eggs. When similarly confronted by my immensity, the female of this species will hold her ground almost indefinitely — body splayed out to shield the nest from all intruders.
But these aren’t the only “watchful spiders”. There are the Jumping spiders such as the one pictured above. When I photographed her guarding her egg case, she scuttled from side to side, nervous and unsure of what to do, sometimes rearing up a little on her rear sets of legs, with pedipalps raised in what seemed to be defiance. After awhile, she relaxed a little and sat motionless, watchful.
And then there was this Goldenrod Crab Spider (Misumena vatia) that guarded her egg case, sealed inside a rugosa rose leaf, in my garden for about a month. Each day, I stopped to visit her as she tightly gripped the carefully sealed leaf packet. Watched while she became increasing desiccated, abdomen gradually collapsing, until eventually, the morning after a hard frost, she was gone.
I could post many more photos, but these are enough to illustrate the point that I would like to make — that these spiders are very committed to the protection of their young. I don’t think many of us realize just how “maternal” these small creatures can be. It’s fascinating to study them in an effort to learn more about their behaviour.
Note: All of the above photos are linked to larger versions for anyone who should want to see the spiders a little better.
bev
Tags: Oblong Running Crab spider, Tibellus oblongus, Misumena vatia, maternal spiders



