Credit&Source: By Gio Diaz (Flickr) trough The Itsy-Bitsy, Repulsive Spider—Yes, There Are Arachnophobic Entomologists (Scientific American)
Encounters With Orb Weavers
Spiders come in packages big and small, from the pinhead-sized Patu digua to the foot-wide nightmare factory known as the giant huntsman spider. There is no reason a spider needs to be that big, nature. No reason save scaring the children.
In North America, the largest spider most of us will ever encounter is the golden orb-weaver (Argiope aurantia). Most likely, you will encounter it with your face, early in the morning, as you walk through one of its distinctively round webs, propelling you from sleepy to OH GOD IT’S IN MY HAIR GET IT OUT AHHHHHH in less than three seconds. It’s the Ferrari of fear.
Eventually you settle down, and you are finally able to appreciate their elaborately woven hunting nets, glistening in the dew. There they sit, one spider sentry per sticky circle, waiting for lunch, or breakfast, or perhaps even elevensies, if spiders eat elevensies.
I came across a fine assortment of orb-weavers recently while passing through Hope, Texas, which is just about the cutest name for a town that there ever was. The spiders were nice enough to let me take their picture. Of course, everyone’s nice in Hope.
I love how the low sun shines through their translucent upper limbs, highlighting the array of sensory hairs. They use those prickly probes to tactilely “hear” their web and the world. Spiders don’t have ears. Which is probably a good thing, since they would look rather silly with them. There was an amazing amount of pigment variation, even between spiders a few feet apart. Rare were the blacks and yellows I’ve seen elsewhere, replaced by mottled khaki and white, certainly a more appropriate color scheme for the limited palette of brown and slightly lighter brown that paints the Texas summer:
(via) Ok maybe it’s not quite that bad. But it’s not far off. Ugh, I can still feel the heat. But I digress …
In case you’re wondering, yes, I did throw that grasshopper into the middle spider’s web, because carnage makes for good photography. The local population of grasshoppers was thereby lowered from 7,438,219,900 to a not-at-all-dangerously-low 7,438,219,899. The orb-weavers of Hope, Texas seem to live in an all-you-can-eat buffet, the Golden Corral for golden orb-weaving spiders.
This male (noted by the smaller body size) had the ‘hopper swaddled in a dinner jacket in less than ten seconds, like an eight-armed Chipotle employee on meth. Dinner was served. Or breakfast.
The bottom picture threw me for a loop. Or rather threw me for a zig-zag. At first glance, I thought maybe that spider was making some sort of avant-garde architectural statement with its web. But then it occurred to me that spiders are clearly postmodernist architects, with their love for simplicity, form meeting function, all that.
A little research at home told me that the chevron-shaped structure is called a stabilimentum. The function of this adornment is still debated, but it’s known that only day-hunting spiders use them, and those that do catch about a third fewer bugs than those that don’t. My favorite theory suggests it’s a trade-off between less chow and helping birds and errant humans named Joe avoid careening through your masterpiece of a meal-catcher. I guess the idea is “keep a bird off it”.
Evolution loves a little give and take.
I’m not sure I’ll ever love spiders, but days like this make me at least strongly like them. A common species, yes, but stopping to smell the science is always an uncommon experience.
A jumping spider clutches its meal, another jumper. (Photo by Ahmet Özkan)
”Portia Jumping Spider stands with its helmet” by POPUMON TiH
This is RobertLovesPi, and I apologize for the off-topic post to this blog. We have until Friday to try to get to 1,500 on this petition drive. Details are at the link; it is related to education and politics, both. We have over 1,000 now. Please help. We NEED help. Thank you.
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