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The Writing Spider (Argiope aurantia) is a spider of many names.  Known as the Yellow and Black Garden Spider, Golden Orb Weaver, Yellow Argiope, Corn Spider, Scribbler Spider, Golden Garden Spider, and Black and Yellow Argiope, just to name a few.

Despite its many identities, this is perhaps one of the most easily recognized species of spider found in gardens all across North America.  It is found in the contiguous 48 states, and Canada, although rare throughout the Rocky Mountains in Colorado, and parts of Canada’s Great Basin.

As plentiful as the common names for this species are, the epithet for this species is appropriately descriptive.  The yellow and black markings on the abdomen of this species are distinctive, but the genus name, Argiope, means ‘silver face’, referring to the fine silver colored hairs found on the cephalothorax of the spiders in this genus.

The species epithet aurantia means ‘golden’, and does refer to the vivid golden yellow markings on the abdomen.

The remnants of our squash patch, where we conducted Our Great Heirloom Squash Experiment this year is now home to this particular female.

There are many species of orb-weavers, the spiders responsible for constructing the truly beautiful, classical spider webs seen in almost every garden.

When I first encountered this female, it was late in the afternoon.  She was sitting perfectly still, directly in the center of her web, patiently awaiting her next meal.

The lighting was poor though, so I made a point of revisiting her the next afternoon.

As I approached her web the next day, the first thing that caught my eye wasn’t the spider, but the half dozen cocooned honey bees, neatly packaged, and stored on the web’s silks.

Her web that afternoon was showing significant signs of wear, no doubt due to the number of honey bees that had become trapped in it during the course of the day.

This species of spider deconstructs, and reconstructs her entire web every day.

The web itself can exceed 2 feet in diameter, and is intricately engineered.  To see her web at its best, I visited her again early the next morning.  Here it is beautifully reconstructed, in minute detail, ready for another day ensnaring prey.

Of all the common names given to this species, I find Writing Spider to be perhaps the most descriptive.

These orb weavers are called Writing Spiders for the series of X’s, or zig zags, that are constructed throughout the center of the web, called stabilimenta.  These can vary from one Argiope species to the next, even between spiders of the same species.  Sometimes these patterns may be vertically aligned through the center of the web, or even circular in pattern.  To our eyes these patterns are distinctive, but merely decorative.  However, it has been argued for many years as to the function of these patterns within the web.

It was once presumed these zig zag fibers were responsible for helping to structurally stabilize the web.  However, these stabilimenta are embellishments, added after the main web is complete, over the top of the existing fibers, and as such are now thought to not contribute much to the overall stability of the web at all.

As orb-weaver webs containing stabilimenta have been shown to catch more prey than webs without them, it was thought that perhaps the stabilimenta were able to specifically attract prey insects to the web.  Some theorized that the stabilimenta scribbled in the center of these webs reflected more UV-light than the surrounding silk fibers, therefore making the stabilimenta more alluring to pollinating insect species.

Most gardeners know that flowers exploit the principle of reflecting UV light to attract insects to their pollen stores.  This is how flowers ensure they will be visited, and pollinated, and in return they reward visiting pollinators with nectar.

However, this theory of UV-reflecting stabilimenta, although plausible, was cast into doubt in 2002 by Zschokke, who found the stabilimenta were not any more UV-reflective than the silks used to construct the rest of the web [1].

As such the stabilmentum, the entire web, may in fact be poorly perceived by insects. However, as the stabilimenta are readily perceived by birds, it was proposed that their function may be more for defense against birds, to prevent them from flying inadvertently through the web, rather than attracting prey.   Regardless, the true function of the stabilimentum remains controversial.

Instead, it may be the bright color of the spider herself that is most alluring to her prey. One recent study showed that brightly colored Argiope spiders catch more prey than those where their coloration was experimentally shielded, or altered.  

Prey insects apparently can percieve the vivid colors on the abdomens of spiders in this genus very well, but not the muted yellow and black banding on the legs [2].  As such, potential prey don’t perceive the overall shape of the spider on the web, at least not until it’s too late.

The yellow and black coloration of this species may also help this spider to resist becoming prey herself.  A vertebrate predator that has learned to avoid similarly colored insects, such as wasps, may also avoid this spider due to the vivid yellow and black pattern on this spider’s abdomen.

This particular spider had constructed her web between some squash leaves, and part of our perimeter deer fence around the orchard.  During one of my visits I managed to work my way around so I could position myself almost directly in front of her.  As I sat there, patiently trying photograph her face, she suddenly darted straight down the center of the web.  She’s a very large spider, the largest I’ve seen here of this species, and as I had a macro lens on the camera, her sudden movement startled me.  Up until now, she’d been completely motionless.

Fortunately I didn’t take my eye away from the viewfinder though, as within just a few brief seconds she had caught, and entombed the prey that had landed squarely in the lower-center of the web.

She swiftly, and adeptly turned her prey, wrapping it snugly in a multi-stranded sheet of silk, and once it was secure, she immobilized it. This species, like many spider species, injects venom in her prey to immobilize it. Note however, although she uses venom to incapacitate her prey, this spider species is not harmful to gardeners, and is a very beneficial species of spider in the garden.

Unlike the bees, that she saved for later meals, this fly was dined on almost immediately, and then discarded.  Perhaps just a light mid-afternoon snack.

As large and formidable as this spider is, she is nearing the end of her life.  Before the first frost she will need to find a mate.  Males of this species, as with many other species of spiders, will not survive breeding. In fact, this species is unique in that the males die during copulation, spontaneously, while attached to the female [3].  This helps to ensure the passage of his genes to the next generation, and prevents other males in the vicinity from mating with the female.  Soon after death though, the female will entomb the male in silk, just as she would any other prey, and he in turn will be consumed.

The female will hopefully soon lay her eggs, which will be wrapped in an intricately woven protective silken sack, at which time her work will be done.  As she won’t venture far from her web, we’ll continue to watch for signs of eggs over the coming weeks.  This short clip shows you what we’ll be looking for:

Unfortunately, the female will not survive once the cold winter weather sets in.  However, if her young avoid predation, they will hatch over winter, within the sack, and not emerge until the first warm weather in spring, when they will finally disperse, to begin the cycle again.

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[1] Zschokke, Samuel.  2002.  Ultraviolet Reflectance of Spiders and Their Webs.  The Journal of Arachnology 30:246-254

[2] Bush, Alex A., Yu, Douglas W., and Herberstein, Marie E.  2008.  Function of Bright Coloration in the Wasp Spider Argiope bruennichi (Araneae: Araneidae) in Proceedings of The Royal Society B. 275:1337-1342.

[3] Foellmer, Matthias W., and Fairbairn, Daphne J. 2003. Spontaneous Male Death During Copulation in an Orb-Weaving Spider.  in Proceedings of The Royal Society B – Biology Letters.  270:S183-S185