GARDEN MAIDEN: Spiders: The good and the ugly not all bad

Though I’m not frozen in fear when arachnids appear in thin air while scanning for ripening fruit, the red tomatoes likely have felt the vibrations of a shriek and then praise of thanks to massive black-and-yellow garden spiders tending to aphids, mosquitoes and Japanese beetles.

Occasionally, such as last month when the last blooming zinnia offered the only spark of color, I will stop and study these intricate creatures. Considered the second most deadly fear (second only to public speaking), spiders do not generally live up to their wicked reputation.

In fact, considering we are out of preferred habitat range of recluse and only female black widows are deadly to humans, the actual level of threat to personal safety from the jumping, shaggy, creepy-crawly, where-did-you-come-from spider dangling right before your eyes is slim to none. Though, I assure you, the perceived threat has often caused me to wet more than my plants.

Learning a few fascinating facts early in horticulture training earned spiders a protected space for pest patrol in my garden and yard and, of late, a peaceful experience of witnessing their intricate habits.

Of the 40,000 known species in the 109 families of the Arachnida class of arthropods, it is hard to believe there are 175 species belonging to the orb weaving genus Argiope, since my whole life I’ve only seen the fat and larger-than-life, black-and-yellow variety, Argiope aurantia. In the Midwest, we erroneously call it a banana spider, a southern region golden silk orb-weaver of a totally different genus, Nehphila, that rarely travels this far north.

When sunset reflected on thin air, I stopped in my tracks. One of the few spiders as large as a human thumb — commonly spinning a 2-foot-diameter web — I wondered if I was looking at an immature garden spider. Sort of like those amazingly patterned stink bug nymphs that I’d rather immortalize in resin pendants than drown in a bucket of water. Instead of the conspicuous bright yellow markings against a deep black body, its body pattern was a morse code of black and yellow dots and dashes coated in a thin film of translucent grey.

With a little help from entomologists at the University of Illinois Extension, I discovered I was getting my first look ever at an entirely different species: a banded garden spider, or Argiope trifasciata.

Not two weeks later, while out adoring the last colorful companion plant blooms on late-sown giant benary’s zinnia, I witnessed a silvery, slender spider vibrate her web to appear bigger when I innocently threatened to prune down her stakes. Sometimes confused with Argiope argentata (silver garden spider), her shimmery silver coat and reddish legs that fade to black are just two traits of sexual dimorphism, the striking differences beween the sexes, seen most obviously in their fully mature adult spiders. Her vivid markings and nearly 3-inch body span upstages the 1/2-inch span of a rather indistinct golden-brown male body with rusty brown legs that fade to black.

This trick amazed me! When I shared it, wondering if I was making it up, experts mentioned that sometimes the table is turned when a parasitic wasp uses this tactic to mimic struggling insects in order to lure the spider to the perimeter of its own web before paralyzing the arachnid, turning it into the wasp’s next meal.

In a similar turn of events, early in spring, a tiny mantis may get wrapped in silken webs, but autumn webs are more likely preyed upon by adult mantids, birds, snakes and wasps, the main threats to adult garden spider survival.

While “Save The Spiders” is not likely brewing as a community movement, knowing that even a small spider eats nearly 2,000 insects a year might encourage a home gardener to offer sturdy stalks of sunflower or zinnia in a sunny spot protected from the wind for a safe spider harbor. In fact, spiders control more harmful pests than both birds and bats combined. If you don’t like bugs, learn to love spiders.

Watching the building of a spider web at dawn fascinates me. Spiders make seven distinct types of silk, though a single species usually uses only one to three while making its web. Strength and stickiness matter. But don’t be surprised if yesterday’s screen against aphids and flies is nowhere to be seen. The Argiope species eats its own web each night and builds a new one the next day.

During construction, Argiope forms concentric circles between solid stakes with a very thin, nonsticky silk to keep tension between anchor points while the sticky lines are laid. Subsequently, the spider goes back and consumes the nonsticky silk before camouflaging behind the trademark zigzag weave, the stabilimentum, down the center of the web.

In the fall, a diminutive male builds a web nearby to begin his courtship. Another play on strumming the silken web is his dance opposite the female, playing his seductive rhythm while sharing her web carefully until she decides he is worthy of copulating. Once allowed within her reach, he seems more like a baby nursing with his awkward fondling and dancing about before harboring securely belly to belly with the female. Within moments of mating, the female generally eats her ex.

Spider egg sacs can have as few as a dozen eggs, or as many as thousands. For Argiope, up to three brown papery sacs protect her once-a-year brood of 1,000 spider eggs. Often seen suspended from the center of her nest for protection against hungry ants, few egg sacs survive the wasps looking for a place to lay their eggs or other burrowing parasitic larvae. Spider eggs cannot survive being frozen solid, so late fall egg sacs are often protected in added layers of web attached securely beneath protective beds of fallen leaves before mama fades to her death at first frost.

Hatchlings that survive the winter emerge from their protective cocoons in early spring and develop quickly. Tactile hair, or setae, compensates for near-sightedness by sensing low-level vibration in the air to hear, and on surfaces to feel, which helps them navigate their course of life. Certain species even have modified setae that are chemosensory, letting them smell and taste with their feet, developing particular tastes such as spotted cucumber beetle or nymph stink bugs.

Some predatory spiders “fish” for their next meal by dangling blobs of sticky silk from above and then reeling in the goods with no need for the hassle of stringing a web. Crab spiders don’t hassle with hunting flea-hoppers, spider mites, armyworms and flies. They simply shift their body color to blend in with the background and ambush their prey without ever spinning a web.

Fascinating Arachnid Facts

• Modern science remains stumped in duplicating a synthetic media the strength of a spider web, nearly five times stronger than steel of the same thickness and weight.

• Tarantula bites are rarely fatal, whereas a female black widow’s venom is 15 times stronger than the poison of a rattlesnake

• Some spiders develop an antifreeze-like compound in their system in order to survive cold winter months.

• Jumping spiders can launch 40 times as far as their own body length, up to 6 inches from a standstill.

• After mating once, the female black widow spider can lay eggs for life, often up to three years.

• Wolf spiders can run 2 feet per second and is the only species of spider known to carry babies on her back after carrying her egg sac around attached to her abdomen for nearly a month before hatching.

• Hummingbirds recycle the silk of spider webs to weave their nests.

Source: factretriever.com

HOLLY KOSTER is a University of Illinois Extension Master Gardener who resides in Grand Ridge. She can be reached by emailing tammies@mywebtimes.com; via Twitter,@gardenmaiden9; or on Facebook, facebook.com/gardenmaiden9.