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Thursday, Oct. 22, 2009

They may be creepy, but garden spiders are harmless to people

Whether walking in the woods, or strolling in my garden, it seems I have been walking into a lot of spider webs lately. That doesn’t bother me, other than the irritation of pulling spider web strands from my face and hair. I don’t suffer from arachnophobia, the fear and loathing of spiders. In fact, I’m rather fond of the eight-legged creatures.

The aptly-named garden spider is the spider I am most familiar with. It is a large yellow and black spider that also is called writing spider, banana spider,and, somewhat unimaginatively, black and yellow spider. While this spider is completely harmless to humans, I can see why some people would be a little nervous running into its elaborate web, with the large spider in the center sporting colors that normally indicate danger.

Garden spiders generally build their webs a couple of feet off the ground, usually in places protected from the wind. Sometimes the webs are much higher in trees or tall shrubs. In my garden, I most commonly find the webs stretched across garden paths and other openings, which tend to be natural flyways for the insects the spider is trying to trap. A little bit inconvenient for the gardener, mind you, but it makes sense.

The main portion of the garden spider’s web is normally about 2 feet across and circular. In the center of the web you can usually find a zigzag pattern known as a stabilimentum. Arachnologists, the scientists that study spiders, aren’t sure about the purpose of the stabilimentum — it may serve to hide the spider in the center of the web or confuse prey insects. It may even warn birds to the presence of the web. After all, building that web is a lot of work and having some clumsy cardinal fly through it every day would be annoying.

One of the most fascinating things about the web is that at the end of every day the garden spider devours the circular portion of the web and then rebuilds it with fresh silk the next morning. The anchoring lines and radial frame of the web remain in place for the entire life of the web.

Garden spiders are common all summer, but we really don’t notice them that much until autumn when the females have become quite large (the males are much smaller and build smaller webs). Most of the female garden spiders are guarding egg sacs right now. The males die after mating, so most of them are long gone. The females will die about the time of our first hard frost and the life cycle will begin again next spring with the emergence of thousands of tiny spiders from the egg sacs.

Besides the yellow and black garden spiders, I’ve also been seeing a lot of granddaddy longlegs lately. I like writing about granddaddy longlegs, also known as harvestmen, because I get to dispel urban myths...and I just love dispelling urban myths!

First off, granddaddy longlegs aren’t spiders at all! They are arachnids, but differ from true spiders in the arrangement of their body parts, as well as the fact that they have no venom or silk glands. Also, granddaddy longlegs are capable of taking in chunks of food, while spiders only ingest liquids.

Remember that part about the glands, because the biggest urban legend concerning granddaddy longlegs is that they are deadly poisonous. I’ve even had people tell me that they are the most venomous spider in North America or even on the planet, but that their fangs are too short to inject humans. Nope. No fangs. No venom glands at all. Totally harmless to humans or pretty much anything bigger than they are.

Unlike spiders, which are nearly all predators (though a spider was found recently in Central America that actually eats plant material), many species of granddaddy longlegs are omnivorous. They’ll eat anything from insects to vegetation and fungi. Some species will even eat carrion and bird droppings.

Most granddaddy longlegs are nocturnal, so when you see them during the day, they are usually resting. Be kind to the night shift workers.

We are just a few weeks from killing frosts, so we won’t have garden spiders and granddaddy longlegs around to admire (or loathe) much longer this year. Personally, I find the webs of garden spiders to be fascinating and well worth the occasional web across the face. As far as granddaddy longlegs, well, they’re harmless and not even spiders, what’s not to love?

Hal Massie is a master gardener and garden writer. Contact him by e-mail at agardenquestion@aol.com or by writing to him in care of The Telegraph, P.O. Box 4167, Macon, GA. 31208-4167.