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Special Issue: Fall Gardens | GREENING

Checking out nature's web sites

Spiders and their silken handiwork -- how the web is strung tells you what kind of arachnid it is -- are in their full glory in the fall. Just take a look around.

October 06, 2005|Emily Green | Times Staff Writer

IN an announcement about the opening of the Spider Pavilion at the Natural History Museum of Los Angeles County, I recently referred to spiders as insects. It brought this response from a reader in Whittier: "Spiders are not insects! Insects have six legs."

The reader is correct. Spiders have eight legs. Although insects and spiders are both arthropods, spiders belong to a distinct class, Arachnida. Unfortunately, the term became known almost exclusively as a root for a word concerning the pathological fear of spiders: arachnophobia.

If you know a sufferer, pass the Valium, because this is the season for arachnophiles. For a few weeks, no Angeleno need go to a museum to see one of the great wonders of nature. Our gardens will be jumping with arachnids. Even seldom-spotted spiders will be tossing draglines across walkways and dangling at face-height in search of their last big fat fly of the season. The orb weavers of the Los Angeles Basin will be spinning their last and most glorious webs of the year.

Spiders are so conspicuous in autumn that far and away the most calls that entomologists get concern them, says James Hogue, collections manager for the biology department at Cal State Northridge and one of the region's most respected entomologists. The sheer volume at the Natural History Museum was one of the things that gave Brian Brown, curator of the entomology section there, the idea of conducting an area-wide spider survey. Homeowners could collect spiders, send them in to the museum and, for the first time, scientists would get a picture of the most frequently spotted spiders in the L.A. area.

For the four years of the study, it has fallen largely to the museum's arachnid specialist, Janet Kempf, to open the post. There have been spiders in vials, spiders in alcohol, smashed spiders, live spiders crawling gratefully out of envelopes, young spiders that she took home and fed until she could identify them. So far she has cataloged 3,919 spiders and counting. Of these, 32 families and more than 175 species have emerged, she says. People collecting more than 50 spiders in their homes and gardens average 30 different species. A schoolchild in Torrance even discovered a brown widow, an African relative of our black widow.

Rather than send Kempf any of the spiders from my garden in central Los Angeles (done right, this requires capturing and killing them by popping the subjects in a jar, freezing them and dropping them in alcohol), I invited her and Hogue over to see what they could find as dawn light came glinting across dew-studded webs.

Strung across the front window was the classic circular, spoked web of a common orb weaver. The spider had retreated to the day position up at the corner, with one foot on a silk line to feel for the sudden movement of an insect landing. Neither Kempf nor Hogue needed to see the spider close up to wager that it was a member of the Neoscona genus. "You can often tell the spider by its web," says Hogue. This one lacked the whitish zigzagging or "stabilamenta," an insect lure that reflects ultraviolet light that would have identified it as another common genus, the Argiope, or golden orb weaver.

Although all spiders can spin, says Kempf, not all make orbs. Through the house, inside the kitchen, up in the ceiling next to the porch door, there were yellow sac spiders, Cheiracanthium mildei to arachnologists -- smart little arachnids with more random-looking webs, waiting for dusk, when flies, moths and gnats might stray inside. It can give a respectable bite if you grab or poke it, but most of us know better. Evidently yellow sacs came from Europe, probably in the furniture or plant shipments.

Sharing the ceiling with the yellow sacs were what most of us call daddy long legs, but which aren't, says Hogue. They're cobweb or cellar spiders, or Pholcus phalangioides, which also emigrated from Europe. Real daddy long legs, he explains, are native, and though arachnids, they are actually not spiders. They are their own order, the Opiliones. Unlike spiders, which make silk to trap prey, have fangs to bite them and venom to paralyze them, real daddies have no fangs, no venom, no silk, and they do not live in ceilings, but outside in grass, where they recycle organic matter. A smashed worm and fallen fruit is their idea of dinner. According to "Insects of the Los Angeles Basin" by Hogue's father, Charles, we have several local genera: Protolophus singularis and Leuronychus pacificus, or, in more common terms, harvestmen or aranas patronas.

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