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Why Spiders Are Not Insects
It's almost time for Halloween, when all self-respecting little ghosts, goblins and ghouls take a special interest in spiders.
We saw this little jumping spider (below) on a pink rose. It doesn't look like it could scare anything--except for maybe a sweat bee or hover fly.
This year the Explorit Science Center of Davis, a hands-on science museum located at 3141 5th St., is taking a special interest in spiders.
The center is sponsoring a number of programs on these critters and posted "Facts About Spiders" on its website.
For one thing, many people think spiders are insects. They're not.
Both spiders and insects are invertebrates, but spiders are not insects.
Insects have a head, thorax and abdomen, and the thorax has three pairs of legs. They also eyes, antennae and mouthparts, the Explorit Science Center website points out. "The entire body is protected by a tough outer covering called an exoskeleton. Animals that share these characteristics are called insects. The group to which they belong is called the Insecta."
Spiders, as the Explorit Science Center explains, have two main body parts. "The body consists of a combined head and thorax called the cephalothorax, and the abdomen. The cephalothorax has the eyes, mouthparts (no antennae) and four pairs of legs. Animals that share these characteristics include ticks, mites, scorpions and spiders. The group is called the Arachnida."
And speaking of spiders, schooolchildren visiting the Bohart Museum of Entomology on the UC Davis campus occasionally ask to "see the spiders." The Bohart is an insect museum (although the officials have been known to showcase a few spiders, too.)
Mark your calendar for Saturday, Oct. 27 for the Bohart's public open house from 1 to 4 p.m. in 1124 Academic Surge on Crocker Drive (nearest intersection is LaRue Road.) This is a pre-Halloween open house and there definitely will be assorted spiders at the insect museum!
A jumping spider on a pink rose soaks in some sun. (Photo by Kathy Keatley Garvey)
Garden spider weaving a web. (Photo by Kathy Keatley Garvey)
Black widow spider with egg sacs. (Photo by Kathy Keatley Garvey)
It's the Nature of Things
The thing about predators and prey is that it's the nature of things.
Take spiders. The many different species have different methods of catching, killing, confining and eating their prey.
Have you ever seen an orbweaver snare a honey bee in its web and then wrap it in silk blankets? The spider injects the bee with poison, feasts on it and/or pulls the carcass out of sight for later consumption.
‘Most spiders have toothed chelicerae, which they use in combination with their movable fangs to mash their prey into a small unrecognizable mass,” write authors Charley Eiseman and Noah Charney in their book, Tracks and Signs of Insects and Other Invertebrates: A Guide to North American Species (Stackpole Books).
"Prey killed by hunting spiders such as tarantulas and wolf spiders have no silk on them, whereas orbweavers swaddle their prey with a thick white layer of white silk," they point out. "Jumping spiders and others eating soft-bodied flies may leave only the wings behind."
Those orbweavers work fast. They indeed "swaddle their prey with a very thick layer of white silk," so thick, so strong and so sticky that there's no escape.
That's the nature of things.
Orbweaver eating its wrapped prey, a honey bee. (Photo by Kathy Keatley Garvey)
Two spiders ganging up on a honey bee. One is administering a fatal bite. (Photo by Kathy Keatley Garvey)
