MORRO BAY — For many people the sight of a spider invokes fear. Tales of poisonous bites of the black widow or the brown recluse have given spiders a bad rap. The truth is spiders are one of the most beneficial creatures on the planet. Still, it pays to be cautious especially when poking around in the woodpile for a log for the fireplace.
There is a special spider that lives locally, the Morro Bay Side Mirror Spider so named because it takes up residence inside the side mirrors on cars! No matter how many times one wipes the web away, in a day or two, it comes back.
Spiders are not insects. They belong to the same scientific family as scorpions, ticks, and mites and are called arachnids. Arachnids differ from insects in that they have two main body parts, simple eyes, and eight legs, jaws with fangs, and silk spinning organs in their abdomen. Insects are made up of three body parts, six legs, antennae, compound eyes, and chewing jaws. Another difference is that some insects can fly but spiders cannot.
Spiders have been around for a long time, nearly 400 million years. They were one of the first animals to live on land.
They are best known for their silk weaving abilities. This strong, sticky substance is secreted as a liquid from spinnerets at the base of the abdomen. It hardens upon contact with air. Webs are constructed with the material but that isn’t the only thing it is used for. The silk is used to make egg sacs, capture and wrap prey. It’s also used to construct a variety of shelters.
These successful animals are predators that hunt and feed on live prey. They use a variety of ways to do this. Some weave webs and others actively hunt.
There are four types of web-weaving spiders: cobweb spiders, cellar spiders, funnel web spiders, and orb weaver spiders. Of these, the orb weaver spider spins the most spectacular web.
These webs are large ovals, each species spinning a distinctive design. Flying insects are trapped by the web. When the spider senses the struggling insect in the web, it advances to it and spins a wrap around it.
Orb weaver spiders can be as large as one inch or as small as one-tenth of an inch. Some are quite colorful and menacing in appearance. However, they are not dangerous.
Most people are familiar with the common house spider, a cobweb spider. They build webs both indoors and outdoors that are irregular in shape. The Morro Bay Side Mirror Spider is most likely a cobweb spider.
Cellar spiders are found in dark, damp places — cellars, crawl spaces, and outbuildings. These spiders have long, slender legs as much as two inches long and are often confused with daddy-long-legs, which are not actually spidered at all.
Of the active hunters, there are wolf spiders, jumping spiders, and nursery web spiders all of which hunt down their food source.
Then there are passive hunters that just lay in wait for their prey. Tarantulas sometimes do this as do crab spiders. Baby crab spiders start off their lives by eating their own mothers. All spiders consume only liquid and they ingest their victims by injecting a substance that turns the unfortunate insides of the victim to liquid.
Some spiders have unique ways of avoiding their predators. The nursery spider is one of these. It lives near water and can actually scamper over the water surface, dive and stay submerged until the danger is past.
Reproduction for some spiders is often hazardous to the males. If they don’t approach their lady love just right, she will eat him. Black widows are so named because the female sometimes consumes the much smaller male after mating. This often occurs because he wasn’t careful enough to retreat over the web via a special trail. Mrs. Black Widow cannot see well and relies on vibrations on her web to locate prey. If Mr. Widow chooses the wrong exit path, she can’t tell that it is her mate dancing around on the web and she dashes forward and deals the death blow.
Spiders lay eggs kept in a silken sac sometimes affixed to a surface and sometimes attached to the female. Hundreds of babies hatch out of the eggs and some spiders carry the young around on their backs for a time.
Spiders are beneficial predators consuming destructive insects in the garden and around the house. They eat mosquitoes, flies, cockroaches, crickets and many other bothersome insects.
Very few spiders have a bite that harms humans. Most bites produce local inflammation and itching. They usually do this because they are trapped against the skin. To prevent this, shake out clothing and shoes before dressing and inspect bedding and towels. Wear gloves when gardening or handling firewood, lumber or rocks. Don’t store boxes under the bed and be careful when handling cardboard boxes. Spiders hide under the folded flaps.