Spiders in Springtime


In the springtime you will see spiders showing up in all kinds of places while they set the table for their summer reproductive season. As the weather warms up, the spiders start looking for ant trails to set up housekeeping. The first step to long term spider management is to eliminate the ants. That’s right, ants! You see, the primary food source for the early stages of development for most spiders is the ever present ant and the occasional tasty gnat or drain fly. From that, they graduate to larger bugs with each stage of their development. Of course spiders also eat each other so, without a ready supply of ants, spiders will end up reducing their own population, often by more than ninety percent! A sac spider’s offspring that survives normally does so at the expense of several of its siblings. Spiders in the house are very seldom a health or safety threat here in San Diego County, but they can be a real nuisance with their unsightly webs and their threatening demeanor. Spider bites usually happen when someone picks up some firewood or moves things around in a shed or garage. It is also quite possible to be bit in bed or putting on clothing with a spider inside.

The following is a list of some of the local spiders that you may come across. Please understand that there is no comprehensive list of NorthCounty spiders. 

Two basic types of spiders that we commonly find around north county homes are web spinners and hunters. Hunting spiders, sometimes called “wolf” spiders (pictured) scurry around, mostly at night, seeking a bug to jump on and eat. They do not use webs to capture their prey and they often have several eyes. The largest of the hunters is the Tarantula, often growing to fist size, and the smallest is a little “Wolf” spider about as big as this “o”.  Spiders feed on each other and on other bugs that they can capture or overpower. Web spinners use their spinnerets to create bug traps and to make nests or egg sacs that they spin for their offspring. Their webs can be tunnels, trap doors, nets, tents, sacs, and intricately patterned orbs. Some of the webs are sticky, and others can be tough enough to use in gun sights!                                                        

Black Widow Spiders are very common here in North County.  They appear around nearly all untreated structures from time to time. The female has a grape shaped body and she can grow, if well fed, as large as a grape. Her appearance is usually black and shiny with black legs also. Her most distinctive feature is a dark orange hourglass shaped marking that is centered on the bottom of her abdomen. Her web is comprised of tough, sometimes sticky strands that are arranged in no particular pattern, but sometimes cover an area more than a yard wide! The male Black Widow is about half the size of the female and he is poisonous also but, like most spiders, his fangs are no match for the thickness of human skin.

A recent immigrant to North County is the Brown Widow Spider pictured on the left. Notice that the hourglass is actually yellow or very pale orange. They are slightly smaller than the Black Widows and share many of their behaviors and characteristics but the Browns will often build their nests under patio furniture and in other places that people frequent. These spiders can and will bite and their poison is very similar to the Black Widows. 

Yellow Sac Spiders are small, light colored hunters that have a racing stripe down their abdomen and are often found in our homes. You would find their egg sacs near their nests in hideaway places, like behind pictures and paintings or between dressers and the wall. They come out at night and run across the walls and ceilings in search of food or a romantic tryst. These spiders can and do bite people when they get trapped in clothing or in bedding. Researchers at UC claim that yellow sac spiders are responsible for more bites on people than any other spider in Southern California. They have four pairs of eyes and they move very quickly when they are disturbed. Check out this website if you would like more information about the Yellow sac spider.  

The best way to control spiders indoors is with a vacuum cleaner that has a hose nozzle. You should clean behind sofas, chairs, chests, and other furniture regularly and occasionally clean behind picture frames on the wall. Weather stripping will keep them from coming inside and you should inspect and replace the brush on the bottom of sliding glass doors when they are worn.

Outdoor spiders are very common locally and they are actually beneficial in that they will make a meal of any insect that they can catch! They are often very difficult to control because they normally stay out of sight during the day and they try to avoid people. Nearly all spiders have fangs and venom but very few of them are dangerous to people. There are a dozen varieties of poisonous spiders in North County that can bite people, all of them are very eager to avoid contact with us and will very seldom bite unless they are forced to do so by direct physical contact. 

Spiders come indoors to get something to eat and to escape inclement weather, the same as we do. It is not at all uncommon to find spiders indoors right after a fall rain or during a cold (or hot) spell, but the main thing that they are after is other arthropods (bugs). An exception to that is when you come across a male hunting spider seeking a mate! We often get calls about large hairy spiders scurrying around the floor during warm weather; these arachnid Lotharios have no interest in attacking anyone and they normally have shorter fangs and less venom than their female counterparts. 

How to keep them out of the house?

1. Close the screen doors

2. Make certain that there are no gaps around your doors and windows

3. Keep the clutter and nesting sites to a minimum

4. And try to cut back on their food supply (insects)

Not sure what your home needs? Let us help.