Spider: The Yellow Sac Spider

Yellow sac spiders can be found all across the United States. Not only is the yellow sac spider found all over the United States it also accounts for more spider bites than any other type of spider in the United States. That is a lot of bites to be caused by yellow sac spiders; unfortunately the number is so high because many times the yellow sac spider bites are misdiagnosed. The symptoms of the bite are similar to the bite from a brown recluse spider, but the yellow sac symptoms are not as severe. Therefore many times physicians diagnose the bite victim as being bit by the yellow sac spider; when in fact, it could have been a brown recluse spider, but the symptoms have not fully developed.

Since the yellow sac spider and the brown recluse spider bites are so similar it is important to know what to do in any case of getting bit by a spider. Read more about what steps to take if bitten by a yellow sac spider in our first aid for spider bites blog. Also it is important to know what a yellow sac spider looks like in order to help identify what kind of bite you may have gotten.

Often times people are bitten in the middle of the night, and may have no idea what really bit them. Other times when people get bit they see the spider, in this case it is best to try to catch the spider or bug that way the doctor can properly diagnose the bite. The yellow sac spider is about the size of a nickel, on average. The yellow sac spider has a body that ranges from one-fourth of an inch to three-eights of an inch long. The eight legs span about an inch in length, and the first set of legs are longer than the other six legs.

spider yellow sac spider

Yellow sac spider.

Another interesting fact is that the males are generally smaller than the female yellow sac spiders. Like most other spiders the yellow sac spider has eight eyes, and their eyes sit in two horizontal lines of four eyes. Also around their feet they have a darker looking coloring to them, it is actually dark dense hair. There is also a darker stripe down the abdomen. Considering the name of the yellow sac spider most people would assume the spider is yellow. Some are yellow tones, while others can range from an orange tone to a green tone. It has been said that the color of the yellow sac spider sometimes depends on what it has most recently eaten, but some do not think that is where the coloring of the yellow sac spider comes from.

The yellow sac spider eats many things, while it mostly hunts for small insects and other spiders. During the fall the yellow sac spider will usually migrate into homes in search of food. While in the summer the yellow sac spider has plenty of food outdoors to feed on, although that doesn’t mean they won’t try to go into houses.

For the most part, yellow sac spiders live outdoors. Outside the yellow sac spider can be found in places like trees, low vegetation and shrubs. Even though the yellow sac spider lives mostly outdoors it can be found within homes. No matter where the yellow sac spider is living it will always make itself a sac to rest in and spend its days. Being a sac spider, the yellow sac spider does not spin a web; rather they make silken sacs to reside in. The sac is also used as a place for them to sleep during the day and hibernate in the winters. Also, the yellow sac spider will spin a sac for its eggs to stay protected in, and for the spiderlings to molt in. The sac is also a way for people to identify that their home may be infested with yellow sac spiders.

If yellow sac spiders have migrated into a home they still will make their sacs to live in. Most often they will set up shop in corners or ceilings of walls. These spots make it easy for people to notice the sacs and proceed from there, the best plan being to call your local pest control company out to your home. Yellow sac spiders look for small places where they can be protected from predators. Many times these areas are the hidden areas inside a home; like the closet, basements, window sills, behind furniture, along baseboards, or in doorframes. The yellow sac spider can crawl up to high to places because they are good climbers. Also their silk can be used as a bridge from one object to a next, especially from high to low places. This tool comes in use both indoors and outdoors for the yellow sac spider. There are also places outdoors where the sacs may be hiding, like under foliage, leaves, stones, or wood. Many people may come in contact with these areas while outside doing yard work or gardening. So be aware of the yellow sac spider inside your home out outside of your home. Here are some tips for preventing yellow sac spiders from getting near your home.

Yellow sac spiders are nocturnal so homeowners won’t really see them running around in the day. Therefore the risk of being bit is higher at night when the yellow sac spiders are running around your house hunting for food. Sometimes the yellow sac spider may crawl into your bed or couch; this is when most bites occur. While people are in bed sleeping or on the couch watching TV or if the yellow sac spider is in your sheets or on your cushions it may panic and feel threatened by your body and therefore will attack or bite you.

The yellow sac spider creates about one generation a year. The female usually will lay her eggs in the summer. She will deposit them into a sac to keep them protected. In this sac will be anywhere from 30-50 eggs. During the process of the eggs developing the female will stay near the sac to protect it. Once the eggs have hatched they will become spiderlings and molt for about two weeks. After that period the spiderlings will set out on their own venture. From there the cycle will just repeat itself, and there will be more and more yellow sac spiders out in the world.

Picture courtesy of www.creativecommons.org

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