The spider needs a reason to bite, which is not a common thing since most spiders are not aggressive and only bite in self-defense. Spiders and snakes are probably the two most feared pests by most people. I can understand the fear for lots of reasons. News media, movie industry, childhood memories, and a host of other sources have contributed to the phobia of both. I’m going to focus on spiders in this blog post since we receive dozens of calls about people allegedly being bit by spiders each month.
The reality of this claim is far from what actually occur. Much study has been done over the years about this to see if there is actually documentation to support these claims. I remember when the movie Arachnophobia came out, much like the movie Jaws, people were afraid to go in the water or their basement. I was actually approached to represent the “exterminator” portrayed in the movie, but declined once I read the part. Our industry at the time never seems to get the respect we deserve as a public health specialist, but that’s another story.
So what are the real facts about spider bites and the likelihood that they could be responsible for all these claims? First let’s take a look at some spider facts.
- Most spiders do produce venom
- Venom is used to subdue their prey
- All spiders have fangs
- Most spider venom is weak
- Not all spiders spin webs
So it seems logical that spiders have earned their reputation, right? Well not really. These facts may seem to be a good match for all the claims of bites. You really have to look at the biology of why spiders bite in the first place. Venom is a spider’s defense mechanism, so to use it prudently is a must. Some species of spiders will take up to 16 days to replenish their supply of venom, so non-prey and people are not a good use of their resources. We are not a food source for spiders. If a spider does bite a human it would be for defense when they feel threatened. Most spider bites to humans happen when they are handled. Most people would rather not handle spiders, so that reduces a huge opportunity for spider bites just on that fact alone.
So what about the daddy of all feared spiders, the Brown Recluse? You’re probably thinking, now we gotcha because there are dozens of news reports that people are bit by the brown recluse each year. I think Malcolm X said “The media’s the most powerful entity on earth. They have the power to make the innocent guilty and to make the guilty innocent, and that’s power, because they control the minds of the masses”.
Here is another little widely unknown fact…they don’t exist here in California! Let me repeat that…They Do Not Exist In California. Let’s take a look at a recent study about this spider and where they do exist. A study, 2055 brown recluse spiders were captured over a six-month period in a Kansas home--400 of these spiders was big enough to inflict envenomation in humans. Despite the number of spiders that could have bitten the occupants, no one was bitten. So how is it that we have so many people claim to have been bitten by a Recluse or knows someone that has?
A true spider bite that has a reaction, a couple of things need to happen. Spiders must have fangs capable of penetrating human skin—many adult spiders lack these fangs to do that. Just because spiders have venom, not all venom triggers a response in humans. Most insects that bite or sting will cause some sort of localized redness, simply because our immune system to the foreign proteins injected can cause classic swelling and redness.
Many dermatologists diagnose the local skin reactions as “spider” bites likely because they assume the cause is what the patient is telling them. Clients tell us that their doctor said it is a spider bite… The clinical definition of a spider bits is very specific, and it is suspected that many skin lesions or skin conditions are misidentified as spider bites. There has to be three conditions to a clinical definition of a spider bite.
- Pain at the site of the bite immediately following the bite
- Collection of a spider
- Identification of the spider by an expert to verify it is capable of producing symptoms
Only then, when all of these conditions are met, is it scientifically a spider bite. I can offer some other situations that may cause “spider like” lesions here.
So after all this is said and done, random, unprovoked spider bites are rare. Spiders are beneficial and help control the non-beneficial pests.