Venom in the Garden of Eatin’?

29 Sep
Stunning Brown Widow

Image via Wikipedia

When it comes to gardening in Southern California there are a lot of pests that gardeners are concerned with.  These pests & insects consume herbs, fruits, and vegetables which the hardworking gardener is hoping to harvest for their own table.  Most of these are of no real threat to the human species & can be easily dispatched.  They can also be eliminated through the use of pesticides and insecticides commonly sold at most home improvement or hardware stores.

Those of the environmental or eco-friendly persuasion can also discover a number of options such as bran flakes for snails & slugs.  Some companies sell farm raised hunting squads such as the inaccurately named Ladybug Hippodamia sp. which is actually named a Lady Beetle can be released to exterminate aphids.  Nature provides us with other pest and insect predators such as arachnids.  These vary in form like the scorpions and spiders which lie in wait to deal death blows to unsuspecting creatures which haplessly cross their path or fall into their web of doom.  So begins our story of spiders, venom, and gardening.

Brown Recluse Loxosceles reclusa & California

A co-worker of mine was relating a tale of someone who had been envenomated by a Brown Widow Latrodectus geometricus and had a particularly nasty reaction to the bite.  In the course of this conversation we discussed the Brown Recluse species Loxosceles reclusa and their reputation.  This brought up a pet peeve of mine.  I can throw a stone anywhere in California and hit somebody who knows of someone who has been envenomated by a Brown Recluse Loxosceles reclusa in the state of California.

I have personally heard at least three stories of Brown Recluse Loxosceles reclusa envenomations just at my day job!  No matter how I have tried to explain.  The people relating the tale refuse to believe that the Brown Recluse Loxosceles reclusa doesn’t exist in California.  I’m unable to convince these amateur entomologists that their predecessors (true entomologists) have been documenting for years that the infamous Brown Recluse Loxosceles reclusa are not here.  Here’s a tip, if the treating physician didn’t see the spider and get confirmation from an entomologist then it wasn’t a Brown Recluse Loxosceles reclusa.  Numerous entomologists report, that doctors treating these envenomations are simply misdiagnosing cases as Brown Recluse Loxosceles reclusa envenomations.  But I digress.

As the story goes, this gentleman was working in the garden; he lifted a stone and was summarily bitten and envenomated by a spider; later identified as a Brown Widow spider Latrodectus geometricus.  This particular envenomation caused what I presume was an allergic reaction which the man was hospitalized for.  This is generally rare in spider envenomations but does happen on occasion.

Of spiders and humans

Spiders number in the 50,000 species range according to the California Poison System[i].  Only a few of these are known as medically important; a nice way of saying they could kill you.  Spiders have long shared our homes and our garden areas.  When we consider the natural order of things it makes logical sense that they have chosen to share our environs.

Humans create buildings and then eat within that building.  Bugs, regardless of what we do, move in to consume the after effects of us eating and living.  The spiders then come to eat the bugs.  The above is obviously more complex than portrayed but you get the idea.  Spiders are also present in our gardens.  They are there to prey on insects that we have attracted due to providing them food.

Spider Venom

Most spider envenomations are considered harmless to humans.  Generally they cause little more reaction than a red bump on the surface of the skin.  Before we go any further into which are dangerous etc let’s get one thing clear.  All spiders are venomous period, not poisonous or any other derivative they are 100% venomous.  For the difference between venom and poison follow our handy link and learn.  Now then, when we look at potentially harmful species of spiders we of course think of the Brown Recluse Loxosceles reclusa, Black Widow Latrodectus hesperus, and Tarantula Theraphosidae sp. for the most part.  Well two out of three isn’t bad, right.  Tarantulas Theraphosidae are not considered to be medically dangerous to humans.  In the Golden State of California we have Black Widows Latrodectus hesperus, Brown Widows Latrodectus geometricus, and Desert Recluse Loxosceles deserta (a similar species and relative of the Brown Recluse Loxosceles reclusa), Jumping Spiders Habronattus sp, and Wolf Spiders Lycosa sp.  These are the species we might be concerned about.


In no way does this mean we should be so fearful as to go and buy the economy size of Raid® and begin a personal mission to eradicate the state of these creatures.  It simply means that we should all be aware of our surroundings.  As a side note, The Merck Manual online states, that less than three deaths a year are caused by spider envenomations.[ii] This tells us we have very little to worry about.  If working outdoors, wear some sturdy gloves and work shoes.  Without any data to back this up, I would speculate spiders would have a tough time puncturing any regular garden glove material as their fangs are too short.

Spider bite

Let’s say for the sake of argument you decide to ignore the above advice.  One day while working outdoors you become an envenomation victim now what?  We must understand that most spider envenomations are not originally noticed when they occur.  Symptoms occur within 24 hours of the envenomation.  Being that as it may, should you actually feel the bite then the following course of actions should be taken.

  1. Remain as calm as possible.  Freaking out and running around moves the venom through your system faster.
  2. Capture the spider without killing it.
  3. Go to a physician if symptoms warrant such.

In no way am I telling you that any red welt that appears to be a spider bite warrants a doctor visit.  There are specific signs and symptoms associated with different spider envenomations.  For a list of symptoms click the link

Spider Behavior

Spiders are not aggressive towards humans unless you come into contact with their home.  Without becoming too anthropomorphic about it, think of how the spider must see us.  We are a gigantic predator so it has no other recourse except to bite as escape is made impossible as seen below.  Evidence shows most spiders do not bite unless they are trapped or pinched in someway; as they would be inside a shoe, glove, or other clothing where they may have taken up residence temporarily.  If you live where there are ‘dangerous’ spiders its much easier to take a moment to shake out your shoes, gloves, and clothing rather than trying to treat a serious envenomation.

The very best thing you can do is to protect yourself through preventative measures mentioned earlier.  At the top of the list should be personal awareness of what species occur in the area you live and to familiarize yourself with their habitats, behaviors, and what they actually look like.  If it is of real concern contact a local entomologist via the internet and I am sure they would be happy to help.



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