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Toxic Spiders Pose Dangers – Letter to the Editor

To the Editor:

The city of Alameda is infested with toxic spiders. No, I’m not talking about the Black Widow. Another two are my concern.

False Black Widow spider

Alameda Post - False Black Widow spider
False Black Widow spider (steatoda grossa). Photo TJ Gehling.

Have you had a muscle cramp that lasts several days? Cramps in a different muscle periodically? Had flu-like symptoms for several weeks but don’t have a fever or the flu? A bite that is evident well after that fact but hurts a lot, swells up, and takes weeks to heal? That could be the FBW. But symptoms can be far worse. If you’re more sensitive to the venom, young, old, or infirm, it could very well lead to a trip to the emergency room.

The False Black Widow spider has the same venom as the Black Widow, a powerful neurotoxin. But, her jaws are weaker, so she injects less venom when she bites. But she bites with alacrity: when she lands on you, it’s often a row of bites.

She’s a cobb weaver with super strong silk and a funnel deep inside. You can spray her web, but she’ll wait until the spray dries then rebuild it. She lays one large egg every three weeks that hatches 300 spiderlings, on average. And they, the spiderlings and the mom, all can and do fly on their feet on the wind. They’ve been found up to 10,000 feet in elevation! So, even if you eradicate all the spiders in your yard, the spiders from neighbors’ yards will reinfest yours each night.

Alameda County Health came out and affirmed “more FBWs than we’d expect to see” and did a study. But there’s no state law, like there is for rats, to cause county health to act. The only way county health will act is if people report bites to their physician and they report it to county health. While many Alamedans experience symptoms from spider bites, they do not report them. However, in Southern California, there are cities that work with their county health departments to protect people from the venomous bites.

Yellow Sac spider

Alameda Post - Yellow Sac spider
Yellow sac spider (Cheiracanthium inclusum). Photo Joseph Berger,

This one doesn’t make a web. The Yellow Sac spider makes a sac that she sleeps in during the day and lays her eggs. She runs around at night hunting insects on walls and ceilings of homes with lights on them or drops from the trees at dusk to run around the yard and plants. Her venom is necrotic – her bite causes the skin to die at the bite site that often leads to an infection that requires medical attention.

Both spiders live everywhere. The False Black Widow is easily found – just look for a messy, strong web, then go out at night with a flashlight: she’ll be out on her web, upside down. The Yellow Sac is harder to see but if you have a porch light, look at your ceiling or go out at dusk to watch them drop from the trees.

Keep toxic spiders from returning

Once you’ve removed a spider, there are several deterrents to discourage them from setting up house again in the same location:

  • Furniture polish from the $1 store: spiders hate this underfoot.
  • A homemade deterrent is to fill a spray bottle with water and 30- 50 drops of cedar oil or peppermint oil, then add several drops of dishwashing liquid to emulsify the oil.
  • There are many other natural, non-toxic, spider deterrents on the market to choose from.
  • Or, you can plant mint in your yard.

I’m writing this in hope that you will be motivated to clear your homes, garbage cans, and properties of these toxic spiders on a regular basis. It would be a public health benefit to all in our community.

Denise Lai,

Editorials and Letters to the Editor

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