Entomologist explains why you shouldn't kill spiders in your home

May 16, 2018 by Matt Bertone, The Conversation
He comes in peace. Credit: Matt Bertone, CC BY-ND

I know it may be hard to convince you, but let me try: Don't kill the next spider you see in your home.

Why? Because spiders are an important part of nature and our indoor ecosystem – as well as being fellow organisms in their own right.

People like to think of their dwellings as safely insulated from the outside world, but many types of spiders can be found inside. Some are accidentally trapped, while others are short-term visitors. Some species even enjoy the great indoors, where they happily live out their lives and make more spiders. These arachnids are usually secretive, and almost all you meet are neither aggressive nor dangerous. And they may be providing services like eating pests – some even eat other spiders.

My colleagues and I conducted a visual survey of 50 North Carolina homes to inventory just which arthropods live under our roofs. Every single house we visited was home to spiders. The most common species we encountered were cobweb spiders and cellar spiders.

Both build webs where they lie in wait for prey to get caught. Cellar spiders sometimes leave their webs to hunt other spiders on their turf, mimicking prey to catch their cousins for dinner.

A cobweb spider dispatches some prey that got snagged in its web. Credit: Matt Bertone, CC BY-ND

Although they are generalist predators, apt to eat anything they can catch, spiders regularly capture nuisance pests and even disease-carrying insects – for example, mosquitoes. There's even a species of jumping spider that prefers to eat blood-filled mosquitoes in African homes. So killing a spider doesn't just cost the arachnid its life, it may take an important predator out of your home.

It's natural to fear spiders. They have lots of legs and almost all are venomous—though the majority of species have venom too weak to cause issues in humans, if their fangs can pierce our skin at all. Even entomologists themselves can fall prey to arachnophobia. I know a few spider researchers who overcame their fear by observing and working with these fascinating creatures. If they can do it, so can you!

Spiders are not out to get you and actually prefer to avoid humans; we are much more dangerous to them than vice versa. Bites from spiders are extremely rare. Although there are a few medically important like widow spiders and recluses, even their bites are uncommon and rarely cause serious issues.

If you truly can't stand that spider in your house, apartment, garage, or wherever, instead of smashing it, try to capture it and release it outside. It'll find somewhere else to go, and both parties will be happier with the outcome.

But if you can stomach it, it's OK to have spiders in your home. In fact, it's normal. And frankly, even if you don't see them, they'll still be there. So consider a live-and-let-live approach to the next you encounter.

Explore further: Recluse or not? Scientists use Twitter to tackle spider questions

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Iochroma
1 / 5 (1) May 17, 2018
Oh my gosh, after putting hundreds of spiders outside for decades, I realized that it does not change the population of spiders or pest insects at all. Now, I smash them all. Into the compost...
Da Schneib
not rated yet May 17, 2018
I regularly kill the ones I can see but I don't hunt them down. If I can see them there's too many or they're too bold. I have cats, and spiders kill fleas; fleas are vermin. My cats don't go outside but they are allowed to sit in open windows behind screens and that's enough for them to get fleas. Spiders also don't exude noxious chemicals.
Whydening Gyre
not rated yet May 17, 2018
Every so often, when I'm on the computer, a spider spins a web down to right in front of the screen. I explain the concept behind computers, internet and Phys.org to him (every time cuz I'm not sure if it's the same spider each time).
Then I put up a little porn (to show the REAL reason computers and the internet came about).
After a while, he works his way back up his silk line and I don't see him (or maybe it's a her) for another week or so...
rrwillsj
not rated yet May 19, 2018
Personally, I celebrate having spiders wherever I am dwelling. As I absolutely loathe disease raddled pest bugs. Been exposed to filthy vermin way more than I care to recall. Never been harmed by a spider and there have been plenty of opportunities.

As WG said, beginning with Arpanet, it has been porn and games that have flogged the evolution of the technology upward and onward to the fabulous machines and fantastical systems we have today.

Cause porn and games! Who can argue with success?
SURFIN85
not rated yet May 21, 2018
Its crucial to learn to live with other species
sascoflame
not rated yet May 21, 2018
Give me a break! Spiders are better than people and we should let them inject us with poison.
Da Schneib
5 / 5 (1) May 21, 2018
They're just spiders. Calm down. Would you rather have flies?
elextech
not rated yet 18 hours ago
Widow spiders? I've never heard of widow spiders. Is the word "black" off limits today, so we can't say "black widow spiders"?

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