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Are daddy-longlegs really as venomous as I’ve heard?

Entomologists estimate there to be around a quintillion individual insects on the planet–and that’s just insects. Bugs are everywhere, but how much do we really know about them? Jeff Lockwood to the rescue! Professor Lockwood is answering all your bug questions–one at a time, that is. Send your question to him care of blog@oup.com and he’ll do his best to find you the answer.

Are daddy-longlegs really as venomous as I’ve heard?

Well, that depends on what you’ve heard.  If people have told you that these creatures are deadly, then those people are dead wrong.  This tale is debunked on the website of the University of California Riverside, and I trust my colleagues at UCR.  I know a several of the entomologists there, and they’re a really smart bunch of scientists (a claim that one might question, given that they chose to live in Riverside, but my concern is for their entomological acumen, not their geographic aesthetics).  So, I’m going to use what they say about daddy-longlegs and if you end up dying from a bite, then it’s on them.

First, let’s get clear on just what creature we’re considering.  I grew up thinking that daddy-longlegs were those spider-like beasties with a spherical body and really long spindly legs that were invariably found in wood piles and in the crawlspace under the house.  However, some folks use the name to refer to cellar spiders—which do have rather long legs.  Both versions of daddy-longlegs are arachnids, along with scorpions, mites and ticks.  However, the creatures of my youth aren’t spiders at all.  They belong to the Order Opiliones, while the true spiders—including cellar spiders—belong to the Order Araneae.  The big difference is that the woodpile version (also called harvestmen) don’t spin silk and their head-thorax-abdomen is crammed into one blob, while the cellar version spins silk and has two body parts (the head and thorax fused in a cephalothorax and the abdomen).  And just to make matters a bit more confusing, the silly Brits call refer to crane flies (which do have long legs but then so do giraffes) as daddy-longlegs, but they also have really weird terms for the hood/trunk of a car and other such things so we’ll just ignore their misnaming of arthropods.

The UCR folks think that most people are referring to cellar spiders when they talk about daddy-longlegs.  I think my colleagues are nuts.  In my estimation, they know their entomology, but not their colloquial terminology.  I suppose that because cellar spiders are common along the Pacific Coast, the UCR faculty hang out at cocktail parties where people sip Chardonnay and ask entomologists about daddy-longlegs in their basements.  Well there’s a big country to the east of California, and out here a daddy-longlegs is most assuredly the sphere-and-legs version.  But let’s move on to the venom-thing.

As for the real daddy-longlegs (Opiliones), these fellows mostly eat decomposing stuff, hence their affinity for woodpiles and crawlspaces.  They’ll nab a smaller creature if the opportunity presents itself.  However, they don’t have fangs or venom glands.  Some species can secrete nasty stuff, so if you’re a small animal then perhaps you could be poisoned.  If a human wants to be harmed by these daddy-longlegs, it might be possible if you gather up a humongous bunch of daddy-longlegs and eat them.  As Paracelsus told us centuries ago, the dose makes the poison—and even water is poisonous in sufficient quantities.

With regard to the “other” daddy-longlegs, there is no record of a cellar spider biting a human and causing any harm (and if you know of such a case, then don’t send me your outraged email—send it to the entomologists as UCR).  For a spider to be deadly to us, it has to be able to bite and its venom has to be potent.  As for biting, cellar spiders have short fangs (perhaps this generates fang-envy in these spiders, but it’s hard to know what a spider is thinking).  That said, brown recluses have short fangs and they can bite humans.  However, the brown recluse is a hunting spider and has strong muscles controlling its fangs—and the cellar spiders wrap their prey in silk, so they don’t need bulked-up musculature.  With regard to venom, there are no toxicology studies of cellar spiders.  So, we don’t know if these daddy-longlegs can bite humans, and we don’t know if their venom is particularly potent.  In other words, there is no basis for believing that they are bad news for people.

The bottom-line—don’t believe the daddy-longlegs-are-deadly myth, unless you’re a soft-bodied arthropod the size of a pinhead or you find yourself trapped in the web of a cellar spider (e.g. you messed up your matter transporter and fused your head onto the body of an insect as seen in that delightful 1958 movie The Fly, which was way better than the 1986 remake, although my UCR colleagues might disagree).

Jeffrey Lockwood was hired as an insect ecologist at the University of Wyoming in 1986. But over the course of 20 years he metamorphosed into a Professor of Natural Sciences & Humanities, with a joint appointment between the Department of Philosophy and in the MFA program in Creative Writing. He teaches courses in natural resource ethics, environmental justice and the philosophy of ecology, along with creative non-fiction writing workshops. He is the author of Six-Legged Soldiers: Using Insects as Weapons of War.

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Recent Comments

  1. John S. Wilkins

    Australia has its own daddy long legs, a spider, Pholcus phalangioides:


    Just to make things more complex.

  2. John S. Wilkins

    Which I now see is the same species as the British one…

  3. R Hankin

    I can’t believe so many people believe the daddy-long legs myth. And I was one of them! At least I know now.

  4. Jack Black

    As intelligent as this writer tries to be he makes the mistake of confusing venom and poison. Most venoms are not poisonous and most poisons are not venomous. A venom is always injected, a poison is always inhaled, absorbed, or ingested. Both are considered toxins. Some toxic compounds are are both venomous and poisonous; most are not. Is that clear? Most venoms are completely harmless when ingested, but not all of them, so don’t eat the stuff.

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