Golden Orb Weaver (Nephila clavipes)

The Human-Spider Struggle

Arachnids have long fascinated—and repelled—people. Scientists are only now starting to understand why.

In April of 2017, researchers Martin Nyffeler and Klaus Birkhofer published a paper in The Science of Nature, a multidisciplinary peer-reviewed science journal, on how much spiders eat every year. The quantity was astonishing: altogether, the global spider community consumes somewhere between 400 and 800 metric tons of insects annually. In other words, as the Washington Post put it, the world’s spiders could eat every human on earth in only 365 days.

This is exactly what some people have been worried about.

Rose hair tarantula (Grammostola rosea)
Black widow (Latrodectus mactans)

Humans have long had irrational feelings for (and homicidal tendencies toward) spiders. On the one hand, we worship spiders as symbols of wisdom and creativity (think Spider Woman, a helper and protector of humans in southwestern Native American cultures; or Anansi, the West African trickster appearing in fables told throughout the African diaspora). On the other hand, we have stories such as Arachnophobia and tales of tarantism, a medieval phenomenon in which one supposed victim of a “tarantula” bite (in actuality, tarantulas are a species of wolf spider whose venom is not harmful to humans) would find a “cure” through a fit of dancing the tarantella, setting off mass hysteria as additional “victims” joined the dance, sometimes overwhelming entire towns.

Spiders could, if they wanted, eat every human on earth in one year.
Yellow garden spider (Argiope aurantia)
Golden orb-weaver (Nephila clavipes)

Why are spiders so terror-inducing for some of us? Scientists, too, have been bugged by this question. Multiple studies in 1980s Europe documented that spiders were one of the top five most feared animals, but they’ve struggled to definitively explain why so many people find spiders so terrifying. Broadly speaking, decades of dueling journal articles have established two schools of thought on the origins of spider phobias: a biologically based reaction, transmitted genetically from our ancestors as a survival mechanism, or a disgust-driven response tied to our individual tolerance for dirty, and potentially diseased, environments and objects. It’s essentially “spiders are dangerous” versus “spiders are gross.” In both cases, this is a matter of perception, not reality—only 0.01 percent of the 40,000 species of spiders in the world are dangerous to humans, and evidence suggests spiders do not transmit disease to humans.

Green lynx spider (Peucetia viridans)

No consensus exists on the theories proposed by either camp. One 2017 study found that babies negatively respond to snakes and spiders, suggesting an intrinsic, biologically based fear, but other researchers are quick to point out that if we’re evolving fears to protect ourselves, we should be similarly terrified of wasps (which, surprisingly, we aren’t). Graham C. L. Davey, an emeritus professor of psychology at the University of Sussex who researches anxiety and worry, has noted that fear of spiders does correspond to a greater disgust response to other “gross” animals—slugs, leeches, cockroaches, etc.—and this forms the basis for the counterargument to the innate-fear theory. Davey points out that this association is stronger in some cultures than others. Medieval Europeans, for example, associated spiders with transmission of disease, but if their belief was a rationalization of an innate, biologically induced fear of spiders, we’d expect it to be more universal across cultures. In fact, in many other areas of the world, spiders are viewed neutrally, or even positively, including in areas that actually do have a number of extremely dangerous spiders, like South America.

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“They’re so small. They could be on me and I don’t even know it. They could go inside my mouth.”
Orange-kneed tarantula (Brachypelma smithii)

Although we can’t find scientific consensus on why humanity has a long-standing fear of spiders, we have gleaned some insights into what exactly makes spiders so unnerving. In 1996, psychology researchers from Flinders University of South Australia surveyed 192 volunteer subjects, mapping fear of spiders against four qualities—“disgust,” “dangerousness,” “unpredictability,” and “uncontrollability”—that make an individual feel vulnerable. They found that fear of spiders correlates strongly with all four “vulnerability variables.”

In other words, the spider is icky, the spider might be venomous, the spider might crawl up your arm, and if the spider wants to bite you, the spider is going to bite you—an all-encompassing nightmare spider experience. Or as my husband, a noted spider hater, puts it: “They’re so small. They could be on me and I don’t even know it. They could go inside my mouth.” (Spiders almost certainly do not want to go inside your mouth, even when you are sleeping.)

Funnel Spider (Kukulcania hibernalis)
Silver orb banded Argiope spider (Argiope trifasciata)

It is possible for people to overcome their arachnophobia. One doctor I spoke to said that educating people about arachnid biology is an effective technique, particularly when paired with gradual exposure to spiders in various states of living and captivity. But not fearing something is not the same as liking it. And some people do like spiders. “I had a traditionally geeky childhood,” says science fiction and fantasy author Adrian Tchaikovsky, who won the Arthur C. Clarke award for 2015’s Children of Time, about a planet of hyper-evolved spiders. That interest in science fiction, fantasy, and other realms of the uncool resulted in Tchaikovsky’s being “somewhat estranged from others,” and led him to develop an affinity for animals that were similarly cast out, like spiders, snakes, and insects. Tchaikovsky’s readers appreciate his own appreciation of arachnids. In addition to Children of Time, his series Shadows of the Apt and his 2016 novel Spiderlight focus on insects and spiders—and the author worked with zoologists to ensure that spiders were presented accurately in Children of Time (well, aside from evolving human-level intelligence and growing much closer in size to people).

Cave spider (Meta menardi)

If you can’t appreciate spiders for their outsider status, you can at least admit they have a lot going for them, ecologically speaking. Spiders should be kept alive to destroy other, even less appealing, insects in both small spaces (your bathroom) and large properties (farms). Dr. Alan Cady of Miami University—whose affection for spiders accompanied a general childhood interest in science and zoology—is currently researching how spiders can be used as biological pest control for crops. Using other animals for this purpose has not worked in the past (famously, the cane toads introduced to protect sugarcane plantations from beetles in Australia both failed to protect the sugarcane harvest and disrupted the local ecosystem) but in Cady’s previous studies, he has proved the capacity existing native spider populations have for eating unwanted insects. Creating refugia, areas where a species can survive through unfavorable conditions, for spiders in cornfields has resulted in statistically significant increases in crop yields, presenting a potential low-cost, pesticide-free method of protecting young crops.

They’re just different, and a little misunderstood, which is something we can all relate to (at least sometimes).
Funnel spider (Kukulcania hibernalis)
Pink toe tarantula (Avicularia avicularia)

I’m not afraid of spiders, to be honest. Growing up, the onset of fall meant a home invasion of wolf spiders. The walls weren’t crawling with them, but you’d try to retrieve a pan from a lower cabinet or visit the laundry room late at night and—surprise!—a big boy, America’s largest wolf spider, suddenly right in front of you. I never managed to squash them (sorry, Spider Grandmother), because not only were they fast, they were extremely determined to get away from me. And that, I realized, was the heart of it; the spiders, as fear-inducing as they could be, just wanted to get away from the giant noisy things with weirdly reduced numbers of eyes. They’re just different, and a little misunderstood, which is something we can all relate to (at least sometimes). Plus, they eat mosquitoes, which are unquestionably the worst animals on earth.

Black widow (Latrodectus mactans)
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