Nothing gets us reaching for the can of bug spray quicker than a creepy crawly scuttling our way.
The approaching end of summer may give us some relief from their biting, stinging, and hiding in our favorite shoes. But the misguided collective wisdom about the insects and spiders in our lives shows no signs of abating.
We asked some experts to help us get to the bottom of whether the following “facts” about insects and spiders are really true.
Are tarantula fangs really too wimpy to hurt you?
There are actually two groups of spiders we call tarantulas, says Charles Griswold, a spider expert at the California Academy of Sciences in San Francisco. Theraphosidae are “big, hairy spiders,” with large fangs that can bite you, he says, “though they’re not particularly aggressive.”
An Antilles pinktoe tarantula. Photograph by Joel Sartore, National Geographic Creative
The American species in this group don’t seem to have particularly dangerous venom, Griswold says, but Asian and African members could be dangerous. Not enough is known about their venom to be sure. (Watch a video of the goliath birdeater tarantula, the world’s largest spider.)
The second group of tarantulas is a kind of wolf spider that lives in Europe. “It’s the source of the legend surrounding the folk dance, the tarantella,” Griswold says. Legend had it that the only way to cure someone of a spider bite—and prevent them from dying—was to dance vigorously.
“The actual wolf spider seems to have no such dangerous venom.”
Do we unwittingly swallow an average of seven to eight spiders a year?
“There’s absolutely no evidence whatsoever that we swallow spiders,” says Griswold. It’s highly unlikely they’d crawl into an open mouth, he says. “If you have your mouth open, you’re probably breathing heavily, which would frighten them.”
In some parts of the world, such as Southeast Asia, people consume spiders, but they do this willingly—as food, Griswold says. (See National Geographic’s animated video on edible insects.)
Could cockroaches really survive a nuclear winter?
That roaches could survive an apocalypse is a popular notion, endearingly rendered in the Pixar movie WALL-E.
An American cockroach. Photograph by Gary Alpert
But according to a 2001 article in the journal American Entomologist, cockroaches are relative wimps when it comes to withstanding radiation. American cockroaches die when exposed to 20,000 rads (a unit of measure for radiation), compared with fruit flies, which can withstand 64,000 rads, and a type of bug called a lesser grain borer, which handles 180,000 rads.
Cockroaches overall can be surprisingly sensitive, says Dan Babbitt, manager of the Insect Zoo and Butterfly Pavilion at the Smithsonian’s Natural History Museum in Washington D.C. “They almost didn’t make it through the last extinction [65 million years ago].”
Jeff Tomberlin, an entomologist at Texas A&M University in College Station, thinks the notion of cockroach as the ultimate survivor has its roots in the fact that roaches are flexible eaters: As long as it’s organic in nature, chances are good that a cockroach can eat it.
“So in a postnuclear world, they [could] find a way to survive,” he says.
Daddy longlegs (also known as harvestmen) have some of the deadliest venom in the world, but their fangs are too small to bite you.
“We hear this one constantly,” says Babbitt. “They have fangs, but they don’t have any venom.”
A close-up of a daddy longlegs on Bioko Island, Equatorial Guinea. Photograph by Christian Ziegler, National Geographic
And technically, they aren’t even spiders, he says. They’re arachnids, the same group as spiders, but they lack a second body section that makes them spiders. (Also see “Ancient Daddy Longlegs Had Extra Set of Eyes.”)
Can earwigs really lay their eggs in your ear?
“No,” says Babbitt. He’s not sure where this notion started, but it’s not true. The earwig is interesting, though, because it’s one of the few insect species to care for its young, he adds.
Other parenting insects include the Madagascar hissing cockroach and the American burying beetle, Babbitt says. (See “Why Are Corpse-Eating Beetles Being Released Into the Wild?”)
Is there a difference between venomous and poisonous?
Yes there is, says spider expert Griswold. “If you get poisoned because something bites you, that’s venom,” he explains. “If you get poisoned because you bit something else, that’s poison.”
It’s the difference between ingesting a toxic substance (poison) versus getting injected with a toxin (venom). (Read about venom’s medical potential in National Geographic magazine.)
Do crane flies really eat mosquitoes?
Ever seen huge, mosquito-like insects fluttering around your walls in the summertime? They’re called crane flies, also known as mosquito hawks.
A crane fly does not eat mosquitoes. Photograph by Darlyne A. Murawski
These insects won’t bite you, nor do they eat mosquitoes, says Texas A&M’s Tomberlin. The adults actually feed on nectar from plants, he explains.
While we’re on the subject, adult mosquitoes also feed on nectar, noted Smithsonian’s Babbitt. The females need protein from blood to produce their eggs—hence the reason they bite you. (If you’re ever mad at mosquitoes, just remember they pollinate a lot of those beautiful flowers in your neighborhood.)
Tell us: What other bug myths do you want laid to rest?
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