10 Creepy-Crawly Facts About Spiders

iStock/pong6400
iStock/pong6400

You don’t have to love ‘em, but there’s no denying that we’d all be a lot worse off without the ecological benefits spiders provide. Join us as we clear up some misconceptions—and revel in some wild facts—about these wonderful arachnids.

1. Spiders can be found nearly everywhere—even on Mount Everest.

It’s a myth that you’re never more than 3 feet from a spider, but they sure are abundant. Scientists recognize over 48,000 different species, distributed across every continent besides Antarctica. Spiders live in all sorts of habitats, from deserts to jungles to wetlands. They even live on some of the world's highest mountains. The tiny Himalayan jumping spider lives at elevations of up to almost 22,000 feet above sea level, and has been found on the slopes of Mount Everest. Meanwhile, the Andes Mountains are populated by high-climbing tarantulas. Seven new species were recently found there, including a skillful burrower that was seen at altitudes above 14,700 feet.

2. The world’s spiders consume millions of tons of insects each year.

According to one 2017 study, the average square meter of land contains roughly 131 spiders. Using relative body sizes and food habits, the study’s authors estimated that “the global spider community” eats a collective 400 to 800 million tons of food—including insects and small vertebrates—per year.

3. Not all spider webs are considered cobwebs.

A spiderweb with dew on it
iStock/vonviper

A cobweb is a specific type of spider web that’s defined by its disheveled appearance. Some webs are well-organized, spiral-like structures made with ring after ring of concentric circles. By contrast, cobwebs don’t really follow any recognizable pattern, per se. They’re tangled, sprawling things made by the aptly named “cobweb spiders” of the Theridiidae family. (Black widows belong to said group.)

4. Some spiders turn their webs into slingshots …

Using its own body like a catapult to create tension between the lines in its web, the Peruvian triangle weaver spider launches itself towards hapless insects. After it springs forward, the arachnid accelerates like crazy. In the span of just one second, the critter’s speed can increase by the equivalent of 1700 miles per hour. During the process, the oscillating web enmeshes the victim, increasing the odds of a kill without requiring the spider to get too close to potentially dangerous prey.

5. … And some like to go ballooning.

A ballooning spider
A ballooning spider near B.K. Leach Memorial Conservation Area in Missouri
Andy Reago & Chrissy McClarren, Flickr // CC BY 2.0

Ballooning is a popular travel strategy among young spiderlings and small-bodied adults. The technique is simple: A wayward arachnid uses silk strands to catch the wind and ride its currents over vast distances. (Frequent fliers may also be taking advantage of earth’s electromagnetic fields [PDF].) In southeastern Australia, mass migrations of hang gliding spider babies are a common sight. Sometimes, it looks as though the sky is raining spiders.

6. The giant huntsman spider is the size of a dinner plate.

First discovered in Laos in 2001, the giant huntsman spider doesn’t build webs; instead, like other huntsman spider species, it actively tracks down the insects it dines upon. From leg tip to leg tip, the giant huntsman measures 12 inches across, giving it the longest leg span of any modern spider. So does that make it the world’s biggest spider overall? Well, that depends on what measurement you’re using. For all its leggy prowess, the giant huntsman is outweighed by the Goliath birdeater tarantula, a 6-ounce juggernaut thought to be the heaviest spider alive today. But while the tarantula is beefier, it’s got a slightly smaller leg span.

7. Male nursery web spiders trade gifts for sex.

A nursery web spider crawls across a leaf.
iStock/Chris_Soucy

Male nursery web spiders (Pisaura mirabilis) approach potential mates with dead insects “gift-wrapped” in silk. That wrapping material is loaded with male pheromones, but female spiders seem to be totally unphased by the amorous chemicals, according to a March 2018 study. Instead, they focus on the food itself. Approaching females empty-handed is a risky proposition: Males who fail to offer gifts are six times more likely to get eaten by their would-be mating partners.

8. “Sea spiders” aren't really spiders.

A sea spider
iStock/RibeirodosSantos

Not every so-called "spider" is an arachnid. Despite their common name, sea spiders aren’t considered true spiders; they belong to a different class called Pycnogonida. Found in every ocean, the spineless creatures suck up food through a hose-like apparatus and crawl around on eight to 12 segmented legs. The biggest species have incredible leg spans of over 28 inches. Just how they might relate to the spider family tree is unclear, though—because the delicate animals are rarely preserved as fossils, scientists aren't quite sure of their origins [PDF]. While some research suggests that they are chelicerates, belonging to the same subphylum as spiders and horseshoe crabs, others believe they may have evolved separately.

9. Indoor plumbing may have led to a decrease in black widow bites.

Black widows (genus Latrodectus) are among the world’s most feared invertebrates, with North America’s three resident species being especially notorious. Their neurotoxic venom can be fatal to humans, so be sure to give the spiders a wide berth. Yet, your chances of being bitten by one are fairly low. Most black widows prefer to hide rather than bite. And even when they do bite, the spiders sometimes withhold their venom, which is better spent on prey than humans.

During the 20th century, the number of reported black widow bites (as well as fatalities) in America significantly declined. We may in part have our changing bathroom habits to thank for that development. Outhouses are ideal spider shelters, but now that indoor plumbing is here to stay, you don’t see many backyard toilet shacks anymore. Experts think the decline of outhouses led to fewer encounters between widow spiders (including black widows and their relatives, brown widows) and people—and thus fewer bites. And though people do still occasionally get bitten, modern medical advancements have made fatalities very rare.

10. The longest-lived spider on record died at age 43.

For over four decades, scientists kept tabs on a wild trapdoor spider known simply as “Number Sixteen.” First sighted in 1974, the tiny female—less than an inch in width—defended a home burrow in Western Australia. Her death due to a wasp sting was announced in April, 2018. Prior to Number Sixteen, the oldest individual spider in recorded history was a Mexican tarantula that reached the age of 28.

Chimpanzees Bond by Watching Movies Together, Too

Windzepher/iStock via Getty Images
Windzepher/iStock via Getty Images

Scientists at the Wolfgang Kohler Primate Research Center in Germany recently discovered that, like humans, chimpanzees bond when they watch movies together, the BBC reports.

In the study, published in Proceedings of the Royal Society B, researchers stationed pairs of chimpanzees in front of screens that showed a video of a family of chimps playing with a young chimp. They found that afterward, the chimps would spend more time grooming and interacting with each other—or simply being in the same part of the room—than they would without having watched the video.

They gave the chimps fruit juice to keep them calm and occupied while they viewed the video, and they chose a subject that chimps have previously proven to be most interested in: other chimps. They also used eye trackers to ensure the chimps were actually watching the video. If you’ve ever watched a movie with friends, you might notice similarities between the chimps’ experience and your own. Drinks (and snacks) also keep us calm and occupied while we watch, and we like to watch movies about other humans. Since this study only showed that chimps bond over programs about their own species, we don’t know if it would work the same way if they watched something completely unrelated to them, like humans do—say, The Lion King.

Bonding through shared experiences was thought to be one of the traits that make us uniquely human, and some researchers have argued that other species don’t have the psychological mechanisms to realize that they’re even sharing an experience with another. This study suggests that social activities for apes don’t just serve utilitarian purposes like traveling together for safety, and that they’re capable of a more human-like social closeness.

The part that is uniquely human about this study is the fact that they were studying the effect of a screen, as opposed to something less man-made. The chimps in question have participated in other studies, so they may be more accustomed to that technology than wild apes. But the study demonstrates that we’re not the only species capable of social interaction for the sake of social interaction.

[h/t BBC]

10 Facts You Should Know About Mosquitoes

tskstock/iStock via Getty Images
tskstock/iStock via Getty Images

Between the itching and the welts and the fears of mosquito-borne viruses, it's easy to forget that mosquitoes are a wonder of evolution, and that maybe they don't get a fair shake from us. Of more than 3000 known species, only 80 actually bite people, and at least one eats other mosquitoes for us. They grow from egg to adult in just five days, begin mating within minutes of hatching, and possess, by way of their stinging mouthparts, some of the coolest appendages in the animal kingdom.

1. Mosquitoes are excellent flyers in bad weather.

The average raindrop is 50 times heavier than the average mosquito, yet they buzz around in the rain with no problems. If a Boeing 747 got whacked with a similarly scaled-up raindrop, there would be 2375 tons of water coming down on it, and things probably wouldn’t turn out as well as they do for the mosquito. How do the insects do it?

A common urban legend said that the bugs were nimble enough to dodge the drops. A few years ago, a team of engineers from the Georgia Institute of Technology watched real mosquitoes and Styrofoam dummy mosquitoes with a high-speed camera during a rainy flight to see if that’s what was really happening. They found that the bugs don’t fly fast enough to dodge the drops, but their slowness is what keeps them from getting knocked out of the sky. A mosquito’s low mass even at slow speed doesn’t provide enough of a target for a raindrop to splash on collision. Instead, the drop just deforms, and doesn’t transfer enough momentum to the mosquito to disrupt its flight.

2. Texas is the mosquito capital of America.

Of the 3000 species of mosquitoes around the world, at least 150 are found in the United States, and 85 of those call Texas home. When people say everything's bigger in Texas, you can also include the biodiversity of the state's biting, disease-carrying insects.

3. Some mosquitoes are truly dangerous to humans ...

The female mosquito, which is the one that stings and sucks blood, is an incredible transmitter of disease and, because of that, the deadliest animal in the world. Each year, the malaria parasites they transmit kill 2 million to 3 million people and infect another 200 million or more. They also spread pathogens that cause yellow fever, dengue fever, Rift Valley fever, Chikungunya and West Nile disease.

4. ... and some mosquitoes are harmless.

Not every species of mosquito sucks blood from people, and among those that do, not every one transmits disease. The blood suckers don’t even need to bite you for every meal. Males live entirely on nectar and other plant fluids, and the females’ diet is primarily plant-based, too. Most of the time, they only go after people when they’re ready to reproduce, because blood contains lipids, proteins, and other nutrients needed for the production of eggs.

5. MosquitoEs actually help the environment.

When you’re rubbing calamine lotion all over yourself, mosquitoes might not seem to serve any purpose but to annoy you, but many species play important ecological roles. The mosquitoes Aedes impiger and Aedes nigripes, which gather in thick clouds in Arctic Russia and Canada, are an important food source for migrating birds. Farther south, birds, insects, spiders, salamanders, lizards, frogs, and fish also eat different mosquito species regularly. Plants need them, too, and some, like the blunt-leaved orchid and endangered monkeyface orchid, rely on mosquitoes as their primary pollinator.

Some mosquito species are also excellent at mosquito control. Species of the genus Toxorhynchites feed on the larvae and immature stages of other mosquitoes and will sometimes even cannibalize members of their own species.

6. Mosquitoes are amazing hunters (as if we needed to tell you that).

Mosquitoes are adept at picking up on the chemicals given off by their human hosts. They can detect the carbon dioxide in our breath, the 1-octen-3-ol in our breath and sweat, and other organic substances we produce with the 70-plus types of odor and chemical receptors in their antennae. These receptors can pick up traces of chemicals from hundreds of feet away, and once the mosquito closes in, it tracks its meal chemically and also visually—and they’re fond of people wearing dark colors.

7. Mosquitoes can be picky.

If it seems like you’re always covered head to toe by bites while people who were sitting right next to you only have one or two, it’s not just paranoia; the skeeters actually are out to get you. Some people happen to give off more of the odors and compounds that mosquitoes find simply irresistible, while others emit less of those and more of the compounds that make them unattractive to mosquitoes—either by acting as repellents or by masking the compounds that mosquitoes would find attractive.

8. A female mosquito's mouth is primed for sucking blood.

A mosquito doesn’t simply sink its proboscis into your skin and start sucking. What you see sticking out of a mosquito’s face is the labium, which sheaths the mouthparts that really do all the work. The labium bends back when a mosquito bites, allowing these other parts to pass through its tip and do their thing. The sharp, pointed mandibles and maxillae, which both come in pairs, are used to pierce the skin, and the hollow hypopharynx and the labrum are used to deliver saliva and draw blood, respectively.

9. Mosquito saliva prevents blood clotting.

The saliva that gets pumped out from the hypopharynx during a bite is necessary to get around our blood’s tendency to clot. It contains a grab bag of chemicals that suppress vascular constriction, blood clotting and platelet aggregation, keeping our blood from clogging up the mosquitoes' labrum and ruining their meal.

10. Mosquitoes can explode.

Blood pressure makes a mosquito's meal easier by helping to fill its stomach faster, but urban legend says it can also lead to their doom. Story goes, you can flex a muscle close to the bite site or stretch your skin taut so the mosquito can’t pull out its proboscis and your blood pressure will fill the bug until it bursts. The consensus among entomologists seems to be that this is bunk, but there is a more complicated way of blowing the bugs up. To make a blood bomb, you’ve got to sever the mosquito’s ventral nerve cord, which transmits information about satiety. When it's cut, the cord can’t tell the mosquito’s brain that its stomach is full, so it’ll keep feeding until it reaches critical mass. At least one researcher found that mosquitoes clueless about how full they were would keep sucking even after their guts had exploded, sending showers of blood spilling out of their blown-out back end.

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