It’s happened to most of us: you’re walking down the sidewalk and suddenly your face makes contact with a spider web. Sputtering and waving your arms, you try to pull it all off. From a distance, you probably look ridiculous. But it gets worse: is the spider itself on you?
If you’re like many people, you are at least a little afraid of spiders. Throughout the world, arachnophobia makes it to top ten lists of fears. Fear of spiders is more common in women than in men and more common in younger people than older. But, is there really a reason to be afraid? While most people’s reaction is automatic and unthinking, science says that spiders are really among our best natural friends.
As of 2015, there are at least 45,700 identified species of spider. They are found on every continent except Antarctica and have become established in every type of habitat. The oldest records of true spiders are between 299 and 318 million years old, with spider-like arachnids first occurring around 386 million years ago.
Spiders belong to the class Arachnida, along with ticks, scorpions and about 100,000 other named species. Like all arachnids, spiders have eight legs. Most have between six and eight eyes, depending on the species, although some have no eyes at all and some have as many as 12. While they are similar to insects in appearance, there are a number of noted differences. They have a two-part body, as opposed to insects’ three-part body. A spider’s legs are all located on the front segment of the body. Unlike insects, they do not have antennae.
With the one known exception of the recently discovered species Bagheera kiplingi, which is an herbivore, all spiders are predators. Most prey on insects and other spiders. A few large species, such as the Goliath birdeater, are large enough that their prey includes birds, lizards or small mammals. Spiders use a range of strategies to catch their prey. Many form sticky webs that capture prey. Others chase their prey or mimic their prey to get close. Others throw out a sticky strand to lasso food. Since spiders’ digestive systems are too narrow to take in solids, they use digestive enzymes to liquefy their food.
Spiders also serve as prey for other animals. They make up part of the diet of insects such as mantids and some wasps, as well as birds, lizards, scorpions and snakes. In some parts of the world, they are also eaten by humans.
Most spiders are short-lived, with a lifespan of two years at the most. However, species like tarantulas can live 25 years or more when kept in captivity.
Spiders come in a number of colors, shapes and sizes. Many, such as the common house spider, are a plain brown or gray color. Others can sport vivid hues of red, yellow or blue. The smallest spider, the patu digua, is about the size of the head of a pin. The largest, the Goliath birdeater, can be the size of a dinner plate.
Like other arachnids, spiders must molt as they grow because their skin does not stretch.
Spiders are mostly solitary and will engage in cannibalism if the chance arises. Because of this, male spiders of most species use a variety of courtship rituals to avoid being eaten by the females they approach. Male spiders are short-lived, but usually survive long enough for a few matings.
Spider males deposit sperm using a syringe-like structure. In many species, the female will eat the spider after mating if she is able to.
Female spiders weave egg-cases, which can contain hundreds or even thousands of eggs. A number of spider females care for their young by sharing food with them or carrying them on their backs. Spiders hatch after the larval stage and are hatched as spiderlings. These young spiders are similar in shape to adults, but are smaller and sexually immature.
Most spider venom is harmless and may, in fact, have medicinal value. A number of types of spider venom are being researched to combat maladies that range from Alzheimer’s disease and strokes to cardiac arrythmia and erectile dysfunction.
At the current time, the Ch’ol Maya people of southeastern Mexico use a beverage made from tarantulas to combat a respiratory disorder that includes coughing and asthma-like symptoms.
In the South Pacific, there are native cultures that use spider silk for fishing nets. They people encourage spiders to weave webs between a pair of bamboo stakes, then use the resulting web for fishing.
Spider silk is the strongest natural fiber known. The silk of one million wild spiders was collected to create a gold-colored tapestry that is displayed in the Natural History Museum in New York. Scientists are attempting genetic engineering to produce spider silk in plants or in goats’ milk. This silk, if produced in large quantities, can be used in protective armor and other applications where strength, flexibility and low weight are valuable.
Spider venom may have applications as a less-polluting form of pesticide. A number of spider venoms are deadly to insects but harmless to vertebrate animals. One spider whose venom is of promise in this area is the Australian funnel-web spider. This spider’s venom is easy to milk in captivity and most insects are susceptible to its poison.
Large tarantulas serve as a food source in parts of the world. In Cambodia, fried tarantula is a popular delicacy. Frying eliminates the irritant hairs on the spiders’ legs. The Piaroa Indians of southern Venezuela catch tarantulas and roast them over open fires.
Tarantulas are also on the menu in a number of insectivore demonstration dinners. These dinners exist to introduce the idea of eating bugs, as the U.N. has urged that people expand their palates to avoid the ecological damage that could occur with a growing population eating meat.
Spiders have long been a part of human mythology. In Greek myth, a talented mortal weaver named Arachne is turned into a spider after challenging the goddess Athena to a weaving contest. In African mythology, the spider is the personification of the trickster god Anansi. Native American culture also included a trickster deity depicted as a spider, which went by a number of regional names. Spiders are also included in the clan totems and rock paintings of Indigenous Australian art.
Many people who are afraid of spiders attribute their fear to spider bites. However, most spiders do not have the ability to penetrate human skin. The majority of spiders will avoid people and will flee before they attempt to defend themselves by biting. In nearly all cases, a spider’s bite is no more serious than a mosquito bite or a bee sting. Through the entire 20th century, there were only around 100 deaths that were conclusively attributed to spider bites.
That is not, however, to say that no there are no spiders that can cause damage. A few of the more spiders with more serious bites:
In most cases, spiders will run instead of biting. Most people who are bitten by spiders are bitten by ones that are inside clothing and get trapped next to the skin. Spider bites are also possible when reaching into dark places; for instance, a spider bite is possible when reaching into a basement closet to pull down a box.
If you are bitten by a spider, keep the wound clean. Antihistamines such as Benadryl and topical hydrocortisone creams can reduce itching. If the bite becomes infected, seek medical attention. If you are worried that you have been bitten by a poisonous spider, seek medical attention. If possible, catch the spider and bring it along for identification.
In general, it is perfectly safe and beneficial to leave spiders alone. They eat other pests and can keep down the insect population around your house.
If you would rather not have them inside, there are ways to discourage them. Insecticides generally do not work, as they are made for insects and spiders are arachnids. Additionally, most insecticides work by touching the insect’s body as it walks; spiders carry their bodies high and so do not come in contact with the poisons.
To eliminate spiders, it is important to remove the places where they will hide. Keep clutter to a minimum and keep storage totes out of living spaces. Some spiders like damp conditions, so keeping areas like the basement dry will help keep down their numbers. Vacuuming thoroughly in the spring when spiders are most active can help eliminate webs and egg cases
In general, however, it is best to adopt a live and let live attitude toward spiders around the home. The average spider eats around 2,000 insects a year, meaning fewer pests biting you, damaging plants or infesting good like beans or rolled oats. As we learn more about spiders, the more we see that they are a valuable partner, instead of a fearsome foe.