Spiders in Your Cellar: Learn About Arachnids
Spiders are fascinating creatures that live virtually everywhere in the world. Spiders can live in mountainous regions, deep in the oceans, in deserts, and in the freezing tundra. Some spiders tunnel underground, live in trees, burrow into rock crevices, or live in houses. Some spiders wait patiently for prey to happen by, and others are predatory hunters.
Spiders Are Arachnids
Spiders are classified as arachnids along with ticks, scorpions, and mites. These creatures have two body segments and eight legs. They do not have antennae or wings. Spiders differ from insects because insects have six legs and spiders have eight legs. Insects usually have wings, and they have three body parts. Arachnids are part of the arthropod animal group, which includes lobsters, crabs, and shrimp. As the largest group in the animal kingdom, arthropods comprise about 80 percent of all animals, which includes more than a million different species. More than 30,000 species of spiders exist, and they are predators. Remains of spiders have been discovered in amber, dating them back about two million years.
The Body of a Spider
The two body segments of spiders are the cephalothorax and the abdomen. The front part, or cephalothorax, includes the eyes, mouth, stomach, brain, and poison glands. The spider's legs are connected to this body part. Tiny pedipalps connect near the fangs and are designed to hold prey while spiders inject venom. The abdomen contains spinnerets, which are the glands that produce silk. Special oils are produced by the spider to keep it from sticking to its web. Spiders don't have bones inside their bodies, but they do have an exoskeleton on the outside of the body. As a spider grows, it molts to shed the exoskeleton. Gradually, a new exoskeleton will form and harden.
All spiders have fangs, and most have venom used to paralyze prey. Some spiders have venom that's strong enough to kill prey. Generally, spider venom is not strong enough to harm humans, although a few spiders do have venom that's strong enough to cause nerve damage in people. Two of these spiders are the brown recluse and the black widow. Bites from these spiders could even cause death if they aren't treated. Although tarantulas look deadly, their bites are similar in strength to a hornet sting.
Smooth as Silk
Every spider can produce silk, but only some of them spin webs. Spiders use silk to spin webs, build walls in burrows, build egg sacs, climb, and wrap prey. Spinnerets on their abdomen are the openings where spiders can release silk. Although the silk looks like a single thin strand, it's actually made up of many strands stuck together. Air hardens the silk to make it strong. Spiders often use their silk as a dragline, which keeps them connected to their home if they drop or fall. Silk comes in different types depending on the spider. It can be stretchy, dry, or sticky. A spider might travel miles while connected to a surface via the silk. This is called ballooning. Some spiders use their silk lines to fish for prey. They may also recycle the silk by eating it so they can make new silk.
Surfing the Web
The ability to spin silk is innate for spiders. Some spiders spin webs, but others hunt aggressively to catch their prey. Many spiders don't have strong eyesight, so they rely on web vibrations to find their prey. When an insect lands on a web, it causes the silk to vibrate. The spider will rush to the insect, wrap it tightly up in silk, inject poison through its fangs that liquefies the inside of the bug, and then suck up the liquid. Orb web spiders spin sticky circular webs designed to trap insects. Some spiders spin a new web every night, while others will continue to repair their webs as they are used. Usually, the spider sits near the center of the web, waiting for hapless prey to come along. Other spiders spin sheet webs. These webs are spun horizontally, and they have sticky lines above to route insects onto the web. Funnel webs are another spider design. These webs are wide at the top and narrow at the bottom, with the spider waiting near the bottom to capture prey.
Spiders that don't spin webs are hunters. Some of these spiders rely on camouflage to hide as they wait for prey to come along. Other spiders actually chase their prey. Hunters often have better eyesight than web-spinners, and they have sharp fangs and stronger venom that can take down even large prey. One example of a hunting spider is the trapdoor spider, which digs a hole and covers the opening with a silk door that it hides behind. When an insect comes near, the spider jumps out and grabs it. Another type of hunting spider, the jumping spider, jumps on its prey. This spider uses a silk line as a safety mechanism in case it misses its prey and needs to get back to its home.
Male spiders need to be careful during the mating game. When the male arrives on a female's web, he sends gentle vibrations through the silk to alert the female. He doesn't want to be confused with an insect and needs to convince the female not to eat him. Some male spiders will do a dance for the female; others even bring a wrapped insect as a gift for the female. If the female doesn't eat the male, she will mate with him. But she may still decide to eat him after they mate. Spiders lay between two and 1,000 eggs at a time. The female will make a silk bed for the eggs, covering them with a silk blanket. She then makes a silk egg sac to contain them, and she hangs it in a safe place, where she will often guard it. Some females stay near the sac until the eggs hatch, while others leave or even die. Many female spiders leave their babies completely unattended after they hatch, but a few will take care of them.
What Are Spiders Afraid Of?
Spiders are small, so they have many enemies. Birds, lizards, toads, and monkeys hunt spiders. Sometimes, ticks will attach themselves to spiders to feed. Humans are also enemies of spiders. But the spider wasp may be one of the top spider enemies. The female wasp can sting the spider and paralyze it. The wasp then digs a hole, inserts the paralyzed spider, and lays an egg in the hole. When the baby hatches out of the egg, it eats the paralyzed spider.
- Black Widow: The adult female black widow spider is the most poisonous spider in North America. These spiders are easily identifiable by their shiny black bodies and red hourglass-shaped mark. The black widow spider lays up to 400 eggs at a time, spins a strong web, and may eat her mate if she confuses him with food.
- Brown Recluse: The brown recluse lives in North America and on other continents. This spider's venom is dangerous to humans, and it typically hides in dark spots such as a cellar, basement, or attic. Brown recluse spiders spin sheet webs.
- Crab Spider: The crab spider changes color to match its surroundings. These spiders like to hide in flowers as they wait for insects.
- Daddy Longlegs: Daddy longlegs are actually not spiders or insects. They are part of a different arachnid family.
- Orb Weaver: The orb weaver's web looks like a bicycle wheel. Orb weavers usually spin their webs in the early mornings so they can catch insects during the day. Orb webs are often spun on windows, grass, and plants.
- Spitting Spider: The spitting spider uses poison glands in its head and spitting glands in its abdomen to spit out a poisonous silk at its prey.
- Tarantula: More than 700 species of tarantulas exist. They are found all over the world, often living in burrows underground. Tarantulas use silk to make doors and walls in their burrows, and they are hunters that will pounce on their prey. When threatened, tarantulas can shoot out their leg hairs at a predator.
- Water Spider: Water spiders spin webs on the surface of water. The web collects air bubbles, which the spider uses to breathe as it sits under the web in the water. Water spiders live in ponds, streams, and lakes.
Spider Myths and Folklore
A Greek myth tells the story about a country girl named Arachne. Arachne spun threads beautifully, and the Greek goddess Athena was jealous of her. Arachne challenged Athena to a weaving contest, and Arachne was so arrogant that she insulted the gods in images woven into her creation. Athena became angry and turned Arachne into a spider, forcing her to weave webs for the rest of her life.
Common House Spiders
- American House Spider: About the size of a nickel, these spiders are usually gray. They spin messy webs in cellars, basements, garages, windows, and concealed areas.
- Wolf Spider: These spiders are hairy and resemble small tarantulas. They don't spin webs, instead hunting their prey. You'll find wolf spiders in cellars, sheds, and garages.
- Black Widow Spider: Black widows hide in tall grass, in corners, and in garages.
- Brown Recluse Spider: The brown recluse spider has a brown body and a violin-shaped mark on its head. These spiders hide in cellars, basements, garages, sheds, and dark corners of homes.
- Daddy Longlegs : Although they look like spiders, they actually are not. These creatures hide under decks, in the lawn, and under house siding.
- Hobo Spider: These spiders are tannish-brown in color, possibly with spots. They usually live outside, although they may hide in shoes and under beds.
- Jumping Spider: With more than 300 species of jumping spiders, these spiders range widely in size and markings. Jumping spiders don't spin webs, and you may see them on walls or ceilings and in attics.
- Yellow Sac Spider: Yellow sac spiders are yellowish or beige in color. You'll see them where walls meet the ceiling or in upper corners in any room of the house.
- Orb Weaver Spider: Orb weavers are brown or gray in color. Look for big webs on the exterior of the house or on decks, especially around outdoor lights.
- Grass Spiders: These brown spiders may look like brown recluse spiders, but they have spinnerets. Grass spiders live around home foundations.