Spiders

Some people are afraid of spiders. Others think they are very interesting animals. Some naturalists joke that spiders are on our team. They mean that spiders help people by catching and eating insects such as flies and mosquitoes. Spiders have many surprising roles in nature. Did you know hummingbirds use spider webs as part of their nests? Why not spend a little time this month watching and learning more about spiders? 

Spiders are arthropods. Arthropods are animals with jointed legs and a hard layer called an exoskeleton covering them all over. Insects are also arthropods. So are crustaceans (things like crabs, crayfish, pillbugsdaphnia and brineshrimp) and millipedes(this page asks you to log-in but just click OK and you will get the page).

Spiders have two main parts to their bodies, eight legs, and can spin silk.

Spiders without Webs

Not all spiders make webs to catch insects. Wolf spiders chase the insects they eat, a little like a wolf chasing a deer or rabbit. Jumping spiders sneak up and jump on their prey. Crab spiders are usually camouflaged to look like the plant they are hiding on so they can grab a surprised insect for a meal. Some of them are as beautiful as the flowers they hide in.

Spiders and Webs

Spiders don't just use webs to catch food, they also use them like climbing ropes, like blankets to protect their eggs, and even like balloons to fly away.

You can use the shape of a spider web to figure out what kind of spider you are looking at. One type of web is called a funnel web. It usually is on the ground, in high grass. It is made of a flat sheet. Behind or below this sheet is another one that sags in the middle towards a hole in which the spider hides. The web doesn't have any sticky threads. Instead, insects get tangled in the slippery web. The spider feels the web move and comes out of the hole to bite and wrap up the insect in silk. Then it takes the insect into the hole to eat.

Another type of web is called an orb web. Orb webs are the webs most people think of when they think about spiders. The orb is flat and round. Part of the web is made of sticky strands of silk. Insects get caught on these and the spider comes over and wraps the insect in more silk so it can't escape. Most orb webs have some strands that are not sticky so the spider can move on the web without getting stuck. The spider knows which threads are safe to walk on.

Find a spider web outdoors and see if there are clues that insects have been caught in it. Try touching the web very gently with a piece of grass to see if the spider will come out to see if it has caught an insect.

See if you can find a spider and watch it make or repair its web. Does it build the web anything like the drawings shown on the Spider Construction Gallery website?

You can save a spider web. Ask your family if you can borrow some hair spray or get some artist fixative from a craft store. Get a sheet of dark colored paper - black construction paper is perfect. Find a nice spider web. Spray the web with hair spray or fixative. Bring the paper up against the web. The web should stick to the paper and be preserved. Try making a model of a spider web out of thread or string.

How many different spiders can you find? Can you find any ones that look kind of pretty?

Spider Adaptations

Different kinds of spiders have different ways of living. Some catch their food with their webs. Others don't.

Some young spiders can fly away from the egg mass they hatched from by ballooning. They climb to the top of a tall grass stem or the end of a twig and spin a long strand of silk into the wind. Then they let go with their legs and fly. They will sometimes ride the wind like this for miles to a new home.

Some spiders have very good eyesight. You can use spiders' eyes to find them in the evening. Wait until it is getting dark out. Take a flashlight outdoors and hold the flashlight against your forehead so it shines in front of you like a miner's light. Walk towards tall grasses or garden flowers. You will see tiny sparkling jewels in the grasses. These are the reflections from the eyes of spiders.

Most spiders can't hurt people. Our skin is too tough for some to bite through. Some can bite people and a few can be harmful. The venom of harmful spiders is poisonous to people. Be careful not to handle spiders in case they can bite.

For a good story about a spider, read Charlotte's Web.
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