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Spiders
Eight hairy legs carry a
garden spider up a small tree early in the morning before anyone
is awake. She looks around with her eight eyes and sees two
small branches close together. She will use these branches as
the frame for her web. Not only will the web by her home,
but it will be her trap to catch her food, too. Thinking
only of her new project, she walks across the top branch until
she comes close to the end. She uses special parts of her
body to make a
sticky place on the branch. These parts are called spinnerets.
Spinnerets are special tubes on the back of spiders. These
tubes have a liquid, like glue, inside of
them that hardens when it is released into the air.
Once the sticky place hardens, the spider can use her spinnerets again to
put out more of the sticky liquid. This time the liquid
will harden into a silk thread. This thread is amazingly
strong. This line is her anchor to the top branch and she uses
it to lowers
herself to the bottom branch. Now the
spinning can begin!
She climbs halfway up her first line to attach
another thread, making a Y. Then she climbs back and forth, making lines from the center to the
branches. These are the rays of the web. The rays come out
from the center to the end, just like the spokes on a bicycle
wheel. The spider can make different kinds of silk thread
from her spinnerets. The
rays are made from a smooth, dry thread.
Once the rays are in place, she climbs back up the top branch to
look over her framework. Garden spiders spin circular webs
called orb webs. With the spokes all set, she is ready to add her spiral circle.
The thread in the circle will be strong and sticky. She begins
at the outer edge, connecting a sticky thread to each ray. She
keeps walking around and around, gradually moving to the
center. When she is done, she will be sitting in the middle,
waiting for a tasty meal.
It doesn’t take long before the sun
rises and a fly gets caught in the garden spider’s web. As the
fly struggles, the vibrations shake the threads, alerting the
spider. Quickly, she races to the fly and sinks her fangs into
it. As she bites the fly, venom is injected and begins to turn
the inside of the fly into liquid. The spider uses her
spinnerets to make a strong cocoon thread. She wraps it around
the fly over and over. After it is all bundled up, she can save
it for dinner. Meanwhile, she repairs her web and waits to
see if any more prey will come along.
The day is coming to an end and
nothing else has been trapped in the web. The
hungry spider comes back to the meal. Her stomach works like a
pump, allowing her to suck the liquid from the fly’s body--like
fly soup! Afterward,
only a hard, empty shell will be left.
Evening comes and the spider must
spin another web. The old one is dusty and damaged. She tears
it down to get ready for another night’s work. She may eat the
old web or throw it away like a little silk ball. Once again,
she repeats the process of laying the silk thread in a pattern.
She keeps moving and is finished in about an hour. Morning
comes and the dew settling on the web looks like a sparkling net of
diamonds!
Interesting facts:
*Spiders are not insects. Instead
of six legs and three body parts, spiders have eight legs and
only two body parts. Insects have a head, thorax, and
abdomen. In spiders, the head and thorax are combined and
called the cephalothorax.
*Spiders are called arachnids. They
are named after Arachnae, a Greek maiden who was a skilled
weaver.
*The Web-throwing spider hangs
upside down and holds a little web in its front legs. When an
insect walks underneath, the spider throws its net over the
insect.
Activities:
*How does a spider walk on its web?
It has oil on its feet. Lay a piece of masking tape on a table
with the sticky side facing up. Touch it with your finger and
see what happens. Now put a tiny bit of oil on you finger and
touch it again. What happened?
*Build your own web with masking
tape. Pretend you are an orb spider that spins a circular web.
Get a roll of masking tape and find an open doorway. Place one
strip across the doorway for your top branch and one near the
middle of the doorway for your bottom branch. Don’t forget to
start with a Y shape! Tape the rays from the center of the web
to the door frame. Now you can start at the top and wind the
tape in a spiral fashion, like a real spider web. When your web
is complete, see how long it takes for a fly to come by. Stand
about 5 feet away from the sticky side of the web and throw
cotton balls at it. How many missed? How many did you catch? |
