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1994-03-01
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Spiders are the largest group of arachnids.
There are more then 34,000 named species
worldwide, including 3,000 species in
North America.
Spiders can easily be identified by their
4 pairs of legs. Each leg is segmented
into many different sections or joints.
Most Spiders have 8 pairs of eyes. A few
have less then 8 and some species have
none at all. The eyes of a spider are
usually arranged in 2 or 3 rows.
Spiders usually have 6 silk glands called
spinnerets located beneath the abdomen.
Not all spiders spin webs, some live in
burrows which they line with silk.
Spiders are not considered insects. They
are from the order of Araneae. (Arachnids)
Insects have only 6 legs, whereas spiders
have two more for a total of 8 altogether.
All spiders are predators. They feed mostly
on insects, but some of the larger species
prey on small animals!
There is a common mistake most people make
about the 'Daddy Long Legs'. This is not
actually a spider at all, it is classified
in the order or 'Opiliones'.
Tarantulas (Family Theraphosidae)
Certain South America species are deadly
poisonous, but the bite of a North American
Tarantula is as dangerous as a bee sting.
There are some male spiders that release
long silken strands, which they use like
parachutes to float in the wind to another
location.
Black Widow Spider (Latrodectus mactans)
Of all spiders, the Black Widow is the most
feared. The female's venom is especially
poisonous to people.
The Fishing Spider (Dolomedes tenerosus)
If disturbed this spider can go below the
water and remain motionless for 30 minutes.
Air trapped by his body allow him to breathe.
Like all arachnids, spiders have an abdomen
and a cephalothorax. These are separated
by a waist or pedicel. The thorax is
protected by a covering called a carapace.
Most spiders lay eggs in silken sacs. Some
place the egg sac in their webs, while others
attach it to twigs and leaves. A few spiders
carry the sac with them at all times.
Spiders should be considered very beneficial
to us because they help keep the enormous
insect population like mosquitoes in check.
The correct term for a newly hatched spider
is a spiderling. The young, though smaller,
resemble their adults from the moment they
emerge from their egg sac.
Contrary to what most people think, only a
few spiders actually bite people, and the
venom of most of these is quite harmless.
Tarantulas (Family Theraphosidae)
Male Tarantulas are short-lived, yet females
have been known to live for as many as 30
years !
Trapdoor Spider (Family Ctenizidae)
These spiders nest in tubelike burrows they
dig into the ground. They seal the nest with
a hinged lid similar to a folding trapdoor.
Spitting Spiders (Family Scytodidae)
There are many types of Spitting Spiders.
They have spitting glands within the thorax
which make a sticky substance to catch prey.
American House Spider (Achae. tepidariorum)
These spiders spin irregular webs made of
sticky strands. When these webs catch dust
and dirt they become 'Cobwebs'.
Black Widow Spider (Latrodectus mactans)
Male Black Widow Spiders do not bite. After
they mate, the female often eats the male
spider earning her the name 'Widow'.
Hammock Spider (Pityohyphantes costatus)
These spiders get their name from the
hammock like sheet web they construct
between fence posts and tree branches.
Orb Weaver Spiders (Araneaus spp.)
Like most spiders who spin webs, they
construct a new web each night. They spin
the web in complete darkness by touch alone!
Barn Spiders (Araneus cavaticus)
These spiders stay in their webs at night
to wait for prey. In the daytime, they move
above it and are attached by a silk line.
The Shamrock Spider (Araneus trifolium)
This spider waits at the side of his web
between grass stems. They make a tent to
hide it by tying leaves together with silk.
The Shamrock Spider (Araneus trifolium)
Their webs are made each night in the grass.
They can be clearly seen with the dew at
sunrise. At night they eat the old one.
Bola Spider (Mastophora bisaccata)
This spider catches prey by producing a
silken line which has drop on the end that
that resembles the South American Bola.
Wolf Spiders (Family Lycosidae)
This spider lives in burrows and seldom
emerges from them. They lie in wait for
prey ready to pounce on a passing insect.
Burrowing Wolf Spiders (Geolycosa spp.)
These spiders construct vertical burrows in
sand several feet deep. They cement the
sand with silk to make the walls sturdy.
Ant-mimic Spiders (Castianeira spp.)
These spiders usually live near anthills.
Their look and antlike behavior helps them
to confuse predators.
Goldenrod Spider (Misumena vatia)
This spider 'Flower Spider' changes its
to yellow which allows it to camouflage
itself on Goldenrod and daisies.
Jumping Spiders (Family Salticidae)
There are many different types of Jumping
Spiders. They get their name from the
spectacular leaps catching their prey.
Jumping Spiders (Family Salticidae)
These spiders have the sharpest vision of
all spiders. When they leap onto their prey,
their spinnerets create a silken dragline.
Many spiders who spin webs do not wait
in them for prey. They attach themselves
to the web by a silk line which senses
the vibrations of a struggling insect.
Species of spiders that spin webs each have
a distinctive pattern. Some are shaped like
funnels, some are round, and others are
zigzagged.