The itsy bitsy spider climbed up the water spout.
Down came the rain and washed the spider out.
Spiders are one of the most feared arachnids in the United States. Some of them are not so itsy bitsy either.
People with arachnophobia tend to feel uneasy in any area they believe could harbor spiders or that has visible signs of their presence, such as webs. If they see a spider they may not enter the general vicinity until they overcome the panic attack that is often associated with their phobia.
It is safe to estimate that hundreds of thousands of people every year are bitten by spiders with no ill effects. Even a bite from a spider listed above may not produce symptoms. The spider may not inject venom, or may inject very little and the wound may heal on its own. In most cases a spider bite will produce a local welt that resembles a mosquito bite, and will subside within 24 hours. However children, the elderly, or people with compromised systems are at greater risk of severe reactions. Allergic reactions can also cause problems with spider bites that are normally not considered dangerous.
If you believe you have been bitten by a spider and are experiencing symptoms that concern you, contact your doctor or your local poison center. If possible, safely bring the spider with you when you seek medical attention. Many spider bites share common symptoms and can be misdiagnosed without the spider. Dead or crushed spiders can still be evaluated for diagnostic purposes.
Facts About Spiders
Most spider bites are not dangerous though all spiders, with the exception of the uloboridae family, have venom. However, due to varying potency of this venom, of the thousands of species in the world relatively few present a threat to humans.
Venom, whether spider or snake venom, can be categorized into two types: neurotoxic or cytotoxic.
The black widow is an example of a spider with neurotoxic venom. This venom directly affects the nervous system, though there may not be much of a noticeable wound at the site of the bite itself. Blocking impulses to the muscles, neurotoxic venom causes cramps, rigidity, and has a general paralyzing effect. This venom kills quicker than cytotoxic venom and is considered more potent. The Australian funnel web spider is an example of a spider with neurotoxic venom.
Spiders like the brown recluse spider have cytotoxic venom. Cytotoxic venom is necrotic venom, from the word, necrosis, which refers to the breakdown of cells and tissue. The bite from a spider with cytotoxic venom will cause a welt resembling a mosquito bite and a noticeable wound. Necrosis will be present and the sore will be slow to heal and could require medical attention to prevent secondary infections. Spider bites of this nature can create severe flu-like symptoms, and in rare cases, can be deadly.
Venom toxicity - the brown
recluse venom can cause significant cutaneous injury with tissue loss and
necrosis.
Habitat - brown recluse is found in the United States from the east to
the west coast, with predominance in the south.
Spider Identification - an
adult spider is 1/4 to 3/4 inch in body - a dark violin shape is located
on the top of the leg attachment region with the neck of the violin pointing
backward toward the abdomen. Unlike most spiders that have 8 eyes, the
brown recluse has 6 eyes arranged in pairs - one pair in front and a
pair on either side.
Black
Widow Spiders ...highly venomous - can be deadly
Venom toxicity - the Back
Widow Spider can inflict a painful bite which can be fatal, especially
to the young and elderly. An effective anti-venom was developed in 1956.
Only a small amount of venom can cause serious illness, as
the poison attacks the nervous system. Systemic envenomisation usually
results in headache, nausea, vomiting, abdominal pain, pyrexia and
hypertension.
The pain around the bite area can be excruciating or it may go unnoticed.
First aid and medical attention should be sought as soon
as possible, if bitten.
If you have heart condition or other heart problem, you may need hospitalization.
Spider Identification -
the body of an adult black widow is about 1/2 inch long. The female black
widow is normally shiny black, with a red hourglass marking on the underside
of the abdomen. The marking may range in color from yellowish orange
to red and its shape may range from an hourglass to a dot.
Habitat - prefers woodpiles,
rubble piles, under stones, in hollow stumps, sheds and garages. Indoors
it can be found in undisturbed, cluttered areas in basements and crawl
spaces.
Hobo Spiders :
venomous - dangerous?
Venom toxicity - although
the bite of the hobo spider is initially painless, the bite can be serious.
After 24 hours, the bite develops into a blister and after 24-36 hours,
the blister breaks open, leaving an open, oozing ulceration. Typically
when the venom is injected, the victim will experience an immediate redness,
which develops around the bite. The most common reported symptom is severe
headache. Other symptoms can include nausea, weakness, fatigue, temporary
memory loss and vision impairment.
In any case, first aid and medical
attention should be sought, if bitten, as and when any adverse health
effects are observed.
Spider Identification -
they are brown in color and the adults measure roughly 1/3 to 2/3 inch
in body length and 2/3 to 2 inches in leg span. Their abdomens have several
chevron shaped markings. Males are distinctively different from females
in that they have two large palpi (mouth parts) that look like boxing
gloves. Females tend to have a larger and rounder abdomen when compared
to males.
Habitat - they
can be found anywhere in Washington, Oregon, Idaho, Montana, Wyoming,
Utah and Colorado.
They rarely climb vertical surfaces and are uncommon above basements
or ground level.
Funnel Web
Grass Spiders: low risk, non-aggressive
Venom toxicity -
the bite of these spiders is of low risk to humans.
Spider Identification -
are common outdoors and are occasionally found indoors. They are
generally brownish or grayish with light and dark stripes near
the head. They have long spinnerets and are moderate-sized (3/4
inch long). Grass spiders construct a large sheet web with a funnel
they use as a retreat. These webs are commonly built on the ground,
around steps, window wells, foundations, and low shrubs.
Habitat - These
spiders are often called grass spiders because they construct their
webs in tall grass, heavy ground cover and the branches of thick
shrubs. Rarely will a funnel web spider be seen indoors, except
for an occasional wandering male. They are found mostly in the
Pacific Northwest states.
Mouse Spiders ...venomous
- painful bite
Venom toxicity - known to cause severe illness, especially to young
children - similar to Red-Back Spider. Although normally not aggressive,
the male mouse spider will bite if provoked, and should be considered
dangerous to humans. It has large hard fangs which can cause a deep painful
bite. First aid and medical attention (ambulance) should be sought as
soon as possible.
Spider Identification - a
medium to large spider of up to 1 and 1/2 inches in body length. The
male Mouse Spider often has a bright red head and elongated fangs.
Habitat
- Mouse spiders are ground dwellers with burrows of more than 3 feet
deep. The male often wanders about during the day on open ground, especially
after rain, in search of females.
Black House
Spiders ...venomous - nausea
Venom toxicity - the bite of the Black House Spider is poisonous
but not lethal. Certain people bitten experience severe pain around the
bite site, heavy sweating, muscular pains, vomiting, headaches and giddiness.
First aid and medical attention (ambulance) should be sought as soon as
possible.
Spider Identification - adults
are about 1/2 inch in body length and of a dark brown to black velvet
textured appearance.
Habitat - this spider spins a lacy, messy
web and is prefers dry habitats in secluded locations. It is commonly
found in window framing, under eaves, gutters, in brickwork, sheds, toilets
and among rocks and bark. Electric lights attract their prey - moths,
flies, mosquitoes and other insects.
Wolf Spiders ...venomous
- non-aggressive
Venom toxicity - the bite of the Wolf Spider is poisonous but not
lethal. Although non-aggressive, they bite freely if provoked and should
be considered dangerous to humans. The bite may be very painful. First
aid and medical attention should be sought as soon as possible, particularly
as to children or the elderly.
Spider Identification - an
adult is 1/2 inch to more than 1 inch in body length - mottled gray to brown
in color, with a distinct Union Jack impression on its back. The female
carries it's young on its back.
Habitat - this spider is a ground dweller,
with a burrow retreat. It has a roving nocturnal lifestyle to hunt their
prey and can move very rapidly when disturbed. Commonly found around the
home, in garden areas with a silk lined burrow, sometimes with a lid or
covered by leaf litter or grass woven with silk as a little fence around
the rim of the burrow.
Trap-Door Spiders
...low risk - non-aggressive
Venom toxicity - the bite of the Trap-Door Spider is of low risk
(non toxic) to humans. It is a non-aggressive spider - usually timid
but may stand up and present it's fangs if harassed. Rarely bites - but
if so it can be painful.
Spider Identification - an
adult is about 1 and 1/2 inches in body length - brown to dark brown
in color - heavily covered with fine hairs. The male has distinct boxing
glove-shaped palps, that is, the two "sensory feelers" at front of its head.
Habitat - this spider
is a ground dweller, with a burrow retreat lined with silk of up to
10 inches in depth and around 1 inch in width - prefers nesting
in drier exposed locations - often has a wafer-like lid on the burrow entrance.
Trap-Door Spiders are commonly found in the drier open ground areas around
the home.
Orb-Weaving Spiders
...low risk - non-aggressive
Venom toxicity - the bite of Orb-Weaving Spiders is of low risk
(not toxic) to humans. They are a non-aggressive group of spiders. Seldom
bite. Be careful not to walk into their webs at night - the fright of
this spider crawling over one's face can be terrifying and may cause
a heart attack, particularly to the susceptible over 40 year olds.
Spider Identification - an
adult is about 2/3 to more than 1 inch in body length - has
a bulbous abdomen - often colorful - dark to light brown pattern. The common
Golden Orb-Weaver Spider has a purplish bulbous abdomen with fine hairs.
Habitat - often found in
summer in garden areas around the home - they spin a large circular web of
6 feet or more, often between buildings and shrubs, to snare flying
insects, such as, flies and mosquitoes.
St Andrews Cross
Spiders ...low risk - non-aggressive
Venom toxicity - the bite of the St Andrews Cross is of low risk
(non-toxic) to humans. They are a non-aggressive group of spiders.
Spider Identification - adult
1/4" to 1/2" in body length - abdomen striped yellow and brown
- as illustrated. The St Andrews Cross Spider usually sits, upside down,
in the middle of its web forming a cross - as illustrated.
Habitat - this spider is a web-weaver
usually found in summer in garden areas around the home. It is considered
beneficial as it spins a large web to snare flying insects, such as flies
and mosquitoes.
Huntsman Spiders ...low
risk - non-aggressive
Venom toxicity - the bite of Huntsman Spiders is of low risk (non
toxic) to humans. They are a non-aggressive group of spiders. However,
a large individual can give a painful bite. Beware in summer when the
female Huntsman Spider is guarding her egg sacs or young.
Spider Identification - an
adult varies greatly around 1/2" in body length - has long legs
- the diameter of an adult including legs may reach 2" - the first
2 pairs of legs are longer than rear two - it is hairy - buff to beige brown
in color, with dark patches on the body.
Habitat - a hunter that prefers to live under
the flaking bark of trees, under flat rocks and under eaves or within
roof spaces of buildings. The Huntsman Spider often wanders into homes
and is found perched on a wall. It is a shy, timid spider that can move
sideways at lighting-fast speed when disturbed.
Tips for controlling Spiders
Non-chemical control of spiders is usually quite effective in reducing spider populations. Outside lights should not be left on at night. Large numbers of flying insects attracted to lights cause spiders to be numerous around garages and under eaves. Trash, lumber piles, bricks, weeds, and outside structures are good breeding places for spiders and should be cleaned up. Inside the home spider webs should be brushed down. The egg sacs should be destroyed to prevent hundreds of young spiders from emerging. Vacuum cleaner attachments may be used to clean walls, and the collected debris should be destroyed.
Chemical control of spiders is difficult outdoors because web spinning spiders do not tend to contact treated surfaces.
Inside the house, space sprays containing pyrethrins or pyrethroids are effective in killing spiders. Space sprays have little residual activity and should be applied when spiders are noticed. When spraying enclosed areas, care should be taken so spiders agitated by the spray do not drop onto the person doing the spraying. Repeat the treatment in 4 weeks to kill young spiders that hatch from eggs.
Dust formulations can be used in crawl spaces, attics, and utility areas to provide long-term protection. The insecticidal dusts tend to cling to the spider webs for long periods of time. When spiders chew their webs to recycle the silk they consume the toxicant and die.
