What do you write
in your report?
Your report must
contain question, hypothesis, experiments or procedures, results and
conclusion.
Report should be as
brief and informative as possible.
You should not write
step-by-step story of doing your project, instead you should focus on
the key information leading to the result.
The method of
research varies. You may design and conduct experiments or you may just
gather information and compile them to get to a more reliable result.
For example if you
are studying about the life cycle and habitat of black widow spiders,
you may attempt to keep a pair of spiders in a glass cage and make
observations. You may also read the reports of other researchers. Your
report must have information showing how does spider reproduce? What is
the life span of spider and at what age it gets to sexual maturity? If
it lays eggs, how many times a year, at what season and how many eggs
each time are produced?
Following
is an example:
Black
Widow Spiders
Genus: Lactrodectus
Phylum: Arthropoda
Sub Phylum: Chelicerata
Class: Arachnida
Order: Araneae
Sub Order: Labidognatha
Family: Therididae
Species: 6
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Geography – Range
BlackWidow spiders inhabit most warmer
regions of the world to latitude of about 45 degrees N. and S. They
occur throughout all 4 deserts of the American Southwest.
Related Species
Widow spiders (Genus Latrodectus) are the best known and largest of the
Cobweb Weavers (Family Therididae). All widows are venomous. Black
Widows comprise about 6 species and inhabit most warmer regions of the
world to a latitude of about 45 degrees N.
The species L. hesperus is common in the western US and is the
Black Widow found in the North American deserts. L. mactans is
the Black Widow common in the eastern and central US. The Brown Widow
Spider, L. geometricus, is also found in the US.
- L. mactans is found in most warm
areas of the world
- L. geometricus is found in Africa
- L. curacaviensis in the Americas
- L. hystrix, L. dahli, and L.
pallidus are found in southern Europe,
northern Africa, and southwestern Asia
Comparisons
The Brown Widow Spider (Lactrodectus geometricus) is not as dangerous as
some other widow spiders because the Brown Widow Spider is less likely
to bite someone, and injects less poison. Still, it is a venomous
creature, and must be taken care of with respect. It is found throughout
the world's tropical regions, has been introduced into southern Texas
and central and southern Florida.
Hundreds of Australians are bitten every year by the Red-back Spider (Lactrodectus
hasselti) a close relative, the Black Widow Spider. The Red-back is
found in all parts of Australia except in the hottest deserts and on the
coldest mountains.
Description
The female Black Widow is shiny black, usually with a reddish hourglass
shape on the underside of her spherical abdomen. Her body is about 1.5
inches long. Adult males are harmless, about half the female's size,
with smaller bodies, longer legs and usually have yellow and red bands
and spots over the back as do the immature stages.
Newly hatched spiderlings are predominately white or yellowish-white,
gradually acquiring more black and varying amounts of red and white with
each molt. Juveniles of both sexes resemble the male and are harmless.
Curious
Facts
Black Widow is considered the
most venomous spider in North America.
The venom of the black widow spider is 15 times as toxic as the
venom of the prairie rattlesnake.
Black Widow spiders are not usually deadly, especially to
adults, because they inject only a small amount of venom.
Only the female Black Widow is venomous; males and juveniles are
harmless..
The female Black Widow eats the male after mating.
The female Black Widow hangs belly upward and rarely leaves the
web.
The Black Widow is also called the "hourglass" or
"shoe-button" spider.
Araneae is the Latin word for spider.
More than 35,000 spider species of spiders occur in the world.
Of these, about 3,400 species in 64 families are found in North
America.
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Vital Stats
Weight: 1 gram.
Length: 1-1.5"
Span: 1-3"
Sexual Maturity: 70-90 days.
Mating Season: Spring
Incubation: 14-30 days
No. of Eggs: 250-700/sac
Birth Interval: 4 to 9 egg sacs/summer
Lifespan: up to 3 years
Typical diet: insects
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Behavior
Both Western and Eastern Black Widows spin webs that lack shape and
form. Their webs are erratic in appearance, and the silk is stronger
than almost all other arachnids. The black widow spider is shy and
nocturnal in habit, usually staying hidden in her web., hanging belly
upward. Although not aggressive, she may rush out and bite when her web
is disturbed or when accidentally trapped in clothing or shoes.
Habitat
On the underside of ledges, rocks, plants and debris, wherever a web can
be strung. Cold weather and drought may drive these spiders into
buildings.
Food & Hunting
Like most arachnids, the Black Widow preys on insects. Prey caught in
the web include a variety of insects (cockroaches and beetles) and other
arthropods. After ensnaring its prey in the web, the Black Widow makes
small punctures in the victim's body and sucks out the liquid contents.
The Black Widow is preyed upon by Mud-Dauber wasps.
Breeding
Adult male Black Widows wander in search of females but do not feed or
bite. Females may occassionally kill and eat a male after mating but
this is more the exception than the rule.
The female then lays several batches, containing up to 750 eggs each, in
one summer. The egg case, about 1/2 inch in diameter, is suspended in
the web. It is white to tan in color and has a paper-like texture. There
may be 4 to 9 egg sacs produced during a summer. Normally, only 1 to 12
young survive after the egg incubation period of 14 to 30 days due to
cannibalism.
The young Black Widows are colored orange and white when they emerge 1
to 4 weeks later. The female Black Widow may live for more than a year
and a half. Growth requires 2 to 4 months, depending on availability of
prey during which the females molt 6 to 8 times and the males 3 to 6
times. Females mature about 90 days after egg sac emergence and live
another 6 months to a year. days longer. Males mature in about 70 days
after emergence and live only another month or two.
Caution
-Venomous!
The venom of the black widow spider is 15 times as toxic as the venom of
the Prairie Rattlesnake. But only a minute amount of the toxin is
injected with a single bite by the spider, so they are rarely fatal.
However, the relatively large amount of injected rattlesnake venom
results in about 15 to 25 percent mortality among those bitten.
The bite itself is often not painful and may go unnoticed. But the
poison injected by the the Black Widow bite can cause abdominal pain
similar to appendicitis as well as pain to muscles or the soles of the
feet. Other symptoms include alternating salivation and dry-mouth,
paralysis of the diaphragm, profuse sweating and swollen eyelids.
Persons younger than 16 and older than 60, especially those with a heart
condition, may require a hospital stay. (Heart and lung failure may
result in death.) A physician can give specific antivenin or calcium
gluconate to relieve pain. Healthy people recover rapidly in two to five
days.
For others, clean the site well with soap and water. Apply a cool
compress over the bite location and keep the affected limb elevated to
about heart level. Aspirin or Tylenol may be used to relieve minor
symptoms. Treatment in a medical facility may be necessary for children
less than 5 years old or for adults with severe symptoms. Call the
Poison Center for additional information.
Be very careful when working around areas where black widow spiders may
be established. Take proper precautions-wear gloves and pay attention to
where you are working. The reaction to a Black widow bite can be
painful, and the victim should go to the doctor immediately for
treatment.
To control the black widow, carefully remove all materials where they
might hide. They can be cleaned out of an area simply by knocking down
the webs, spiders, and round, tan egg sacs with a stick and crushing
them underfoot. Removal or destruction of the egg sacks may help control
the population. This spider is resistant to many insecticides.
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