Agriculture
Growing Healthier Tomato Plants
Getting the dirt on carbon
Treating peanut allergy bit by bit
Amphibians
Toads
Tree Frogs
Salamanders and Newts
Animals
Pothole Repair, Insect-style
Big Squid
The Secret Lives of Grizzlies
Behavior
Babies Prove Sound Learners
Why Cats Nap and Whales Snooze
Baby Number Whizzes
Birds
Backyard Birds
Swifts
Waterfowl
Chemistry and Materials
Spinning Clay into Cotton
Bang, Sparkle, Burst, and Boom
Picture the Smell
Computers
Toxic Dirt + Avian Flu = Science Fair Success
A New Look at Saturn's rings
Play for Science
Dinosaurs and Fossils
Downsized Dinosaurs
Have shell, will travel
A Rainforest Trapped in Amber
E Learning Jamaica
2014 GSAT Results for Jamaican Kids
E Learning in Jamaica WIN PRIZES and try our Fun Animated Games
Results of GSAT are in schools this week
Earth
A Dire Shortage of Water
Earth's Poles in Peril
Earth Rocks On
Environment
Eating Up Foul Sewage Smells
Plant Gas
Saving Wetlands
Finding the Past
If Only Bones Could Speak
Chicken of the Sea
Stone Age Sole Survivors
Fish
Flashlight Fishes
White Tip Sharks
Eels
Food and Nutrition
A Pepper Part that Burns Fat
Chew for Health
Chocolate Rules
GSAT English Rules
Who vs. Whom
Order of Adjectives
Problems with Prepositions
GSAT Exam Preparation Jamaica
GSAT Exam Preparation
Mastering The GSAT Exam
Preparing for the GSAT Exam
GSAT Exams Jamaica Scholarships
GSAT stars reap scholarship glory
Results of GSAT are in schools this week
Access denied - Disabled boy aces GSAT
GSAT Mathematics
Detecting True Art
E Learning in Jamaica WIN PRIZES and try our Fun Animated Games
It's a Math World for Animals
Human Body
From Stem Cell to Any Cell
Hear, Hear
Prime Time for Broken Bones
Invertebrates
Horseshoe Crabs
Hermit Crabs
Sponges
Mammals
Cows
Donkeys
Weasels and Kin
Parents
Children and Media
Expert report highlights the importance to parents of reading to children!
What Not to Say to Emerging Readers
Physics
Echoes of a Stretched Egg
Extra Strings for New Sounds
Spin, Splat, and Scramble
Plants
Fastest Plant on Earth
Hungry bug seeks hot meal
Flower family knows its roots
Reptiles
Box Turtles
Pythons
Tortoises
Space and Astronomy
World of Three Suns
Melting Snow on Mars
Galaxies Divide Sharply Along Color Lines
Technology and Engineering
Young Scientists Take Flight
Beyond Bar Codes
Space Umbrellas to Shield Earth
The Parts of Speech
Countable and Uncountable Nouns
Adjectives and Adverbs
What is a Noun
Transportation
Reach for the Sky
Where rivers run uphill
Morphing a Wing to Save Fuel
Weather
Weekend Weather Really Is Different
Science loses out when ice caps melt
A Change in Climate
Add your Article

Black Widow spiders

The black widow spider is a spider notorious for its neurotoxic venom. It is a large widow spider found throughout the world and commonly associated with urban habitats or agricultural areas. In South Africa, the black widow is also known as the button spider. Adult female black widow spiders are shiny black with an hourglass shaped marking on the bottom of its abdomen which, although most commonly red, may range in color from white to yellow to various shades of orange and red. They also bear a small, usually red (colors vary) dot near the spinerettes, which is separate from the hourglass. In some varieties, the two halves of the hourglass shape may be separated into two separate dots. A large female black widow spider can grow to 1.5 inches (38 mm), counting legspan. The body is about 0.5 inches (13 mm). Male black widow spiders are half the size of the female or smaller. They have longer legs and a smaller abdomen in relation to their body size. They are also usually dark brown with varying colors of stripes/dots, with no hourglass mark. Juvenile black widow spiders start white, molting to dark brown to black exoskeletons with white, yellow, orange and red stripes and/or dots on their backs. As with many poisonous creatures, the brightly coloured markings serve as a warning to predators. Eating a black widow will normally not kill a small predator (birds, et cetera), but the sickness that follows digestion is enough for the creature to remember that the bright red means not to eat. Prey: Black widow spiders typically prey on a variety of insects, but occasionally they do feed upon woodlice, diplopods, chilopods and other arachnids). When the prey is entangled by the web, L. mactans quickly comes out of its retreat, wraps the prey securely in its strong web, then punctures and poisons its prey . The venom takes about ten minutes to take effect, meanwhile the prey is held tightly by the spider . When movements of the prey cease, digestive enzymes are released into the wound . The black widow spider then carries its prey back to its retreat before feeding. Enemies: There are various parasites and predators of widow spiders in North America, though apparently none of these have ever been evaluated in terms of augmentation programs for improved biocontrol. Parasites of the egg sacs include the flightless scelionid wasp Baeus latrodecti, and members of the chloropid fly genus Pseudogaurax. Predators of the adult spiders include a few wasps, most notably the blue mud dauber Chalybion californicum, and the spider wasp Tastiotenia festiva. Other species will occasionally and opportunistically take widows as prey, but the preceding all exhibit some significant specific preference for Latrodectus. Venom: Although their venom is extremely potent, these spiders are not especially large. The actual amount of venom injected by a bite is very small in physical volume. When this small amount of venom is diffused throughout the body of a healthy, mature human, it usually does not amount to a fatal dose. Deaths in healthy adults from black widow bites are relatively rare in terms of the number of bites per thousand people. Human Deaths: Only sixty-three deaths were reported in the United States between 1950 and 1989. On the other hand, the geographical range of the widow spiders is very great. As a result, far more people are exposed, world-wide, to widow bites than are exposed to bites of more dangerous spiders, so the highest number of deaths world-wide are caused by members of their genus. Widow spiders have more potent venom than most spiders, and 5% of reported bites result in fatalities. Venom action: Black widow venom spreads rapidly throughout the body and acts by causing the release of the neurotransmitter acetylcholine, which is involved in muscular contraction. Once in the blood, the toxin is moved by the circulation and deposited in the nerve ends where they insert into the muscle. Most strongly affected are back, abdomen, and thigh muscle areas. The venom acts at the nerve ends to prevent relaxation of the muscle, causing tetany - or constant, strong, painful contractions of the muscles. Standard treatments usually involve symptomatic therapy with pain medication, muscle relaxants, and, rarely, antivenin. The venom does not typically cause problems at the bite site itself, unless a secondary skin infection occurs. Currently, there are three recognized species of black widow found in North America: The southern black widow (L. mactans), the northern black widow (L. variolus), and the western black widow (L. hesperus). As the name indicates, the southern widow is primarily found (and is indigenous to) the southeastern United States, ranging from Florida to New York, and west to Texas and Oklahoma. Specimens have been found further west as well. The northern widow is found primarily in the northeastern US and southeastern Canada, though its ranges overlap that of L. mactans quite a bit. The western widow is found in the western half of the United States, as well as in southwestern Canada and much of Mexico.

Black Widow spiders
Black Widow spiders








Designed and Powered by HBJamaica.com™