Nephila clavipes
Encyclopedia
Nephila clavipes is a species of golden orb-web spider. It lives in the warmer regions of the Americas
. The large size and bright colours of the species make it distinctive. The female is much larger than the male.
In the United States
, it ranges throughout the coastal southeast and inland, from North Carolina
to Texas
. Its distribution in many regions seems localized, and it may be completely absent (or just hard to find) over wide areas. Conversely, in some arboreal or swampy nooks, adults and their webs can be found in large concentrations, especially near the coast. Golden orb-weavers are especially numerous in the time after summer and before fall in the south-eastern and southern U.S. This species is widespread — and often common — in large parts of Central America
and warmer regions of South America
.
The web
of a mature female can reach one meter in width, the yellow threads appearing as a rich gold in sunlight. Males come into the female's web for copulating
. After mating the female spins an egg sac on a tree, laying hundreds of eggs in one sac. While it is venomous
to humans, it will only bite if pinched, and if doing so, the bite is usually relatively harmless and only leads to slight redness and localized pain.
The silk of N. clavipes has recently been used to help in mammal
ian neuron
al regeneration. In vitro
experiments showed that a single thread of silk can lead a severed neuron through the body to the site it was severed from. With a tensile strength
of 4×109 N/m2, it exceeds that of steel
by a factor of six. It is not recognized by the immune system
.
Americas
The Americas, or America , are lands in the Western hemisphere, also known as the New World. In English, the plural form the Americas is often used to refer to the landmasses of North America and South America with their associated islands and regions, while the singular form America is primarily...
. The large size and bright colours of the species make it distinctive. The female is much larger than the male.
In the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
, it ranges throughout the coastal southeast and inland, from North Carolina
North Carolina
North Carolina is a state located in the southeastern United States. The state borders South Carolina and Georgia to the south, Tennessee to the west and Virginia to the north. North Carolina contains 100 counties. Its capital is Raleigh, and its largest city is Charlotte...
to Texas
Texas
Texas is the second largest U.S. state by both area and population, and the largest state by area in the contiguous United States.The name, based on the Caddo word "Tejas" meaning "friends" or "allies", was applied by the Spanish to the Caddo themselves and to the region of their settlement in...
. Its distribution in many regions seems localized, and it may be completely absent (or just hard to find) over wide areas. Conversely, in some arboreal or swampy nooks, adults and their webs can be found in large concentrations, especially near the coast. Golden orb-weavers are especially numerous in the time after summer and before fall in the south-eastern and southern U.S. This species is widespread — and often common — in large parts of Central America
Central America
Central America is the central geographic region of the Americas. It is the southernmost, isthmian portion of the North American continent, which connects with South America on the southeast. When considered part of the unified continental model, it is considered a subcontinent...
and warmer regions of South America
South America
South America is a continent situated in the Western Hemisphere, mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere. The continent is also considered a subcontinent of the Americas. It is bordered on the west by the Pacific Ocean and on the north and east...
.
The web
Spider web
A spider web, spiderweb, spider's web or cobweb is a device built by a spider out of proteinaceous spider silk extruded from its spinnerets....
of a mature female can reach one meter in width, the yellow threads appearing as a rich gold in sunlight. Males come into the female's web for copulating
Mating
In biology, mating is the pairing of opposite-sex or hermaphroditic organisms for copulation. In social animals, it also includes the raising of their offspring. Copulation is the union of the sex organs of two sexually reproducing animals for insemination and subsequent internal fertilization...
. After mating the female spins an egg sac on a tree, laying hundreds of eggs in one sac. While it is venomous
Spider bite
A spider bite is an injury resulting from the bites of spiders or other closely related arachnids.Spiders are active hunters and rely heavily on their bites to paralyze and kill their prey before consuming it. They also bite in self defense...
to humans, it will only bite if pinched, and if doing so, the bite is usually relatively harmless and only leads to slight redness and localized pain.
The silk of N. clavipes has recently been used to help in mammal
Mammal
Mammals are members of a class of air-breathing vertebrate animals characterised by the possession of endothermy, hair, three middle ear bones, and mammary glands functional in mothers with young...
ian neuron
Neuron
A neuron is an electrically excitable cell that processes and transmits information by electrical and chemical signaling. Chemical signaling occurs via synapses, specialized connections with other cells. Neurons connect to each other to form networks. Neurons are the core components of the nervous...
al regeneration. In vitro
In vitro
In vitro refers to studies in experimental biology that are conducted using components of an organism that have been isolated from their usual biological context in order to permit a more detailed or more convenient analysis than can be done with whole organisms. Colloquially, these experiments...
experiments showed that a single thread of silk can lead a severed neuron through the body to the site it was severed from. With a tensile strength
Tensile strength
Ultimate tensile strength , often shortened to tensile strength or ultimate strength, is the maximum stress that a material can withstand while being stretched or pulled before necking, which is when the specimen's cross-section starts to significantly contract...
of 4×109 N/m2, it exceeds that of steel
Steel
Steel is an alloy that consists mostly of iron and has a carbon content between 0.2% and 2.1% by weight, depending on the grade. Carbon is the most common alloying material for iron, but various other alloying elements are used, such as manganese, chromium, vanadium, and tungsten...
by a factor of six. It is not recognized by the immune system
Immune system
An immune system is a system of biological structures and processes within an organism that protects against disease by identifying and killing pathogens and tumor cells. It detects a wide variety of agents, from viruses to parasitic worms, and needs to distinguish them from the organism's own...
.
External links
- Mating pair
- Pictures of N. clavipes (free for noncommercial use)
- Gravity favours smaller males : Review of scientific article on why males are much smaller than females