Latrodectus

Kingdom: Animalia

Phylum: Arthropoda

Class: Arachnida

Order: Araneae

Family: Theridiidae

Genus: Latrodectus

Latordectus or Widow Spiders is a genus of spiders containing 31 different species. They get their name from the mating rituals commonly found in this genus of the female spiders eating the male after mating although this is not found in most species in this genus.

The venom found in the most famous species the black widow spider is called latrotoxin which is a neurotoxin resulting in latrodectism. Latrodectism is caused as the venom moves through the body causing the release of neurotransmitters. The symptoms start with severe pain in the bitten area then slowly spreads to surrounding muscle tissue, and then once the venom enters the blood it is carried by the circulatory system causing the toxin to spread to the nerve endings this stops the nerve endings from relaxing the muscle tissue causing tetany. The bite is particularly harmful from female black widows do to their large venom glands.

The characteristic hourglass is actually not always present in female spiders sometimes appearing all black. Male black widows are about a quarter the size of the female with a bite that is not considered dangerous to humans.

The silk form the species L. Hesperus is six times less dense then steel and has a tensile strength of 1290 plus or minus 160 MPa making them also stronger then steel. The problem from comes when you consider harvesting the silk, the spiders have to be kept in their own container and it takes a long time to get a lot of it making it difficult to use.