Scientific name: Latrodectus hesperus
Country: United States
Continent: North America
Diet: Insects: insectivore, also small reptiles, small mammals
Food & feeding: Carnivore
Habitats: Urban, temperate forest & woodland, temperate grassland
Conservation status: Not threatened
Relatives: Red-back spider
Description: The black widow spider gets its name from the popular belief that the females eat the males after mating. In fact, this is a phenomenon which rarely occurs in nature. The males' venom sacs cease to develop at an early age, as they do not feed during adulthood and instead spend their time searching for mates. The females, on the other hand, are one of the most venomous spiders, although their bites are not usually fatal for humans because they inject only a small amount of venom. Females are easily recognised by their shiny black body with a red hourglass marking on the underside of the abdomen. Their bodies are about 8-10 mm long. The males are half the size of the females, with smaller bodies and longer legs. They usually have markings on their backs, as do the immature stages.
Lifestyle: Black widows are found on the underside to ledges, rocks, plants and debris, including dustbins and outside toilets! They use silk to weave tangled-looking webs, usually near the ground or in dark places. The tips of their legs are non-stick, which prevents them from becoming trapped in their own webs.
Black widow spider toxin contains chemicals that harm the nervous systems of their prey. This means that a quick bite will paralyse prey much larger than the spider, allowing the spider to continue its meal without risk of a further struggle. The spider also injects other chemicals (called enzymes) into its prey that turn the flesh into a soup that the spider can suck up through its tubular mouthparts.
Family & friends: Black widows are solitary. They will readily eat other spiders entering their webs - other black widows included!
Keeping in touch: Generally black widows do not keep in touch. Males must contact a female to mate - and he must approach carefully to avoid being eaten. He vibrates her web in a certain manner that she recognises, allowing him to approach her without risk.
Growing up: After mating in the spring, the female goes on to lay several egg sacs during the summer months, each containing up to 100-300 eggs. The egg case is about 1.5 mm in diameter and suspended in the web. It is white to tan in colour and has a paper-like texture. Eggs take three weeks to mature at which point up to 100 young may hatch. These are then incubated for 14 to 30 days, after which only one to 12 will survive, due to cannibalism. The females mature in about 90 days and live about three years. By contrast males live only a month or two.
Conservation news: While not at risk of extinction, most people try to kill these spiders on sight due to their dangerous reputation. However, this is often an over reaction as the females will only bite if accidentally handled. For the most part they are shy, retiring little creatures, useful for eating other insect pests. The red widow spider (L. bishopi), a close relative to the black widow, is very rare.