Western Exterminators - Pest Control Services California, Arizona, Nevada

Spiders: Black Widow Spider | Brown Recluse Spider | House Spider (American house Spider)

	Common name:	Latin name:	Class:	Order:	Family:
	Black Widow Spider	Lactrodectus spp.	Arachnida	Araneae	Theridiidae

	Size:
	Female is about 1/2 inch (12-13 mm) long, including the abdomen which is 1/4-3/8 inch (7.2-9.6 mm) in diameter; length including legs is 1 1/2 to 1 3/8 inches (38-43 mm); male is half that size.
	Characteristics:
	Abdomen is almost spherical. Common name comes from the belief that the female eats the male after mating, which rarely happens in nature.
	Color:
	Females are usually black, sometimes brownish, with two reddish triangular markings on the underside that are often joined to look like an hourglass shape or are sometimes only a single triangular mark. Usually have red markings above the spinnerets. Males usually have a color pattern on upper surface; a row of red spots with white lines or bars going out to the sides. Eyes: 8 with 2 side pairs almost touching. Last tarsal segment of 4th pair of legs has toothed bristles; claws on all lower leg segments. Young spiders are orange and white, becoming blacker with age, with markings like males on upper side; also 1 or 2 reddish markings on underneath side.
	Where Found:
	Around the world; 5 species in the United States. Lactrodectus hesperus, the western widow spider, is found in the western U.S. and western Canada.
	Comparison:
	Widow Spiders are all quite similar to each other, but are distinct from other spiders.
	Habitat:
	Live in protected places such as woodpiles, under stones and decks, in hollow trees or stumps, rodent burrows, low branches, as well as in dry places in barns, sheds, meter boxes, and barrels.
	Food:
	Insects caught by hanging upside-down from irregular webs about one foot in diameter. The female avoids light and tends to seek prey at night.
	Biology:
	Most over-winter as immature spiderlings, becoming adults in spring, dying in late July. In some species females may live for two or more years after maturity; some males up to six months. Development from egg to adult takes nearly a year. Incubation period: 8-30 days. Females lay eggs in closely woven silk sacs 3/8-1/2 inches in diameter that turn from white to pale brown. Spiderlings have first molt within egg sac. Second instar (stage) spiderlings spin silk threads and "balloon" out on a breeze. There are 4-9 instars in 54-107 days, each instar with a different color and/or pattern.
	Damage:
	Only the female's bite is poisonous. Males do not develop venom sacs into maturity, and do not attack prey as an adult. Spiderlings are poisonous only if eaten during first 18 days, but lose their poison after that. Adult venom is different, a neurotoxin. Female is not aggressive except after egg laying and when guarding her eggs
	Invasion:
	Enter seldom-used, cluttered parts of garages, basements, crawl spaces.
	Control:
	Spider control is a six-step process. In general, control strategy should include: 1) Inspection- Determines conditions that might need correction in order to achieve desired level of control. 2) Identification- Determines target pest and possibly treatment strategy due to species habits. 3) Prevention- Building conditions allowing entry. Lighting that may attract their prey. 4) Sanitation- Debris outside such as wood-piles, high weeds, rocks and overgrown shrubs give shelter. Indoors eliminate clutter and vacuum areas out of normal access regularly. 5) Mechanical Measures- mechanical removal of webs greatly enhances a control program. Since spiders reuse their silk, a light dusting of remaining webs with a non-repellant insecticide dust will aid in control 6) Pesticide Application- Application of pest control materials will reduce the active population and give overall control when performed along with the above listed recommendations. When using any pesticide, be sure it is registered for the target pest/location. Read the entire label prior to use. Follow all label directions, restrictions, and precautions. For large infestations or multiple sightings, we recommend using the services of a professional exterminator.