Spider Black Widow Spider

Color: Shiny black with red hourglass on underside of abdomen.

Size: Body may be up to 3/4-inch in length with the abdomen reaching 3/8-inch in diameter.

The webs are frequently constructed underneath boards, stones, or the seats of outdoor privies. They also found along foundation slabs, behind shrubs, and especially where brick or wood siding extends close to ground level. This spider does not usually enter residence, though it may do so occasionally.

Sedentary, solitary, cannibalistic, and nocturnal. The only social life it exhibits is when it mates. During the daylight hours, this spider spends its time in the silken tunnel of its web, which is the core of the snare. The female black widow spider hangs upside down in her web; her red hourglass marking is a visible warning signal. This spider will drop out of its web at the slightest disturbance and pretend that it is dead. The female black widow is usually clumsy when she is not in intimate contact with the lines of her snare. Latrodectus mactans is a tangled web weaver. Its irregular, funnel-shaped web of coarse silk has a definite plan. Three structural levels can be recognized: an uppermost complex of supporting threads, a central zone of tangle threads, and a lower zone of vertical trap threads. Also, the black widow spider is greatly active in the autumn months and its web is spread over everything. In addition, most of these spiders live only a year, but the yearly population is divided into two faunas, one identified with spring and the second with fall.

Ordinarily it feeds on insects; however, it also consumes wood lice, diplopods, chilopods and other arachnids.

Black widow spider venom contains toxins that are neurotoxin (toxic to the nervous system). The severity of a person’s reaction to the bite depends on the area of the body where the bite occurs; the person’s size and general sensitivity; the amount of venom injected; the depth of bite; the seasonal changes in venom potency; and the temperature. The bite produces a sharp pain similar to a needle puncture, which usually disappear rapidly. After a variety of other symptoms, convulsions and death may result with some victims, especially if the person is sensitive to the venom and no treatment is received. An antivenom specific for the black widow is readily available to most physicians.

• Remove piles of bricks, firewood, and other debris that may serve as suitable homes for spiders or move them further from your home.
• Be cautious when picking up or moving objects, particularly in outbuildings such as shed or garages, or in shady undisturbed areas such as under parked cars or in flower pots.
• Although they are not commonly found indoors it is always a good idea to shake out and check clothing before putting it on (for brown spiders and scorpions as well).
• Manage household, yard and garden insect pests (roaches, crickets etc.). Lack of food will discourage spiders and force them to move elsewhere.
• Keep outdoor lighting off as much as possible to prevent luring insects which the spiders feed upon.
• Remove collections of paper, boxes, rubbish piles in the house, attic, storage areas, etc
• Trim weeds around the building foundation and remove debris to discourage insects and spiders from living next to a structure.
• Seal openings and install screens and door sweeps to prevent spiders (as well as other unwanted pests) from moving indoors.
• Use a vacuum cleaner to remove webs, spiders and their egg sacs. Spider elimination includes prevention of entry, reduction of spider food and any condition that might encourage spider invasion or reproduction.