The many species of genus Latrodectus are known as the widow spiders and are best known in theUnited Statesas the black widows. In this country, the common species have very large, rounded abdomens that bear a pattern of two red triangles (point to point) on the underside and commonly a line of small red spots down the top center.
These are smooth spiders with only a few obvious bristles on the legs. Males are about half the length of females, with large females approaching half an inch (about1.1 cm) in body length; males also are brightly colored with curved red lines on the sides and top of the abdomen. Exotic species of widow spiders are similar in shape but may have white patterns on the abdomen or be largely shades of brown.
Widow spiders are notorious for their toxic bite that is dangerous to humans, at least in theory. Species vary greatly in their toxicity, but the commonU.S.species have indeed killed children in the past, though not in recent decades because an antivenin is now available. Their venom is one of the most deadly known, but fortunately it is injected in extremely small quantities, so it seldom produces more than minor symptoms (pain, sweating, difficulty in breathing due to tightness of the chest muscles and diaphragm) that pass in a few days under medical observation. Many bites produce no symptoms and are assumed to be “dry” (venomless) bites. If you are bitten by a widow spider, seek medical attention but don’t panic— adults seldom have become even seriously ill as a consequence. Children, with their low body weight, may be in more immediate danger and may need antivenin.
These spiders typically build open, very irregular webs and prey snares near the ground in a dark spots, such as under bark slabs or in the corners of outbuildings. There they feed on tiny insects. Males sometimes live in the corners of the females’ webs and they may share food, though occasionally the males are eaten after mating. Most males survive mating, however, so the term widow spider is misleading.
Keep these spiders (though dangerous, they can be collected or purchased in some areas) in small, dark containers that are relatively dry (50 percent humidity) and allow females to build webs. Fruit flies and pinhead crickets are good foods. The terraria of these spiders should be placed inside a larger cage that can be securely sealed and locked to prevent escapes and unauthorized entries.