Black Widow Spiders :: Biology Biological Spiders Research Spider Essays

Adult black widow spiders have a shiny, black, rounded, circular abdomen and are about 1/3 inch long (about 1-1/2 inches when their legs are spread). Adult spiders have two reddish or yellowish triangles on their bottom which looks like an hourglass marking, and their body color is dark colored usually black or sometimes dark brown. They are usually recognized because of their red or red-orange hourglass design on the bottom of their abdomen. This pattern is changeable and may look like two separated spots. In some spiders there is no pattern on the abdomen. The immature stages of both sexes of the widow spiders have red or red-orange or yellow spots and strips on the top of their abdomen. Females are colored gray or pale brown. Their color gets darker as they get older. The hourglass pattern on the underside of the abdomen forms throughout their development. Male widow spiders are smaller about 1/4 inch long, and they're usually not black in overall color, instead it looks like a light brown or gray. Male widows have an hourglass pattern too. When they are full-grown they have large knob-like shapes called pedipalps, which start from the head. But to females they still look the same. Newly hatched spiderlings are white or a yellowish-white, eventually turning blackish when they get older. Adolescents of both sexes look like the male. Black Widow spiders build loose and uneven mesh-type webs of rough silk in dark places usually outdoors. And build their webs near the ground (sometimes inside of houses) but mainly they build them outside. Black Widows can be found near the ground in dark undisturbed areas. Nest sites are near holes made by small animals, or around construction openings and woodpiles. Also they can be found around low shrubs which are usual sites for widow spiders. Black widows are also found inside in dark undisturbed areas like behind furniture or under desks and in undisturbed basement areas and crawl spaces of homes are areas where black widow nests are. They don't produce a web like the weaving spiders do or the funnel pattern webs that the funnel weaver spider's make. The female lays eggs in silken cocoon sacs about 1/2-inch in width. The sack is a pear shaped, and is a creamy yellow, light gray, or light brown in color. They usually lay about 300 to 400 eggs per sac and have 4 to 9 egg