Four species of widow spiders occur in Florida: the southern black widow, the northern black widow, the red widow, and the brown widow (Figure 3a–d). All these species are rather large spiders, about 11/2 inches long with the legs extended. To catch prey, widow spiders weave a strong web of irregular strands. The web is often found in rock formations or wood piles. Strands of black widow web were used to form the crosshairs of gun sights during World War II due to the strength and durability of the silk material.
The southern black widow and the northern black widow are a shiny jet-black. The southern black widow has a red hourglass marking on the underside of the abdomen and another red spot at the tip end of the abdomen. The northern black widow has a row of red spots located in the middle of its back and two reddish triangles resembling an hourglass on the underside of the abdomen. The red widow spider has a reddish orange head, thorax, and legs, and a black abdomen. The abdomen may have a dorsal row of red spots with a yellow border. The red widow lacks a complete hourglass under the abdomen but may have one or two red spots. The brown widow spider varies in color from gray to light brown or black. The abdomen has variable markings of black, white, red and yellow. On the underside of the abdomen it has an orange or yellowish-red hourglass marking.
The southern black widow is the most widespread widow spider in Florida. It is usually found outdoors in protected places such as in hollows of stumps, discarded building materials, rodent burrows, storm sewers, and under park benches and tables. Around houses, the southern black widow is found in garages, storage sheds, crawl spaces under buildings, furniture, ventilators, and rainspouts.
The northern black widow is found west of Tallahassee. It is mainly found in forests with irregular, loosely woven webs 3 to 20 feet above the ground.Read More