Some of the most beautiful spiders make up the family Araneidae, the orb weavers; they’re noted for building large webs in trees and shrubs and on houses, each web consisting of several circles of silk and an elaborate system of sticky silk threads in the center. Though sometimes sold, they also are easily collected in the later summer, and they commonly live until the first frosts of autumn.
Many species are half an inch (1.2 cm) long or more, with very long legs and impressive color patterns on the oval or even sculptured abdomen. Often found in most parts of the United States are thornbacks (genera Gasteracantha and Micrathena), which have large, hard, thornlike spines on the abdomen; orchard spiders, (Leucauge spp.), which have a delicate silvery pattern; many species of garden spiders (Argiope spp.) with their relatively elongated abdomens bearing bright colors; and the confusing species of shamrock spiders (Araneus spp.), which have long bristles on the legs and rounded abdomens that often feature a pattern of yellow spots.
Sometimes seen on dealer lists are true silk spiders of genus Nephila spp., which includes several species from around the world in warm climates. Most are about an inch (2.5 cm) long, with long legs that bear cuffs of dense bristles around at least one set of joints on most legs. The abdomen is elongated and rather boxlike with distinctly flat sides, and usually has a pattern that includes several pairs of bright yellow spots against a tan to greenish background. One silk spider, Nephila clavipes, is common from the southeasternUnited Statesinto the American tropics. It builds gigantic, finely woven webs between trees in moist lowland forests; the webs usually appear incomplete, as if missing a section, and the sticky threads in the center are yellow.
Many silk spiders and other orb weavers can be kept in a special thin terrarium between two panes of glass a foot (30 cm) or more square that are held apart by strips of wood about 2 inches (5 cm) wide. The whole terrarium is sealed around except for a screened hole at the top for adding food and water.
These spiders also can be accommodated in gallon (3.8 L) jars and even in ordinary aquaria, where they will spin webs to fit the container. They seldom come to the ground and should be lightiy misted daily (excessive water may break the webs), and fed on fruit flies and similar insects. Some orb weavers tear down their webs each evening and build new ones each night. These are considered intelligent spiders with many interesting behavior patterns.