Of more than 30,000 species of spiders worldwide, only a small percentage are normally encountered by people. Belonging to the phylum Arthropoda and class Arachnida and exhibiting a vast array of colors, shapes, and sizes, spiders use their coloration for defense, attraction, identification and warning. Beneficial in controlling insect populations, most spiders are relatively harmless and rarely have human contact. Spiders can be found in and around homes, which provide them an abundant insect food source.