The term, creosote bush, actually refers to widespread species of the genus, Larrea. In the warm deserts of North America, creosote bush is dominant over large areas. The branched shrubs may range in height from 2 to 10 feet. Its stems are black and its leaves are resinous and green. Creosote bush growth is typically limited by water and nitrogen availability. Various adaptations have enabled the Larrea species to survive the drastic climatic changes that have occurred since the last ice age. For one, the shrubs are extremely drought tolerant. Second, the species also possess chemical defenses designed to reduce herbivory. Creosote bush resins are largely composed of the lignan, nordihydroguaiaretic acid. This compound appears to function as a feeding deterrent for phytophagous insects. The…