Preference trials were conducted to test the hypothesis that preference of insect herbivores for leaves of tundra plants is related to life form of the plant. Leaves of 42 plant species belonging to deciduous shrub, semi-deciduous shrub, evergreen shrub, forb, and graminoid life forms were tested. Larvae of four generalist-feeding Lepidoptera larvae consistently selected for deciduous shrubs and against evergreen shrubs and graminoids. Consistent preferences were also found for species within life forms using the Lepidoptera larvae and sawfly larvae selecting from an array of deciduous shrubs. Similar preferences of vertebrate herbivores are reviewed. The results are consistent with the carbon/nutrient balance hypothesis of plant defense. Deciduous shrubs growing on nutrient rich sites have rapid growth, high leaf turn-over, and little investment in defence. Slow growing evergreen shrubs are favored on nutrient poor sites; slow leaf turnover favors investment in defense of leaves.