In laboratory experiments, western cherry fruit flies, Rhagoletis indifferens Curran, were exposed to sweet cherries, aphid honeydew, and bird feces to determine fly longevity and fecundity. Longevity was not sustained in females and males exposed to intact unripe cherries or no food, whereas it was in females exposed to intact, fully-ripe cherries, and in females and males exposed to opened unripe or ripe cherries. Females exposed to intact fully-ripe cherries alone usually survived as long as females exposed to sucrose-yeast diets, but fecundity of flies exposed to cherries (79.5–110.8 eggs/female) was lower than that of flies exposed continuously to sucrose-yeast diets (277.5–326.2 eggs/female). Longevity of flies exposed to aphid honeydew was sustained and was similar to that of flies exposed to intact ripe cherries, sucrose-yeast, and sucrose diets. However, exposure to aphid honeydew or bird feces in the absence of ripe cherries did not result in high fecundity (4.6–32.2 eggs/female). Despite the inability of flies to extract nutrients from unripe cherries and the moderate fecundity of flies that were exposed to intact ripe cherries alone, R. indifferens was clearly capable of using its principal host fruit for both sustained longevity and egg production. Results suggest cherries damaged by birds throughout the season and intact fully-ripe cherries later in the season can contribute about the same nutrition as honeydew to female longevity, but that cherries contribute significantly more than either honeydew or bird feces to fecundity in nature.