The brown planthopper, Nilaparvata lugens is a pest of rice, feeding on phloem and transmitting plant viruses. Phloem is rich in sugars but poor in amino acids and proteins. The amino acids in the plant sap are not balanced in the proportions needed by the planthopper. The plant hopper consumes excess of some amino acids. The nitrogen from those amino acids is processed into uric acid. Unlike other insects that eliminate the uric acid as waste, the plant hopper stores uric acid.
Nilaparvata lugens hosts symbionts that can metabolize uric acid. In periods of starvation, the symbionts can metabolize the uric acid to release ammonia used in the synthesis of amino acids.
M.J. O’Donnell and Andrew Donini. Nitrogen Excretion and Metabolism in Insects. In: Acid-Base Balance and Nitrogen Excretion in Invertebrates pp 109-126.