FemaleOrthogalumna terebrantisWallwork oviposited only on their natural host plant, waterhyacinth—Eichhornia crassipes (Mart.) Solms, in group tests with 22 species of plants. The nymphs fed on waterhyacinth and only slightly on 3 other test plants. In the field,O. terebrantiswas common and often abundant on waterhyacinth, occasionally was found onEichhornia azurea(Swartz) Kunth, and rarely onPontederia lanceolataNutt. In laboratory tests, adults survived longer on waterhyacinth when the leaves bore feeding spots of weevils of the genusNeochetinaor had patches of epidermis removed manually, or on algae than on waterhyacinth leaves with unbroken epidermis; adults did not penetrate the unbroken epidermis of waterhyacinth to feed.