Conteúdo alimentar em macrófitas aquáticas carnívoras: Utricularia foliosa L. e U. hydrocarpa Vahl. (Tubiflorae, Lentibulariaceae)

Qualitative and quantitative aspects of the feeding contents of Utricularia foliosa and U. hydrocarpa (Tubiflorae, Lentibulariaceae) were studied in order to assess the impact of these macrophytes in the control of the aquatic organisms populations. The macrophytes were collected in Lagoa Amarela and Lagoa da Barra around Parque Estadual do Rio Doce in the state of Minas Gerais. The feeding contents of the utricle were compared to the perifiton (microalgae) and zooplankton associated to the macrophytes stems and the phytoplankton free in the water column. The obtained results indicated that the two species of Utricularia used exclusively the periphyton and did not use the food particles available in the water column. The high densities of the periphyton inside the utricle ( U. foliosa = 362 to 1062 org/mm 2 and U. hydrocarpa = 79 to 968 org/mm 2 ) suggest that the plants can play a potential control on the population of sessile organisms but probably have little influence on the plankton limnetics populations.