The foliar consumption rate of two insect species was evaluated: one chewing species Omaguacua longibursae (Geometridae) and one miner species of the Heliozelidae family. Both were present on the foliage of Nothofagus alpina and N. obliqua, which had different leaf morphologies. The results showed that for both insect species the foliar consumption rate was similar between the two Nothofagus species, suggesting that morphological, and possibly chemical differences, were not important for feeding of the larval stages of these insects.Se evaluó la tasa de consumo foliar de dos especies de insectos, una especie masticadora Omaguacua longibursae (Geometridae) y una especie minadora de la familia Heliozelidae, ambas sobre el follaje de Nothofagus alpina y N. obliqua que tienen diferencias en su morfología foliar. Los resultados indicaron que en ambas especies de insectos la tasa de consumo foliar es similar sobre los dos Nothofagus, sugiriendo que las diferencias morfológicas y posiblemente químicas son irrelevantes en la alimentación de los estadios larvarios de estos insectos.