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.