Bromeliads provide habitat and food resources for various organisms. Besides the nectar and pollen, the leaf and fruit tissues of these plants supply food for various animal groups. Among the groups that feed on bromeliads, herbivores are the ones that cause the most damage to these plants; among such organisms, some are well known, such as butterfly and moth caterpillars. Here we will describe some of the ecological relationships between the butterflies Strymon serapio and moths Castnia invaria in association with the rupicolous habitat-forming bromeliad Encholirium spectabile. In rocky outcrops of the Brazilian Semiarid Caatinga, S. serapio caterpillars were frequently observed in the blooms of E. spectabile and adults in the leaves, as well as adults of C. invaria. However, in C. invaria the larvae develop inside the bromeliads. Adults of both species were associated with E. spectabile throughout the year in the study area. We observed S. serapio eggs and larvae mainly during the beginning of the dry season, and the eggs of C. invaria, occur mainly during the rainy season. Regarding the daily activity period, the two species show diurnal habits. Caterpillars of S. serapio develop mutualistic relations with ants of the genus Crematogaster in the blooms of E. spectabile. This is the first record for this kind of ant-butterfly interactions taking place in Encholirum bromeliads, although they have already been cited for other species of Bromeliaceae. The record of these interactions in E. spectabile suggests that these bromeliads are relevant for local biodiversity, also regarding interactions with species of commercial interest, which use the E. spectabile as a host plant..