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Differences in pollinator effectiveness modulate the evolution of specialized pollination systems and reliance on specific pollinators for plant reproduction. Some Neotropical plant families rely predominantly on hummingbirds for pollination, including Bromeliaceae. However, apparently hummingbird-specialized bromeliads are known to be visited by other floral visitor groups, which may contribute to their reproduction. Here, we investigated the importance of hummingbird pollination in two bromeliads from the open restinga vegetation in the Atlantic rainforest, with contrasting levels of morphological specialization and differences in breeding systems: the more generalist, self-incompatible Aechmea nudicaulis and more specialized, self-compatible Vriesea neoglutinosa. Experimental exclusion of hummingbirds showed that fruit set is considerably reduced in both species when only insects are allowed to visit the flowers. Single visitation experiments revealed that in A. nudicaulis hummingbirds are more efficient than ants in facilitating pollination per visit, but in V. neoglutinosa, hummingbirds are as efficient as bees and ants. One hummingbird species, Amazilia fimbriata, has a pivotal role in the maintenance of ecosystem functionality by pollinating these dominant plants in the system. However, the relative efficacy of hummingbirds seems to be more related to the breeding system of the plants than the morphological specialization of flowers. [ABSTRACT FROM AUTHOR]