Numerous studies have examined foraging strategies of pollinators in continental landscapes, but relatively little is known about island pollinators. We investigated four native plant communities and their potential pollinators on Mauna Loa Volcano on Hawai'i Island across two environmental gradients: elevation (middle and high) and succession (early and late). The effects of elevation and successional stage on visitation rates and degree of plant specialization were compared. Elevation had a significant effect on visitation rates with plants at mid elevation receiving the most visits, whereas succession had little effect on visitation rates. Both succession and elevation impacted plant specialization, with plants at late-succession and high-elevation sites being more specialized in terms of their diversity of flower visitors. Metrosideros polymorpha (Myrtaceae) received the most forager visits, even when it was not the most abundant plant flowering. Endemic Hylaeus bees (Hymenoptera: Colletidae) were the dominant visitors across all sites (64%–91% of visits), and endemic birds were observed only at mid elevation, primarily in the late-succession site. Considering the paucity of natural history studies on Hawaiian Hylaeus, further investigation of their potential role as pollinators of native Hawaiian plants is necessary.