Knowledge about the floral ecology of native plants is fundamental for effective conservation efforts, as many of these species are at risk from habitat destruction and fragmentation. In south Florida, the imperiled pine rockland habitat holds numerous native plants that depend on animals for their reproduction. Many of these plants have not been studied and their floral ecology remains unknown, particularly night-blooming species, whose study is especially challenging. Guettarda scabra (Rubiaceae), a native night-blooming species in south Florida's pine rocklands, relies on insects for pollination. Three primary questions guide this study: (1) Which arthropods visit G. scabra flowers during the day and night? (2) Which are the plant's effective pollinators? (3) What is the chemical profile of G. scabra's floral scent, and what role do its components have in attracting pollinators? Through field observations and controlled experiments, I provide a detailed account of the arthropods visiting flowers of G. scabra, along with a thorough evaluation of their role as potential pollinators in this species. I also characterize the chemical profile of the flower scent and explain how the compounds present are likely fine-tuned to the attraction of the most effective pollinator found. My findings show G. scabra is visited by a wide range of arthropods, mostly Lepidoptera and Hymenoptera whose populations rely on floral rewards from this species during late summer, when flowering season has passed for most of the other local plants. My experiments revealed that G. scabra has a specialized pollination system where nocturnal hawkmoths are the only effective pollinators, while diurnal visitors behave as nectar and pollen thieves. Finally, I found that the chemical profile of the floral scent in G. scabra fits that of night-blooming plants pollinated by nocturnal hawkmoths. My work highlights the critical role that G. scabra plays as a nectar resource in the dwindling pine rockland habitat, provides baseline data on the local diversity and natural history of insect flower visitors, and establishes a baseline knowledge of the chemical ecology of this species. My findings yield needed information to support efforts to conserve pine rocklands and the plants and animals that inhabit them.
