Scent emissions and floral nutrients of Carludovicoideae (Cyclanthaceae) and their importance for associated beetles

To better understand the complex pollination biology of Carludovicoideae (Cyclanthaceae), four species from French Guiana were investigated in both the field and laboratory. The pistillate flowers of all species of the subfamily have long staminodes up to 10 cm long or more, which emit scent and apparently attract beetles during anthesis. Scent was collected by standard headspace methods and analyzed in the laboratory by GC/MS. The histology of staminodes, measurements of inflorescence temperatures, and analyses of the floral nutrients were performed. The staminodes have two ducts with a mucilage-like liquid containing sugar, which provides nourishment for beetle visitors. In Evodianthus funifer, four of the six beetle morphospecies (Curculionidae: Acalyptini) were pollinators and oviposited in staminate flowers. The remaining pair of morphospecies were non-pollinators, and avoided entering the inflorescence, while only cutting the staminodes for possible oviposition on the ground. Staminate flowers and staminodes have a high energy content, providing for larval development of the beetles. Our findings revealed that the staminodes released aromatic components, miscellaneous cyclic components, and terpenoids. Some of the major scent compounds of E. funifer and Ludovia lancifolia, i.e., (E,E)-alpha-farnesene-2(3),9(10)-diepoxid and 3-methylen-2-(pent-2(Z)-enyl)-cyclopentanol, are new to science. Also, Carludovicoideae are a subfamily of plants that attract beetle pollinators through highly specific scent compounds, making them comparable to species of Araceae, Magnoliaceae, and Annonaceae.