Dear Friends & Colleagues,
Herewith details of a new paper, just published.
The Wong Lab.
Flowering mechanisms, pollination strategies and floral scent analyses of syntopically coflowering Homalomena spp. (Araceae) on Borneo
Hoe Y. C., M. Gibernau, A. C. D. Maia & Wong S. Y.
Plant Biology DOI: 10.1111/plb.12431
In this study, the flowering mechanisms and pollination strategies of seven species of the highly diverse genus Homalomena (Araceae) were investigated in native populations of West Sarawak, Borneo. The floral scent compositions were also recorded for six species thereof. The selected taxa belong to three out of four complexes of the section Cyrtocladon (Hanneae, Giamensis and Borneensis). The species belonging to the Hanneae complex exhibited longer anthesis (53 – 62 hrs) than those of the Giamensis and Borneensis complexes (ca 30 hrs). Species belonging to the Hanneae complex underwent two floral scent emission events in consecutive days, during the pistillate and staminate phases of anthesis. In species belonging to the Giamensis and Borneensis complexes, floral scent emission was only evident to the human nose during the pistillate phase. A total of 33 volatile organic compounds (VOCs) were detected in floral scent analyses of species belonging to the Hanneae complex, whereas 26 VOCs were found in samples of those belonging to the Giamensis complex. The floral scent blends contained uncommon compounds in high concentration, which could ensure pollinator discrimination. Our observations indicate that scarab beetles (Parastasia gestroi and P. nigripennis; Scarabaeidae, Rutelinae) are the pollinators of the investigated species of Homalomena, with Chaloenus schawalleri (Chrysomelidae, Galeuricinae) acting as a secondary pollinator. The pollinators utilise the inflorescence for food, mating opportunities and safe mating arena as rewards. Flower-breeding flies (Colocasiomyia nigricauda and C. aff. heterodonta; Diptera Drosophilidae) and terrestrial hydrophilid beetles (Cycreon sp.; Coleoptera, Hydrophilidae) were also frequently recovered from inflorescences belonging to of all studied species (except H. velutipedunculata), but they probably do not act as efficient pollinators. Future studies should investigate the postmating isolating barriers among syntopically co-flowering Homalomena sharing the same visiting insects.