Pollination ecology and floral scent chemistry of Philodendron fragrantissimum(Araceae)

ABSTRACTIn French Guiana, Philodendron fragrantissimum(Hook.) G.Don was specifically pollinated by a single species of night-active cyclocephaline scarab, Cyclocephala simulatrixHöhne. Its inflorescences exhibited short-lasting anthesis (~30 h) and characteristic floral traits such as floral thermogenesis, edible/nutritious floral tissues, and profuse floral scent emission. Our insect exclusion experiments indicate that entomophilous cross-pollination is obligatory for P. fragrantissimum, with olfactory signalling playing a pivotal role in pollinator attraction. Three volatile organic compounds – methyl benzoate, (Z)-jasmone, and dehydrojasmone – dominate the floral scent of pistillate phase inflorescences (84–99%), but their relative proportions were different according to the headspace sampling method used, dynamic or static. Local pollination services provided by both female and male C. simulatrixare effective, as evidenced by a high visitation rate (>70%) that resulted in 55% of the inflorescences maturing into infructescences. Moreover, pollination was highly efficient, since 2–3 beetles sufficed to pollinate an average 94% of the pistillate flowers.