Flowering biology of Geonoma irena and G-cuneata var. sodiroi (Arecaceae)

The phenology and flowering of two sympatric understory palms from western Ecuador, until recently regarded as conspecific, is described. Geonoma irena BORCHS. flowers throughout the year. Anthesis lasts 11-14 weeks per inflorescence, with overlapping male and female phases. Flowers open in the midmorning, and are visited mainly by meliponid and halictid bees. Geonoma cuneata var. sodiroi (BURRET) SKOV flowers from December to April, with a distinct peak in February. Anthesis lasts 6-8 days per inflorescence, with non-overlapping male and female phases. Flowers open at dawn, and are visited mainly by drosophilid and sphaerocerid flies. The flowering pattern of the two species match different specific behavioural features of their insect visitors. The study provides an example of how differences in reproductive biology may act as an important barrier to gene flow between related, co-occurring taxa.