Floral biology, nectar dynamics and reproductive system of the phalaenophilous species Dracaena trifasciata (Asparagaceae)

Abstract

While there have been consistent indications of pollination by lepidopterans within the Sansevieria Clade (genus Dracaena, Asparagaceae), the floral biology of these plants remains largely unexplored. This study comprehensively describes the floral and reproductive biology of Dracaena trifasciata, a widely cultivated species within the group. Our investigation involved the characterization of floral anthesis and morphometry, of the nectar secretion process, testing the effects of nectar removal, and evaluating the reproductive system. Our findings reveal that the floral traits of D. trifasciata strongly align with the phalaenophily syndrome (i.e., moth pollination), featuring white flowers, a short floral tube, and nocturnal anthesis. The nectar of the species accumulates at the base of the floral tube through continuous secretion, persisting throughout the night. Although the effect is subtle, successive nectar removal leads to a reduction (approximately 16%) in the total nectar produced by unvisited flowers. The species is self-compatible but lacks the ability for self-pollination. In the studied population, results from controlled experimental pollination treatments suggest an evident deficiency of pollinators to produce fruits. Future investigations may clarify whether these patterns are consistent across various cultivars and locations globally. We suggest that D. trifasciata flowers could be an important resource to Lepidoptera species in anthropized areas.