Reproductive biology of Gongora galeata (Orchidaceae) in central Veracruz, Mexico

Abstract

Background and Aims: Outcrossing pollination mediated by euglossine bees has played an important role in evolving complex floral traits in orchids, so their study denotes the adaptation processes in highly specialized pollination systems. Anthesis time, floral display size, flower development, transition of sexual function, pollinator identity and behavior, and reproductive output of Gongora galeata were determined in Veracruz, Mexico. Methods: Floral phenology of 25 individuals of Gongora galeata was surveyed during two flowering seasons (2017-2018) in a locality in order to study the reproductive biology of the species. Additionally, sexual function transition in the flower was studied in 15 individuals. Key results: Gongora galeata showed asynchronous flowering, with around 17 flowers arranged in two inflorescences by plant. Floral buds developed three days earlier in 2017 than in 2018. Floral anthesis lasted for 3-4 days, initiating in staminate phase. Pollinaria removal triggered, but did not constrain, the change to pistillate phase in flowers. Male individuals of Euglossa villosa visited and pollinated by slide mechanism the flowers of orchid. The bees visited one hour earlier the flowers of the orchid in 2017 than in 2018, resulting in a 70% increase of fruit production in 2017. Conclusions: Gongora galeata exhibited changes in its flowering phenology and the sexual function transition in the flower was an inherent process on the plant and independent on the activity of Euglossa villosa. This study highlights the importance to understand the functioning of specialized pollination systems in face of future changes in the pollination system.