Reproductive Ecology of Euglossine Bee-pollinated Orchid Catasetum Integerrimum Hook (Ochidaceae)

Abstract

Catasetum is a dimorphic and dioecious genus of orchids with a pollinaria release mechanism triggered by pollinator visitation. The reproductive ecology of Catasetum integerrimum Hook (Orchidaceae) was characterized in Central Veracruz, Mexico. For that, it was determined whether floral senescence and fruit production are resulted of pollination efficiency in the species, and if so, to what extent present reproductive event constraint the investment in subsequent reproductive event. In the sampled population, efficient pollinaria removal/deposition triggered floral senescence. Eulaema polychroma bee visited earlier and with lower frequency the staminate than pistillate flowers. Alleviating pollen limitation increased fruit production but it caused a reduction in flower and fruit production in the subsequent reproductive event. C. integerrimum seemed to exhibit reproductive cost-saving mechanisms linked to the pollinator identity and behavior, whereas pollinator efficiency appeared to be mediated by dioecism and dimorphism in floral traits. This study highlights the importance to understand the adaptive significance of dimorphic floral traits in animal-pollinated plants, stimulating new research avenues on the role of pollinators in maintaining safe reproduction threshold of plants.