Pollination biology of a tree species of Cupania: synchronous dichogamy, generalist phenotype and predominance of stingless bees

Abstract

Background and aims: We know little about the pollination biology of tropical tree species associated with the pollination system by diverse insects (DI). We studied the floral biology, breeding system, and floral visitors of Cupania oblongifolia.

M&M: Experiments and observations were carried out in an area of the Atlantic Forest.

Results: The flowers are small and greenish and produce little nectar. The species is diclinous-monoecious but the anthesis of female and male flowers is temporally separated into the inflorescences, with little or no overlap (i.e., synchronized dichogamy). Fruit set did not differ after cross- and self-pollinations and natural conditions, indicating the absence of both self-incompatibility and pollen limitation. Flowers of C. oblongifolia were visited by 87 species of Hymenoptera, Diptera, Lepidoptera, and Coleoptera. Male flowers were more visited and 20 species visited the two morphs. Floral visitors were mostly rare and about 80% of the visits were made by Hymenoptera, mainly stingless bees. Two species of Scaptotrigona were eudominant.

Conclusions: The floral phenotype fits on the description of DI systems. Many species of insects were recorded but stingless bees predominated. Meliponini constitutes the most abundant anthophilous group in Neotropical forests, thus pollination systems associated with them are expected. Based on our results, it is possible to forecast that some species classified as DI based on floral phenotype and visitor richness may be strongly associated with a certain group of pollinators, denoting a lower degree of generalization