Calibrachoa elegans is an endemic annual species from the "canga" region in the iron quadrangle, Minas Gerais, Brazil. The study of its reproductive biology involved cross-pollination experiments, self-incompatibility tests and observations of the pollination process. Results of manual pollination experiments showed that the studied population is allogamous. Interruption of pollen tube growth in the style of self-pollinated flowers confirmed the occurrence of self-incompatibility reactions. Pollination is effected only by females of Hexantheda missionica (Colletinae, Apoideae), which show high fidelity to flowers of C. elegans; males use the flowers as a nectar source, as stops between flights when searching for females, and as shelter during the night. They prepare the shelter by cutting and removing anthers and style. The populations of Hexantheda missionica found in Minas Gerais are the first records of this species for southeastern Brazil and probably represent remnants that reached this region during the past, but are now disjunct and isolated from those in southern Brazil.
Reproductive biology; conservation; biogeography; Hexantheda missionica; Calibrachoa elegans
