ABSTRACT. The family Convolvulaceae is widely distributed in tropical regions, mainly in open areas. Convolvulaceae fl owers are characterized mainly by being beautiful and ephemeral, attracting many fl ower visitors that belong to diff erent taxonomic groups. This work aimed to investigate the interactions between insects and fl owers of Jacquemontia bracteosa (Convolvulaceae), focusing on the pollination effi ciency, in an area in the Brazilian semiarid. From November 2011 to October 2012, fl oral biology of J. bracteosa was investigated as well as the fl ower visit frequency, behavior, and morphology of fl oral visitors. The fl owers of J. bracteosa are white, showy and open early in the morning, lasting less than 12 hours, with fruiting occurring both by selfi ng and outcrossing fecundation. A total of 337 specimens insects were collected on J. bracteosa fl owers during the fi eld observations. The Neotropical bee, Ancyloscelis apiformis, was considered the most effi cient pollinator of J. bracteosa. This bee showed appropriate behavior, high frequency (64% of the total sample), and was constant on the fl owers. Furthermore, they arrived soon when the fl owers began to open and presented 90% of effi ciency in tests of fl ower pollination of J. bracteosa. Other native bee species also visited the fl owers of J. bracteosa and may be considered potential pollinators because they presented behavior and morphology compatible with the fl owers. This study suggests that maintenance of weeds or ruderal plants, especially those that also have ornamental potential in anthropic area, may be an option for the preservation of local native pollinators, which are threatened by environmental degradation.