Summary
During a period of one year samples of bee nectar from 302 Melipona seminigra merrillae Cock, and 302 Melipona rufiventris paraensis Ducke from Manaus (22-27) per month) were examined. Sixteen (5,3%) samples from M. seminigra and 11 (3,6%) samples from M. rufiventris did not contain any pollen. Of the 286 (94,7%) remaining samples of M. seminigra, 80 (20%) had one type of pollen, 88 (30,8%) had two, and 118 (41,2%) had 3 or more different types. Of the 291 (96,4%) remaining samples from M. rufiventris, 33 (11,3%) had pollen of a single species of plant, 54 (18.6%) had two, and 204 (70,1%) of three or more different types. A total of 60 different types of pollen from 29 families, 42 genera, and 39 species of plants were recognized. It is suggested that the greater frequency of visits to more than one species in nectariferous flowers (72%) than to polliniferous ones (39%) is due to strategies developed in order to make the bees visit male flowers for pollen and later the females, for nectar.