Fauna de euglossina (Hymenoptera: Apidae) da Amaz？nia sul-ocidental, Acre, Brasil

male orchid bees were collected between december 2005 and september 2006 in 11 forest areas of different sizes in the region of rio branco, acre, southwestern amazonia, brazil. the bees were attracted by 6 aromatic compounds and collected by insect nets and scent baited traps. a total of 3,675 males of euglossina in 4 genera and 36 species were collected. eulaema cingulata (fabricius) was the most common (24.6%), followed by eulaema meriana (olivier) (14.6%), euglossa amazonica dressler (10.5%), eulaema nigrita lepeletier (10.5%) and eulaema pseudocingulata (oliveira) (7.2%). cineole was the scent that attracted the greatest number of individuals (23.8%) and methyl salicylate the greatest number of species (28) for both methods of sampling. thirty one bees of 9 species with pollinar orchid attached to their bodies were collected. the accumulative number of species stabilized after the 48th collection. few species were abundant; the great majority were represented by less than 50 bees. the lack of standardized sample protocols limited very much the conclusions derived from comparisons among the majority of studies on euglossina assemblages. however, the results presented here suggest that the state of acre is very rich in those bees compared to other regions.