High diversity of bees detected in guarana crop and natural habitat due to the use of combined sampling methods

Bees are the main pollinators of native and agricultural plants. Identifying and knowing these insects responsible for the environmental service of pollination is essential for the maintenance and management of pollination in agricultural systems, especially in a high diversity biome as the Amazon rainforest. Some crops in this region are dependent of benefited by wild pollinators, especially native plants like guarana. To address methodological aspects of monitoring bee diversity, samplings were carried out in an agricultural environment (guarana crop, Paullinia cupana) surrounded by Amazon natural habitat at Manaus, Amazonas State. We used three combined methods (two passive traps: Malaise and yellow pan-traps, and one active: hand nets) in different periods, with the same number of samplings (12 each). In total, 4,143 native bees belonging to 171 species were sampled; 117 species (1,926 individuals) were collected with Malaise trap, 15 (91 individuals) with pan-traps, and 114 (2,126 individuals) through active sampling. Only seven species were common to all methods, 60 species on two methods and 104 species were unique to one sampling method (50 with Malaise, two with pan-traps, and 52 with hand nets). We reinforce the need for complementary sampling to known bee diversity as the best strategy here was the joint use of active samples and Malaise traps. Recently the concern with Amazon preservation has aroused worldwide interest, a fact that shreds of evidence the need for studies of biodiversity and taxonomy in several areas, since very little is known of this vast region.