The effects of forest fragmentation on the patterns of vertical abundance and richness of solitary wasp and bee communities was investigated near Manaus, Amazonas. Wasps and bees were trap-nested at 1,5, 8 and 15 m above the ground in continuous primary forestand isolated forest fragments. In general, the number of nests and species increased with height for both groups. In particular, bee species richness at 15 m was almost twice that at 1,5 mm. However, one species of Trypoxylon Latreille, 1796 (Sphecidae) consistently nested in the understorey. Thus, patterns of abundance and richness distributions indicated stratification. A contingency analysis showed that fragmentation altered stratification of nesting activity of the wasp community in fragments. However, a similar pattern was not found for the bees. These results are discussed with particular reference to prey and floral resources availability and microclimatic conditions.
Forest fragmentation; Amazonia; stratification; solitary wasps; solitary bees