The Agreste is a transition region of tropical rainforest and Caatinga in northeastern Brazil. In this region, the majority of the native Atlantic Rainforest was destroyed to give place to livestock farming. It is not known whether degraded areas maintain a diversified bee-plant community or not and which kinds of bee-plant interactions occur. The vegetation at the study site comprises pastures, ruderal vegetation and minute remanents of rainforest vegetation. Both bees and associated plants were collected monthly, from August 2001 to July 2002, sampling during two consecutive days from 5:30 am to 5:30 pm. We collected a total of 1004 bees from 79 species. Apidae was the most abundant and species-rich bee family (732 individuals, 43 species) followed by Halictidae (194 individuals and 20 spp.), Megachilidae (47 individuals and 13 spp.), Colletidae (16 individuals and 2 spp.) and Andrenidae (15 individuals and 1 sp.). Only three species of eusocial bees and five of euglossine bees were recorded, even though both groups are diversified in Neotropical rainforests. The absence of native stingless bees of the genera Plebeia, Frieseomelitta, Partamona, Scaptotrigona and Trigonisca, as well as of other euglossine bee species, is probably due to the lack of nesting sites and to the paucity of pollen and nectar resources in this disturbed area. The bees visited flowers of 87 plant species, mainly of herbs and small shrubs. Isolated rainforest trees in the pasture as well as cultivated fruit crops contributed to some extent to maintain a diversified native bee community.
Bee-plant interaction; diversity; Northeastern Brazil; species richness; pollination
