Monday, August 6, 2007 - 1:30 PMCOS 17-1: Restoration of native bee populations
Isabel Alves-dos-Santos, University of São Paulo
Bees are important organisms in the ecosystems due to the pollination service they promote. Bee populations have been suffering consider decline due to deforest and habitat fragmentation as well monoculture activities, which destroy their nest possibilities and their preferred plants. Simple friendly actions showed good results for the permanence and the enlargement of bee populations in the environment. The social meliponines stingless bees which usually depend on cavities on trunks can be raise in artificial boxes and after certain periods the hives can be divided forming new colonies. These practices can be performed by local people, associated to meliponiculture activities. The solitary bee which have different nidification habitats in wood cavities or in the ground required special attention when they are specialized to certain pollen source, as is the case of Peponapis species oligoletic to Cucurbita flowers. The females nidifie in the ground adjacent to the pumpkins plantation and the persistence of the nests aggregation shows to be associated to area where the farmers do not plough out the soil, use less insecticide and keep the cultures for long periods. The carpenter bees (Xylocopa) depend on the availability of wood for the nest construction. The offer of old tree trunks (like eucalyptus) in the field increases the Xylocopa population rapidly, because the next generation use to nidifie in the same place. The same is valid to many other solitary bees that use pre-existing cavities, like Megachile, Anthidiini, Tetrapedia and Centris. Their population is easily enlarged with wood trap nests like bamboos or blocks with handmade cavities. These friendly actions promote also financial return to the farmers, since these bees are efficient pollinators of cultures like pumpkins, passion fruits, wild cherry and many other crops. The enlarging of nest possibilities showed to be crucial for the maintenance of any bee species.