The diversity of stingless bees is affected by the proportion of Atlantic Rainforest cover
Marcela de Matos Barbosa, Milton Cézar Ribeiro , Eduardo Andrade Botelho de Almeida , Roberto Gaioski Junior , Vera Lucia Imperatriz-Fonseca , Denise Araujo Alves
Department of Biology, FFCLRP, University of São Paulo, Ribeirão Preto, Brazil; Department of Ecology, IB, São Paulo State University, Rio Claro, Brazil ; Department of Biology, FFCLRP, University of São Paulo, Ribeirão Preto, Brazil ; Department of Entomology and Acarology, ESALQ, University of São Paulo, Piracicaba, Brazil ; Vale Institute of Technology - Sustainable Development, Belém, Brazil ; Department of Entomology and Acarology, ESALQ, University of São Paulo, Piracicaba, SP, Brazil
Stingless bees have an utmost importance to ecosystem due to the role played by them in pollinating Neotropical flowering plants. These bees are sensible to environmental changes especially because of their dependence on tree hollows used to build their nests. We expect, therefore, that the amount of forest cover might influence on the structure of social bee communities. In this respect, we should consider that human-altered landscapes have influenced on availability of suitable nesting sites of many native bee populations. The objectives of this study were threefold: (a) to assess the state of stingless bee assemblies in areas of Atlantic Forest; (b) to evaluate the usage of nest traps by these bees; and (c) to analyze the importance of forest cover to the diversity of species. The study was held in 14 areas in Atlantic Forest; within each area we installed 80 trap-nests on tree trunks and actively searched for hollow tree nests. Over the period of 2 years, 151 nests were identified from 22 different stingless bee species, which were mostly collected during spring time. Tetragonisca angustula was the most abundant species (45.69%) followed by Scaptotrigona xanthotricha (8.60%). The capture ratio was 0.067 swarms/trap, from the total of seventy-five occupied trap nests. From this total, 66.7% traps nests were colonized by T. angustula. We observed a preference for the large traps (3L) and also for large trees from natural nests. The response of stingless bee diversity as a function of forest amount was highly positive significant (r2= 0.81). In addition, we also observed a peak of bee diversity between 30 and 42% of forest cover. Overall, our results show that trap-nests can be used as tool to assist conservation of stingless bees and that their diversity is affected by the proportion of forest cover in this Brazilian rainforest that has undergone significant loss.