Abelhas Euglossini no bioma cerrado: diversidade, estimativa populacional e estrutura genética

Abstract

The Euglossini bees has a wide distribution in the Neotropical region, occurring in different types of vegetation formation. The Cerrado biome is composed of different physiognomies, such as savanna and forest. Among Cerrado humid forest physiognomies, we can mention the seasonal semideciduous forest (SSF) and gallery forest (GF), which present different flora and microclimatic conditions. Recent studies in SSF of Cerrado showed the occurrence of a low abundance of individuals compared with surveys in SSF in the Atlantic Forest biome, despite a similar richness. The overall objective was (i) to estimate the diversity of bees and population size of the most frequent species of Euglossini in SSF fragments of Cerrado; (ii) to assess the genetic diversity of Euglossa pleosticta; and (iii) to evaluate the influence of vegetation types (SSF/GF) and seasonality on Euglossini community. For population and genetic analyzes, samplings was carried out between October 2012 and April 2013 in five fragments of SSF in five consecutive days, using seven aromatic baits.The marking of individuals was performed by removing the pre-tarsus and one of tarsomeres (PTT) according to the day of collection. The PTT was used for subsequent genetic analysis of Euglossa pleostica using heterologous molecular markers. In order to study the influence of phytophysiognomies and season in the bee community, monthly samplings from October 2012 to September 2013 were performed in another fragment of SSF and one of MG. A total of 256 males of euglossine, distributed in 12 species were captured and marked. We estimated a population size of Euglossa imperialis in one of the fragments (1222 ± 162.6 individuals) and in another fragment Euglossa cordata (44 ± 9.4). Using the concept of ecological guild (orchid bees), it was possible to estimate the populations of those three fragments which were: 3772 ± 436.2, 376 ± 62.3 to 1424 ± 242.2 individuals. For Eg. pleosticta three loci presented an allele with a dominant frequency over others in the same loco. The estimated gene flow indicated a higher percentage of non-migrant individuals in both populations. In the experiment about influence of phytophysignomies on the euglossini bee communities, it was not observed difference in species diversity between fragments, but there was an interaction between phytophysignomies and season, with the FES presenting the highest abundance in the wet season. We conclude that euglossini bees have small populations in the sampled fragments,there is a limited gene flow among populations Eg. pleosticta and that species diversity is similar in the different phytophysignomies, despite the significant interaction between vegetation type and season on the bees abundance.