The orchid bee fauna in the Brazilian savanna: do forest formations contribute to higher species diversity?

Abstract

The Neotropical savanna is characterized by a set of different phytophysiognomies occurring in a wide expanse of Brazilian lands. Based on the known higher diversity of orchid bees in forests rather than in savanna formations, we hypothesized that the occurrence of forest formations inside the Brazilian savanna increases the diversity of euglossine bees in that domain and that there are species more associated with these environments. To test this hypothesis, we sampled the euglossine fauna in eight forest and woody savanna remnants and analyzed their community structure. We sampled 1,010 males of 13 species of orchid bees. Bee abundance and species richness ranged from 30 to 341 individuals and from 4 to 12 species, respectively. The forest remnants showed the highest diversity indices and species richness. Our data suggest that some species of Euglossa are mainly associated with forest remnants. We concluded that environmental heterogeneity in the Neotropical savanna contributes to higher diversity of euglossine and that some species are more frequently found in forested habitats. Additionally, considering that some sampled species are typical of the Atlantic and Amazon forests, our data reinforce the hypothesis that forest environments inside the Brazilian savanna can be considered bio-corridors for orchid bees.

Diversity and Temporal Variation in the Orchid Bee Community (Hymenoptera: Apidae) of a Remnant of a Neotropical Seasonal Semi-deciduous Forest

“…imperialis in savanna areas (Nemésio & Faria, 2004, Alvarenga et al 2007, Silva & De Marco, 2014Silveira et al, 2015). However, the close association of this species to forest habitats (Rebêlo & Moure, 1995) can be confirmed by the increased abundance of it in communities occurring in areas with that phytophysiognomy, as reported by Silveira et al (2015) and also observed in this study.…”

“…cingulata occur in the gallery forest of the São Francisco river under the semi-arid climate of the caatinga region. In a study on the diversity of the euglossine bees in forest and woody savanna remnants within the Brazilian savanna domain, Silveira et al (2015) reported the occurrence …”

Influence of landscape structure on Euglossini composition in open vegetation environments

“…For example, the females of all Euglossini species collected can build their nests on preexisting cavities in the ground, including the savanna soil (Zucchi et al 1969, Augusto & Garófalo 2007). These bees can also occupy empty termites and ant nests (Zucchi et al 1969 conditions are common in grass-woody savanna and that preferences for more open areas were previously reported, one can propose that this vegetation type is a potential adequate environment to the nesting behavior of the most abundant Euglossini bees in the studied region, although such proposition calls for additional empirical verification (Rebêlo & Garófalo 1997, Silveira et al 2015, Juncá et al 2005. The scarcity or total absence of floral and nesting resources in the landscape can also explain the negative effect of the proportion of rupestrian grass-woody savanna.…”

“…Given the importance of Euglossini bees for wild pollination as well as the practicity of its sampling, many studies adopted them as biological models in order to understand how bees in general use their environment and how they can be affected by habitat loss, fragmentation and homogenization in landscapes (Powell & Powell 1987, Tonhasca et al 2002b, Viana et al 2006, Brosi et al 2007, Mendes et al 2008, Brosi 2009, Knoll & Penatti 2012, Silveira et al 2015, Aguiar et al 2015. However, these studies present mixed results, with most of them poorly delineated and conducted in forested environments.…”

“…They are pollinators of many plant species representatives of dozens of botanical families (Dressler 1982, Cameron 2004 and are potentially long-range pollinators that can be important in highly heterogeneous environments such as the neotropical forests (Janzen 1971, Wikelski et al 2010. Although commonly associated with forested environments, these bees are also present in open vegetation types such as the Brazilian savanna, called "Cerrado" (Knoll & Penatti 2012, Silveira et al 2015. The Brazilian savanna is one of the world's biodiversity hotspots and is under great pressure because of agricultural expansion and lack of conservation reserves (Myers et al 2000, Klink & Machado 2005, Bellard et al 2014.…”