Papers by Fernando Amaral da Silveira
— The influence of pollen grain volume on the quantitative analysis of food stored by bees ... more — The influence of pollen grain volume on the quantitative analysis of food stored by bees is examined. It is concluded that percentages calculated from counts of pollen types in mixed samples of bee food are not reliable estimates of the relative importance of each pollen source to bees. Methodologies to weight frequencies by volumetric correction are discussed.
SURVEY OF THE WILD BEES OF THE "ZONA DA MATA" OF MINAS GERAIS, BRAZIL. III. SECONDARY FOREST lN V... more SURVEY OF THE WILD BEES OF THE "ZONA DA MATA" OF MINAS GERAIS, BRAZIL. III. SECONDARY FOREST lN ViÇOSA REGION (HYMENOPTERA, APOIDEA). The outcome of a wild bee fauna survey in a secondal)' forest is reported. Sampling was carried out mainly on herbaceous and shrubbyvegetation under and at the border ofthe forest. Results are compared with data collected with the same methodology from a previously surveyed grassland nearby. The secondal)' forest was ri cher in A nthophoridae and Apidae species, and less diverse in Megachilidae. Similarity between the two habitats was low. Several unidentified species of Ceratinula, Trichocerapis mirabilis and the sti ngless bees Melipona bicolor, M. quadrifasciata, M. marginata, Paratrlgona s ubnuda, Scaptotrigona tubiba and S. xanthotricha, are among the species dependent on the forest environment to survive. Bee population densities in lhe forest understol)' are as large as the largest values found for open vegetation in Southeastern Brazil; species richness is also comparable to those of other areas in Southeastern Brazil. Sampling strategies are discussed.
We carried out a field study on the life history and sex allocation of the ground-nesting solitar... more We carried out a field study on the life history and sex allocation of the ground-nesting solitary bee Diadasina distincta (Hymenoptera: Anthophoridae). This species is multivoltine, undergoing five generations a year between February and September. The numerical sex ratio of this species was female biased overall (approximately 38% males) and showed a strong and consistent seasonal pattern. The numerical sex ratio was extremely female biased (approximately 20% males) from February until May, and then slightly male biased (approximately 60% males) from June until September. Females were 3.26 times the size of males, and so the overall investment ratio was female biased throughout the year. The overall female bias and seasonal variation in sex allocation is unlikely to be explained by models that invoke overlapping generations or competition between brothers for mates (local mate competition). We suggest that a possible explanation for the female bias in the early part of the season is local resource enhancement (LRE): nesting near larger numbers of sisters reduces parasitism. LRE is likely to decrease in importance in the later part of the season, when the biased numerical and investment ratios may be explained by models in which male and female offspring gain different fitness returns from resources invested.
The gene flow among commercial varieties and wild species of cotton has been studied in the conte... more The gene flow among commercial varieties and wild species of cotton has been studied in the context of environmental risk analysis of genetically modified cotton. Due to the importance of bees in the pollen transfer among cotton plants and the possible effects of Bt toxin on them, an inventory of flower visitors has been conducted in different cotton species and in different production regions. Initially, the surveys were conducted in Brasília (DF), (February/April/2003) in Gossypium hirsutum var. Delta Opal and in Campina Grande (PB), (September-October/2003, in the wild species: G. barbadense, G. mustelinum and in G. hirsutum var. Maria Galante). The surveys were conducted weekly in one or two periods of the day and the sampling effort was about 40h in each area. In Brasília, 23 species were collected and in Campina Grande, 21, with only four species out of 40 being common to both cotton areas. In DF the most abundant species were Apis mellifera, Paratrigona lineata and Trigona sp...
Brazilian Journal of Biology, 2015
Eucalyptus plantations are frequently used for the establishment of bee yards. This study was car... more Eucalyptus plantations are frequently used for the establishment of bee yards. This study was carried on at Fazenda Brejão, northwestern region of the State of Minas Gerais, Brazil. This farm is covered both with native Cerrado vegetation (Brazilian savanna) and eucalyptus plantations. This paper reports on the botanic origin of pollen pellets and honey collected from honeybee (Apis mellifera) hives along a thirteen-month period (January 2004 to January 2005). The most frequent pollen types found in the pollen pellets during the rainy season were Trema micrantha (Ulmaceae), Copaifera langsdorffii (Fabaceae), an unidentified Poaceae, unidentified Asteraceae-2, Cecropia sp. 1 (Cecropiaceae) and Eucalyptus spp. (Myrtaceae); during the dry season the most frequent pollen types were Acosmium dasycarpum (Fabaceae), Cecropia sp. 1 (Cecropiaceae) and Eucalyptus spp. (Myrtaceae). Pollen grains of Baccharis sp. (Asteraceae), Cecropia sp. 1 (Cecropiaceae), Copaifera langsdorffii (Fabaceae), Mi...
Brazilian journal of biology = Revista brasleira de biologia, 2005
Notas Biogeográficas Sobre Espécies Raras de Euglossina (Hymenoptera: Apidae: Apini) que Ocorrem ... more Notas Biogeográficas Sobre Espécies Raras de Euglossina (Hymenoptera: Apidae: Apini) que Ocorrem na Mata Atlântica Brasileira RESUMO-Indivíduos de espécies de Euglossina, raras nas coleções entomológicas, têm sido coletados recentemente. O significado desses exemplares para o conhecimento da biogeografia e estado de conservação de espécies raras dessa subtribo é discutido. Em especial, são apresentados dois novos registros para Minas Gerais, que ampliam significativamente a distribuição geográfica conhecida das espécies que representam: um macho de Eufriesea aeneiventris (Mocsáry), cujo último registro datava de 1943, coletado em isca de salicilato de metila no Parque Estadual do Rio Doce e um macho de Eulaema seabrai Moure, coletado em flor na área urbana de Sabará. Este é, também, o primeiro registro desta espécie para o estado de Minas Gerais.
Diversidade e Distribuição de Abelhas Euglossinas (Hymenoptera: Apidae), com uma Lista Revisada d... more Diversidade e Distribuição de Abelhas Euglossinas (Hymenoptera: Apidae), com uma Lista Revisada de Espécies RESUMO-O objetivo do presente estudo foi investigar os padrões de distribuição e diversidade das abelhas euglossinas (Euglossina). Análises de agrupamento e de correlação foram aplicados a dados extraídos de 28 levantamentos de euglossinas na Região Neotropical. Os 28 sítios de coleta agruparamse em três regiões biogeográfi cas principais que, de forma geral, correspondem à Bacia Amazônica, à Mata Atlântica e à América Central. As três áreas, assim como as sub-regiões de cada uma delas, coincidem, em geral, com os componentes biogeográfi cos identifi cados para outras abelhas e organismos com base em análises fi logenéticas. A Floresta Amazônica, como um todo, apresentou a fauna mais rica e os mais elevados índices de endemismo. A Mata Atlântica, por outro lado, apresentou a fauna mais pobre e os mais baixos índices de endemismo. No entanto, há que se destacar que um importante bioma neotropical, o cerrado, é praticamente desconhecido no que diz respeito à sua fauna de abelhas euglossinas. Pelo menos 30% das espécies listadas são endêmicas de cada bioma. Uma lista atualizada das espécies de Euglossina é apresentada.
Zootaxa
A second species of Actenosigynes from the Mantiqueira mountain range, in the southeastern Brazil... more A second species of Actenosigynes from the Mantiqueira mountain range, in the southeastern Brazilian state of Minas Gerais, is described. This new taxon can be readily distinguished from the type species of the genus, A. fulvoniger (Michener, 1989), by its entirely black-pubescent mesosoma and by the light-yellow pilosity on its terga, among other characters. Females of the two known species are illustrated for the first time and a key is presented for their identification. Analysis of the pollen extracted from the scopa of the holotype of the new species and field observations of A. fulvoniger indicate that both species of Actenosigynes are oligolectic on flowers of Loasaceae as pollen sources. This presumed couple of sister species is the first example of a speciation event related to the isolation of populations of temperate and subtropical bee species on the top of southeastern-Brazilian mountains. It suggests that complexes of sibling species may exist among the other bee speci...
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Papers by Fernando Amaral da Silveira