The Neotropics bee fauna is very rich with 5000 recognised species, including 33 genera (391 species) of Meliponini, but it is estimated to be at least three fold greater in species richness. Deforestation, agriculture intensification and introduction/spread of exotic competing bee species are considered the main threats to most indigenous species, although other less obvious causes can affect the populations of some bee species locally. Efforts to conserve the native bee fauna include better knowledge of bee richness and diversity (standardized surveys, larger bee collections and appropriate identification of bee species) and of their population dynamics, raising of public and policy makers' awareness, commercial applications of bee products and services such as pollination and preservation of natural habitat.

o 55'W), Atlantic Forest, was studied in ten colonies, and in two periods: from July to September 1993 and from August to September 1995. The colonies were grouped in weak, medium and strong, according to the diameter of the combs, which can provide a good idea of the number of cells built. 855 observations were accomplished for 5 minutes, every half-hour, from 8 to 18 hours. The total number of bees that entered and left the hive and the number of bees that arrived with mud, pollen and resin, besides the number that went out with debris in that period were counted. It was also registered the temperature and the relative humidity of the air. The total external activity, as well as pollen collection, was maximum in the first hours of the morning, mainly in strong colonies. Weak colonies moved their maximum activity approximately to 12 hours. Pollen collection declined gradually, while mud and resin collection rose; removal of debris was greater in the beginning of the morning and in the end of the afternoon. Flight activity increased as relative humidity of the air rose, being optimum for strong colonies in the range between 80%-89%, and for the weakest colonies between 70%-79%. The minimum temperature observed for exit of the bees was 11 o C, with optimum temperatures ranging between 17 o C and 22 o C. The results showed that the general state of the colony influences the different strategies of food collection and that these bees should be adapted to environments of high relative humidity as the Atlantic forest.Key words: stingless bees, flight activity, climate conditions, resource collection. RESUMOA influência do estado da colônia na atividade de vôo do meliponíneo Melipona bicolor bicolor Lepeletier (Apidae, Meliponinae)A atividade de vôo de Melipona bicolor bicolor, proveniente de Cunha (23 o 05'S, 44 o 55'W), Mata Atlântica, foi estudada em dez colônias, em dois períodos: de julho a setembro de 1993 e de agosto a setembro de 1995. As colônias foram agrupadas em fracas, médias e fortes, segundo o diâmetro dos favos de cria, que pode fornecer uma idéia do número de células de cria construídas. Foram realizadas 855 observações durante 5 minutos, a cada meia hora, das 8 às 18 horas, quando era contado o número total de abelhas que entravam e saíam, o número de abelhas que chegava com barro, pólen e resina, além do número que saía com detritos das colméias naquele período. Foram também registradas a temperatura e a umidade relativa do ar. A atividade externa total, assim como a coleta de pólen, foi máxima nas primeiras horas da manhã, principalmente nas colônias fortes. Colônias fracas deslocaram a atividade máxima para as 12 horas, aproximadamente. A coleta de pólen declinou gradualmente,

Supergeneralists, defined as species that interact with multiple groups of species in ecological networks, can act as important connectors of otherwise disconnected species subsets. In Brazil, there are two supergeneralist bees: the honeybee Apis mellifera, a non-native species, and Trigona spinipes, a native stingless bee. We compared the role of both species and the effect of geographic and local factors on networks by addressing three questions: 1) Do both species have similar abundance and interaction patterns (degree and strength) in plant-bee networks? 2) Are both species equally influential to the network structure (nestedness, connectance, and plant and bee niche overlap)? 3) How are these species affected by geographic (altitude, temperature, precipitation) and local (natural vs. disturbed habitat) factors? We analyzed 21 plant-bee weighted interaction networks, encompassing most of the main biomes in Brazil. We found no significant difference between both species in abundance, in the number of plant species with which each bee species interacts (degree), and in the sum of their dependencies (strength). Structural equation models revealed the effect of A. mellifera and T. spinipes, respectively, on the interaction network pattern (nestedness) and in the similarity in bee’s interactive partners (bee niche overlap). It is most likely that the recent invasion of A. mellifera resulted in its rapid settlement inside the core of species that retain the largest number of interactions, resulting in a strong influence on nestedness. However, the long-term interaction between native T. spinipes and other bees most likely has a more direct effect on their interactive behavior. Moreover, temperature negatively affected A. mellifera bees, whereas disturbed habitats positively affected T. spinipes. Conversely, precipitation showed no effect. Being positively (T. spinipes) or indifferently (A. mellifera) affected by disturbed habitats makes these species prone to pollinate plant species in these areas, which are potentially poor in pollinators.

Flight activity of Plebeia pugnax Moure (in litt.) was studied in six colonies coming from Cunha, SP, from July to October 1994. Twice a week, from 8:00 a.m. to 6:00 p.m., for 5 minutes every half-hour, all the bees entering and leaving the hives were counted. Six hundred counts were made and the materials that foragers carried were recorded. Data were analysed in relation to temperature, relative humidity, light intensity and day time. Foragers' flight activity was relatively constant in a wide range of temperature, from 22 o C to 34 o C. The minimum temperature for the beginning of flight activity was 14 o C. Effective flight activity (when foragers of all colonies were leaving the hives) occurred at 15 o C. These bees also flew within a wide range of relative humidity, from 30% to 100%, decreasing slowly after 50%. Flight activity increased as light intensity rose and it has also increased as the hours passed by, reaching a peak around midday and decreasing gradually afterwards. Pollen was collected all day long, while resin collection was relatively constant and debris transportation was slightly higher after 10:00 h. From all known Plebeia species, this one flew on the lowest temperature ever registered for this genus.Key words: flight activity, stingless bees, climatic factors. C. Estas abelhas também voaram em uma ampla faixa de umidade relativa, de 30% a 100%, diminuindo paulatinamente acima de 50%. A atividade de vôo aumentou ao mesmo tempo em que a intensidade luminosa elevou-se e esta também aumentou com o passar das horas, alcançando um pico ao redor do meio-dia e decrescendo gradualmente depois. Foi coletado pólen ao longo de todo o dia, enquanto a coleta de resina foi relativamente constante e o transporte de detritos foi ligeiramente superior depois das 10 h. De todas as espécies de Plebeia conhecidas, esta voou na temperatura mais baixa já registrada para esse gênero. RESUMOPalavras-chave: atividade de vôo, meliponíneos, fatores climáticos. Rev. Brasil. Biol., HILÁRIO, S. D., IMPERATRIZ-FONSECA, V. L. and KLEINERT, A. de M. P.

Os constituintes voláteis das secreções cefálicas de 11 espécies brasileiras de abelhas sem ferrão da linha Tetragonisca -Tetragona foram analisados. Foram identificados 145 compostos, por cromatografia gasosa e espectrometria de massas, dentre os quais 72 ésteres, 22 álcoois, 16 ácidos carboxílicos, 13 terpenos, 8 aldeídos, 4 compostos aromáticos, 2 lactonas e 1 diidropirano. As relações estruturais, origem e a distribuição detes compostos são discutidas. Com respeito à composição qualitativa e quantitativa, cada espécie mostra um buquê de odores, os quais são obtidos a partir de componentes poucos específicos. Em algumas espécies proximamente relacionadas foram observadas similaridades no buquê de odores. As fragmentações no espectro de massas de ésteres graxos e dos ésteres insaturados derivatizados com DMDS são discutidas em detalhes.The volatile constituents of cephalic secrections of 11 Brazilian social stingless bee species of the Tetragonisca -Tetragona line have been analysed. By gas chromatography/mass spectrometry 145 compounds could be identified which include 72 esters, 22 alcohols, 16 carboxylic acids, 13 terpenoids, 8 aldehydes, 7 ketones, 4 aromatic compounds, 2 lactones and 1 dihydropyran. Structural relations, origin, and distribution of these compounds are discussed. With respect to qualitative and quantitative composition, each species shows a specific odour pattern which is made up by less specific components. To a certain extent, closely related species show some similarities in the odour bouquets.The mass spectrometric fragmentation patterns of typical wax type esters and DMDS derivatives of unsaturated esters are discussed in detail.

-(The bee flora of the sea coastal sand dunes of Abaeté, Salvador, Bahia State, Brazil). The bee plant community in a fragment of 8.2 ha in the Environmental Protection Area of "Lagoas e Dunas de Abaeté", in Salvador, Bahia, Brazil (12º56' S /38º21' W) was investigated. Between January and December 1996, three times a month, blooming plants were sampled. Floral traits such as size, shape, symmetry, sexuality, anther dehiscence, and colour; floral rewards and flowering period were recorded for each species. Restinga, a sand dune scrub is the vegetation type, formed mainly by shrubs and subshrubs. Ninety-seven plant species were observed, Fabaceae was the richest family in number of species. Bees visited 66 species but concentrated their visits in 12 species (79.4% of total of individuals). Waltheria cinerescens St. Hilaire and Byrsonima microphylla A. Juss. were the most abundant species in the area. Floral resources were available for the bees during the whole year but the number of flowers was greater at the low rainfall season. In general, flowers remained open during the whole day; most of them were monoclinous (89% of species), small, tubular, pink-purple (32%) and cream (31%), actinomorphic (63%) and arranged in inflorescences. Most of the species are mellitophilous (85%), it means that bees are probably the main pollen vector in this ecosystem.Key words -Apoidea, bee plants, restinga, sand dunes RESUMO -(A flora apícola de uma área restrita de dunas litorâneas, Abaeté, Salvador, Bahia). A comunidade de plantas visitadas por abelhas foi estudada em um fragmento de 8,2 ha na Área de Proteção Ambiental das Lagoas e Dunas de Abaeté, Salvador, Bahia (12º56' S e 38º21' W). Entre janeiro e dezembro de 1996, três vezes ao mês, as plantas floridas eram amostradas, registrando-se para cada espécie o período de floração, hábito e características florais como: cor, forma, sexualidade, simetria, deiscência das anteras e recurso oferecido ao visitante. O tipo de vegetação local é a restinga, composta principalmente por arbustos e subarbustos. Foram observadas 97 espécies vegetais e a família Fabaceae foi a mais rica em número de espécies. Das espécies observadas, 66 foram visitadas por abelhas, sendo que 12 delas foram predominantemente visitadas (79,4% do total de indivíduos). Waltheria cinerescens St. Hilaire e Byrsonima microphylla A. Juss. foram as espécies mais abundantes. Os recursos florais estiveram disponíveis ao longo de todo o ano, havendo maior produção de flores nos meses de menor precipitação. A maioria das flores esteve aberta durante todo o dia. Predominaram flores actinomorfas (63%), monóclinas (89%), pequenas, tubulares e reunidas em inflorescências, cujas cores mais freqüentes são lilás (32%) e creme (31%). A maioria era melitófila (85%), significando que as abelhas são, provavelmente, os principais responsáveis pela reprodução sexual das espécies vegetais nessas dunas.Palavras-chave -Apoidea, dunas litorâneas, plantas apícolas, restinga

We analyzed aspects of the community structure of Apoidea of a restricted area of dunes with restinga vegetation in Salvador, Bahia, Brazil. Standardized samples were taken for one year, 3 times a month from 6:00 a.m. to 6:00 p.m. A total of 3983 individuals (3770 females and 213 males) of 49 species, grouped into 13 morpho-functional types and belonging to five families, were collected from flowers in its majority. The fauna of Abaeté is composed by large solitary bees, best represented by Anthophoridae followed by Apidae; Halictidae; Megachilidae and Colletidae. Bees were active throughout the year, with peaks of abundance in periods of low rainfall. Daily activity was greatest between 08:00 and 14:00 hours, when relative humidity was lower and temperature higher. The abundance pattern and the richness were very similar to other habitats in the Brazilian Northeast. Of the species sampled, 49% were represented by less than eight individuals. The six most abundant species were represented by 84% of the total individuals collected. The availability of resources seems to be the main factor regulating bee flight activity in Abaeté. The foraging activity was related positively to the intensity of flowers in the field.Key words: bee's abundance; bee diversity; community structure, restinga and dunes, morpho-functional groups, Northeast Brazil. ResumoAspectos da estrutura da comunidade de Apoidea de uma área restrita de dunas com vegetação de restinga em Salvador, Bahia, Brasil, foram analisados. Amostragens, com metodologia padronizada, foram realizadas durante 1 ano, 3 vezes por mês, das 6:00h às 18:00h. Um total de 3983 indivíduos (3770 fêmeas e 213 machos) de 49 espécies, agrupadas em 13 categorias morfo-funcionais, pertencentes a 5 famílias, foram coletados nas flores. Em sua maioria, a fauna de Abaeté é composta por abelhas solitárias de porte grande, cuja maior representatividade, tanto em espécies quanto em indivíduos, é de Anthophoridae, seguida por Apidae; Halictidae; Megachilidae e Colletidae. As abelhas estiveram ativas durante todo o ano, apresentando picos de abundância no período de menor precipitação pluviométrica. A atividade diária foi maior entre 8:00h e 14:00h, compreendendo o período em que a umidade relativa decrescia e a temperatura aumentava. O padrão de abundância e a riqueza foram bastante semelhantes ao de outros habitats no nordeste brasileiro. 49% das espécies amostradas foram representadas por menos de 8 indivíduos e apenas 6 espécies predominaram, representando 84% do total de indivíduos coletados. A disponibilidade de recursos parece ser o principal fator regulador da atividade de vôo das abelhas em Abaeté, ao longo do ano. A atividade de forrageamento foi relacionada positivamente com a intensidade de flores no campo. Palavras

The floral phenology and reproductive biology of six sympatric arboreal Myrtaceae species were studied in the coastal plain forest (Ubatuba, Brazil, 44°48′W 23°22′S), from September 1999 to April 2002. Flowering started in the transition from the driest to the most humid season (Sep/Oct) and lasted until March. The sequence with which the species flowered each year was consistently the same. However, the timing of flowering onset, peak, end, and overlap differed from one year to another. Myrtaceae species were classified as xenogamic according to the pollen:ovule ratios, but two of them seem to present some degree of self-compatibility. Flowers of all species opened at sunrise and lasted for 1 day. Bombus morio (Apidae: Bombini) was the most common visitor followed by Melipona rufiventris (Apidae: Meliponini). Buzz pollination in Myrtaceae was common at the study area and seems to be related to bees' behaviour and to some aspects of flowers' morphology.