Bees provide a vital pollination service to many important crops and wildflowers yet are experiencing population declines across European and North American agricultural landscapes. The conservation of bee communities on farmland is a priority of the UK agri-environment schemes, which support pollinators through the provision of natural and semi-natural habitat, foraging resources and nesting sites. Data are needed to evaluate the effectiveness of these interventions in supporting bee communities and to allow the refinement of effective, evidence-based policy. This thesis examines the effectiveness of agri-environment management, though the provision of natural habitat, foraging resources and nesting sites, in supporting solitary bees, an important group of pollinators of which there are 250 species in the UK. Cavity nesting solitary bees and wasps were surveyed on 19 farms situated across central southern England, ranging from farms under no agri-environment scheme, to farms showcasing higher-level agri-environment management. Data on bee and wasp communities was collected by deploying solitary bee nest boxes. These nest boxes are marketed widely as nesting resources for solitary bees and are provided to farmers as part of Higher Level agri-environment schemes. Over the course of the study, 4002 solitary bees and wasps, comprising 10 species, were recorded. Natural Habitat: A positive relationship was identified between the abundance and species richness of bees and wasps and the proportion of natural habitat across farms. The availability of natural habitat also had a positive influence on the structural stability of bee and wasp parasitism networks; a positive association was identified with network link density. Link density measures the mean number of links per species within a network. Higher measures of link density are believed to confer greater resilience to species loss as individuals have more flexibility to switch interaction partner, limiting the risk of a cascade of secondary species extinctions. This set of results is encouraging, suggesting that the natural habitat types being promoted are effective in supporting solitary bee and wasp communities. Foraging resources: Examination of bee foraging preferences, through next generation sequencing of brood cell pollen DNA, demonstrated that the agri-environment scheme sown wildflower mixes do not support the foraging requirements of solitary bees effectively. Of the 15 plants included currently in the wildflower mixes that were recorded as present on the study farms, pollen from only one species, Ranunculus acris, was used by the bees. Rosa canina was identified as the most popular forage plant. The leaves of this species are also a preferred nesting material for Megachile leafcutter bees, providing strong justification for the inclusion of R. canina within the selection of hedgerow plants encouraged by agri-environment schemes. Tripleurospermum inodorum and Trifolium repens were also identified as good candidates for inclusion in wildflower seed mixtures. Nesting sites: A strong positive relationship between the density of solitary bee nest boxes and the rate of brood cell parasitism was identified, indicating that a high local density of nest boxes may expose bee larvae to a higher risk of parasitism. An enhanced risk of larval mortality could counteract the benefit of additional nest site provision. No significant effect of nest box provision on nest box colonization was identified across these study sites, suggesting that their placement across landscapes to encourage more pollinators may be counter-productive. It would be prudent to advise, given the results of this study, for the provision of a small number of dispersed nest boxes, this might more accurately mimic the availability of nesting resources in nature and reduce the risk of enhanced parasitism rates.

Abstrakt.Syftet med denna studie är att ta reda på vad som kan göras i trädgårds- och balkongmiljöer för solitära bins överlevnad, då arter redan gått förlorade eller är rödlistade på grund av dåliga förutsättningar i fråga om habitat. Hur kan utformningen av designförslag se ut för trädgård och balkong? Vad innehåller lämpliga habitat samt hur ser hotbilden ut för solitära bin? Målet med denna litteraturstudie var att finna svar på mina frågeställningar. Utifrån de fakta som framkommit från resultaten har sedan designförslag utformats för trädgårds- och balkongmiljöer. Ökad biotopyta från forna tiders mosaiklandskap kan i ny tappning utformas som trädgårds- och balkongmiljöer i form av giftfria och blomrika små ängar, blommande kantzoner, diken och rabatter, krukväxter, blommande träd och buskar. Solitära bin behöver husrum, vatten att dricka och mat att äta i form av nektar- och pollenrika växter. De behöver blommande växter från tidig vår till sen höst för att överleva. Viktigt att sprida kunskap och förståelse för hur solitära bin lever sina liv så att människor kan samarbeta för att nå långsiktiga hållbara habitatlösningar. Solitära bin behöver många blommande växtytor som kan fungera som spridningskorridorer in i de urbana miljöerna där varenda liten kvadratmeter blommande yta har betydelse. Solitära bin ökar i antal med ökad biotopyta är fakta som designförslagen baserats på. Förödande hot för solitära bin är bland annat blombrist i urbana miljöer, besprutning med olika gifter, tambin som sprider sjukdomar, människans rädsla för små kryp samt förändrade livsmiljöer. / Abstract. The purpose of this study is to find out what can be done in gardens and balconies for solitary bees survival, species have already been lost or are red-listed because of poor conditions in terms of habitat. What can design-proposals look like for gardens and balconies? What do suitable habitats contain and what do threats look like for solitary bees?The goal with this literature study was to find answers to my questions. Based on facts that emerged from the results, design proposals have been made for gardens and balconies. Increased biotope-surface from ancient times mosaic-landscape can in modern environments like gardens and balconies be designed as non-toxic and flower-rich meadows, flowering border zones, ditches and flower beds, potted plants, flowering trees and shrubs. Solitary bees need shelter, water to drink and food to eat as in nectar and pollen-rich plants. They need flowering plants from early spring to late autumn to survive. It´s important to spread knowledge and understanding how solitary bees live their lives, that people can cooperate to achieve long-term sustainable habitat solutions. Solitary bees need many flowering plant-surfaces that can act as dispersal corridors in to urban environments, where every single square meter flowering-surface is of importance. Solitary bees increase in number with increasing biotope-surfaces which are facts that design proposals are based on. Devastating threats for solitary bees are floral shortage in urban areas, spraying with various poisons, domestic bees spreading diseases, human fear of small insects and altered habitats.

Em abelhas, como nos demais himenópteros, a haplodiploidia e o mecanismo de determinação do sexo restringem o tamanho efetivo da população. Ademais, a nidificação próxima ao sítio natal pelas fêmeas das espécies solitárias restringe o fluxo gênico materno e causa alta viscosidade populacional. Centris é um gênero de abelhas solitárias da tribo Centridini, encontradas em distintos locais, como matas contínuas ou fragmentos florestais, bem como em ambientes urbanos; as espécies C. analis e C. tarsata se destacam no gênero pela abundância com que são encontradas nestas localidades. São abelhas poliléticas ou generalistas na coleta de pólen e nidificam em cavidades pré-existentes. Em razão de seu porte médio, presume-se que não apresentem alta capacidade de dispersão. Fêmeas de algumas espécies do gênero apresentam comportamento filopátrico. Estes dados nos levam a supor que espécies com traços biológicos similares tenham suas populações naturalmente estruturadas (subdivididas). Para testar esta hipótese, foram analisadas algumas regiões do genoma mitocondrial (DNAmt) de abelhas Centridini residentes em áreas urbanas. As duas subunidades da citocromo c oxidase (COI e COII), bem como o RNA transportador de leucina (RNAtLeu), apresentaram baixo nível de variação intra-específica, e a dificuldade em amplificar estas regiões para uma das espécies impediu a utilização destas regiões para análises populacionais. Desta forma, foram selecionadas duas regiões gênicas com taxas de variação intra-específicas distintas, o gene citocromo b (cytb) e a subunidade maior do DNA ribossômico (16S). Por ser uma molécula de herança materna, a análise destas regiões gênicas nos permitiu obter informações a respeito de colonização e o número de linhagens maternas. Os resultados deste trabalho sugerem que as populações de Centris tarsata e Centris trigonoides apresentam baixa e moderada estruturação, respectivamente. Para C. analis, a espécie mais bem amostrada, o excesso de picos duplos apresentados nos eletroferogramas dificultou a interpretação dos resultados. Foi possível ainda verificar diferenças na distribuição haplotípica de machos e fêmeas de C. tarsata, sugerindo a ocorrência de uma dispersão enviesada para machos, caracterizando uma dispersão sexo-assimétrica. / In bees, as in other hymenopterans, the haplodiploidy and mechanism of sex determination constrain the effective population size. Moreover, the nesting close to home site by the females of solitary species restricts maternal gene flow and causes high population viscosity. Centris is a genus of solitary bees of the tribe Centridini found in different locations, such as continuous forests or forest fragments, as well as in urban environments; the species C. analis and C. tarsata stand out in the genre for the abundance that are found in these locations. They are polyletics bees, or generalists in collecting pollen, and nest in cavities pre-existing. In reason of its medium size, it is presumed that do not present high dispersal capacity. How some species of the genus are phylopatric, we presume that other also presenting similar behavior. These data lead us to suppose that species with similar traits have their populations naturally structured (subdivided). To test this hypothesis, we analyzed urban populations of four species of Centris for some regions of mitochondrial genome (mtDNA). The two subunits of cytochrome c oxidase (COI and COII) and the tRNA leucine (tRNALeu) showed a low level of intraspecific variation, and the difficulty to amplify those regions for one species prevented the use of these regions to population analysis. Thus, we selected two gene regions with distinct rates of intra-specific variation, the gene cytochrome b (cytb) and the large subunit ribosomal DNA (16S). As a molecule maternally inherited, the analysis of the mitochondrial genes enabled us to obtain informations about colonization through the number of maternal lineages. Our results suggest that Centris tarsata and Centris trigonoides populations exhibit low and moderate genetic structuring, respectively. In C. analis, the species most well sampled, the excess of double peaks showed in the electropherograms difficults the interpretation of results. Also, for the species C. tarsata was possible to verify differences between males and females, suggesting the occurrence of a male skewed dispersion and an asymmetrical dispersion.

It has been argued that organic farming sustains a higher biodiversity than conventional farming. This might promote the ecosystem services that exist in agricultural landscapes such as pollination and pest control. Here, I examined the effect of farming system (organic vs. conventional) with respect to the time since farming system transition, landscape heterogeneity and plant richness on pollinating and predatory insects. In total, data from 30 farms were used, of which 20 were organic and 10 were conventional. The data were analyzed using general linear models and model averaging. The results show that insect groups responded differently to various factors. Pollinators were more sensitive to landscape complexity, showing an increase of abundance and species richness with an increased heterogeneity. Predators on the other hand reacted to farming system, where there was an increase in abundance and species richness on organic farms.

Em abelhas, como nos demais himenópteros, a haplodiploidia e o mecanismo de determinação do sexo restringem o tamanho efetivo da população. Ademais, a nidificação próxima ao sítio natal pelas fêmeas das espécies solitárias restringe o fluxo gênico materno e causa alta viscosidade populacional. Centris é um gênero de abelhas solitárias da tribo Centridini, encontradas em distintos locais, como matas contínuas ou fragmentos florestais, bem como em ambientes urbanos; as espécies C. analis e C. tarsata se destacam no gênero pela abundância com que são encontradas nestas localidades. São abelhas poliléticas ou generalistas na coleta de pólen e nidificam em cavidades pré-existentes. Em razão de seu porte médio, presume-se que não apresentem alta capacidade de dispersão. Fêmeas de algumas espécies do gênero apresentam comportamento filopátrico. Estes dados nos levam a supor que espécies com traços biológicos similares tenham suas populações naturalmente estruturadas (subdivididas). Para testar esta hipótese, foram analisadas algumas regiões do genoma mitocondrial (DNAmt) de abelhas Centridini residentes em áreas urbanas. As duas subunidades da citocromo c oxidase (COI e COII), bem como o RNA transportador de leucina (RNAtLeu), apresentaram baixo nível de variação intra-específica, e a dificuldade em amplificar estas regiões para uma das espécies impediu a utilização destas regiões para análises populacionais. Desta forma, foram selecionadas duas regiões gênicas com taxas de variação intra-específicas distintas, o gene citocromo b (cytb) e a subunidade maior do DNA ribossômico (16S). Por ser uma molécula de herança materna, a análise destas regiões gênicas nos permitiu obter informações a respeito de colonização e o número de linhagens maternas. Os resultados deste trabalho sugerem que as populações de Centris tarsata e Centris trigonoides apresentam baixa e moderada estruturação, respectivamente. Para C. analis, a espécie mais bem amostrada, o excesso de picos duplos apresentados nos eletroferogramas dificultou a interpretação dos resultados. Foi possível ainda verificar diferenças na distribuição haplotípica de machos e fêmeas de C. tarsata, sugerindo a ocorrência de uma dispersão enviesada para machos, caracterizando uma dispersão sexo-assimétrica. / In bees, as in other hymenopterans, the haplodiploidy and mechanism of sex determination constrain the effective population size. Moreover, the nesting close to home site by the females of solitary species restricts maternal gene flow and causes high population viscosity. Centris is a genus of solitary bees of the tribe Centridini found in different locations, such as continuous forests or forest fragments, as well as in urban environments; the species C. analis and C. tarsata stand out in the genre for the abundance that are found in these locations. They are polyletics bees, or generalists in collecting pollen, and nest in cavities pre-existing. In reason of its medium size, it is presumed that do not present high dispersal capacity. How some species of the genus are phylopatric, we presume that other also presenting similar behavior. These data lead us to suppose that species with similar traits have their populations naturally structured (subdivided). To test this hypothesis, we analyzed urban populations of four species of Centris for some regions of mitochondrial genome (mtDNA). The two subunits of cytochrome c oxidase (COI and COII) and the tRNA leucine (tRNALeu) showed a low level of intraspecific variation, and the difficulty to amplify those regions for one species prevented the use of these regions to population analysis. Thus, we selected two gene regions with distinct rates of intra-specific variation, the gene cytochrome b (cytb) and the large subunit ribosomal DNA (16S). As a molecule maternally inherited, the analysis of the mitochondrial genes enabled us to obtain informations about colonization through the number of maternal lineages. Our results suggest that Centris tarsata and Centris trigonoides populations exhibit low and moderate genetic structuring, respectively. In C. analis, the species most well sampled, the excess of double peaks showed in the electropherograms difficults the interpretation of results. Also, for the species C. tarsata was possible to verify differences between males and females, suggesting the occurrence of a male skewed dispersion and an asymmetrical dispersion.

The health of pollinators, especially bees, is of the utmost importance to success of many agricultural ecosystems. Microorganisms can cause diseases in bees; such microbes are pathogenic. The ability of a pathogen to cause harm to its host (such as a bee) is termed its virulence. Studying the evolution of different levels of virulence can lead researchers to a better understanding of pathogens, and potentially predict how much harm a pathogen can cause in the future. We studied the evolution of virulence levels for a fungal disease of bees. This group of fungi is composed of 28 species, and some cause a disease in bees called chalkbrood while others do not. Using what we know about virulence evolution we wanted to see if the pathogens could infect all bees, if the pathogens varied in virulence when infecting at the same time as another pathogen, and if solitary bees had any behavioral adaptations that might increase or decrease chalkbrood infection. By using DNA sequences, the relationship between the genetic structures of each of the fungal species was studied, and we found that pathogens of solitary bees grouped together while pathogens of social bees (honey bees) were not part of this group. We then found that a solitary bee pathogen did not infect honey bees very well, and vice versa. The nuances of the relationship between two solitary bee pathogens were examined more closely to determine how the two pathogens interact in this bee. In this case, under varying conditions of infection, one pathogen always maintained a similar level of virulence and spore production, while the other pathogen varied in these measures. In addition, when doses of these fungi were fed to bee larvae at different times, more bees survived than when the doses were given at the same time, suggesting that bee immune responses are very important. Finally, we found no evidence of any specific behaviors of solitary bees exposed to infective spores that would suggest these bees have behaviors that are evolved to alter chalkbrood levels in populations.

CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel Superior / Este trabalho teve como objetivo conhecer a abundÃncia, diversidade e frequÃncia das abelhas visitantes florais em Ãreas de cultivo de cajueiro comercial prÃximo e longe de mata nativa. A pesquisa foi realizada de agosto a novembro de 2012, em pomares comerciais no municÃpio de Horizonte, CearÃ. A metodologia constou na marcaÃÃo de cinco diferentes gradientes de distÃncia (40m, 80m, 120m, 160m e 200m) da mata nativa em 10 Ãreas de cultivo de cajueiro anÃo precoce para a contagem e registro dos visitantes florais observados em 500 panÃculas durante o percurso de transectos realizado em seis horÃrios distintos (7h, 9h, 11h, 13h, 15h e 17h) a cada 15 dias . AlÃm disso, eram realizadas coletas com rede entomolÃgica em seis Ãrvores selecionadas, cinco minutos em cada Ãrvore, em Ãrea de 25m x 50m. Foram coletadas 368 visitantes florais entre abelhas sociais (331), abelhas solitÃrias (21) e outras espÃcies (16) visitantes florais nas panÃculas do cajueiro. A relaÃÃo entre a abundÃncia de insetos e horÃrio da coleta revela que para todas as abelhas coletadas, os horÃrios de 7h e 9h foram os que apresentaram a maior abundÃncia de insetos visitando as flores do cajueiro, principalmente de meliponÃneos. A frequÃncia de visitantes florais do cajueiro em 500 panÃculas nos meses de floraÃÃo, tanto em Ãreas com mata nativa quanto sem mata nativa, nÃo variou em funÃÃo do perÃodo de florada (p>0,05), da mesma forma que nÃo houve diferenÃa significativa (p>0,05) no nÃmero mÃdio de abelhas quando comparado as diferentes distÃncias durante as contagens nas Ãreas com mata nativa e sem mata nativa. As abelhas sociais foram as mais abundantes e destas, 176 foram Apis mellifera e 159 meliponÃneos. Jà as abelhas solitÃrias foram pouco representadas por coleta, tendo Centris spp. e Xylocopa (Neoxylocopa) cearensis sido vistas somente em algumas Ãreas de estudo, nÃo apresentando efeito significativo (p>0,05) quanto ao local (com ou sem mata nativa), Ãrea, horÃrio e dia de coleta. Conclui-se com esse estudo que a presenÃa do fragmento de mata nativa prÃxima à borda de cultura, nÃo influenciou na abundÃncia de visitantes florais nas distÃncias selecionadas, contudo a existÃncia de remanescentes de mata nativa prÃximo aos cajueirais, possibilitou a permanÃncia das abelhas sociais nas Ãreas de cultivo durante todo o perÃodo de florada, principalmente nos horÃrios em que as flores do cajueiro estÃo mais receptivas à polinizaÃÃo. / This study aimed to understand the abundance, diversity and frequency of bees visiting flowers in cashew tree growing areas near and far from commercial native forest. The research was conducted during the blooming season in 2012, from August to November in commercial orchards in the city of Horizonte, CearÃ. The methodology consisted in marking five different gradients of distance (40m, 80m, 120m, 160m and 200m) in all 10 areas to perform and record count of floral visitors in 500 panicles during transect conducted at six different times (7h, 9h, 11h, 13h, 15h and 17h), and captured with an insect net in six selected trees, five minutes at each cashew tree in an area of 25m x 50m. We collected 368 flower visitors among social bees (331), solitary bees (21) and other species (16) floral visitors in panicles of cashew. The relationship between insect abundance and time of collection reveals that for all bees collected, the hours of 7h and 9h of the morning were those with the greatest abundance of insects visiting the flowers of cashew mainly of stingless bees. The frequency of flower visitors in 500 cashew flowering panicles in the months, both in areas with native vegetation as no native forest, did not vary according to the period of flowering (p>0.05), just as there was no significant difference (p>0.05) in the mean number of bees compared the different distances during the counts in areas with native forest fragment and native forest without. Social bees were the most abundant group and among them 176 were Apis mellifera and 159 stingless bees. Solitary bees were poorly represented and Centris spp. and Xylocopa (Neoxylocopa) cearensis were seen only in a few areas showing no significant effect (p>0.05) on the site (with or without native forest), area, time and day of collection. We conclude from this study that the presence of native forest fragment near the edge of culture, did not influence the abundance of floral visitors on selected distances, however the existence of remnant native forest near the cashew trees, allowed to remain in social bees growing areas during the flowering period, mainly at times when the flowers of cashew are more receptive to pollination.

No description available.

Identifying the resources that limit bee populations is essential both for bee conservation and pollination management in agroecosystems. Land-use change typically leads to decreased habitat availability for wild pollinators including loss of nesting habitat, which is an essential but often-overlooked resource for wild bees. Cavity-nesting bees, such as many Osmia spp. (Hymenoptera: Megachilidae), occupy holes in wood or reeds to build their nests; due to their nesting habits, they are frequently scarce in agricultural settings, although, under the right circumstances, these bees can be ideal pollinators of apple and other orchard crops. Artificial nesting structures (“bee hotels”, “trap nests”, or “nest boxes”) are used to study cavity-nesting bees and have been posited as solutions for promoting bee conservation. To evaluate the effects of additional nesting habitat on the local abundance of Osmia spp., and on bees more generally, artificial nesting structures for cavity-nesting bees were installed at 24 sites in apple orchards around Ottawa in 2021 and 2022. Each site had two treatments: one with nest boxes, and one without (control). Transect walks were conducted to measure overall bee contact (including contact by Osmia spp.) with apple blossoms and, after the end of apple bloom, with flowers in the undergrowth and/or in shrubs. Numbers of apple buds and developing fruit were also recorded. Osmia spp. and overall bee numbers were both significantly higher in the treatment with nest boxes (44% and 15% higher, respectively, in 2021, and 113% and 47% higher, respectively, in 2022); however, there was no difference in fruit set (apple count/bud count) between the two treatments. Thus, nest boxes seem to locally increase Osmia spp. numbers as well as total bee numbers, but they have no apparent effect on apple yield, likely because apple production was not pollinator limited in the years of this study. These findings suggest that bee populations in apple orchards are limited by nesting resources, which has important implications for orchard management practices and bee conservation policy.

Estudos de ecologia de comunidade e conservação são importantes para entender quais áreas com diferentes fitofisionomias podem manter maior número de espécies coexistindo. Também é possível compreender o nicho trófico das abelhas, sendo este relacionado com a diversidade de recursos alimentares disponíveis e a sobreposição entre espécies de uma guilda. Uma ferramenta que atualmente vem sendo utilizada em estudos ecológicos de interações inseto-planta são as redes mutualísticas e suas métricas. Com essas ferramentas é possível inferir ou até prever as consequências da extinção de espécies e as perturbações ambientais, além de variações nos padrões para a comunidade como um todo, e a ecologia das abelhas e plantas. A partir disso o objetivo deste trabalho foi caracterizar e analisar a estrutura da comunidade de abelhas e vespas e o nicho trófico da comunidade de abelhas que nidificam em cavidades preexistentes em áreas de Cerrado e Mata semidecídua. A área de estudo foi a Estação Ecológica Jataí que apresenta diferentes fitofisionomias. Os dados foram obtidos com a utilização do método de ninhos-armadilha instalados em seis pontos, três no cerrado e três na mata semidecídua, em agosto de 2015. Foi utilizado o método de análise polínica e redes mutualísticas para o estudo do nicho trófico das abelhas. Foram amostradas 11 espécies de abelhas e oito de vespas, e essas comunidades apresentaram espécies com ampla distribuição geográfica o que confere a condição de generalistas por explorarem uma alta diversidade de ambientes. Elas tiveram mais nidificações no período chuvoso, refletindo na maior sobreposição temporal das abelhas nesse período. Entretanto na estação seca, a sobreposição temporal das vespas foi maior. Os dados obtidos de riqueza e abundância das abelhas amostradas na mata foram diferentes do cerrado, o que indica que, realmente, as espécies podem ter suas populações mudando significativamente de um ambiente para o outro como consequência de mudanças nos vários fatores abióticos e bióticos. A dieta das abelhas amostradas se mostrou bastante variada, um grande número de tipos polínicos de 14 famílias de plantas. A família mais importante para Anthidiini e Euglossini foi Fabaceae. Como já conhecida, a relação entre Centris e plantas que disponibilizam óleo, Malpighiaceae foi a família mais utilizada por C. analis. Já para as espécies de Tetrapediini, a família Euphorbiaceae foi mais frequente. As espécies se mostraram, de maneira geral, com comportamento generalista uma vez que suas amplitudes de nichos foram altas. Por outro lado, em alguns momentos, como foi possível perceber na sobreposição de nicho, essas fêmeas adotaram comportamentos mais especialistas. As Tetrapedia tiveram as maiores sobreposições de nicho entre elas mesmas, mas também utilizaram as espécies de plantas mais abundantes. Ludwigia foi o tipo polínico mais importante na dieta das abelhas para o cerrado enquanto que Gliricidia, Dalechampia, Serjania e Desmodium foram centrais na dieta da mata. As redes para ambas fitofisionomias e anos de coletas foram aninhadas e não-modulares, como esperado para redes mutualísticas. Além disso, provavelmente pelo bom estado de preservação, as redes foram robustas, indicando que a comunidade não está frágil à perda de espécies. A comunidade apresentou um comportamento mais especialista no cerrado e não alterou muito em relação aos dois anos. A especialização das populações foi maior, de maneira geral, para a área de cerrado, com exceção de Epanthidium erythrocephalum. A grande diferença nos parâmetros como composição, abundância e métricas de rede em comparação com outros estudos mostra a importância de se conhecer a dinâmica de cada área para pensar de maneira mais eficiente em estratégias específicas de recuperação e preservação de áreas naturais / Studies on community ecology and conservation are important to understand which areas with different phytophysiognomies can maintain a great number of species coexisting. It also understand the trophic niche of bees and this is associated with the diversity of food resources available and with the overlap between species of a guild. A tool that currently is being used in ecological insect-plant studies, mutualistic networks and their metrics. With these tools, it is possible to infer or even predict the consequences of the species extinction, the environmental disruption of the community as a whole, variations in community patterns and bee-plant ecology. Therefore, the aim of this study was to characterize and analyze the community structure of bees and wasps and the trophic niche of bees that nest in preexisting cavities in Brazilian savannah and semideciduous mesophytic forest. The study area was the Estação Ecológica de Jataí that presents different phytophysiognomies. The data were obtained from the method of trap-nests installed in six areas, three in the brazilian savannah and three in the semideciduous mesophytic forest, in August 2015. The methodology of pollen analysis and mutualistic networks was used to study the trophic niche of bees. Eleven species of bees and eight wasps species were sampled and this community showed species with high geographic distribution that confers the status of generalists by exploring a great variety of environments. They nested more in the rainy season reflecting in the larger temporal overlap of the bees in that period. Besides that, the wasps were higher time ovelap in the dry season. The richness and abundance of bees in the forest was different from Brazilian savannah, what can indicate that the species can have their populations changing significantly from one environment to another because of changes in the various abiotic and biotic factors. The diet of bees showed a variety of pollen types of 14 plants families. The most important family to Anthidiini and Euglossini was Fabaceae. As well documented, the relationship between Centris and plants that provide oil, Malpighiaceae was the most used family for C. analis. For the Tetrapediini species, the family Euphorbiaceae was the most frequent. All species showed a generalist behavior once their breath niche was high. On the other hand, in a few moments, as it was possible to observe in the niche overlap, the species adopted a more specialist behavior. Tetrapedia had the highest overlap niche among them, but they used the most abundant plants in the area. Ludwigia was the most important pollen type in the bees` diet in the Brazilian savannah, while Gliricidia, Dalechampia, Serjania e Desmodium were the most central in the diet of bees in the forest. The networks for both phytophysiognomies and year of sampling, was nested and not modular, as expected in mutualistic networks. Besides, probably, because of the good state of conservation of the study area, the networks were robust, indicating that the community is not fragile to the loss of species. The community showed a more specialist behavior in the Brazilian savannah and did not change much over the two years. The specialization of populations was greater, in the most cases, in the Brazilian savannah, except Epanthidium erythrocephalum. The important difference among the parameters such as composition, abundance and network metrics compared to other studies shows the importance of knowing the dynamics of each area to think more efficiently about specific strategies for recovery and preservation of natural areas