Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico / A populaÃÃo de abelhas vem declinando em todo mundo, e abelhas de grande porte, por necessitarem de maiores provimentos de alimento estÃo sendo mais afetadas pelas alteraÃÃes ambientais. Isso cria a necessidade de desenvolvermos alternativas e programas de conservaÃÃo para essas abelhas. AlteraÃÃes no tamanho corporal servem como indicativo desse declÃnio populacional. Dessa forma essa pesquisa teve como objetivo verificar mudanÃas no tamanho corporal das abelhas, principalmente nas abelhas de grande porte, como à o caso do gÃnero Bombus e desenvolver iniciativas de criatÃrio racional para conservaÃÃo da espÃcie nativa Bombus brevivillus gerando novas informaÃÃes à respeito dessa espÃcie que tem sido pouco estudada no Nordeste brasileiro. Dentre as milhares de espÃcimes presentes no Naturalis Museu, na Holanda, nÃs mensurados 4510, divididos em 18 espÃcies diferentes, aproximadamente 250 indivÃduos por espÃcie, entre machos e fÃmeas e distribuÃdos entre os anos de 1866 e 2013. NÃs tambÃm descrevemos o comportamento de nidificaÃÃo e as caracterÃsticas da colÃnia de B. brevivillus no estado do CearÃ, Brasil, e transferimos quatro colÃnias para caixas de madeira que permitiam o seu criatÃrio racional. NÃs obtemos informaÃÃes sobre os tipos polÃnicos utilizados, o padrÃo de forrageamento, a coleta de recursos, a influÃncia das variaÃÃes climÃticas nas atividades externas das operÃrias e sobre o desenvolvimento e estabelecimento das colÃnias em caixas racionais. Os resultados sugerem que 18 espÃcies de abelhas estudadas estÃo se tornando menores ao longo do tempo, sendo essa reduÃÃo no tamanho maior em fÃmeas de grande porte. Com relaÃÃo à abelha nativa B. brevivillus, as observaÃÃes mostraram que esta espÃcie parece ser oportunista em ralaÃÃo aos locais de nidificaÃÃo e proteÃÃo das crias e nÃo investe muito na construÃÃo do ninho e na proteÃÃo da prole. As colÃnias produziram um excelente nÃmero de operÃrias, que apresentaram, atà mesmo em caixas racionais, um intenso forrageamento e completaram seu ciclo normalmente, caracterÃsticas que podem ser Ãteis para fins de polinizaÃÃo comercial. / The bee population is declining around the world, and the big bodies bees, that require larger food provisions are particularly more affected by environmental changes. This creates the need to develop alternatives and conservation programs for these bees. Changes in body size are indicative of population decline. Thus, the objective of study was to verify the changes in body size of the bees, especially big bodied bees like the Bombus genus and develop rational breeding initiatives for conservation of native species Bombus (Thoracobombus) brevivillus generating new information about this species that is little studied in the Brazilian Northeast. We measured a total of 4510 specimens, of 18 different species, approximately 250 specimens per specie, equally divided over males and females and more or less regularly distributed over the entire study period (1866-2013). We also describe for the first time the nesting behavior and the colony of Bombus (Thoracobombus) brevivillus, and transferred four colonies to rational breeding boxes, to obtain information about pollen types used, foraging behavior, the resources collect, about the colonies development in rational breeding and the influence of climatic variations to the external activities of workers. Our results suggest that bees are becoming smaller over time, and larger species are more being more affected. About our native bumble bee B. brevivillus the observations showed that this specie seems to be opportunistic in relation to nesting sites and brood protection and does not invest much in nest building and offspring protection. Bombus brevivillus invest heavily in brood production and colony development, before producing reproductive individuals. Therefore, the colonies produce a great number of workers, a trait that could be useful for commercial pollination purposes.

Cattleya é um gênero Neotropical com 114 espécies, sendo mais da metade destas exclusivas do Brasil. Embora as espécies de Cattleya sejam de grande importância horticultural, o número de trabalhos relativos à polinização, sistema reprodutivo e comportamento dos polinizadores é bastante reduzido. No presente trabalho foram analisadas onze populações para quatro espécies, das quais três são ameaçadas (de acordo com os critérios da IUCN) e nativas de Cattleya do Rio Grande do Sul, Brasil. Apresentamse resultados de caracterização morfológica, fenologia floral, sistema reprodutivo, remoção e deposição de polinários, sucesso na formação de frutos e interações com os polinizadores para C. coccinea, C. intermedia, C. tigrina e C. purpurata. Foi documentada pela primeira vez a polinização de C. intermedia, C. purpurata e C. tigrina por quatro espécies de abelhas dos gêneros Xylocopa, Bombus e Epicharis. A visitação exclusiva por beija-flores foi corroborada para C. coccinea. De um modo geral, as espécies mostraram-se autocompatíveis, mas polinizadores dependentes. Verificou-se nas quatro espécies ausência de néctar e um sistema de polinização baseado no mecanismo por engodo. Encontrou-se que em todas as espécies estudadas a taxa de visitas é baixa e a frutificação em condições naturais é infrequente. Verificou-se nas quatro espécies um maior sucesso na formação de frutos através de polinização cruzada. / Cattleya Lindl. is a Neotropical genus that comprises 114 species with more than a half restricted to Brazil. In spite of the horticultural importance of the Cattleya species their pollination, reproductive system, and behaviour of its pollinators is poorly known. In this work were analized eleven populations of four species, of which three are endangered (according to the IUCN criteria) native species of Cattleya from Rio Grande do Sul, Brazil. Here are shown data and results of morphological caracterization, floral phenology, reproductive system, pollinary removal and deposition, fruit set success, and interactions with the pollinator for C. coccinea, C. intermedia, C. tigrina and C. purpurata. It was documented for first time the pollination of C. intermedia, C. purpurata and C. tigrina by four bee species from the genus Xylocopa, Bombus and Epicharis. The exclusive visitation from the hummingbird was confirmed for C. coccinea. All studied species are selfcompatible, but pollinator dependent. There were also verified a lack of reward, and a pollination system based on deceit for the four species. The findings show that in all the studied species the visitation ratio is low, and the natural fruiting has a low frequency. All studies species showed higher fruit production after cross-pollination.

At certain stages of a bumblebee colony life cycle workers lay eggs. Not all workers reproduce, however, since many continue to forage and care for the nest. This leads to questions regarding what differentiates a reproductive worker from a non-reproductive one. It is hypothesized that a form of reproductive competition takes place, where the most behaviourally dominant worker becomes reproductively dominant. The behaviour of orphaned Bombus impatiens pairs was recorded and aggression, social interactions, egg-laying, and ovarian development were identified. Experiment 1 examined the association between aggression and egg-laying. Contrary to the hypothesis, the most aggressive worker did not lay more eggs. When the ovarian development of workers was manipulated and two workers with developed ovaries were paired (Experiment 3), they were more aggressive than pairs with discouraged ovarian development. This provides support for the supposition that aggression and reproduction are related, however, it is only partial support as worker pairs with encouraged ovarian development did not lay more eggs. Since aggression is believed to be only one part of behavioural dominance, Experiment 2 studied the association between social interactions and aggression and reproduction. Results showed that when two socially active bees were paired they were more aggressive than pairs including one or two socially inactive bumblebees. No significant difference in ovarian development between socially active pairs and socially inactive pairs was found. Brood presence was also predicted to affect reproductive control. Experiment 1 found egg-laying and aggression were more likely to co-occur in the absence of brood. Results from Experiment 2 supplemented the first experiment since the absence of brood increased rates of aggression and ovarian development in pairs. Whereas the results confirm aggression has a role in worker reproduction the findings also reveal that behavioural dominance does not equate to reproductive dominance under all conditions. The primary contributions of this thesis were the development of a method to distinguish behavioural dominance from reproductive dominance and determining their relationship under different environments (brood presence) and experimental manipulations (ovarian development). These contributions further define dominance in Bombus impatiens.

This dissertation explored the way in which bumblebees' visual system helps them discover their first flower. Previous studies found bees have unlearned preferences for parts of a flower, such as its colour and shape. The first study pitted two variables against each other: pattern type: sunburst or bull's eye, versus the location of the pattern: shapes appeared peripherally or centrally. We observed free-flying bees in a flight cage using Radio-Frequency Identification (RFID) tracking. The results show two distinct behavioural preferences: Pattern type predicts landing: bees prefer radial over concentric patterns, regardless of whether the radial pattern is on the perimeter or near the centre of the flower. Pattern location predicts exploration: bees were more likely to explore the inside of artificial flowers if the shapes were displayed near the centre of the flower, regardless of whether the pattern was radial or concentric. As part of the second component, we implemented a mathematical model aimed at explaining how bees come to prefer radial patterns, leafy backgrounds and symmetry. The model was based on unsupervised neural networks used to describe cognitive mechanisms. The results captured with the results of multiple behavioural experiments. The model suggests that bees choose computationally "cheaper" stimuli, those that contain less information. The third study tested the computational load hypothesis generated by the artificial neural networks. Visual properties of symmetry, and spatial frequency were tested. Studying free-flying bees in a flight cage using motion-sensitive video recordings, we found that bees preferred 4-axis symmetrical patterns in both low and high frequency displays.

No description available.

Pollination by insects is of great importance for the global food production. There is a specific need for pollination by bees in greenhouses and tunnel cultivations to increase the quantity, quality and market value of the crops. Imported bee colonies from central Europe are used for pollination of Swedish crops and have a great economic importance but are also a threat to wild Swedish bees by posing a risk of pathogen transmission between the bee species. The aim of this study was to investigate how imported bees affect the prevalence of pathogens amongst wild bees.  Analysis was performed on 236 wild bees collected in near proximity to tunnel cultivation, greenhouse cultivation and collected from two control landscapes. The abdomen of the bees was used to extract RNA/DNA for further detection and quantification of ten pathogens using qPCR. The proportion of infected bees within each group was calculated based on the results from the qPCR analysis. A two-proportion z-test was used to determine whether the difference in pathogen prevalence between the four groups was of statistically significant at α = 0.05. The results show that there was no significant difference when comparing the presence of all pathogens between bees in the test groups and the bees in the control groups (p= 0,29- 0,33). However, the prevalence of three viruses was significantly higher among bees collected in the near proximity of a greenhouse compared with bees collected from the near proximity of a tunnel cultivation (p< 0,003). For Slow bee paralysis virus the prevalence was 2,5 times higher and for Deformed wing virus and Black queen cell virus the prevalence was 3,5 and 1,3 times higher among bees collected near a greenhouses compared to near a tunnel cultivation.

Pollinating insects are important for many plants and for the human population. To be able to monitor pollinators and assess improvements made for them, it is important to get information about pollinator population changes. Therefore, it is essential that the methods used to collect data are accurate (i.e. that they represent the pollinator fauna). One commonly used method is pan-traps, but this method is suggested to be affected by the abundance of surrounding flowers. The results in the present study showed that catches in pan-traps can be affected by flower cover and the colour of the flowers, depending on which colours are preferred by the insects. The effects differed when looking at a larger scale (2-6 ha) and a smaller scale (25 m2) around the pan-traps. When comparing cover of flowers with catches in pan-traps in the small scale there were some results that showed linear positive correlations (expected), but also, negative linear and quadratic correlations. In contrast, in the large scale there were no significant positive linear correlations. When comparing catches in hand-net and pan-traps, only in one out of six taxonomical groups there were a correlation. The results in this study show that catches in pan-traps can be misleading if catches are done to survey pollinator population fauna and the cover of flowers is not considered.

Over 80% of wild angiosperms are reliant upon animal pollination for fruit and seed set and bees and other insects provide a vital pollination service to around a third of the crops we produce. Habitat loss, climate change and disease spread all threaten pollinator populations, with local declines and range contractions in honeybees and bumblebees leading to concerns that crop production may suffer as a result of pollinator shortages. Whilst agriculture and wildlife are often presented as being at odds with one another, the relationship between farmers growing pollination dependent crops, and the bees and insects that service them could be mutualistic. Flowering crops planted by farmers can provide an important source of forage to wild bees, whilst in return wild bees can contribute to ensuring farmers achieve adequate yields of marketable crops. The potential of this mutualistic relationship can be maximised by farmers by adopting management practices that reduce harm to, and enhance the wellbeing of, the wild bees around their farm. A group of common pesticides (neonicotinoids) used by farmers have recently been linked to pollinator ill health. Sub-lethal effects resulting from exposure to the neonicotinoid imidacloprid have been reported in honeybees and bumblebees, with bumblebee reproductive success found to diminish as a result of exposure to field realistic doses of this agrochemical. Here, the mechanism behind the reduced queen production in bumblebee colonies is suggested, with bees exposed to imidacloprid showing reduced efficiency in foraging for pollen. Farmers dependent upon pollinating insects for crop production can opt to avoid the use of pesticides known to harm these insects, however future studies are needed to identify safer alternatives that can be use in their place. Farmers can choose to increase the number of bees at their farms by utilising domesticated honeybees and purchasing commercially reared bumblebees. The use of these pollinators can ensure a minimum number of bees in the vicinity of a crop, and facilitate the production of crops at times when wild bee numbers are low. Concerns have been raised, however, regarding the use of commercially reared bees, mostly in regard to pathogen and parasite transmission, but also in respect to the possibility of outcompeting native species. Here the frequency and severity of attacks on commercial Bombus terrestris colonies, by the wax moth, an understudied bumblebee pest, are examined. Wax moths were found to infest almost half of the bumblebee nests deployed at fruit farms, with around a third of infestations resulting in nest destruction. Farmers investing in commercial bees will want to reduce the impact of harmful pests that may result in a reduced pollination service being delivered. Wax moth infestation rates at the study farms using commercial bees were high and the potential of a ‘spill- back’ effect on wild bees was examined. No evidence was found to suggest that nests in close proximity to these farms were any more or less likely to suffer from an attack than nests situated further away. Nest size was found to be the most significant predictor of an infestation, with larger nests more prone to wax moth attacks. Whilst farmers can utilise domesticated and commercially reared bees, relying on one source of pollination is inherently risky, and the most robust service will likely be provided by a range of pollinators. As well as reducing the use of chemicals known to harm beneficial insects, farmers can improve the habitat around their farms to help encourage and sustain wild pollinator populations. Sowing flower strips has been found to increase the abundance and diversity of pollinating insects, however, studies linking the use of these strips to crop production are lacking. Here we demonstrate for the first time that sowing small flower strips, adjacent to strawberry crops serviced by both wild and managed bees, can increase the overall number of pollinators foraging on the crop. This thesis contributes to our understanding of the implications of farm management decisions on pollinator health. It provides experimentally based evidence to guide farmers in making informed decisions regarding the future of crop pollination services and highlights the need for an integrated approach to managing pollination services for sustainability.

Bumblebees are important pollinators, commercially used in large-scale plant growing in greenhouses. Their males produce marking pheromones for mating, which attract young bumblebee queens. These pheromones are often a complicated mixture of chemicals, which is produced in the male labial gland, and the mixture itself is specific for each bumblebee species. The regulation of bumblebee sexual pheromone biosynthesis is largely unknown, and this Master's thesis is focused on the analysis of the mechanisms which lead to the regulation of the Bombus terrestris male pheromone's fat-acid and terpenes biosynthesis, specifically on stereospecific enzymatic reduction of double bond of farnesol. This thesis studies the influence of potential neurohormones on a specific enzymatic mixture, which is involved in the pheromone biosynthesis. Methods used in this project include biochemical, analytic and molecular-biology methods.

Bumblebees have shown both long and short-term declines throughout their range. These declines may be attributed to a range of factors including changes in land use, alterations in climatic conditions and species introductions. However, management strategies for bumblebee conservation often focus on provision of summer forage resources and other factors are frequently overlooked. Provision of spring forage and nesting sites for bumblebee queens are rarely considered, though colony foundation and early colony growth are two of the most sensitive stages in bumblebee life history. Here, the efficacy of certain agri-environment prescriptions for providing spring forage and nest sites for bumblebees is assessed, highlighting a need for specific schemes targeted towards the provision of these vital resources in the rural environment. The nesting ecology of bumblebees is poorly understood because wild colonies are difficult to locate. However, a greater knowledge of the colony-level effects of environmental change is crucial to understanding bumblebee declines. Attracting bumblebee queens to nest in artificial domiciles could provide a valuable tool for studying colony-level responses. However, domicile trials and the findings of a literature review presented here demonstrate that this approach may be largely impractical for use in the UK. Conversely, a nationwide public bumblebee nest survey produced numerous data regarding nest site preferences among bumblebee species and also demonstrated that citizen science may also provide a sensitive method for detecting declines in currently common bumblebee species. An understanding of the ecology of species interactions and coexistence can provide valuable insights into factors that may influence declines. Data presented here suggest that coexistence between some bumblebee species may be maintained by resource partitioning based on diel activity patterns that are linked to species-specific environmental tolerances. If this is the case, the potential role of climate change in bumblebee declines may be severely underestimated. There is also increasing evidence that genetic factors may play a role in bumblebee losses, accelerating declines of small, fragmented populations as a result of reduction in genetic diversity and inbreeding depression. Here, the feasibility of reintroducing British B. subterraneus (now extinct in the UK) from New Zealand into England is assessed using population genetic techniques. The findings suggest that the population history of B. subterraneus in New Zealand has resulted in a dramatic loss of genetic diversity and high genetic divergence from the original UK population, suggesting that it may not be a suitable for use in the reintroduction attempt. This work draws together some understudied aspects of bumblebee ecology with a particular focus on nest site requirements, availability of spring forage, mechanisms of avoidance of inter-specific competition and population genetic processes. The potential role of these in bumblebee declines is considered and new data relevant to the conservation of these important species is presented. It is hoped that this work will inform future management strategies for bumblebee conservation, highlight areas in need of further study and provide a sound starting point for future research in these areas.