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African honeybee workers, Apis mellifera scutellata can activate their ovaries under queenless conditions to produce male (haploid) offspring. In contrast, laying workers of the Cape honeybee, Apis mellifera capensis, produce female (diploid) offspring via thelytokous parthenogenesis. In the early 1990’s colonies of A. m. capensis were transported into the distribution area of A. m. scutellata (corresponding to the summer rainfall region of South Africa), leading to the “capensis calamity”. Laying workers of A. m. capensis invaded and killed colonies of A. m. scutellata leading to losses of thousands of commercial colonies. A survey of the apiaries in the A. m. scutellata region was conducted over 18 months from 1997 to 1998, to determine the extent of the problem. It was found that the parasites were established in many apiaries throughout the distribution range of A. m. scutellata. As the problem seemed to be more severe with commercial and migratory beekeepers, the apiaries surveyed were divided into risk groups related to beekeeping practices. The low risk group included apiaries of beekeepers in areas that are separated from commercial beekeepers and their high risk activities. These low risk colonies were sedentary vs the migration to high risk ares eg. Aloes, sunflower pollination areas, citrus and other fruit pollination areas of the high risk apairies. The apiaries were monitored and records of the colonies’ condition were taken. Samples of workers were collected for dissection. It was found that the low risk group had a lower rate of infection, a higher production of brood and honey and a higher rate of survival over a 12 month period. The significant characteristics for identifying infection of a colony were determined as being the colour of the workers, the brood pattern, the presence of multiple eggs in cells and the presence of the queen. Indeed, the presence of dark workers with a black scutellum, an irregular brood pattern, the presence of multiple eggs in cells and the absence of queen were all prevalent in infected colonies. As sample of workers from all inspected colonies were dissected and the average ovariole counts as well of the development stage of the ovaries proved to be significant variables in the diagnosis. Other variables eg. Ovariole counts, spermatheca size and aggression proved to be not significant, but in conjunction with other variables, could be used for diagnosis. The genetic nature of the invasive parasitic population was determined using polymerase chain reaction (PCR) analysis. Nine loci were tested and the DNA fingerprints of all individuals sampled throughout the summer rainfall region were proved to be identical. This genetic identity led to the descripter of these individuals as a pseudoclone. In contrast, workers of A. m. scutellata were tested with the same loci and showed the normal distribution of an out-breeding population. In order to investigate the spread of the parasite within an apiary, colonies were exposed to heavily infected hives and inspected regularly. Ninety five percent of the colonies had either died or absconded within 12 months. It is concluded that this phenomenon of social parasitism is the consequence of apicaultural activities and that it can be managed by adopting low risk beekeeping practices. / Dissertation (MSc (Zoology and Entomology))--University of Pretoria, 2007. / Zoology and Entomology / unrestricted

Orientador: Ricardo de Oliveira Orsi / Resumo: As abelhas melíferas são importantes agentes polinizadores em cultivos agrícolas e áreas de vegetação nativa e diretamente responsáveis pela produção apícola. Entretanto, grandes perdas de colônias manejadas vêm sendo registradas mundialmente, sendo a ampliação do uso de agrotóxicos uma das principais causas que pode estar associada a esse fenômeno. No presente trabalho, observou-se por meio de análises morfológicas, que a exposição de abelhas nutrizes em colônias, durante seis dias, a pastas de pólen contaminadas com doses ambientalmente relevantes do inseticida sistêmico fipronil (2,5 ppb) e fungicida piraclostrobina (850 ppb), isolados ou em associação, promoveu redução na altura das células secretoras das glândulas mandibulares; e que a associação dos agrotóxicos também reduziu o reservatório dessas glândulas. Nas glândulas hipofaringeanas, o número de ácinos que compõem a glândula não foi alterado, porém, a exposição aos agrotóxicos ocasionou redução na área dessas estruturas. Em conjunto, essas alterações podem reduzir a capacidade de secreção de geleia real pelas abelhas nutrizes. Estudos do proteoma da cabeça das abelhas utilizando a técnica 2D-PAGE para o fracionamento de proteínas, com identificação das proteínas em spots que apresentaram diferença de expressão (comparando grupos expostas e não-expostos aos agrotóxicos) por ESI-MS/MS, demonstraram alterações na expressão de proteínas pertencentes a família das principais proteínas geleia real (MRJPs); e de proteínas... (Resumo completo, clicar acesso eletrônico abaixo) / Doutor

INTRODUCTION:Honey bees, Apis mellifera, have a diverse community of pathogens. Previous research has mostly focused on bacterial brood diseases of high virulence, but milder diseases caused by fungal pathogens have recently attracted more attention. This interest has been triggered by partial evidence that co-infection with multiple pathogens has the potential to accelerate honey bee mortality. In the present study we tested whether co-infection with closely related fungal brood-pathogen species that are either specialists or non-specialist results in higher host mortality than infections with a single specialist. We used a specially designed laboratory assay to expose honey bee larvae to controlled infections with spores of three Ascosphaera species: A. apis, the specialist pathogen that causes chalkbrood disease in honey bees, A. proliperda, a specialist pathogen that causes chalkbrood disease in solitary bees, and A. atra, a saprophytic fungus growing typically on pollen brood-provision masses of solitary bees.RESULTS:We show for the first time that single infection with a pollen fungus A. atra may induce some mortality and that co-infection with A. atra and A. apis resulted in higher mortality of honey bees compared to single infections with A. apis. However, similar single and mixed infections with A. proliperda did not increase brood mortality.CONCLUSION:Our results show that co-infection with a closely related fungal species can either increase or have no effect on host mortality, depending on the identity of the second species. Together with other studies suggesting that multiple interacting pathogens may be contributing to worldwide honey bee health declines, our results highlight the importance of studying effects of multiple infections, even when all interacting species are not known to be specialist pathogens.

Honey bee population decline has been attributed to a variety of causes including infestation of hives with Varroa destructor mites. Fluvalinate has been extensively used in the United States to combat these mites for nearly 30 years, despite its high toxicity to honey bees. The objectives of the current research project were to investigate the extent of fluvalinate contamination in commercially available wax and to define exposure pathways from the contaminated wax and fluvalinate-impregnated strips to larval and adult honey bees. All of the commercial wax tested in the current study contained elevated fluvalinate concentrations, ranging from 170 to 1040 ng/g wet weight, indicating a need for regulation of the sources of wax being rendered for resale. Based on the negative logarithm of the partition coefficient between wax and pollen (-0.54) and the fact that all of the tested wax samples contained elevated concentrations of fluvalinate, it is evident that fluvalinate has the potential to actively transfer from the contaminated wax into bee hive matrices. This point was confirmed by adding fluvalinate-dosed wax, fluvalinate-impregnated strips, or a combination of the two to 10-frame hives. Larvae and adult bees from those hives were checked for fluvalinate exposure using gas chromatography-mass spectrometry analysis. Larvae had detectable concentrations of fluvalinate in all three treatments. Bioaccumulation in adult bees was significantly affected by the interaction between treatment type and application time. In other words, residues were comparable from hives that only had fluvalinate-dosed wax to those that were actively being treated with impregnated strips, strongly suggesting that transfer of fluvalinate from wax into adult bees was an important exposure route. In conclusion, exposure of fluvalinate from contaminated wax and treatment strips to larvae and adult honey bees is an important factor that needs to be considered when applying miticides and evaluating risk in honey bee hives.

Acidentes envolvendo abelhas africanizadas são freqüentemente relatados, particularmente na América do Sul. As picadas de abelhas causam reações localizadas e sistêmicas e os sintomas do envenenamento incluem náuseas, vômitos, hemólise, falência renal e coagulação intravascular disseminada. Durante muito tempo todas as reações tóxicas eram atribuídas à presença de uma fosfolipase A2, mesmo sendo o veneno uma mistura complexa de substâncias. A melitina, o componente mais abundante e tóxico do veneno de abelha, é um peptídeo de 26 aminoácidos com a habilidade de interagir e danificar membranas celulares. A melitina é também capaz de modular muitas proteínas, aumentando a diversidade de atividades biológicas do peptídeo. Até recentemente, acreditava-se que a estrutura tri-dimensional biologicamente ativa do peptídeo, que possui conformação em hélice, era um tetrâmero. Neste trabalho avaliamos a conformação da melitina e seus estados oligoméricos em solução por dinâmica molecular e a interferência da melitina na função plaquetária. Aqui está demonstrado que a melitina possui uma conformação randômica em condições fisiológicas e que sua estrutura tri-dimensional sofre alterações de acordo com as condições ambientais. Ainda, foi demonstrada uma nova atividade biológica do peptídeo melitina. O peptídeo é capaz de induzir a 8 agregação plaquetária de forma dose-dependente e de interagir diretamente com a superfície de plaquetas. A correlação entre a conformação da melitina e suas atividades biológicas é discutida. Os resultados aqui apresentados podem ser valiosos no entendimento do papel da melitina nas coagulopatias induzidas por veneno de abelha. O estudo estrutural mostrado aqui pode ser aplicado para explicar as diferentes atividades do peptídeo. / Accidents involving africanized bees are frequently reported, particularly in South America. Bee stings cause localized and systemic reactions and the symptoms of envenomation include nausea, vomiting, hemolysis, kidney failure and disseminated intravascular coagulation. For a long time, all toxic reactions were ascribe to the presence of a phospholipase A2, despite of being the venom a complex mixture of substances. Melittin, the most abundant and the major toxic component of bee venom, is a 26 amino acid peptide with the ability to interact and disrupt cell membranes. Melittin is also able to modulate many proteins, enhancing the wide range of the peptide biological activities. The biologically active tridimensional structure of the peptide, which has a helical conformation, has been described until now as a tetramer. In this work we evaluated the conformation of melittin and its oligomeric states in solution by molecular dynamics simulations and performed studies of melittin effect on platelet function. Here we demonstrate that melittin has a random conformation under physiological conditions and its tridimensional structure changes under different environmental conditions. Moreover, here we describe a new biological activity of melittin. The peptide is able to induce platelet aggregation in a dose10 dependent manner and can interact directly with the platelet surface. The correlation between melittin conformation and biological activity is discussed. Our results might contribute to elucidate the role of melittin in bee venom induced coagulopathies. The structural data gathered in this work may explain the different activities of the peptide.

The European honey bee, Apis mellifera, is a primarily beneficial insect for mankind. It has been utilized by humans for thousands of years for the products and services it provides. Crop pollination and honey production are two of the most economically beneficial activities of the honey bee. Though they have been important for many centuries and immeasurable amounts of effort have been expended investigating the methods and means to harness their natural abilities, a far lesser amount of attention has been directed towards exploring their molecular makeup. These experiments involve identifying modification of gene transcription as a result of exposure to a pheromone or a parasite. This data will provide information on the general types of transcripts involved in the biochemical response of the honey bee to the two stimuli and will also provide specific candidates for further investigation of their potential role in downstream behavioral events.

The European honey bee, Apis mellifera, is a primarily beneficial insect for mankind. It has been utilized by humans for thousands of years for the products and services it provides. Crop pollination and honey production are two of the most economically beneficial activities of the honey bee. Though they have been important for many centuries and immeasurable amounts of effort have been expended investigating the methods and means to harness their natural abilities, a far lesser amount of attention has been directed towards exploring their molecular makeup. These experiments involve identifying modification of gene transcription as a result of exposure to a pheromone or a parasite. This data will provide information on the general types of transcripts involved in the biochemical response of the honey bee to the two stimuli and will also provide specific candidates for further investigation of their potential role in downstream behavioral events.

Originally described from the Asian honey bee, Apis cerana, the microsporidian Nosema ceranae is an obligate, intracellular parasite that has recently been discovered infecting the western honey bee, Apis mellifera. More research on the biology of N. ceranae as well as on the impact it may have on A. mellifera is greatly needed. However, conducting studies on N. ceranae is not only dependent on seasonal availability of Nosema spores, but also on reliable methods for determining spore viability. This study presents the results of using cryogenics to provide long term storage of viable N. ceranae spores and a differential staining procedure that details how to use bright field microscopy with the fluorescent viability dye, propidium iodide (PI), and the fluorescent stain, 4', 6-diamidino-2-phenylindole (DAPI) to differentiate viable and nonviable spores. Using these methods, it was found that freezing N. ceranae at -70 °C in 10% glycerol yielded the lowest mean rate of spore mortality after thawing (24.2% ± 2.2).