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El polen apícola es uno de los productos de la colmena más conocido. Las abejas melíferas (Apis mellifera L.) lo recolectan como una de sus principales fuentes de alimento. Si bien ha sido utilizado por las civilizaciones egipcia y griega atribuyéndole propiedades terapéuticas y “rejuvenecedoras”, no fue hasta después de la Segunda Guerra Mundial que comenzó a aumentar la producción y su consumo. Actualmente sus características composicionales lo constituyen en un excelente suplemento nutricional y debido a sus propiedades bioactivas es considerado un alimento funcional. Por otra parte, el polen es uno de los productos de la colmena que presenta mayor variabilidad composicional atribuido principalmente a las diferentes floraciones visitadas por las abejas. En este sentido, el análisis entomopalinológico es apropiado para clasificarlo como multi o monofloral siendo este último más estable composicionalmente, aunque también puede sufrir algunas variaciones según la zona de producción. Por esta razón, es imprescindible caracterizar al polen apícola fisicoquímicamente para poder asegurar su calidad endógena y brindar información completa al potencial consumidor. Así, el principal objetivo de este trabajo de tesis es desarrollar metodologías analíticas que permitan determinar la composición del polen de abeja recolectado en la zona centro de Argentina. Inicialmente la clasificación entomopalinológica de las muestras se realizó mediante la acetólisis de los granos de polen evitando la separación por colores de las cargas corbiculares, que es la etapa del proceso que demanda más tiempo. Desde el punto de vista físico-químico se desarrolló una metodología rápida y de bajo costo para la determinación de humedad y proteínas totales en un pool de cargas corbiculares empleando espectroscopía en el infrarrojo cercano (NIR) y técnicas quimiométricas tales como SPA-MLR e iSPA-PLS. Además, la utilización del modelo iSPA-PLS-DA permitió la clasificación de las muestras en relación a un contenido proteico de 20%. Por otra parte, se pusieron a punto técnicas de microanálisis para evaluar el contenido de polifenoles, flavonoides y proteínas en cargas corbiculares individuales estableciendo los respectivos coeficientes de variación. De esta manera se confirmó la elevada variabilidad que presentan los mencionados parámetros en la matriz apícola probablemente relacionados al origen botánico. Asimismo, se construyó un modelo quimiométrico en base a espectroscopía NIR para estimar el contenido de polifenoles totales en cargas individuales de polen corbicular. Finalmente, en relación al tratamiento poscosecha, se llevó adelante un ensayo cuantitativo in vitro de actividad antimicrobiana utilizando un extracto etanólico de propóleos como preservante de polen fresco como una alternativa de conservación de bajo costo. Los resultados obtenidos en esta tesis indican que el polen de abeja recolectado en la zona centro de Argentina presenta muy buenas características nutricionales y bioactivas en base al contenido de proteínas, polifenoles y flavonoides definidos principalmente por los taxones Brassicaceae (mayormente Diplotaxis tenuifolia), Eucalyptus sp. y Lotus sp. La incorporación de las metodologías desarrolladas en este trabajo para realizar el control de calidad de este producto apícola permitiría el correcto rotulado del producto comercial o, incluso definir su destino para las diferentes industrias (alimenticia, farmacéutica, cosmética). / Bee pollen is one of the best-known beehive products. Honey bees (Apis mellifera L.) collect it as one of their main food sources. Although it has been used by the Egyptian and Greek civilizations ascribing therapeutic and "rejuvenating" properties to it, it was after the Second World War that the production and consumption increased. Currently, its compositional characteristics make it an excellent nutritional supplement, and due to its bioactive properties, it is considered a functional food. On the other hand, bee-pollen is the hive product that presents the greatest compositional variability, attributed mainly to the different blooms visited by bees. In this sense, the entomopalynological analysis is suitable to classify it as multi or monofloral, being the latter more stable in its composition, although it may also undergo some variations depending on the production area. For this reason, it is essential to perform a physicochemical characterization of the bee-pollen to ensure its endogenous quality and provide complete information to the potential consumer. Thus, the main objective of this thesis is to develop analytical methodologies that allow determining the composition of the bee-pollen collected in central Argentina. Initially the entomopalynological classification of the samples was carried out through the acetolysis of the pollen grains, avoiding the separation by colours of the corbicular pellets, which is the stage of the process that requires more time. From the physicochemical point of view, a rapid and low-cost methodology was developed for the determination of moisture and total proteins in a pool of bee-pollen pellets using near-infrared spectroscopy (NIR) and chemometric techniques such as SPA-MLR and iSPA-PLS. Moreover, the use of the iSPA-PLS-DA model allowed the classification of the samples concerning a protein content of 20%. On the other hand, microanalysis techniques were developed to evaluate the content of polyphenols, flavonoids and proteins in individual corbicular loads, establishing the respective variation coefficients. In this way, the high variability of the mentioned parameters presented in the apicultural matrix was confirmed, probably related to botanical origin. Likewise, a chemometric model based on NIR spectroscopy was constructed to estimate the total polyphenols content in individual loads of corbicular pollen. Finally, concerning postharvest treatment, a quantitative in vitro antimicrobial activity test was carried out using an ethanolic extract of propolis as a preservative for fresh pollen as a low-cost conservation alternative. The results obtained in this thesis indicate that the bee-pollen collected in central Argentina has very good nutritional and bioactive characteristics based on the content of proteins, polyphenols, and flavonoids defined mainly by the Brassicaceae taxa (mostly Diplotaxis tenuifolia) , Eucalyptus sp. and Lotus sp. The incorporation of the methodologies developed in this work to carry out the quality control of this beekeeping product would allow the correct labelling of the commercial product or even define its destination for the different industries (food industry, pharmaceuticals, cosmetics).

Biomass feedstock is a viable alternative to finite fossil fuel resources to provide many of the same—plus others that petrochemicals cannot—chemical building blocks required to fabricate durable and high-performance materials. We demonstrate here for the first time a new generation of synthesized elastomers, namely bio-based engineering elastomers (BEE). These are of particular significance because they are synthesized from monomers derived from biomass, by routes which are suitable for large scale production, and they exhibit thermo-mechanical properties at least equivalent to current commercial petrochemical-derived elastomers. Bio-based monomers in large scale production, such as sebacic acid, itaconic acid, succinate acid, 1,3-propanediol, and 1,4 butanediol are chosen to generate the first synthetic BEE matrix through melting polycondensation—a comparatively simple reaction scheme offering good control and the potential for low cost, large-scale production. A novel linear BEE, an almost non-crystalline copolyester elastomer with low glass transition temperature (Tg) containing double bonds is designed and synthesized using multiple monomers (to help suppress crystallization). Silica nanoparticles are then introduced into the BEE matrix to achieve significant strengthening and improved environmental stability. Chemical crosslinks formed by peroxide and the pendant double bonds in the copolyester macromolecules endow the BEE with both the necessary high elasticity and required environmental stability. The BEE nanocomposites obtained exhibit excellent thermomechanical properties, such as an ultimate tensile strength of 20 MPa.

The effects of miticides on the reproductive physiology of queens and drones were examined. The first study examined the effects of Apistan (fluvalinate), Check Mite+ (coumaphos), and Apilife VAR (74% thymol) on sperm production and viability in drones. Drones from colonies treated with each miticide were collected at sexual maturity. Sperm production was determined by counting the number of sperm in the seminal vesicles. Sperm for viability assays was analyzed by dual fluorescent staining. Apilife VAR and coumaphos significantly lowered (P<0.0001) sperm production and coumaphos treatments caused a significant decrease (P<0.0001) in the sperm viability. The effects of miticides on queens was examined by treating queen-rearing colonies and examining the number and viability of sperm in the spermathecae of newly mated queens. Queens from each treatment group were collected after mating and the spermathecae were removed and analyzed. Colonies treated with coumaphos failed to provide viable queens and were excluded. Apilife VAR was found to significantly decrease (P<0.0016) sperm viability. No significant differences in sperm numbers were found between treatments. The effect of miticides on sperm viability over time was also examined. Drones were reared as described, but the spermatozoa were collected as pooled samples from groups of drones. The pooled samples from each treatment were subdivided and analyzed periods of up to 6 weeks. Random samples were taken from each treatment (n = 6 pools) over a period of 6 weeks. The exposure of drones to coumaphos during development significantly reduced sperm viability for all 6 weeks, and caused a large decline in week 6. The potential impacts of these results on queen performance and failure are discussed. / Master of Science in Life Sciences

Host-associated microbial communities, also known as microbiomes, are essential to the health of their hosts, and disturbance of these communities can negatively impact host fitness. The honey bee gut microbiome is a relatively simple host-associated community that makes an excellent model system for studying microbiome stability. In addition, honey bees are essential agricultural pollinators, so factors that impact their health are important for food security. The presented research focused on the stability of the honey bee gut microbiome in response to disturbance from the antibiotic tetracycline. Tetracycline was chosen because it is the most commonly used antibiotic in beekeeping, and may have negative effects on bees through the disruption of their gut microbiomes. The first study presents a new fecal sampling method for studying the honey bee gut microbiome of individual bees over time. This method accurately represented bacterial community structure in the gut microbiome as determined with 16S rRNA gene amplicon sequencing, as fecal and whole gut samples did not differ significantly for individual bees. The fecal sampling technique was then used to examine changes to individual honey bee gut bacterial communities before and after tetracycline exposure. Minimal differences in gut community structure were detected prior to and five days after tetracycline treatment. However, there was variability in how individual gut microbiomes were affected by tetracycline treatment, highlighting the importance of intraspecific variation in response to disturbance. The second study investigated whether the timing of disturbance during a host's life impacts microbiome community stability. Newly emerged bees were treated with tetracycline, returned to their hive, and recollected 7 or 14 days later. The gut communities of the bees were then characterized using 16S rRNA gene amplicon sequencing. Gut microbiome structure of bees treated with tetracycline at emergence differed from controls both 7 and 14 days after emergence, with the antibiotic-treated bees having lower community richness overall. This study showed that early life disturbance of host-associated microbial communities can influence microbiome structure later in life. The final study describes the occurrence of antibiotic resistance genes (ARGs) in honey bee gut bacterial symbionts from hives across the US. Honey bee gut metagenomes were sampled from hives at 13 apiaries located in a transect from Virginia to Washington, and ARG presence was assessed across the sites. We also specifically quantified the abundances of two common tetracycline resistance genes (tet(B) and tet(M)) across apiaries. ARGs, both for antibiotics used in beekeeping and unrelated antibiotics, were detected in honey bee gut bacteria from all apiaries. Tetracycline resistance genes were the most common across all apiaries, and the abundance of two tetracycline resistance genes varied by apiary. Members of the honey bee gut microbiome contained different proportions of ARGs, but taxa within a single family contained similar proportions, possibly indicating phylogeny plays a role in ARG accumulation. In particular, Gilliamella and Frischella, both in the family Orbaceae, contained the highest percentages of ARGs. The results from this study suggest honey bee bacteria act as reservoirs of ARGs. Overall, the presented research contributes to the field of biology by highlighting the importance of intraspecific variation in host-associated microbial communities and presenting a new method for studying honey bee gut microbiome variation at the individual-level, showing that early life events in honey bees influence microbiome development, and suggesting that honey bee bacterial symbionts have adapted to deal with antibiotic disturbance through the accumulation of ARGs. / Doctor of Philosophy / Nearly all animals, including honey bees, have communities of bacteria that live on and in them. These communities, called microbiomes, are often essential to the health of their hosts. For instance, communities of gut bacteria can be important for breaking down food for digestion. Honey bees have approximately 10 bacterial species that consistently live in their guts and provide these types of services to their host. As with many bacterial communities, these beneficial bacteria can be impacted by exposure to antibiotics, even though antibiotics can also be important for treating or preventing dangerous bacterial infections. In honey bee hives, the antibiotic tetracycline is used to prevent bacterial disease. However, tetracycline may simultaneously be negatively impacting colony health through disruption of the honey bee gut microbiome. The goal of the presented work was to understand how tetracycline impacts the honey bee gut microbiome. In my first chapter, I demonstrate a new fecal sampling method that will allow us to understand how gut microbiomes from individual bees change over time. I first compared the bacteria found in fecal samples to those in the whole guts of bees and found that the bacterial communities of the fecal samples and guts were very similar, indicating that fecal sampling is a good method for studying the honey bee gut microbiome. I then used my fecal sampling method to determine how individual honey bee gut microbiomes respond to antibiotic disturbance over time. I collected fecal samples from adult bees prior to treatment, treated the bees with tetracycline, and after five days of being maintained in the lab, recollected fecal samples. My results showed few changes to the bacterial communities before and after treatment, suggesting some honey bee gut microbiomes may be resistant to tetracycline. In my second chapter, I addressed whether exposure to antibiotics early in life had long-term impacts on the gut microbiome. I treated bees at the start of adulthood with tetracycline, returned the bees to their hive for 7 or 14 days, and assessed their microbiome. Tetracycline treatment at the beginning of adulthood changed the gut microbiome later in life, as the microbiomes of tetracycline-treated bees and controls differed from one another both 7 and 14 days after exposure. This chapter shows that disturbances to microbiomes during early life can also affect microbiomes later. My third chapter addressed how honey bee bacteria have adapted to antibiotic use by identifying antibiotic resistance genes (ARGs) in honey bee gut bacteria from 13 hives located in a transect across the US from the state of Washington to Virginia. I found a variety of antibiotic resistance genes in honey bee gut bacteria, both associated with beekeeping and likely environmental contamination. The prevalence of antibiotic resistance genes in honey bee bacteria may help us track antibiotic resistance in the environment. Ultimately, my dissertation contributes to our understanding of how antibiotic use affects honey bees by changing their gut microbiome.

Honey bees, Apis mellifera Linn., provide vital economic and ecological services via pollination while concurrently facing multiple interconnected stressors impacting their health. Many crops like apples, peaches, and cherries that add diversity and nutrition to our diet are wholly or partially dependent upon the pollination services of insects. Orchard crops are self-incompatible and commonly regarded as crops reliant on the pollination services of insects, and while previous studies have focused on the impact of bees to orchard crops during bloom, fewer studies have examined the reciprocal relationship of the orchards on honey bees, particularly across the entire foraging season. Here we investigated the foraging dynamics of honey bees in an orchard crop environment in Northern Virginia, United States. We decoded, mapped, and analyzed 3,710 waggle dances, which communicate the location of a valuable resource in the environment, for two full foraging seasons (April-October, 2018-2019), and, concurrent to the dance filming, collected pollen from returning foragers. We found that bees forage locally the majority of the time (< 2 km) throughout the season, with some long-range distances occurring in May after bloom (both 2018 and 2019) and in fall (2019). The shortest communicated median distances (0.50 km and 0.53 km), indicating abundant food availability, occurred during September in both years, paralleling the bloom of an important late season resource, goldenrod (Solidago). We determined, through plotting and analyzing the communicated forage locations and from the collected pollen from returning foragers, that honey bees forage more within apple orchards after the bloom (29.4% and 28.5% foraging) compared to during bloom (18.6% and 21.4% foraging) on the understory of clover and plantain. This post bloom foraging also exposes honey bees to the highest concentration of pesticides across the entire foraging season (2322.89 ppb pesticides versus 181.8 during bloom, 569.84 in late summer, and 246.24 in fall). Therefore, post bloom apple orchards supply an abundance of forage, but also the highest risk of pesticide exposure, which may have important implications for management decisions of bees in orchards. / Master of Science in Life Sciences / Honey bee hives have been declining significantly in the United States, driven by a multitude of issues and stressors including pesticide exposure, disease, pests such as varroa mites, and poor nutrition caused by natural land being converted into development or agriculture. Agricultural landscapes, in particular, are often monocultures are saturated with pesticides creating a potentially hazardous environment, yet reliant on bees to provide pollination for crops. Because of this interconnected relationship between bees and flowers and the effects of stressors agricultural systems cause have with pollinators, it is necessary to understand how honey bees forage in these environments and what potential health risks they face. We investigated honey bees foraging dynamics in an apple orchard in Northern Virginia, United States by observing honey bee waggle dance behavior, where bees literally waggle back and forth for a certain time and at a certain angle telling their nestmates where a resource is, and collecting pollen from returning forager bees to better understand when, where, and upon what honey bees forage throughout the foraging season, which is when flowers are available and the weather warm enough (April – October). We found that bees mostly forage locally near the hive throughout the season, indicating that sufficient amount of food was available even after short bloom time of the apple (April to mid-May). We determined, through plotting and analyzing the waggle dance locations, that honey bees forage more within apple orchards after the bloom on mostly clover and plantain. This abundance of post bloom foraging also exposes honey bees to the highest amounts of pesticides across the entire foraging season. Post bloom apple orchards supply an abundance of forage, but also the highest risk of pesticide exposure to honey bees.

The honey bee is a widely managed crop pollinator that provides the agricultural industry with the sustainability and economic viability needed to satisfy the food and fiber needs of our society. Excessive use of agrochemicals such as the acaricides coumaphos and tau-fluvalinate, and the fungicide, chlorothalonil is implicated in the reduced number of managed bee colonies available for crop pollination services. Here, I report the effects of pesticide exposures on the nutritional and immune health of the honey bee. Total protein concentration was significantly reduced in the coumaphos- and chlorothalonil-treated individuals compared to the pesticide-untreated bees. Total carbohydrate concentration was significantly reduced in the tau-fluvalinate-, coumaphos-, and chlorothalonil-treated individuals compared to the pesticide-untreated bees. Total lipid concentration was significantly decreased in the chlorothalonil-treated individuals compared to the pesticide-untreated bees. Body weight was significantly reduced for the tau-fluvalinate-, coumaphos-, and chlorothalonil-treated individuals, respectively, compared to the pesticide-untreated bees. Head width was significantly reduced for the chlorothalonil-treated individuals whereas the wing length was significantly reduced for the coumaphos and chlorothalonil-treated individuals, respectively, compared to the pesticide-untreated bees. Phenoloxidase activity was significantly increased in the coumaphos-treated individuals compared to the pesticide-untreated bees. Glucose oxidase activity was significantly increased in the chlorothalonil-treated individuals compared to the pesticide-untreated bees. While more research is needed to verify the observed effects of the pesticides on the nutritional and immunity health of the honey bee, it is important for beekeepers to consider alternative methods for control of varroa mites and the use of fungicides near their colonies. / Master of Science in Life Sciences

Yes / This paper responds to the dearth of research into women's negative intra-gender relations and lack of understanding as to why and how these relations manifest. Through a qualitative study of women elite leaders' experiences in UK organizations, the research considers how gendered contexts, women doing gender well and differently simultaneously, intra-gender competition and female misogyny may explain negative intra-gender social relations between women. We consider micro-aggression research and women's abjection and offer a unique conceptualization of intra-gender micro-violence with themes of disassociating, suppression of opportunity and abject appearance. The themes illustrate how the masculine symbolic order shapes and constrains women elite leaders' social relations with other women. We conclude that raising consciousness to intra-gender micro-violence between women is important as a means of disruption; to facilitate women and men's acceptance of intra-gender differences between women; and to open up opportunities and possibilities for women in organizations.

As pollinators bumble bees play the crucial role of contributing to propagation of flowering plants in favour of food production as well as biodiversity. Over the course of a few decades bumble bees have seen a remarkable decline, with contributing factors being climate change, pesticides and pathogens such as viruses and parasites. In Sweden, commercially reared bumble bees are bought for the purpose of pollination in fruit and berry plantations. However, these reared bumble bees are a suspected contributor to a spillover of pathogens to wild bees in the same area. The aim of the study was to determine the prevalence of five viruses and five parasites in wild bumble bees nearby commercially reared bumble bees and to determine seasonal variation in pathogen distribution. qPCR was used for analysis of Acute bee paralysis virus, Deformed wing virus, Slow bee paralysis virus, Black queen cell virus and Sacbrood virus as well as the parasites Crithidia bombi, Apicystis bombi, Nosema bombi, Sphaerularia bombi and Locustacarus buchneri. The results showed a statistically significant, 4,8 times higher prevalence of A. bombi nearby commercially reared bumble bees in greenhouses compared to control landscapes. The results were also compared to pathogen prevalences in bumble bees caught in June the same year, showing a significantly higher prevalence in a majority of the parasites. It also showed a decrease in all viruses except Black queen cell virus, where the decrease might be explained by RNA degradation.