La sélection génétique d'abeilles mellifères (Apis mellifera) offre à l'industrie apicole la possibilité de combattre le parasite Varroa destructor et ainsi réduire la dépendance envers les acaricides. En effet, certaines populations d'abeilles possèdent des traits comportementaux hygiéniques héritables qui leur permettent de résister au Varroa. Cependant, les liens entre ces différents traits comportementaux ne sont pas encore bien définis, ce qui limite le progrès génétique. Dans ce contexte, nous avons mesuré les traits comportementaux de résistance au Varroa suivants : les tests de mort du couvain par congélation (freeze-kill brood assay, FKB) et de l'aiguille (pin-kill brood assay, PKB), le varroa-sensitive hygiene (VSH), le retrait des pupes, le mite non-reproduction (MNR) et la réoperculation des cellules de couvain. Ces mesures ont été utilisées pour calculer les corrélations et deux d'entre elles étaient négatives et significatives: (1) entre la réoperculation des cellules infestées par le Varroa et la réoperculation totale et (2) entre la réoperculation des cellules infestées par varroa et le varroa-sensitive hygiene (VSH). Nous avons également sélectionné le meilleur modèle prédictif des niveaux d'infestation par le varroa dans les colonies en utilisant l'approche « step-wise » basée sur le critère AIC. Notre modèle révèle que le MNR et le FKB sont significativement liés à la population de varroas avec une relation négative, tandis que la réoperculation était significativement liée à des niveaux d'infestation de varroas avec une relation positive. Ainsi, les scores MNR ou FKB plus élevés sont significativement reliés à de faibles niveaux d'infestation d'acariens dans les colonies à la fin août, tandis qu'une activité de réoperculation des cellules de couvain plus élevée est significativement reliée à un niveau d'infestation élevé d'acariens dans les colonies. Notre travail indique que le comportement de réoperculation pourrait être un trait de caractère utile pour aider la sélection de lignées d'abeilles résistante à Varroa mais que d'autres travaux doivent être faits pour mieux comprendre sa signification. / The genetic selection of honeybees (Apis mellifera) offers the beekeeping industry the possibility of combating the Varroa destructor parasite and thus reducing its dependence on acaricides. Indeed, some bee populations have heritable hygienic behavioural traits that allow them to resist Varroa infestation. However, the links between these different behavioural traits are not yet well defined, which limits genetic progress. In this context, we measured the following behavioural Varroa resistance traits: freeze-kill brood assay (FKB) and pin-kill brood assay (PKB), varroa-sensitive hygiene (VSH), pupae removal, mite non-reproduction (MNR) and recapping activity. Correlations between these measures show that two are negative and significant: (1) between the recapping of cells infested with Varroa and the total number of recapped cells and (2) between the recapping of cells infested with Varroa and varroa-sensitive hygiene (VSH). We also selected the best predictive model of varroa infestation levels using the "step-wise" approach based on the AIC criterion. Our model revealed that MNR and FKB were significantly related to the varroa population levels with a negative relationship, while recapping was significantly related to mite infestation levels with a positive relationship. Thus, a higher MNR or FKB score is significantly related to low levels of mite infestation in colonies at the end of August, while a higher recapping activity is significantly related to a high level of mite infestation. Our work indicates that recapping behavior could be a useful trait to aid the selection of Varroa-resistant bee lines but that further work needs to be done to better understand its significance.

The varroa mite is a primary driver behind periodical losses of honey bee colonies. The mite requires bees for food and reproduction and, in turn, elicits physiological deficiencies and diseases that compromise bee colony health. The mite nervous system is a target site for existing acaricides. These acaricides not only have adverse health effects on bees, but resistance limits their use to reduce mites and diseases in bee colonies. Voltage-gated chloride channels are involved in the maintenance of nerve and muscle excitability in arthropod pests, which suggests that these channels might be exploited as targets for acaricides. Apistan® (the pyrethroid tau-fluvalinate), Checkmite+® (the organophosphate coumaphos), and Apivar® (the formamidine amitraz) are control products for mite management. The effectiveness of these chemistries has diminished as a result of the increasing incidence resistance in mite populations. I report a toxicological analysis of stilbene products against acaricide-susceptible and -resistant mites. My results find a significant increase in metabolic detoxification enzyme activities in acaricide-resistant mites compared to susceptible mites. Acetylcholinesterase of coumaphos-resistant mites was significantly less sensitive to the toxic coumaphos metabolite compared to susceptible mites, which suggests target-site insensitivity as a mechanism of acaricide resistance. The stilbene product DIDS had significantly higher field efficacy to acaricide-resistant mites compared to Apistan®- and CheckMite+®. These data suggest that DIDS, and other stilbene products, might serve as candidate chemistries to continue field efficacy testing of alternative acaricides for Apistan® and CheckMite+® resistant mites. / Master of Science in Life Sciences

Throughout the last five decades, European Honey bee (Apis mellifera) colonies have been heavily damaged by invading Varroa mites (Varroa destructor), and, more recently, small hive beetles (Aethina tumida). These pests infest A. mellifera colonies throughout Virginia, with V. destructor feeding upon the lipids of their hosts and spreading viruses, and A. tumida feeding extensively on hive products and brood. Because V. destructor has historically demonstrated acaricide resistance, this study examined V. destructor resistance to three common acaricides (amitraz, coumaphos, and tau-fluvalinate) throughout the three geographic regions of Virginia using glass vial contact bioassays; the results showed no resistance in the sites tested. To gain better insights into A. tumida pharmacology, several known acetylcholinesterase (AChE) inhibitors and three novel insecticides (previously shown to have low mammalian toxicity) were tested against an A. tumida laboratory colony through in vivo and in vitro bioassays. The results of these bioassays indicated that coumaphos was most selective and topically effective against A. tumida, while only one experimental compound was selective against A. tumida, with 29-fold less potency than coumaphos. These results can help apiculturists in making informed pest management choices and can lead to future studies further examining V. destructor resistance and optimizing A. tumida insecticide treatments. / Master of Science in Life Sciences / Beekeepers throughout the world have experienced great economic loss and observed a troubling decline in European Honey bee colonies over the past fifty years due to Varroa mite infestations. Varroa mites feed on the fat body of bees, depriving them of nutrients and infecting them with various diseases. Attempts made to control Varroa mites with synthetic chemicals throughout the years have led to acaricide resistance. To look at resistance in Virginia’s mite populations, resistance testing was performed on Varroa mite populations throughout the three geographic regions of Virginia, and these studies showed that there was not resistance in these populations. Another significant hive pest that is increasingly prevalent in the United States is the small hive beetle (SHB), which feeds on bee brood and hive products. SHB management tactics are still being explored, and this project tested various known insecticide treatments against small hive beetles and bees, as well as three insecticide treatments that were designed for mosquito control and have low toxicity to mammals. The results of this study showed that, of the insecticides tested, coumaphos was the most selective against SHB. This information can help beekeepers in Virginia make informed choices when deciding how to treat Varroa mite infestations, and can add to the knowledge base of those fighting small hive beetle infestations.

A apicultura brasileira melhorou muito após a introdução da abelha africana em 1956 pelo geneticista Warwick Kerr e a ocorrência da sua hibridização com as abelhas europeias já presentes no país. Entre outras vantagens, esta abelha híbrida ou Africanizada é relativamente resistente às doenças e parasitas que normalmente afligem as abelhas. A apicultura depende de recursos naturais e apresenta oscilações de produção de acordo com as condições do clima e ambiente regionais. Em épocas de ausência de floradas, a reserva de alimento na colônia é insuficiente e o fornecimento de alimentação artificial às abelhas torna-se aconselhável. Vários estudos com suplementações proteicas para abelhas têm sido realizados com a finalidade de proporcionar maior nutrição nos períodos de escassez de alimento no campo. Entretanto, há de se avaliar também os efeitos destes suplementos nas populações parasitárias das abelhas, como a do ácaro Varroa destructor. Este ácaro constitui uma importante praga e está presente praticamente no mundo todo. Os objetivos principais deste estudo consistiram em avaliar a dinâmica da população de V. destructor quanto aos graus de infestação e reprodução em colônias de abelhas Africanizadas localizadas em um apiário de Ribeirão Preto-SP, relacionando com as principais variáveis climáticas (primeira etapa) e com o fornecimento de dieta proteica complementar (segunda etapa). De agosto de 2013 a outubro de 2016, foram realizados experimentos com abelhas operárias, tanto em adultas (1ª etapa) como em crias (1ª e 2ª etapas). Para a segunda etapa, considerou-se também as variáveis de mapeamento das colônias, como pólen, néctar, cria aberta e cria operculada e as variáveis de sazonalidade, levando-se em conta as quatro estações do ano. Para ambas as etapas observou-se a presença ou ausência natural de rainha nas colônias e sua influência sobre a infestação e reprodução de varroas. Os resultados mostraram, quanto às variáveis climáticas, relação significativa e negativa da temperatura do ar com a infestação de varroas nas abelhas adultas. A umidade relativa do ar apresentou relação significativa e positiva com a infestação do ácaro, tanto em adultas como nas crias. Nenhuma variável climática considerada neste estudo (temperatura, umidade ou precipitação), mostrou evidência de influência sobre a reprodução dos ácaros. Houve um aumento de mais de 3% no grau de infestação de varroas nas crias de abelhas em colônias que receberam a dieta proteica adicional (de 7,83% para 10,97%), em comparação às colônias controle. Entretanto, este aumento não foi significativo. Quanto à reprodução de varroas, o fornecimento da dieta proteica apresentou influência significativa sobre o aumento do número de ácaros encontrados por célula infestada, somente nos meses de setembro de 2015 e fevereiro de 2016. As variáveis de mapeamento apresentaram relação significativa com a infestação de varroas, sendo negativa quanto ao pólen ou crias abertas e positiva quanto ao néctar ou crias operculadas. Nenhuma dessas variáveis apresentaram efeitos significativos sobre a reprodução de varroas. As infestações de varroas foram maiores no outono, em seguida o verão, o inverno e a primavera. Houve diferença significativa entre os valores de infestação entre as estações, exceto entre verão e outono e entre inverno e primavera. A reprodução do ácaro foi maior no outono e em seguida o inverno, o verão e a primavera. Não houve diferença significativa na reprodução do ácaro somente entre as estações verão e primavera. A ausência de rainha influenciou significativamente no aumento da infestação de ácaros na segunda etapa dos experimentos. / Brazilian beekeeping improved considerably after the introduction of the African bee in 1956 by the geneticist Warwick Kerr and its hybridization with the European honey bees that had been introduced in the 1800s. Among other advantages, this hybrid or Africanized bee is relatively resistant to the diseases and parasites that normally affect bees. Apiculture depends on natural resources, which vary with climate and regional environment. When there is a lack of flowers in the field, food reserves in the colony can soon become insufficient. Under such conditions, it is advisable to offer artificial feed to the bees. Various studies with protein supplements have been conducted to provide improved nutrition, especially during dearth periods. However, it is important to determine how such supplements may affect bee health, including infestation with bee parasites, such as the mite Varroa destructor. This mite is an important pest worldwide. Our objectives were to examine the population dynamics of V. destructor in Africanized honey bee colonies in Brazil, as a function of climate and colony factors and of feeding with protein diets. From August 2013 to October 2016, infestations were investigated in adult bees and in honey bee brood. Maps were made of the allocations of pollen, nectar, open and sealed brood in the combs. Data was also taken concerning climate variables during the four seasons. The effect of the presence versus absence of the queen was also investigated through hive manipulations. There was a significant negative correlation of infestation on adult bees with air temperature. Relative humidity was significantly correlated with infestations of the mite on adult bees and in the brood. None of the three climate variables measured (temperature, humidity and rainfall) significantly affected mite reproduction. Brood infestation rates were increased in colonies that were fed a protein diet (10.9 versus 7.83%); however, this difference was not significant. The mean number of mites per bee brood cell was significantly greater in colonies fed a protein diet during only two months of the study, these being September 2015 and February 2016. Some of the mapping variables were significantly correlated with mite infestation. There was a negative correlation of pollen and unsealed brood area with infestation rate, while mite infestation rate was positively correlated with nectar and sealed brood areas. None of the mapping variables was significantly correlated with mite reproduction. Infestation rates were highest in autumn, followed by summer, winter and spring. Mite reproduction was highest in autumn, followed by winter, summer and spring. Mite reproduction did not differ significantly between spring and summer. Loss of the queen significantly increased infestation in the bee brood.

Darbo tema: „Bičių šeimos kaip gamybos priemonės tyrimai“. Duomenys rinkti 2012-2013 metais iš 10 bitynų, kurie yra šiaurės rytų Aukštaitijos regione. Apklausti 5 bitininkai profesionalai ir 5 bitininkai mėgėjai. Raktiniai žodžiai: bitės, Varroa destructor erkės. Apie 64 proc. Lietuvos bitininkų savo bitynuose nekeičia bičių motinėlių, todėl sumažėja bičių produktyvumas. Taip pat, didžiausia bitynų problema yra Varroa destructor erkės, kadangi jos ne tik nualina bičių šeimą, bet yra viena iš esminių priežasčių, dėl bičių mirtingumo po žiemojimo. Darbo tikslas yra įvertinti veiksnius, labiausiai įtakojančius bičių populiacijos mažėjimui ir bičių produktyvumui. Taip pat išanalizuoti bitininkų kompetenciją bitininkystės srityje mėgėjų ir profesionaliuose bitynuose. Darbo uždaviniai: įvertinti bičių šeimų produktyvumą profesionaliuose bitynuose ir mėgėjų bitynuose: • Įvertinti Varroa destructor erkių paplitimą bičių šeimose; • Įvertinti Varroa destructor įtaką bičių šeimų produktyvumui; • Palyginti veislinių ir mišrūnių bičių produktyvumą; • Nustatyti, bičių šeimų, kuriose buvo keistos motinėlės produktyvumą ir atsparumą Varroa destructor erkėms; • Įvertinti medaus kokybinius rodiklius tirtuose bitynuose pagal medaus techninio reglamento reikalavimus; Atlikus analizę paaiškėjo, kad: • Produktyviausios bičių šeimos, kuriose bičių motinėlė keičiama kas du metus, ir nesirgo varoze. • Bičių šeimos sergančios varoze yra mažiau produktyvios. Iš sergančios šeimos profesionaliame... [toliau žr. visą tekstą] / Topic of the paper: “Research of a beehive as a mean of production”. Data collected from 10 apiaries in the region of northeast Upper Lithuania in the year 2012-2013. 5 professional and 5 amateur beekeepers were interviewed. Key words: bees, Varroa destructor mites. It is argued that about 64% of Lithuanian beekeepers apiaries does not change the queen bee, which reduces the productivity of the bees. Also, the biggest problem of the apiaries is Varroa destructor mites, which not only exhausts a beehive, but it is one of the most significant reasons for bee mortality after hibernation. Aim of the paper is to evaluate the most influential factors in declining of bee population and productivity. Also to analyze beekeepers competency in the fields of amateur an professional apiaries. Tasks of the paper: evaluate the productivity of bee colonies in professional and amateur apiaries. • Evaluate the spread of Varroa destructor mites in beehives; • Evaluate the influence of Varroa destructor to the beehive productivity; • Compare the productivity of pedigree and hybrid bees; • Identify beehives that productivity and immunity were affected by Varroa destructor mites; • Evaluate qualitative indicators of honey according to honey technical regulation requirements; The analysis shows that: • The most productive beehives are the ones where the queen bee is substituted every two year and never had varroasis; • Beehives that had varroasis are less productive. 35 kg or 27% less honey is... [to full text]

Submitted by Socorro Pontes (socorrop@ufersa.edu.br) on 2017-03-13T13:17:05Z No. of bitstreams: 1 FranklinAS_DISSERT.pdf: 1406892 bytes, checksum: 31ccee360ab84a9af3e75803363344c4 (MD5) / Made available in DSpace on 2017-03-13T13:17:05Z (GMT). No. of bitstreams: 1 FranklinAS_DISSERT.pdf: 1406892 bytes, checksum: 31ccee360ab84a9af3e75803363344c4 (MD5) Previous issue date: 2016-02-27 / Africanized honey bees (Apis mellifera) from the region of the Semiarid Potiguar has two main diseases: varroatose, whose agent is the mite Varroa destructor and, the Nosemosis disease, recently introduced in the state, whose agent was previously identified in the area of our experimental apiaries as being the microsporide Nosema ceranae. The objectives of this study were to evaluate the effects of direct insolation and shading on the hives, in relation to the mite infestation rate in the adult bees and in the worker brood; on hygienic behavior and on the Nosemosis disease. The experiment was conducted in CETAPIS / UFERSA in the Mossoró-RN city. It were used 10 beehives installed under a metallic structure covered by dry leaves of coconut, it was built on the east-west direction, and with a capacity to absorbed about 90% of the direct insolation. Ten other beehives were installed under the direct effect of insolation, about 15 meters in relation to the former group. The results showed that during the dry season period the hives installed in the shade had an average infestation rate (%) in adult bees significantly lower (P <0.01) than in hives installed in the sun. Although the results show a smaller infestation trend on the bee brood of hives installed in the shade, no significant differences were observed (P = 0.253). Already hygienic behavior was very low, considering that the bees were Africanized bees and it were captured in the region during the swarming season. However, there was a significant negative correlation between the hygienic behavior and the mite infestation rate in adult bees. The nosemosis disease showed one prevalence of 100% in the experimental apiary, however, the average number of spores per bee can be considered very low, being significantly higher during the harvest period than in the off season period's, however, this results did not show significant differences between the hives receiving direct insolation and that ones under shade / As abelhas africanizadas (Apis mellifera) da região do Semiárido Potiguar apresentam duas doenças principais: A varroatose cujo agente é o ácaro Varroa destructor, e a nosemose, recentemente introduzida no estado, cujo agente foi identificado anteriormente na região dos apiários experimentais como sendo o microsporídio Nosema ceranae. Os objetivos desta pesquisa foram avaliar os efeitos diretos da insolação e do sombreamento sobre colmeias em relação à taxa de infestação do ácaro em abelhas adultas e nas crias; sobre o comportamento higiênico e sobre a doença nosemose. O experimento foi realizado no CETAPIS/UFERSA em Mossoró, RN, onde, utilizou-se 10 colmeias instaladas sob uma latada construída no sentido leste-oeste, coberta com folhas de coqueiro que absorvia cerca de 90% da insolação e, outras 10 sob efeito direto da insolação. As coletas foram feitas no período da safra (chuvoso), nos dias 30/01, 20/03, 09/4 e 10/05, e no período da entressafra (seca), nos dias 18/08, 23/09, 07/10 e 30/11. Os resultados mostraram que durante o período de entressafra as colmeias instaladas na sombra apresentaram uma taxa de infestação média (%) (6,54 ± 0,59) em abelhas adultas menor (P<0.01) do que nas colmeias instaladas no sol (9,71 ± 1,02). Embora os resultados tenham mostrado uma tendência de infestação menor nas crias em colmeias instaladas na sombra, em relação as instaladas no sol, não foram observadas diferenças significativas (P=0.253). Já o comportamento higiênico (%) foi muito baixo para as colmeias na sombra e no sol (57, 61 ± 6,44 e 57,33 ± 7,96) respectivamente. No entanto, observou-se uma correlação negativa significativa entre este comportamento e a taxa de infestação do ácaro em abelhas adultas. Quanto à nosemose, foram encontrados esporos em todas as colmeias tanto no sol quando na sombra, mas no entanto, o número médio de esporos por abelha pode ser considerado muito baixo, sendo significativamente maior no período de safra (200.000 ± 40. 869) do que na entressafra (31.250 ± 3.900), no entanto, não se obteve diferenças significativas entre as colmeias na sombra e no sol / 2017-03-13

The aim of this thesis was to monitor the Varroa destructor parasitic mite in correlation with the microclimatic conditions of the Carniolan honey bee (Apis mellifera carnica). The rate of infestation of selected bee colonies at different locations was assessed in three-day intervals. At the same time, the microclimate in the hives was observed. The monitoring took place from April to mid-October. Also, the effect of the microclimate on the mite fall count was evaluated. During the whole evaluation, the highest average daily fall count was 2.08 mites per day at honeybee colonies at location 1 and 2; 1.97 at location 3. There was no statistically significant difference (P > 0.05) between those locations. The comparison of fall count between the moths of observation revealed, that highest fall count was during September (3.03 mites per day) and the lowest fall count was in April (0.41 mites per day; P 0.001). The rates of dependence (assessed by correlation analysis) between the fall count and microclimatic conditions in individual colonies varied. The strongest correlation between hive temperature and fall count (r = -0.45, P 0.05) was found at location 2. A low correlation was found at location 1 (r = -0.17, P 0.05). On the other hand, location 3 showed an insignificant and inconclusive correlation between hive temperature and fall count (r = 0.003, P > 0.05). The aggregate data (without distinction of location or month) showed significant (P 0.05) correlation between fall count and hive temperature (r = -0.14). The correlation between relative air humidity in hive and the fall count was statistically insignificant and low (r = -0.02, P > 0.05). The results revealed that the degree of correlation between the hive microclimate and the development (fall count respectively) of the Varroa destructor population is different for each colony. The monitoring of the dead Varroa destructor females is an appropriate complementary tool to diagnose a colony's infestation. The statistical analysis confirmed that with the decreasing summer and end-of-summer temperatures the Varroa destructor population grows and it is necessary to take measures to suppress its growth due to the development of the honey bee long-term winter generation.

Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.

No description available.

Managed honey bee colonies face severe winter losses in northern climates. In my studies, interactions between genotypes of bees (genetically selected stock and unselected stock) with different levels of resistance and tolerance to varroa mites were assessed under a variety of treatment combinations to quantify effects of queen pheromone, acaricide treatment, wintering method, ventilation condition and pathogen infection on the costs and benefits associated with mite removal and mite-tolerance behaviors. In most of the experiments, mite-resistance caused greater varroa mite mortality within selected stock relative to unselected stock. Artificial and natural sources of queen pheromone caused greater varroa mite mortality within honey bee colonies relative to queenless colonies. While mite resistance had significant benefits, I showed that when producers selected colonies containing some mite resistance traits, it was traits associated with mite-tolerance and not mite-resistance were maintained and contributed to wintering success. Tolerance was effective at two levels of mites as obtained by late autumn treatment of colonies with oxalic but treatment did not improve wintering performance of either stock. Selected stock showed greater colony size, survival and resulted in more viable colonies in spring in comparison to unselected stock with similar initial mite levels (0.16 mites per bee). Selected stock showed greater relative wintering success than unselected stock when wintered indoors than when wintered outdoors but indoor wintering improved colony survival in both stocks relative to outdoor wintering. Carbon dioxide level increased within the winter bee cluster when colonies were maintained under restricted-ventilation (mean 3.82±0.031%, range 0.43-8.44%) and restricted ventilation increased mite mortality by 138% relative to standard-ventilation (mean 1.29±0.031%, range 0.09-5.26%), but restricted-ventilation did not affect bee mortality in comparison to standard-ventilation. In a laboratory study, I showed that Nosema inoculation (with co-infections of N. ceranae and N. apis) suppressed the effectiveness of mite removal behavior within selected bees relative to unselected bees. N. ceranae was more abundant than N. apis. Bees with greater mite removal capacities had higher costs associated with varroa-resistance as indicated by greater bee mortality rates when inoculated with varroa but bee mortality was not affected in Nosema inoculated bees.