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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Studium fyziologie a hledání proteomických nástrojů pro supresi a detekci Varroa destructor / Study of physiology and searching of proteomic tools useful in suppression and detection of Varroa destructor

Holenková, Martina January 2012 (has links)
This work is focused on the study of physiology and proteome of the the mite Varroa destructor and on comparison with the honeybee Apis mellifera. Varroa is currently a major problem for beekeeping, because infects most of the colonies. The control of the mite can not be done without residues both in the hive and for example in the honey or other resources used by the man. Another problem can also be the simultaneously discussed issue of the connection with the Colony Collapse Disorder. The internal anatomy of V. destructor was studied by using paraffin histology. On histological sections stained using hematoxylin and PAS was possible to observe the mite digestive system, but also egg, ovaries or brain. The primary aim of this study was to identify the proteins of mite V. destructor and bee A. mellifera as a host of this parasite. For the electrophoretic separation was used two- dimensional gel electrophoresis, where the second dimension was carried out using 12% and 15% SDS-PAGE. The most abundant spots were selected for analysis using MALDI TOF/TOF mass spectrometry. The most abundant protein identified in samples of V. destructor was hexamerin, arginine kinase or hemelipoglycoprotein precursor. Hexamerins were also identified as the major proteins in the pupae samples. On the contrary the main...
2

Identificação de vírus que afetam apis mellifera associados ao ácaro ectoparasita varroa destructor em apiários do Rio Grande do Sul

Garcia, Fernanda Wiesel 30 April 2014 (has links)
Submitted by Ana Damasceno (ana.damasceno@unipampa.edu.br) on 2016-10-13T18:21:12Z No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Identificacao de virus que afetam apis mellifera.pdf: 2079239 bytes, checksum: 490f111cf7ddb616e9d3cc3373a5be07 (MD5) / Made available in DSpace on 2016-10-13T18:21:12Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Identificacao de virus que afetam apis mellifera.pdf: 2079239 bytes, checksum: 490f111cf7ddb616e9d3cc3373a5be07 (MD5) Previous issue date: 2014-04-30 / A apicultura é uma atividade de importância econômica e ambiental. O clima e a flora do Brasil somados à presença da abelha africanizada conferem um excelente potencial apícola. Entretanto, as abelhas são suscetíveis a uma variedade de doenças. Vários são os patógenos que podem acometer abelhas melíferas, sendo o foco deste trabalho a relação entre o ácaro Varroa destructor e os vírus que acometem abelhas. V. destructor é um ectoparasita, sendo a varroose, doença causada por este ácaro, responsável pela mortalidade de milhares de colônias de Apis mellifera em várias partes do mundo. Entretanto, os danos causados pela varroose variam com a raça de abelhas e condições climáticas. Embora o ácaro cause poucos danos nas colônias de abelhas africanizadas no Brasil, a coexistência deste ectoparasita com determinados tipos virais pode comprometer seriamente a saúde da colônia, uma vez que muitos destes vírus tem sua transmissão relacionada ao ectoparasita, apontando este como um vetor da infecção. Portanto, faz-se necessária a identificação de quais vírus estão associados ao ácaro e que, possivelmente, utilizam-se do ácaro como vetor. Dentro deste contexto, objetivamos verificar a existência de vírus associados ao ácaro V. destructor em espécimes coletadas em apiários de diferentes regiões do Rio Grande do Sul. Foram realizadas coletas de ácaros em apiários localizados em oito municípios gaúchos. A partir das amostras coletadas, foi realizada extração de RNA total e síntese de cDNA. O cDNA sintetizado foi submetido à PCR utilizando-se 9 pares de primers para detecção de vírus que afetam abelhas e um par de primers para controle endógeno. As amostras foram submetidas a eletroforese em gel de agarose. Identificou-se, em três apiários, a presença dos vírus SBV (Vírus da Cria Ensacada) e VDV-1 (Vírus Varroa destructor-1) associados ao ácaro V. destructor. Estes dados são inéditos uma vez que estudos semelhantes nunca foram realizados no Brasil ou em abelhas africanizadas e poderão servir de base no desenvolvimento de programas de controle deste parasita. / Beekeeping is an activity that has both economic and environmental importance. Brazil has excellent climate and flora for beekeeping, and alongside the presence of Africanized bee populations, it has great potential for apiculture. However, Apis mellifera bees are susceptible to a variety of diseases. There are several pathogens that can affect honeybees and the focus of this work is to assess the relationship between the Varroa destructor mite and viruses that affect bees in the state of Rio Grande do Sul. V. destructor is an ectoparasite and the disease caused by this mite may be responsible for the death of thousands of colonies of A. mellifera in several parts of the world. However, the damage caused by the varroa mite vary according to the race of the affected bees and weather conditions. Although the varroa mite cause little damage in colonies of Africanized bees in Brazil, the coexistence of this ectoparasite with certain types of viruses can seriously compromise the health of the colony, since many of these viruses use the mite for transmission, pointing this as a probable vector. Therefore, it is necessary to identify which viruses are associated with the mite and that possibly use it as vector. Within this context, the objective of this work is to verify the presence of viruses associated with the V. destructor mite in specimens collected in apiaries in different regions of Rio Grande do Sul. Mite collections were made in apiaries located in eight different cities in the state. Collected samples were subjected to total RNA extrection and cDNA synthesis was performed. The synthesized cDNA was subjected to PCR using nine primer pairs for detection of viruses affecting bee and one pair of primers for endogenous control. Amplified samples were subjected to electrophoresis on agarose gel. With this work, we have been able to identify in the presence of SBV and VDV-1 virus associated with V. destructor mite in three different apiaries. The obtained data are novel, since similar studies have never been conducted before in Brazil or using Africanized bee colonies, and could be used as basis in development of control strategies of this parasite.
3

The host parasite relation of the parasitic mite Varroa destructor (Anderson and Trueman) and the honeybee races A. m. syriaca (Skorikov) and A. m. carnica (Pollmann) in Jordan

Attal, Yehya Zaki Khalid al- January 2006 (has links)
Zugl.: Hohenheim, Univ., Diss., 2006
4

Parasite-host interactions between Varroa destructor Anderson and Trueman and Apis mellifera L. influence of parasitism on flight behaviour and on the loss of infested foragers = Parasit-Wirtsbeziehungen zwischen Varroa destructor Anderson und Trueman und Apis mellifera L./ vorgelegt von Jasna Kralj.

Kralj, Jasna. Unknown Date (has links)
University, Diss., 2004--Frankfurt (Main). / Zsfassung in engl. und dt. Sprache.
5

Identificação de Vírus que Afetam Apis Mellifera Associados ao Ácaro Ectoparasita Varroa Destructor em Apiários do Rio Grande do Sul

Boldo, Juliano Tomazzoni 30 April 2014 (has links)
Submitted by Sandro Camargo (sandro.camargo@unipampa.edu.br) on 2015-05-07T22:33:38Z No. of bitstreams: 1 126110036.pdf: 2091532 bytes, checksum: 8020f2b19bedcc2aebd080e502846a88 (MD5) / Made available in DSpace on 2015-05-07T22:33:38Z (GMT). No. of bitstreams: 1 126110036.pdf: 2091532 bytes, checksum: 8020f2b19bedcc2aebd080e502846a88 (MD5) Previous issue date: 2014-04-30 / A apicultura é uma atividade de importância econômica e ambiental. O clima e a flora do Brasil somados à presença da abelha africanizada conferem um excelente potencial apícola. Entretanto, as abelhas são suscetíveis a uma variedade de doenças. Vários são os patógenos que podem acometer abelhas melíferas, sendo o foco deste trabalho a relação entre o ácaro Varroa destructor e os vírus que acometem abelhas. V. destructor é um ectoparasita, sendo a varroose, doença causada por este ácaro, responsável pela mortalidade de milhares de colônias de Apis mellifera em várias partes do mundo. Entretanto, os danos causados pela varroose variam com a raça de abelhas e condições climáticas. Embora o ácaro cause poucos danos nas colônias de abelhas africanizadas no Brasil, a coexistência deste ectoparasita com determinados tipos virais pode comprometer seriamente a saúde da colônia, uma vez que muitos destes vírus tem sua transmissão relacionada ao ectoparasita, apontando este como um vetor da infecção. Portanto, faz-se necessária a identificação de quais vírus estão associados ao ácaro e que, possivelmente, utilizam-se do ácaro como vetor. Dentro deste contexto, objetivamos verificar a existência de vírus associados ao ácaro V. destructor em espécimes coletadas em apiários de diferentes regiões do Rio Grande do Sul. Foram realizadas coletas de ácaros em apiários localizados em oito municípios gaúchos. A partir das amostras coletadas, foi realizada extração de RNA total e síntese de cDNA. O cDNA sintetizado foi submetido à PCR utilizando-se 9 pares de primers para detecção de vírus que afetam abelhas e um par de primers para controle endógeno. As amostrasforam submetidas a eletroforese em gel de agarose. Identificou-se, em três apiários, a presença dos vírus SBV (Vírus da Cria Ensacada) e VDV-1 (Vírus Varroa destructor-1) associados ao ácaro V. destructor. Estes dados são inéditos uma vez que estudos semelhantes nunca foram realizados no Brasil ou em abelhas africanizadas e poderão servir de base no desenvolvimento de programas de controle deste parasita. / Beekeeping is an activity that has both economic and environmental importance. Brazil has excellent climate and flora for beekeeping, and alongside the presence of Africanized bee populations, it has great potential for apiculture. However, Apis mellifera bees are susceptible to a variety of diseases. There are several pathogens that can affect honeybees and the focus of this work is to assess the relationship between the Varroa destructor mite and viruses that affect bees in the state of Rio Grande do Sul. V. destructor is an ectoparasite and the disease caused by this mite may be responsible for the death of thousands of colonies of A. mellifera in several parts of the world. However, the damage caused by the varroa mite vary according to the race of the affected bees and weather conditions. Although the varroa mite cause little damage in colonies of Africanized bees in Brazil, the coexistence of this ectoparasite with certain types of viruses can seriously compromise the health of the colony, since many of these viruses use the mite for transmission, pointing this as a probable vector. Therefore, it is necessary to identify which viruses are associated with the mite and that possibly use it as vector. Within this context, the objective of this work is to verify the presence of viruses associated with the V. destructor mite in specimens collected in apiaries in different regions of Rio Grande do Sul. Mite collections were made in apiaries located in eight different cities in the state. Collected samples were subjected to total RNA extrection and cDNA synthesis was performed. The synthesized cDNA was subjected to PCR using nine primer pairs fordetection of viruses affecting bee and one pair of primers for endogenous control. Amplified samples were subjected to electrophoresis on agarose gel. With this work, we have been able to identify in the presence of SBV and VDV-1 virus associated with V. destructor mite in three different apiaries. The obtained data are novel, since similar studies have never been conducted before in Brazil or using Africanized bee colonies, and could be used as basis in development of control strategies of this parasite.
6

Identificação de vírus que afetam apis mellifera associados ao ácaro ectoparasita varroa destructor em apiários do Rio Grande do Sul

Garcia, Fernanda Wiesel 30 April 2014 (has links)
Submitted by Ana Damasceno (ana.damasceno@unipampa.edu.br) on 2016-11-30T18:54:51Z No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Identificação de vírus que afetam apis mellifera associados ao ácaro ectoparasita varroa destructor em apiários do Rio Grande do Sul.pdf: 2079239 bytes, checksum: 490f111cf7ddb616e9d3cc3373a5be07 (MD5) / Made available in DSpace on 2016-11-30T18:54:51Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Identificação de vírus que afetam apis mellifera associados ao ácaro ectoparasita varroa destructor em apiários do Rio Grande do Sul.pdf: 2079239 bytes, checksum: 490f111cf7ddb616e9d3cc3373a5be07 (MD5) Previous issue date: 2014-04-30 / A apicultura é uma atividade de importância econômica e ambiental. O clima e a flora do Brasil somados à presença da abelha africanizada conferem um excelente potencial apícola. Entretanto, as abelhas são suscetíveis a uma variedade de doenças. Vários são os patógenos que podem acometer abelhas melíferas, sendo o foco deste trabalho a relação entre o ácaro Varroa destructor e os vírus que acometem abelhas. V. destructor é um ectoparasita, sendo a varroose, doença causada por este ácaro, responsável pela mortalidade de milhares de colônias de Apis mellifera em várias partes do mundo. Entretanto, os danos causados pela varroose variam com a raça de abelhas e condições climáticas. Embora o ácaro cause poucos danos nas colônias de abelhas africanizadas no Brasil, a coexistência deste ectoparasita com determinados tipos virais pode comprometer seriamente a saúde da colônia, uma vez que muitos destes vírus tem sua transmissão relacionada ao ectoparasita, apontando este como um vetor da infecção. Portanto, faz-se necessária a identificação de quais vírus estão associados ao ácaro e que, possivelmente, utilizam-se do ácaro como vetor. Dentro deste contexto, objetivamos verificar a existência de vírus associados ao ácaro V. destructor em espécimes coletadas em apiários de diferentes regiões do Rio Grande do Sul. Foram realizadas coletas de ácaros em apiários localizados em oito municípios gaúchos. A partir das amostras coletadas, foi realizada extração de RNA total e síntese de cDNA. O cDNA sintetizado foi submetido à PCR utilizando-se 9 pares de primers para detecção de vírus que afetam abelhas e um par de primers para controle endógeno. As amostras foram submetidas a eletroforese em gel de agarose. Identificou-se, em três apiários, a presença dos vírus SBV (Vírus da Cria Ensacada) e VDV-1 (Vírus Varroa destructor-1) associados ao ácaro V. destructor. Estes dados são inéditos uma vez que estudos semelhantes nunca foram realizados no Brasil ou em abelhas africanizadas e poderão servir de base no desenvolvimento de programas de controle deste parasita.
7

Transmission of deformed wing virus (DWV) between Varroa destructor and the European honeybee (Apis mellifera) : in vitro and in vivo studies

Bradford, Emma Louise January 2019 (has links)
The European honeybee (Apis mellifera) is a managed insect pollinator of global economic importance. Over the last few decades honeybees have been undergoing a major health crisis, with one of the biggest causes the parasitic mite, Varroa destructor and its role in changing the viral landscape of deformed wing virus (DWV), which consists of two major variants: DWV-A and DWV-B. Prior to the start of this project there was limited information known about the mechanisms behind the relationships between Varroa, DWV and honeybees. The overarching aim of this project was to further enhance our understanding of these complex relationships, focusing on the impact of Varroa DWV transmission and differences between the main DWV variants. One of the initial obstacles to understanding these complex interactions was the inability to accurately quantify DWV variants. Prior to the start of this project, there was a need for an accurate assay for the quantification of DWV-A, DWV-B and total DWV, allowing the role of both variants in viral transmission and establishment to be investigated. While primers did exist for DWV quantification, the majority did not distinguish between variants, or provide accurate levels of DWV. Given these challenges in variant detection, a new assay for the quantification of DWV-A, DWV-B and total DWV was designed and validated. The assay consists of an external plasmid standard with distinct sections, for the detection of variants and total DWV. This DWV variant plasmid assay was essential for further transmission studies in this project. DWV variant transmission was explored using a variety of different methods. A new in vitro feeding system was used, to allow investigations into Varroa DWV variant transmission in isolation. The feeding system utilises locust haemolymph, allowing changes in DWV transmission to be detected. In multiple feeding experiments significant changes in DWV transmission were detected. Significant changes in DWV composition within feeding Varroa were detected with decreased levels of DWV, and changing variant levels. Switches in variant composition within mites and transmission rates occurred during Varroa in vitro feeding. These variant switches occurred in both directions from DWV-A to DWV-B, and DWV-B to DWV-A dominance. These changes in mite variant composition corresponded to changes in levels of replicating strands. iv These changes in DWV transmission, composition and replicating strand detection were only seen due to the use of this in vitro feeding system. The in vitro work provided valuable information about Varroa variant transmission and composition changes during feeding but this is not a natural system. Honeybee pupae from a Varroa-free area with extremely low DWV titres provided the opportunity to investigate Varroa variant transmission and pupal DWV establishment. Over 96 hours total DWV levels underwent a 1339408X fold increase, within pupae following Varroa feeding, with a sharp increase after 12 hours, followed by a plateau after 60 hours. Within this time period, DWV-A underwent a similar increase, while DWV-B increased at a much slower rate (33X fold change). In contrast to the in vitro work, mite DWV levels did not decrease during feeding. The impact of natural Varroa cell infestation on L5 larvae was investigated, showing no significant effects between pupal total DWV levels and mite density, and DWV levels between infested and none-infested larvae. However, this lack of significance could be attributed to the use of L5 larvae, which had only undergone a maximum of 24 hours Varroa feeding within the cell. Additionally, the use of two drug treatments (ribavirin and hydroxyurea) to reduce DWV levels was explored. Both drug treatments were tested against Varroa and honeybees, using a variety of methods: immersion (Varroa), injections (honeybees) and feeding (both). While neither drug treatment resulted in consistent DWV decreases, some reduction in DWV levels were seen following Varroa soaking in drug solutions. A significant decrease in DWV was seen in honeybees following bolus and ad libitum feeding of drug treatments. Overall, information and insights have been gained regarding the complex relationship between Varroa, honeybees and DWV. A new DWV variant qPCR assay was developed and utilised in subsequent studies. DWV variant switches in both transmission rates and mite composition were found to occur in in vitro studies. Differences in DWV variant establishment within honeybees were detected following Varroa in vivo feeding, in low DWV pupae. Though the tested drug treatments did not affect DWV levels, this highlights the difficultly facing the establishment of any DWV treatment.
8

Differential gene expression of varroa-tolerant and varroa-susceptible honey bees (Apis mellifera) in response to Varroa destructor infestation

2013 July 1900 (has links)
The honey bee is one of the most familiar insects in the world, and plays an important role in the global economy providing essential pollination services to crops, fruit trees and vegetables. However, honey bee health is severely threatened by the ectoparasitic mite Varroa destructor, which feeds on the hemolymph of pupal and adult bees, resulting in loss of nutrients and circulatory fluids, decreased overall body weight and eventually the death of the bees. To investigate the molecular defense mechanisms of the honey bee against varroa mite infestation, we employed DNA microarray analysis to compare gene expression of two contrasting honey bee colony phenotypes selected from the Saskatraz breeding program. One designated as G4 is susceptible to the varroa mite, while the other designated as S88 is highly tolerant to the varroa. Total RNAs were isolated from bees at two different stages, dark-eyed pupa and adult worker, infected or non-infected with varroa mites, and used for DNA microarray analysis. The results showed that distinct sets of genes were differentially regulated in the varroa-tolerant and varroa-susceptible honey bee phenotypes, with and without varroa infestation. In both phenotypes, there were more differentially-expressed genes identified at the pupal stage than at the adult stage, indicating that at the pupal stage honey bees are more responsive to the varroa infestation than adult bees. In the phenotype comparisons, substantially more differentially-expressed genes were found in the tolerant than susceptible line, indicating that the tolerant phenotype has an increased capacity to mobilize the expression of the genes in response to varroa mite infestation. Based on function, the differentially-expressed genes could be classified into groups that are involved in olfactory signal transduction, detoxification, metabolism and exoskeleton formation, implying several possible mechanisms for the host-parasite interaction and resistance. Quantitative RT-PCR was used to confirm the data obtained from the DNA microarray hybridization. Eleven out of twelve genes selected based on the microarray data showed consistent expression patterns measured by both methods. Overall, comprehensive evaluation of the gene expression of honey bees in response to the mite infestation by DNA microarray has revealed several possible molecular mechanisms for the host defense against the pest. Identification of highly differentially expressed genes between the two phenotypes provides potential biomarkers that can be used for breeding honey bees resistant to the varroa mite.
9

Development of a Precision Mite Management Program for the Control of the Ectoparasite Varroa destructor in Hives of Apis mellifera L.

Means, Jackson C. 03 June 2014 (has links)
The European honey bee, Apis mellifera, is an important pollinator of horticultural and agricultural field crops, providing ≈ 90% of all commercial pollination services (Genersch et al. 2010). The recent rise in colony loss due to Colony Collapse Disorder (CCD) has been a source of concern for both beekeepers and the apiculture industry. One of the factors implicated in CCD is infestation by the ectoparasitic mite, Varroa destructor. Initial efforts to control the mite relied heavily on regular application of miticides without regard to actual mite infestation levels. This approach has led to problems of resistance in the mite and contamination of the hive and hive-products. Because it is unlikely that miticides will be removed as an option for mite management, a precision mite management (PMM) approach using information on the spatiotemporal distribution of the mite to improve sampling and treatments is seen as a viable option, particularly with respect to treatment costs and impacts on the environment. The primary objective of this study was to develop an understanding of the spatiotemporal distribution of the Varroa mite and bee brood within hives for the purpose of developing a PMM approach for the mite. Varroa mite populations were sampled from May to June, 2012 and February to October, 2013. Sampling was conducted with three commonly used sampling methods: soapy water roll (SWR), brood uncapping, and a modified sticky board; brood uncapping, however, was discontinued during the study due to hive the labor cost and harmful effects of this method to the hives. Similar trends in mite population levels were observed using the soapy water roll and sticky board sampling methods. Spearman's nonparametric analysis showed that there was a significant correlation (ρ = 0.47, P<0.001) in mite population levels for the soapy water roll and sticky board methods for sampling conducted from February to September, 2013 (the SWR method was not used in October). This was despite the fact that there was no significant correlation (ρ= -0.03, P = 0.8548) between the two sampling methods during the spring sampling period from February to April, 2013. The observed lack of correlation between the two sampling methods in early spring was likely due to the low population of brood in the hive, which caused the majority of the mites to remain on adult bees. Mites per 100 adult bees, therefore, appear to reflect mite population levels within the hive more closely than mite fall on sticky borad during the February to April sampling period. This suggests that the soapy water roll method is a better method for estimating mite population levels within the hive in the early spring compared with the sticky board method. Geospatial analyses of the distributions of mite fall on the sticky boards were conducted using geostatistics and Spatial Analysis by Distance IndicEs (SADIE). Both analyses showed that mite fall on the sticky board was generally aggregated and the aggregation increased with mite population levels. The average range of the variogram from geostatistical analysis was estimated at 4 sticky board cells; this range value was increased to 5 cells and was used to develop a systematic outside-range sampling protocol for mites on a sticky board. The results showed that the accuracy of the systematic outside-range sampling compared well with that of the traditional sticky board counting method in estimating total mite fall, but required only 60% of the effort (i.e., counting 63 instead of 105 cells). SADIE analysis showed that there is an overall association between the distribution of mite fall on a sticky board and the distribution of brood within a hive. A greater degree of correspondence was also observed in the association of drone and mite distributions during May to June; greater correspondence in worker brood and mite associations was observed in August and September. These differences may be due to relative amounts of the two types of brood present within the hive. A test of the efficacy of precision application of Varroa mite treatment based on the association between drone brood and mite fall resulted in a significantly greater reduction in mite levels on the sticky board using a traditional miticide treatment method compared with the control and precision treatments (𝜒2 =362.571; df = 2; P <0.0001); mite population levels with the precision method, however, were significantly reduced compared with the control. / Master of Science in Life Sciences
10

Apis mellifera unicolor (Latreille 1804, Hymenoptera Apidae) et Varrroa destructor (Anderson and Trueman, 2000, Acari : Varroidae) à Madagascar : diversité génétique, impact et comportement hygiénique / No English title available

Rasolofoarivao, Henriette 28 November 2014 (has links)
Madagascar figure parmi les cinq premiers pays « hot spots » prioritaires pour la conservation de la biodiversité mondiale, Apis mellifera unicolor est son abeille endémique. Depuis 2010, V. destructor a été introduit à Madagascar. Les objectifs de cette thèse étaient : d'étudier la diversité et la structure génétique de l'abeille A. m. unicolor et de l'acarien V. destructor, d'évaluer l'impact de V. destructor sur les colonies, d'étudier le comportement hygiénique des colonies. Nos résultats confirment que l'ensemble des échantillons collectés font partie de la lignée africaine, plus de 99% ont été identifiés comme A. m. unicolor. Malgré sa faible diversité nucléaire, les populations présentent une structuration génétique organisée en deux sous clusters correspondant à des régions géographiques. Un seul haplotype de V. destructor a été détecté, l'haplotype coréen (K1-1). Les études génétiques ont montré une proportion élevée de génotype homozygote (69.5%) et un nombre élevé de MLG sur les Hauts Plateaux par rapport à la côte Est. La présence de MLG particulier sur les Hauts Plateaux conforte l'hypothèse de son introduction dans la capitale. La propagation de V. destructor à Madagascar est relativement lente, sa dispersion reste encore confinée à certaines régions des Hauts Plateaux et de la côte Est. L'impact de parasite est sévère, en un an, la perte des colonies infestées est estimée à 60 %. En se basant sur le pourcentage des cellules nettoyées après 6 h de test à l'aiguille, l'efficacité des colonies à détecter et à désoperculer les cellules est comparable à celles des abeilles hygiéniques africanisées et semble beaucoup plus élevée que celle des abeilles européennes. La présence de colonies hautement hygiéniques au sein des populations offre une opportunité pour un futur programme de sélection de souches tolérantes. / Madagascar is among the top five priorities "hotspots" for global biodiversity conservation. Apis mellifera unicolor was an endemic honey bee. In 2010, Varroa destructor has been reported parasitizing A. m. unicolor. Objectives of this thesis were i) to study the genetic diversity and structure of both A. m. unicolor and V. destructor, ii) to estimate the impact of V. destructor on colonies, and iii) to investigate the hygienic behaviour of colonies. Our results confirm that all honey bees collected belonged to the African lineage and more than 99% were identified as A. m. unicolor. Despite its low nuclear genetic diversity, two genetic clusters have been detected, corresponding to geographic regions. Only one haplotype of V. destructor was detected, the Korean haplotype (K1-1). Genetic studies showed a higher proportion of homozygous genotype (69.5%) and a high number of MLG (Multi- Locus Genotypes) in the High Lands compared to the East coast. The presence of particular MLG on the High Land reinforces the assumption of its introduction into the capital. The spread of V. destructor in Madagascar is relatively slow, its presence remains confined to the High Land and the East coast. The impact of the parasite on A. m. unicolor was severe; with about 60% of colony losses in a year reported. Based on the percentage of cleaned cells observed 6 hour after pin killing broods, the efficiency colonies to detect and uncap cells was comparable to those of Africanised hygienic honey bees and was much higher than those of European honey bees. The detection of highly hygienic colonies is a great opportunity to develop a programme of selection of tolerant honey bee strains.

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