Effet d'une exposition larvaire a un analogue de l'hormone juvenile sur l'acceptation... more Effet d'une exposition larvaire a un analogue de l'hormone juvenile sur l'acceptation et le comportement social des adultes au sein d'une colonie. 3. Journees de la Recherche Apicole
The ectoparasitic mite, Varroa destructor, is unarguably the leading cause of honeybee (Apis mell... more The ectoparasitic mite, Varroa destructor, is unarguably the leading cause of honeybee (Apis mellifera) mortality worldwide through its role as a vector for lethal viruses, in particular, strains of the Deformed wing virus (DWV) and Acute bee paralysis virus (ABPV) complexes. Several honeybee populations across Europe have well-documented adaptations of mite-resistant traits but little is known about host adaptations towards the virus infections vectored by the mite. The aim of this study was to assess and compare the possible contribution of adapted virus tolerance and/or resistance to the enhanced survival of four well-documented mite-resistant honeybee populations from Norway, Sweden, The Netherlands and France, in relation to unselected mite-susceptible honeybees. Caged adult bees and laboratory reared larvae, from colonies of these four populations, were inoculated with DWV and ABPV in a series of feeding infection experiments, while control groups received virus-free food. Vir...
Apoptosis is not only pivotal for development, but also for pathogen defence in multicellular org... more Apoptosis is not only pivotal for development, but also for pathogen defence in multicellular organisms. Although numerous intracellular pathogens are known to interfere with the host's apoptotic machinery to overcome this defence, its importance for host-parasite coevolution has been neglected. We conducted three inoculation experiments to investigate in the apoptotic respond during infection with the intracellular gut pathogen Nosema ceranae, which is considered as potential global threat to the honeybee (Apis mellifera) and other bee pollinators, in sensitive and tolerant honeybees. To explore apoptotic processes in the gut epithelium, we visualised apoptotic cells using TUNEL assays and measured the relative expression levels of subset of candidate genes involved in the apoptotic machinery using qPCR. Our results suggest that N. ceranae reduces apoptosis in sensitive honeybees by enhancing inhibitor of apoptosis protein-(iap)-2 gene transcription. Interestingly, this seems n...
Apres la France et l'Europe, l'Amerique du Nord subit des problemes de mortalites massive... more Apres la France et l'Europe, l'Amerique du Nord subit des problemes de mortalites massives d'abeilles. Un deficit d'abeilles pour la pollinisation et les resultats d'enquetes aupres des apiculteurs attestent clairement que ce phenomene est tres preoccupant pour l'apiculture americaine. Le declin de ce pollinisateur peut constituer un probleme environnemental grave pour les ecosystemes.
Voltage-gated Ca(2+) channels allow the influx of Ca(2+) ions from the extracellular space upon m... more Voltage-gated Ca(2+) channels allow the influx of Ca(2+) ions from the extracellular space upon membrane depolarization and thus serve as a transducer between membrane potential and cellular events initiated by Ca(2+) transients. Most insects are predicted to possess three genes encoding Cavα, the main subunit of Ca(2+) channels, and several genes encoding the two auxiliary subunits, Cavβ and Cavα2δ; however very few of these genes have been cloned so far. Here, we cloned three full-length cDNAs encoding the three Cavα subunits (AmelCav1a, AmelCav2a and AmelCav3a), a cDNA encoding a novel variant of the Cavβ subunit (AmelCavβc), and three full-length cDNAs encoding three Cavα2δ subunits (AmelCavα2δ1 to 3) of the honeybee Apis mellifera. We identified several alternative or mutually exclusive exons in the sequence of the AmelCav2 and AmelCav3 genes. Moreover, we detected a stretch of glutamine residues in the C-terminus of the AmelCav1 subunit that is reminiscent of the motif found i...
The concept of sustainability in agriculture has been translated into a range of operational eval... more The concept of sustainability in agriculture has been translated into a range of operational evaluation frameworks at territory, farm or production system level. However, these frameworks are not adapted to beekeeping farms: what then can be called “sustainability” in the case of beekeeping farms? Which components of the apicultural system management and context have to be considered to describe and assess this sustainability? Our study, based on a participatory approach, aims at adapting the concept of sustainability to the specificities of beekeeping farms, in France and at developing an adapted framework to assess it at farm level. To take into account the diversity of situations of beekeeping farms and their social, economic and environmental particularities, professional beekeepers and other stakeholders from the beekeeping sector were involved in the specification of sustainability for beekeeping farms through individual interviews and collective exchanges. We present here the...
Les Systemes Multi-Agents (SMA) ont montre depuis plusieurs annees leur adequation a modeliser et... more Les Systemes Multi-Agents (SMA) ont montre depuis plusieurs annees leur adequation a modeliser et simuler les systemes complexes. Nous suivons cette approche pour modeliser une colonie d'abeilles situee dans une ruche Dadant, ou plusieurs dizaine de milliers d'individus interagissent, dans le but d'evaluer l'impact d'actions locales au niveau des abeilles (e.g. pratiques apicoles) sur la colonie. Nous nous concentrons ici sur l'activite de butinage, en nous interessant plus particulierement aux interactions des butineuses avec l'environnement exterieur de la ruche, tres different en terme de granularite et d'echelle. Nous presentons un module parametrable et compatible agent, dont le but est de modeliser et de simuler le butinage en fonction de la meteo et des sources de nourriture environnantes. Les premiers resultats montrent qu'un phenomene d'auto-organisation des butineuses, resultant de leur comportement et des mecanismes de recrutement, ...
Chemical communication is one of the most fascinating areas of social insect science among which ... more Chemical communication is one of the most fascinating areas of social insect science among which honeybee is the most known model. More than 50 pheromonal compounds had been identified in the honeybee, most of them triggering releaser effects to the receivers, and the queen mandibular pheromone had been the first primer pheromone identified in the animal kingdom. This chapter focuses on the latest findings in this topic, particularly the discovery of brood pheromones and the worker inhibitor pheromones regulating behavioral development of the nurse workers. We describe the finding of chemicals produced by the honeybee larvae involved in their recognition by the varroa mite. This work lead to the characterization of a brood pheromone involved in the recognition of the larvae and their needs by the workers and having primer effects on hypopharyngeal gland secretions and ovary development. This blend of chemical compounds also delays the age at first foraging, so that the larvae can ma...
Citizen Science contributes significantly to the conservation of biodiversity, but its applicatio... more Citizen Science contributes significantly to the conservation of biodiversity, but its application to honey bee research has remained minimal. Even though certain European honey bee (Apis mellifera) populations are known to naturally survive Varroa destructor infestations, it is unclear how widespread or common such populations are. Such colonies are highly valuable for investigating the mechanisms enabling colony survival, as well as for tracking the conservation status of free-living honey bees. Here, we use targeted Citizen Science to identify potentially new cases of managed or free-living A. mellifera populations that survive V. destructor without mite control strategies. In 2018, a survey containing 20 questions was developed, translated into 13 languages, and promoted at beekeeping conferences and online. After three years, 305 reports were collected from 28 countries: 241 from managed colonies and 64 from free-living colonies. The collected data suggest that there could be t...
RNA viruses play a significant role in the current high losses of pollinators. Although many stud... more RNA viruses play a significant role in the current high losses of pollinators. Although many studies have focused on the epidemiology of western honey bee (Apis mellifera) viruses at the colony level, the dynamics of virus infection within colonies remains poorly explored. In this study, the two main variants of the ubiquitous honey bee virus DWV as well as three major honey bee viruses (SBV, ABPV and BQCV) were analyzed from Varroa-destructor-parasitized pupae. More precisely, RT-qPCR was used to quantify and compare virus genome copies across honey bee pupae at the individual and subfamily levels (i.e., patrilines, sharing the same mother queen but with different drones as fathers). Additionally, virus genome copies were compared in cells parasitized by reproducing and non-reproducing mite foundresses to assess the role of this vector. Only DWV was detected in the samples, and the two variants of this virus significantly differed when comparing the sampling period, colonies and pa...
Effet d'une exposition larvaire a un analogue de l'hormone juvenile sur l'acceptation... more Effet d'une exposition larvaire a un analogue de l'hormone juvenile sur l'acceptation et le comportement social des adultes au sein d'une colonie. 3. Journees de la Recherche Apicole
The ectoparasitic mite, Varroa destructor, is unarguably the leading cause of honeybee (Apis mell... more The ectoparasitic mite, Varroa destructor, is unarguably the leading cause of honeybee (Apis mellifera) mortality worldwide through its role as a vector for lethal viruses, in particular, strains of the Deformed wing virus (DWV) and Acute bee paralysis virus (ABPV) complexes. Several honeybee populations across Europe have well-documented adaptations of mite-resistant traits but little is known about host adaptations towards the virus infections vectored by the mite. The aim of this study was to assess and compare the possible contribution of adapted virus tolerance and/or resistance to the enhanced survival of four well-documented mite-resistant honeybee populations from Norway, Sweden, The Netherlands and France, in relation to unselected mite-susceptible honeybees. Caged adult bees and laboratory reared larvae, from colonies of these four populations, were inoculated with DWV and ABPV in a series of feeding infection experiments, while control groups received virus-free food. Vir...
Apoptosis is not only pivotal for development, but also for pathogen defence in multicellular org... more Apoptosis is not only pivotal for development, but also for pathogen defence in multicellular organisms. Although numerous intracellular pathogens are known to interfere with the host's apoptotic machinery to overcome this defence, its importance for host-parasite coevolution has been neglected. We conducted three inoculation experiments to investigate in the apoptotic respond during infection with the intracellular gut pathogen Nosema ceranae, which is considered as potential global threat to the honeybee (Apis mellifera) and other bee pollinators, in sensitive and tolerant honeybees. To explore apoptotic processes in the gut epithelium, we visualised apoptotic cells using TUNEL assays and measured the relative expression levels of subset of candidate genes involved in the apoptotic machinery using qPCR. Our results suggest that N. ceranae reduces apoptosis in sensitive honeybees by enhancing inhibitor of apoptosis protein-(iap)-2 gene transcription. Interestingly, this seems n...
Apres la France et l'Europe, l'Amerique du Nord subit des problemes de mortalites massive... more Apres la France et l'Europe, l'Amerique du Nord subit des problemes de mortalites massives d'abeilles. Un deficit d'abeilles pour la pollinisation et les resultats d'enquetes aupres des apiculteurs attestent clairement que ce phenomene est tres preoccupant pour l'apiculture americaine. Le declin de ce pollinisateur peut constituer un probleme environnemental grave pour les ecosystemes.
Voltage-gated Ca(2+) channels allow the influx of Ca(2+) ions from the extracellular space upon m... more Voltage-gated Ca(2+) channels allow the influx of Ca(2+) ions from the extracellular space upon membrane depolarization and thus serve as a transducer between membrane potential and cellular events initiated by Ca(2+) transients. Most insects are predicted to possess three genes encoding Cavα, the main subunit of Ca(2+) channels, and several genes encoding the two auxiliary subunits, Cavβ and Cavα2δ; however very few of these genes have been cloned so far. Here, we cloned three full-length cDNAs encoding the three Cavα subunits (AmelCav1a, AmelCav2a and AmelCav3a), a cDNA encoding a novel variant of the Cavβ subunit (AmelCavβc), and three full-length cDNAs encoding three Cavα2δ subunits (AmelCavα2δ1 to 3) of the honeybee Apis mellifera. We identified several alternative or mutually exclusive exons in the sequence of the AmelCav2 and AmelCav3 genes. Moreover, we detected a stretch of glutamine residues in the C-terminus of the AmelCav1 subunit that is reminiscent of the motif found i...
The concept of sustainability in agriculture has been translated into a range of operational eval... more The concept of sustainability in agriculture has been translated into a range of operational evaluation frameworks at territory, farm or production system level. However, these frameworks are not adapted to beekeeping farms: what then can be called “sustainability” in the case of beekeeping farms? Which components of the apicultural system management and context have to be considered to describe and assess this sustainability? Our study, based on a participatory approach, aims at adapting the concept of sustainability to the specificities of beekeeping farms, in France and at developing an adapted framework to assess it at farm level. To take into account the diversity of situations of beekeeping farms and their social, economic and environmental particularities, professional beekeepers and other stakeholders from the beekeeping sector were involved in the specification of sustainability for beekeeping farms through individual interviews and collective exchanges. We present here the...
Les Systemes Multi-Agents (SMA) ont montre depuis plusieurs annees leur adequation a modeliser et... more Les Systemes Multi-Agents (SMA) ont montre depuis plusieurs annees leur adequation a modeliser et simuler les systemes complexes. Nous suivons cette approche pour modeliser une colonie d'abeilles situee dans une ruche Dadant, ou plusieurs dizaine de milliers d'individus interagissent, dans le but d'evaluer l'impact d'actions locales au niveau des abeilles (e.g. pratiques apicoles) sur la colonie. Nous nous concentrons ici sur l'activite de butinage, en nous interessant plus particulierement aux interactions des butineuses avec l'environnement exterieur de la ruche, tres different en terme de granularite et d'echelle. Nous presentons un module parametrable et compatible agent, dont le but est de modeliser et de simuler le butinage en fonction de la meteo et des sources de nourriture environnantes. Les premiers resultats montrent qu'un phenomene d'auto-organisation des butineuses, resultant de leur comportement et des mecanismes de recrutement, ...
Chemical communication is one of the most fascinating areas of social insect science among which ... more Chemical communication is one of the most fascinating areas of social insect science among which honeybee is the most known model. More than 50 pheromonal compounds had been identified in the honeybee, most of them triggering releaser effects to the receivers, and the queen mandibular pheromone had been the first primer pheromone identified in the animal kingdom. This chapter focuses on the latest findings in this topic, particularly the discovery of brood pheromones and the worker inhibitor pheromones regulating behavioral development of the nurse workers. We describe the finding of chemicals produced by the honeybee larvae involved in their recognition by the varroa mite. This work lead to the characterization of a brood pheromone involved in the recognition of the larvae and their needs by the workers and having primer effects on hypopharyngeal gland secretions and ovary development. This blend of chemical compounds also delays the age at first foraging, so that the larvae can ma...
Citizen Science contributes significantly to the conservation of biodiversity, but its applicatio... more Citizen Science contributes significantly to the conservation of biodiversity, but its application to honey bee research has remained minimal. Even though certain European honey bee (Apis mellifera) populations are known to naturally survive Varroa destructor infestations, it is unclear how widespread or common such populations are. Such colonies are highly valuable for investigating the mechanisms enabling colony survival, as well as for tracking the conservation status of free-living honey bees. Here, we use targeted Citizen Science to identify potentially new cases of managed or free-living A. mellifera populations that survive V. destructor without mite control strategies. In 2018, a survey containing 20 questions was developed, translated into 13 languages, and promoted at beekeeping conferences and online. After three years, 305 reports were collected from 28 countries: 241 from managed colonies and 64 from free-living colonies. The collected data suggest that there could be t...
RNA viruses play a significant role in the current high losses of pollinators. Although many stud... more RNA viruses play a significant role in the current high losses of pollinators. Although many studies have focused on the epidemiology of western honey bee (Apis mellifera) viruses at the colony level, the dynamics of virus infection within colonies remains poorly explored. In this study, the two main variants of the ubiquitous honey bee virus DWV as well as three major honey bee viruses (SBV, ABPV and BQCV) were analyzed from Varroa-destructor-parasitized pupae. More precisely, RT-qPCR was used to quantify and compare virus genome copies across honey bee pupae at the individual and subfamily levels (i.e., patrilines, sharing the same mother queen but with different drones as fathers). Additionally, virus genome copies were compared in cells parasitized by reproducing and non-reproducing mite foundresses to assess the role of this vector. Only DWV was detected in the samples, and the two variants of this virus significantly differed when comparing the sampling period, colonies and pa...
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Papers by Yves Le Conte