Jean-Daniel Charriere | Swiss Federal Research Station Agroscope (original) (raw)
Papers by Jean-Daniel Charriere
In den letzten beiden Jahren sind verschiedene Dispenser fur die Langzeitbehandlung von Bienenvol... more In den letzten beiden Jahren sind verschiedene Dispenser fur die Langzeitbehandlung von Bienenvolker mit Ameisensaure gegen die Varroa auf den Markt gekommen. Mit den 5 in der Schweiz am meisten verkauften Ameisensaure-Dispensern Apidea, Burmeister, FAM-Liebefeld, WynaDeluxe und Kramerplatte haben wir einen Vergleichstest angestellt. Dabei wurde die Wirksamkeit einer zweimaligen Anwendung im August und September gepruft. Subjektive Aspekte wie z.B. die Anwenderfreundlichkeit der Dispenser oder der Zeitaufwand fur die Behandlung sind in diesem Test nicht berucksichtigt.
Pest Management Science, May 11, 2021
BACKGROUND: A national survey on pesticides in recycled beeswax originating from beekeeping has b... more BACKGROUND: A national survey on pesticides in recycled beeswax originating from beekeeping has been conducted in Switzerland for almost three decades. It allowed obtaining a good overview of the lipophilic products used for beekeeping within the last 30 years. RESULTS: The use of the veterinary drugs containing bromopropylate or tau-fluvalinate two decades ago led to substantial residues in commercial beeswax. These contaminants are still detectable although in Switzerland the corresponding products have been out of use for many years. The level of coumaphos substantially increased in 2015 up to an annual value of 3.25 mg•kg −1 , suggesting that at least a few beekeepers used coumaphos-containing products. Consequently, an information campaign was launched, and the annual value decreased again. Maximal levels of thymol up to an annual value of 87.5 mg•kg −1 were measured in 2009. Since that time, a steady decrease of thymol residues suggests that beekeepers less frequently use thymol-containing products. Twenty-five years ago, 1,4-dichlorobenzene (PDCB) was widely used for the control of the wax moth, resulting in residues in beeswax up to an annual value of 10.9 mg•kg −1 whereas nowadays, PDCB residues are rarely detected in Swiss beeswax. CONCLUSIONS: Our survey illustrates that several beekeeping-associated pesticides persist in recycled beeswax for many years. Most recent analyses show lower residue levels in Swiss beeswax as compared to previous years. Nowadays Swiss beekeepers mostly use hydrophilic substances for treatment against the Varroa destructor that do not accumulate in beeswax, thus reducing exposure of the honey bees to lipophilic contaminants.
Agrarforschung Schweiz, 2017
Frontiers in insect science, Dec 10, 2021
Neonicotinoids as thiamethoxam and thiacloprid are suspected to be implicated in the decline of h... more Neonicotinoids as thiamethoxam and thiacloprid are suspected to be implicated in the decline of honey bee populations. As nicotinic acetylcholine receptor agonists, they disturb acetylcholine receptor signaling in insects, leading to neurotoxicity and are therefore globally used as insecticides. Several behavioral studies have shown links between neonicotinoid exposure of bees and adverse effects on foraging activity, homing flight performance and reproduction, but the molecular aspects underlying these effects are not well-understood. In the last years, several studies through us and others showed the effects of exposure to neonicotinoids on gene expression in the brain of honey bees. Transcripts of acetylcholine receptors, hormonal regulation, stress markers, detoxification enzymes, immune system related genes and transcripts of the energy metabolism were altered after neonicotinoid exposure. To elucidate the link between homing flight performance and shifts in gene expression in the brain of honey bees after neonicotinoid exposure, we combined homing flight activity experiments applying RFID technology and gene expression analysis. We analyzed the expression of endocrine factors, stress genes, detoxification enzymes and genes linked to energy metabolism in forager bees after homing flight experiments. Three different experiments (experiment I: pilot study; experiment II: "worst-case" study and experiment III: laboratory study) were performed. In a pilot study, we wanted to investigate if we could see differences in gene expression between controls and exposed bees (experiment I). This first study was followed by a so-called "worst-case" study (experiment II), where we investigated mainly differences in the expression of transcripts linked to energy metabolism between fast and slow returning foragers. We found a correlation between homing flight duration and the expression of cytochrome c oxidase subunit 5A, one transcript linked to oxidative phosphorylation. In the third experiment (experiment III), foragers were exposed in the laboratory to 1 ng/bee thiamethoxam and 8 ng/bee thiacloprid followed by gene expression analysis without a Christen et al. Flight Activity and Gene Expression subsequent flight experiment. We could partially confirm the induction of cytochrome c oxidase subunit 5A, which we detected in experiment II. In addition, we analyzed the effect of the feeding mode (group feeding vs. single bee feeding) on data scattering and demonstrated that single bee feeding is superior to group feeding as it significantly reduces variability in gene expression. Based on the data, we thus hypothesize that the disruption of energy metabolism may be one reason for a prolongation of homing flight duration in neonicotinoid treated bees.
Virulence, May 26, 2020
Melissococcus plutonius is a bacterial pathogen that causes epidemic outbreaks of European foulbr... more Melissococcus plutonius is a bacterial pathogen that causes epidemic outbreaks of European foulbrood (EFB) in honey bee populations. The pathogenicity of a bacterium depends on its virulence, and understanding the mechanisms influencing virulence may allow for improved disease control and containment. Using a standardized in vitro assay, we demonstrate that virulence varies greatly among sixteen M. plutonius isolates from five European countries. Additionally, we explore the causes of this variation. In this study, virulence was independent of the multilocus sequence type of the tested pathogen, and was not affected by experimental coinfection with Paenibacillus alvei, a bacterium often associated with EFB outbreaks. Virulence in vitro was correlated with the growth dynamics of M. plutonius isolates in artificial medium, and with the presence of a plasmid carrying a gene coding for the putative toxin melissotoxin A. Our results suggest that some M. plutonius strains showed an increased virulence due to the acquisition of a toxin-carrying mobile genetic element. We discuss whether strains with increased virulence play a role in recent EFB outbreaks.
International Journal of Systematic and Evolutionary Microbiology
A novel, facultatively anaerobic, Gram-stain-positive, motile, endospore-forming bacterium of the... more A novel, facultatively anaerobic, Gram-stain-positive, motile, endospore-forming bacterium of the genus Paenibacillus , designated strain 2.1T, was isolated from a colony of Apis mellifera affected by European foulbrood disease in Switzerland. The rod-shaped cells of strain 2.1T were 2.2–6.5 µm long and 0.7–1.1 µm wide. Colonies of strain 2.1T were orange-pigmented under oxic growth conditions on solid basal medium at 35–37 °C. Strain 2.1T showed catalase and cytochrome c oxidase activity. Its polar lipid profile consisted of diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, aminophospholipid and phospholipid. The only respiratory quinone was menaquinone 7, and the major cellular fatty acids were anteiso-C15 : 0, anteiso-C17 : 0, iso-C15 : 0, iso-C17 : 0 and palmitic acid (C16 : 0), which is consistent with other members of the genus Paenibacillus . The G+C content of the genomic DNA of strain 2.1T was 53.3 mol%. Phylogenetic analyses based on the 16S rRNA gene...
Journal of Apicultural Research
This article presents managed honey bee colony loss rates over winter 2019/20 resulting from usin... more This article presents managed honey bee colony loss rates over winter 2019/20 resulting from using the standardised COLOSS questionnaire in 37 countries. Six countries were from outside Europe, including, for the first time in this series of articles, New Zealand. The 30,491 beekeepers outside New Zealand reported 4.5% of colonies with unsolvable queen problems, 11.1% of colonies dead after winter and 2.6% lost through natural disaster. This gave an overall colony winter loss rate of 18.1%, higher than in the previous year. The winter loss rates varied greatly between countries, from 7.4% to 36.5%. 3216 beekeepers from New Zealand managing 297,345 colonies reported 10.5% losses for their 2019 winter (six months earlier than for other, Northern Hemisphere, countries). We modelled the risk of loss as a dead/empty colony or from unresolvable queen problems, for all countries except New Zealand. Overall, larger beekeeping operations with more than 50 colonies experienced significantly lower losses (p < 0.001). Migration was also highly significant (p < 0.001), with lower loss rates for operations migrating their colonies in the previous season. A higher proportion of new queens reduced the risk of colony winter loss (p < 0.001), suggesting that more queen replacement is better. All three factors, operation size, migration and proportion of young queens, were also included in a multivariable main effects quasi-binomial GLM and all three remained highly significant (p < 0.001). Detailed results for each country and overall are given in a table, and a map shows relative risks of winter loss at the regional level.
Journal of Pest Science
Beekeepers have various options to control the parasitic mite Varroa destructor in honey bee colo... more Beekeepers have various options to control the parasitic mite Varroa destructor in honey bee colonies, but no empirical data are available on the methods they apply in practice. We surveyed 28,409 beekeepers maintaining 507,641 colonies in 30 European countries concerning Varroa control methods. The set of 19 different Varroa diagnosis and control measures was taken from the annual COLOSS questionnaire on honey bee colony losses. The most frequent activities were monitoring of Varroa infestations, drone brood removal, various oxalic acid applications and formic acid applications. Correspondence analysis and hierarchical clustering on principal components showed that six Varroa control options (not necessarily the most used ones) significantly contribute to defining three distinctive clusters of countries in terms of Varroa control in Europe. Cluster I (eight Western European countries) is characterized by use of amitraz strips. Cluster II comprises 15 countries from Scandinavia, the...
Apis mellifera filamentous virus (AmFV) is a large double stranded DNA virus of honey bees, but i... more Apis mellifera filamentous virus (AmFV) is a large double stranded DNA virus of honey bees, but its relationship with other parasites and prevalence are poorly known. We analyzed individual honey bees from three colonies at different times post emergence in order to monitor the dynamics of the AmFV gut colonization under natural conditions. Prevalence and loads of microsporidia and trypanosomes were also recorded, as well as five common honey bee RNA viruses. The results show that a high proportion of bees get infected with AmFV during the first week post-emergence (75%) and that AmFV DNA levels remained constant. A similar pattern was observed for microsporidia while trypanosomes seem to require more time to colonize the gut. No significant associations between these three infections were found, but significant positive correlations were observed between AmFV and RNA viruses. In parallel, the prevalence of AmFV in France and Sweden was assessed from pooled honey bee workers. The data indicate that AmFV is almost ubiquitous, and does not seem to follow seasonal patterns, although higher viral loads were significantly detected in spring. A high prevalence of AmFV was also found in winter bees, without obvious impact on overwintering of the colonies.
https://www.agroscope.admin.ch/agroscope/de/home/publikationen/suchen/agroscope-transfer.htm
Genome Biology and Evolution, 2020
Historical specimens in museum collections provide opportunities to gain insights into the genomi... more Historical specimens in museum collections provide opportunities to gain insights into the genomic past. For the Western honey bee, Apis mellifera L., this is particularly important because its populations are currently under threat worldwide and have experienced many changes in management and environment over the last century. Using Swiss Apis mellifera mellifera as a case study, our research provides important insights into the genetic diversity of native honey bees prior to the industrial-scale introductions and trade of non-native stocks during the 20th century—the onset of intensive commercial breeding and the decline of wild honey bees following the arrival of Varroa destructor. We sequenced whole-genomes of 22 honey bees from the Natural History Museum in Bern collected in Switzerland, including the oldest A. mellifera sample ever sequenced. We identify both, a historic and a recent migrant, natural or human-mediated, which corroborates with the population history of honey be...
BMC Genomics, 2021
Background With numerous endemic subspecies representing four of its five evolutionary lineages, ... more Background With numerous endemic subspecies representing four of its five evolutionary lineages, Europe holds a large fraction of Apis mellifera genetic diversity. This diversity and the natural distribution range have been altered by anthropogenic factors. The conservation of this natural heritage relies on the availability of accurate tools for subspecies diagnosis. Based on pool-sequence data from 2145 worker bees representing 22 populations sampled across Europe, we employed two highly discriminative approaches (PCA and FST) to select the most informative SNPs for ancestry inference. Results Using a supervised machine learning (ML) approach and a set of 3896 genotyped individuals, we could show that the 4094 selected single nucleotide polymorphisms (SNPs) provide an accurate prediction of ancestry inference in European honey bees. The best ML model was Linear Support Vector Classifier (Linear SVC) which correctly assigned most individuals to one of the 14 subspecies or different...
Insects, 2021
European foulbrood (EFB) is an infectious disease of honey bees caused by the bacterium Melissoco... more European foulbrood (EFB) is an infectious disease of honey bees caused by the bacterium Melissococcus plutonius. A method for DNA isolation and conventional PCR diagnosis was developed using hive debris, which was non-invasively collected on paper sheets placed on the bottom boards of hives. Field trials utilized 23 honey bee colonies with clinically positive symptoms and 21 colonies without symptoms. Bayes statistics were applied to calculate the comparable parameters for EFB diagnostics when using honey, hive debris, or samples of adult bees. The reliability of the conventional PCR was 100% at 6.7 × 103 Colony Forming Unit of M. plutonius in 1 g of debris. The sensitivity of the method for the sampled honey, hive debris, and adult bees was 0.867, 0.714, and 1.000, respectively. The specificity for the tested matrices was 0.842, 0.800, and 0.833. The predictive values for the positive tests from selected populations with 52% prevalence were 0.813, 0.833, and 0.842, and the real acc...
Journal of Apicultural Research, 2019
This short article presents loss rates of honey bee colonies over winter 2017/18 from 36 countrie... more This short article presents loss rates of honey bee colonies over winter 2017/18 from 36 countries, including 33 in Europe, from data collected using the standardized COLOSS questionnaire. The 25,363 beekeepers supplying data passing consistency checks in total wintered 544,879 colonies, and reported 26,379 (4.8%, 95% CI 4.7-5.0%) colonies with unsolvable queen problems, 54,525 (10.0%, 95% CI 9.8-10.2%) dead colonies after winter and another 8,220 colonies (1.5%, 95% CI 1.4-1.6%) lost through natural disaster. This gave an overall loss rate of 16.4% (95% CI 16.1-16.6%) of honey bee colonies during winter 2017/18, but this varied greatly from 2.0 to 32.8% between countries. The included map shows relative risks of winter loss at regional level. The analysis using the total data-set confirmed findings from earlier surveys that smaller beekeeping operations with at most 50 colonies suffer significantly higher losses than larger operations (p < .001). Beekeepers migrating their colonies had significantly lower losses than those not migrating (p < .001), a different finding from previous research. Evaluation of six different forage sources as potential risk factors for colony loss indicated that intensive foraging on any of five of these plant sources (Orchards, Oilseed Rape, Maize, Heather and Autumn Forage Crops) was associated with significantly higher winter losses. This finding requires further study and explanation. A table is included giving detailed results of loss rates and the impact of the tested forage sources for each country and overall.
Journal of Apicultural Research, 2018
Conceived the idea for the paper and wrote a first draft. † Did data processing and editing, all ... more Conceived the idea for the paper and wrote a first draft. † Did data processing and editing, all statistical analysis for the results in the table and text, produced the relative risks map, and contributed to the text of the article.
Genes, Jan 20, 2018
In Europe, approximately 84% of cultivated crop species depend on insect pollinators, mainly bees... more In Europe, approximately 84% of cultivated crop species depend on insect pollinators, mainly bees. (the Western honey bee) is the most important commercial pollinator worldwide. The Gram-positive bacterium is the causative agent of European foulbrood (EFB), a global honey bee brood disease. In order to detect putative virulence factors, we sequenced and analyzed the genomes of 14 strains, including two reference isolates. The isolates do not show a high diversity in genome size or number of predicted protein-encoding genes, ranging from 2.021 to 2.101 Mbp and 1589 to 1686, respectively. Comparative genomics detected genes that might play a role in EFB pathogenesis and ultimately in the death of the honey bee larvae. These include bacteriocins, bacteria cell surface- and host cell adhesion-associated proteins, an enterococcal polysaccharide antigen, an epsilon toxin, proteolytic enzymes, and capsule-associated proteins. In vivo expression of three putative virulence factors (endo-alp...
Journal of Apicultural Research, 2016
In this short note we present comparable loss rates of honey bee colonies during winter 2015/16 f... more In this short note we present comparable loss rates of honey bee colonies during winter 2015/16 from 29 countries, obtained with the COLOSS questionnaire. Altogether, we received valid answers from 19,952 beekeepers. These beekeepers collectively wintered 421,238 colonies, and reported 18,587 colonies with unsolvable queen problems and 32,048 dead colonies after winter. This gives an overall loss rate of 12.0% (95% confidence interval 11.8-12.2%) during winter 2015/16, with marked differences among countries. Beekeepers in the present study assessed 7.6% (95% CI 7.4-7.8%) of their colonies as dead or empty, and 4.4% (95% CI 4.3-4.5%) as having unsolvable queen problems after winter. The overall analysis showed that small operations suffered higher losses than larger ones. A table with detailed results and a map showing response and relative risks at regional level are presented.
Die Biodiversität bildet die Grundlage für viele Prozesse, wie zum Beispiel die natürliche Bestäu... more Die Biodiversität bildet die Grundlage für viele Prozesse, wie zum Beispiel die natürliche Bestäubung oder Schädlingsregulation (funktionelle Biodiversität). Damit Bestäuber und andere Nützlinge diese Funktionen effi zient erfüllen können, sollen sie mit massgeschneiderten Blühstreifenmischungen gefördert werden. Es handelt sich dabei um gezielt angelegte Blühstreifen direkt im Feld (Nahrungsquellen), ergänzend zu naturnahen Landschaftselementen wie Buntbrachen, Hecken oder extensiv genutzten Wiesen (Überwinterungs-oder Schutzlebensräume). Bestäuber und andere Nützlinge sind auf ein reichhaltiges Nahrungsangebot während der ganzen aktiven Saison angewiesen. In der intensiven Kulturlandschaft kann das Nahrungsangebot für die pollen-und nektarsuchenden Insekten nach dem Abblühen von Kulturen, Bäumen und Wiesen allerdings knapp werden. Um diese Nahrungslücke zu schliessen, trägt die mindestens 100-tägige Biodiversitätsförderfl äche "Blühstreifen für Bestäuber und andere Nützlinge" durch ein reiches Nektar-und Pollenangebot während den Sommermonaten zur Verbesserung des Nahrungsangebotes für Bestäuber und Nützlinge bei.
In den letzten beiden Jahren sind verschiedene Dispenser fur die Langzeitbehandlung von Bienenvol... more In den letzten beiden Jahren sind verschiedene Dispenser fur die Langzeitbehandlung von Bienenvolker mit Ameisensaure gegen die Varroa auf den Markt gekommen. Mit den 5 in der Schweiz am meisten verkauften Ameisensaure-Dispensern Apidea, Burmeister, FAM-Liebefeld, WynaDeluxe und Kramerplatte haben wir einen Vergleichstest angestellt. Dabei wurde die Wirksamkeit einer zweimaligen Anwendung im August und September gepruft. Subjektive Aspekte wie z.B. die Anwenderfreundlichkeit der Dispenser oder der Zeitaufwand fur die Behandlung sind in diesem Test nicht berucksichtigt.
Pest Management Science, May 11, 2021
BACKGROUND: A national survey on pesticides in recycled beeswax originating from beekeeping has b... more BACKGROUND: A national survey on pesticides in recycled beeswax originating from beekeeping has been conducted in Switzerland for almost three decades. It allowed obtaining a good overview of the lipophilic products used for beekeeping within the last 30 years. RESULTS: The use of the veterinary drugs containing bromopropylate or tau-fluvalinate two decades ago led to substantial residues in commercial beeswax. These contaminants are still detectable although in Switzerland the corresponding products have been out of use for many years. The level of coumaphos substantially increased in 2015 up to an annual value of 3.25 mg•kg −1 , suggesting that at least a few beekeepers used coumaphos-containing products. Consequently, an information campaign was launched, and the annual value decreased again. Maximal levels of thymol up to an annual value of 87.5 mg•kg −1 were measured in 2009. Since that time, a steady decrease of thymol residues suggests that beekeepers less frequently use thymol-containing products. Twenty-five years ago, 1,4-dichlorobenzene (PDCB) was widely used for the control of the wax moth, resulting in residues in beeswax up to an annual value of 10.9 mg•kg −1 whereas nowadays, PDCB residues are rarely detected in Swiss beeswax. CONCLUSIONS: Our survey illustrates that several beekeeping-associated pesticides persist in recycled beeswax for many years. Most recent analyses show lower residue levels in Swiss beeswax as compared to previous years. Nowadays Swiss beekeepers mostly use hydrophilic substances for treatment against the Varroa destructor that do not accumulate in beeswax, thus reducing exposure of the honey bees to lipophilic contaminants.
Agrarforschung Schweiz, 2017
Frontiers in insect science, Dec 10, 2021
Neonicotinoids as thiamethoxam and thiacloprid are suspected to be implicated in the decline of h... more Neonicotinoids as thiamethoxam and thiacloprid are suspected to be implicated in the decline of honey bee populations. As nicotinic acetylcholine receptor agonists, they disturb acetylcholine receptor signaling in insects, leading to neurotoxicity and are therefore globally used as insecticides. Several behavioral studies have shown links between neonicotinoid exposure of bees and adverse effects on foraging activity, homing flight performance and reproduction, but the molecular aspects underlying these effects are not well-understood. In the last years, several studies through us and others showed the effects of exposure to neonicotinoids on gene expression in the brain of honey bees. Transcripts of acetylcholine receptors, hormonal regulation, stress markers, detoxification enzymes, immune system related genes and transcripts of the energy metabolism were altered after neonicotinoid exposure. To elucidate the link between homing flight performance and shifts in gene expression in the brain of honey bees after neonicotinoid exposure, we combined homing flight activity experiments applying RFID technology and gene expression analysis. We analyzed the expression of endocrine factors, stress genes, detoxification enzymes and genes linked to energy metabolism in forager bees after homing flight experiments. Three different experiments (experiment I: pilot study; experiment II: "worst-case" study and experiment III: laboratory study) were performed. In a pilot study, we wanted to investigate if we could see differences in gene expression between controls and exposed bees (experiment I). This first study was followed by a so-called "worst-case" study (experiment II), where we investigated mainly differences in the expression of transcripts linked to energy metabolism between fast and slow returning foragers. We found a correlation between homing flight duration and the expression of cytochrome c oxidase subunit 5A, one transcript linked to oxidative phosphorylation. In the third experiment (experiment III), foragers were exposed in the laboratory to 1 ng/bee thiamethoxam and 8 ng/bee thiacloprid followed by gene expression analysis without a Christen et al. Flight Activity and Gene Expression subsequent flight experiment. We could partially confirm the induction of cytochrome c oxidase subunit 5A, which we detected in experiment II. In addition, we analyzed the effect of the feeding mode (group feeding vs. single bee feeding) on data scattering and demonstrated that single bee feeding is superior to group feeding as it significantly reduces variability in gene expression. Based on the data, we thus hypothesize that the disruption of energy metabolism may be one reason for a prolongation of homing flight duration in neonicotinoid treated bees.
Virulence, May 26, 2020
Melissococcus plutonius is a bacterial pathogen that causes epidemic outbreaks of European foulbr... more Melissococcus plutonius is a bacterial pathogen that causes epidemic outbreaks of European foulbrood (EFB) in honey bee populations. The pathogenicity of a bacterium depends on its virulence, and understanding the mechanisms influencing virulence may allow for improved disease control and containment. Using a standardized in vitro assay, we demonstrate that virulence varies greatly among sixteen M. plutonius isolates from five European countries. Additionally, we explore the causes of this variation. In this study, virulence was independent of the multilocus sequence type of the tested pathogen, and was not affected by experimental coinfection with Paenibacillus alvei, a bacterium often associated with EFB outbreaks. Virulence in vitro was correlated with the growth dynamics of M. plutonius isolates in artificial medium, and with the presence of a plasmid carrying a gene coding for the putative toxin melissotoxin A. Our results suggest that some M. plutonius strains showed an increased virulence due to the acquisition of a toxin-carrying mobile genetic element. We discuss whether strains with increased virulence play a role in recent EFB outbreaks.
International Journal of Systematic and Evolutionary Microbiology
A novel, facultatively anaerobic, Gram-stain-positive, motile, endospore-forming bacterium of the... more A novel, facultatively anaerobic, Gram-stain-positive, motile, endospore-forming bacterium of the genus Paenibacillus , designated strain 2.1T, was isolated from a colony of Apis mellifera affected by European foulbrood disease in Switzerland. The rod-shaped cells of strain 2.1T were 2.2–6.5 µm long and 0.7–1.1 µm wide. Colonies of strain 2.1T were orange-pigmented under oxic growth conditions on solid basal medium at 35–37 °C. Strain 2.1T showed catalase and cytochrome c oxidase activity. Its polar lipid profile consisted of diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, aminophospholipid and phospholipid. The only respiratory quinone was menaquinone 7, and the major cellular fatty acids were anteiso-C15 : 0, anteiso-C17 : 0, iso-C15 : 0, iso-C17 : 0 and palmitic acid (C16 : 0), which is consistent with other members of the genus Paenibacillus . The G+C content of the genomic DNA of strain 2.1T was 53.3 mol%. Phylogenetic analyses based on the 16S rRNA gene...
Journal of Apicultural Research
This article presents managed honey bee colony loss rates over winter 2019/20 resulting from usin... more This article presents managed honey bee colony loss rates over winter 2019/20 resulting from using the standardised COLOSS questionnaire in 37 countries. Six countries were from outside Europe, including, for the first time in this series of articles, New Zealand. The 30,491 beekeepers outside New Zealand reported 4.5% of colonies with unsolvable queen problems, 11.1% of colonies dead after winter and 2.6% lost through natural disaster. This gave an overall colony winter loss rate of 18.1%, higher than in the previous year. The winter loss rates varied greatly between countries, from 7.4% to 36.5%. 3216 beekeepers from New Zealand managing 297,345 colonies reported 10.5% losses for their 2019 winter (six months earlier than for other, Northern Hemisphere, countries). We modelled the risk of loss as a dead/empty colony or from unresolvable queen problems, for all countries except New Zealand. Overall, larger beekeeping operations with more than 50 colonies experienced significantly lower losses (p < 0.001). Migration was also highly significant (p < 0.001), with lower loss rates for operations migrating their colonies in the previous season. A higher proportion of new queens reduced the risk of colony winter loss (p < 0.001), suggesting that more queen replacement is better. All three factors, operation size, migration and proportion of young queens, were also included in a multivariable main effects quasi-binomial GLM and all three remained highly significant (p < 0.001). Detailed results for each country and overall are given in a table, and a map shows relative risks of winter loss at the regional level.
Journal of Pest Science
Beekeepers have various options to control the parasitic mite Varroa destructor in honey bee colo... more Beekeepers have various options to control the parasitic mite Varroa destructor in honey bee colonies, but no empirical data are available on the methods they apply in practice. We surveyed 28,409 beekeepers maintaining 507,641 colonies in 30 European countries concerning Varroa control methods. The set of 19 different Varroa diagnosis and control measures was taken from the annual COLOSS questionnaire on honey bee colony losses. The most frequent activities were monitoring of Varroa infestations, drone brood removal, various oxalic acid applications and formic acid applications. Correspondence analysis and hierarchical clustering on principal components showed that six Varroa control options (not necessarily the most used ones) significantly contribute to defining three distinctive clusters of countries in terms of Varroa control in Europe. Cluster I (eight Western European countries) is characterized by use of amitraz strips. Cluster II comprises 15 countries from Scandinavia, the...
Apis mellifera filamentous virus (AmFV) is a large double stranded DNA virus of honey bees, but i... more Apis mellifera filamentous virus (AmFV) is a large double stranded DNA virus of honey bees, but its relationship with other parasites and prevalence are poorly known. We analyzed individual honey bees from three colonies at different times post emergence in order to monitor the dynamics of the AmFV gut colonization under natural conditions. Prevalence and loads of microsporidia and trypanosomes were also recorded, as well as five common honey bee RNA viruses. The results show that a high proportion of bees get infected with AmFV during the first week post-emergence (75%) and that AmFV DNA levels remained constant. A similar pattern was observed for microsporidia while trypanosomes seem to require more time to colonize the gut. No significant associations between these three infections were found, but significant positive correlations were observed between AmFV and RNA viruses. In parallel, the prevalence of AmFV in France and Sweden was assessed from pooled honey bee workers. The data indicate that AmFV is almost ubiquitous, and does not seem to follow seasonal patterns, although higher viral loads were significantly detected in spring. A high prevalence of AmFV was also found in winter bees, without obvious impact on overwintering of the colonies.
https://www.agroscope.admin.ch/agroscope/de/home/publikationen/suchen/agroscope-transfer.htm
Genome Biology and Evolution, 2020
Historical specimens in museum collections provide opportunities to gain insights into the genomi... more Historical specimens in museum collections provide opportunities to gain insights into the genomic past. For the Western honey bee, Apis mellifera L., this is particularly important because its populations are currently under threat worldwide and have experienced many changes in management and environment over the last century. Using Swiss Apis mellifera mellifera as a case study, our research provides important insights into the genetic diversity of native honey bees prior to the industrial-scale introductions and trade of non-native stocks during the 20th century—the onset of intensive commercial breeding and the decline of wild honey bees following the arrival of Varroa destructor. We sequenced whole-genomes of 22 honey bees from the Natural History Museum in Bern collected in Switzerland, including the oldest A. mellifera sample ever sequenced. We identify both, a historic and a recent migrant, natural or human-mediated, which corroborates with the population history of honey be...
BMC Genomics, 2021
Background With numerous endemic subspecies representing four of its five evolutionary lineages, ... more Background With numerous endemic subspecies representing four of its five evolutionary lineages, Europe holds a large fraction of Apis mellifera genetic diversity. This diversity and the natural distribution range have been altered by anthropogenic factors. The conservation of this natural heritage relies on the availability of accurate tools for subspecies diagnosis. Based on pool-sequence data from 2145 worker bees representing 22 populations sampled across Europe, we employed two highly discriminative approaches (PCA and FST) to select the most informative SNPs for ancestry inference. Results Using a supervised machine learning (ML) approach and a set of 3896 genotyped individuals, we could show that the 4094 selected single nucleotide polymorphisms (SNPs) provide an accurate prediction of ancestry inference in European honey bees. The best ML model was Linear Support Vector Classifier (Linear SVC) which correctly assigned most individuals to one of the 14 subspecies or different...
Insects, 2021
European foulbrood (EFB) is an infectious disease of honey bees caused by the bacterium Melissoco... more European foulbrood (EFB) is an infectious disease of honey bees caused by the bacterium Melissococcus plutonius. A method for DNA isolation and conventional PCR diagnosis was developed using hive debris, which was non-invasively collected on paper sheets placed on the bottom boards of hives. Field trials utilized 23 honey bee colonies with clinically positive symptoms and 21 colonies without symptoms. Bayes statistics were applied to calculate the comparable parameters for EFB diagnostics when using honey, hive debris, or samples of adult bees. The reliability of the conventional PCR was 100% at 6.7 × 103 Colony Forming Unit of M. plutonius in 1 g of debris. The sensitivity of the method for the sampled honey, hive debris, and adult bees was 0.867, 0.714, and 1.000, respectively. The specificity for the tested matrices was 0.842, 0.800, and 0.833. The predictive values for the positive tests from selected populations with 52% prevalence were 0.813, 0.833, and 0.842, and the real acc...
Journal of Apicultural Research, 2019
This short article presents loss rates of honey bee colonies over winter 2017/18 from 36 countrie... more This short article presents loss rates of honey bee colonies over winter 2017/18 from 36 countries, including 33 in Europe, from data collected using the standardized COLOSS questionnaire. The 25,363 beekeepers supplying data passing consistency checks in total wintered 544,879 colonies, and reported 26,379 (4.8%, 95% CI 4.7-5.0%) colonies with unsolvable queen problems, 54,525 (10.0%, 95% CI 9.8-10.2%) dead colonies after winter and another 8,220 colonies (1.5%, 95% CI 1.4-1.6%) lost through natural disaster. This gave an overall loss rate of 16.4% (95% CI 16.1-16.6%) of honey bee colonies during winter 2017/18, but this varied greatly from 2.0 to 32.8% between countries. The included map shows relative risks of winter loss at regional level. The analysis using the total data-set confirmed findings from earlier surveys that smaller beekeeping operations with at most 50 colonies suffer significantly higher losses than larger operations (p < .001). Beekeepers migrating their colonies had significantly lower losses than those not migrating (p < .001), a different finding from previous research. Evaluation of six different forage sources as potential risk factors for colony loss indicated that intensive foraging on any of five of these plant sources (Orchards, Oilseed Rape, Maize, Heather and Autumn Forage Crops) was associated with significantly higher winter losses. This finding requires further study and explanation. A table is included giving detailed results of loss rates and the impact of the tested forage sources for each country and overall.
Journal of Apicultural Research, 2018
Conceived the idea for the paper and wrote a first draft. † Did data processing and editing, all ... more Conceived the idea for the paper and wrote a first draft. † Did data processing and editing, all statistical analysis for the results in the table and text, produced the relative risks map, and contributed to the text of the article.
Genes, Jan 20, 2018
In Europe, approximately 84% of cultivated crop species depend on insect pollinators, mainly bees... more In Europe, approximately 84% of cultivated crop species depend on insect pollinators, mainly bees. (the Western honey bee) is the most important commercial pollinator worldwide. The Gram-positive bacterium is the causative agent of European foulbrood (EFB), a global honey bee brood disease. In order to detect putative virulence factors, we sequenced and analyzed the genomes of 14 strains, including two reference isolates. The isolates do not show a high diversity in genome size or number of predicted protein-encoding genes, ranging from 2.021 to 2.101 Mbp and 1589 to 1686, respectively. Comparative genomics detected genes that might play a role in EFB pathogenesis and ultimately in the death of the honey bee larvae. These include bacteriocins, bacteria cell surface- and host cell adhesion-associated proteins, an enterococcal polysaccharide antigen, an epsilon toxin, proteolytic enzymes, and capsule-associated proteins. In vivo expression of three putative virulence factors (endo-alp...
Journal of Apicultural Research, 2016
In this short note we present comparable loss rates of honey bee colonies during winter 2015/16 f... more In this short note we present comparable loss rates of honey bee colonies during winter 2015/16 from 29 countries, obtained with the COLOSS questionnaire. Altogether, we received valid answers from 19,952 beekeepers. These beekeepers collectively wintered 421,238 colonies, and reported 18,587 colonies with unsolvable queen problems and 32,048 dead colonies after winter. This gives an overall loss rate of 12.0% (95% confidence interval 11.8-12.2%) during winter 2015/16, with marked differences among countries. Beekeepers in the present study assessed 7.6% (95% CI 7.4-7.8%) of their colonies as dead or empty, and 4.4% (95% CI 4.3-4.5%) as having unsolvable queen problems after winter. The overall analysis showed that small operations suffered higher losses than larger ones. A table with detailed results and a map showing response and relative risks at regional level are presented.
Die Biodiversität bildet die Grundlage für viele Prozesse, wie zum Beispiel die natürliche Bestäu... more Die Biodiversität bildet die Grundlage für viele Prozesse, wie zum Beispiel die natürliche Bestäubung oder Schädlingsregulation (funktionelle Biodiversität). Damit Bestäuber und andere Nützlinge diese Funktionen effi zient erfüllen können, sollen sie mit massgeschneiderten Blühstreifenmischungen gefördert werden. Es handelt sich dabei um gezielt angelegte Blühstreifen direkt im Feld (Nahrungsquellen), ergänzend zu naturnahen Landschaftselementen wie Buntbrachen, Hecken oder extensiv genutzten Wiesen (Überwinterungs-oder Schutzlebensräume). Bestäuber und andere Nützlinge sind auf ein reichhaltiges Nahrungsangebot während der ganzen aktiven Saison angewiesen. In der intensiven Kulturlandschaft kann das Nahrungsangebot für die pollen-und nektarsuchenden Insekten nach dem Abblühen von Kulturen, Bäumen und Wiesen allerdings knapp werden. Um diese Nahrungslücke zu schliessen, trägt die mindestens 100-tägige Biodiversitätsförderfl äche "Blühstreifen für Bestäuber und andere Nützlinge" durch ein reiches Nektar-und Pollenangebot während den Sommermonaten zur Verbesserung des Nahrungsangebotes für Bestäuber und Nützlinge bei.