Background With the completion of a single nucleotide polymorphism (SNP) chip for honey bees, the technical basis of genomic selection is laid. However, for its application in practice, methods to estimate genomic breeding values need to... more
Background With the completion of a single nucleotide polymorphism (SNP) chip for honey bees, the technical basis of genomic selection is laid. However, for its application in practice, methods to estimate genomic breeding values need to be adapted to the specificities of the genetics and breeding infrastructure of this species. Drone-producing queens (DPQ) are used for mating control, and usually, they head non-phenotyped colonies that will be placed on mating stations. Breeding queens (BQ) head colonies that are intended to be phenotyped and used to produce new queens. Our aim was to evaluate different breeding program designs for the initiation of genomic selection in honey bees. Methods Stochastic simulations were conducted to evaluate the quality of the estimated breeding values. We developed a variation of the genomic relationship matrix to include genotypes of DPQ and tested different sizes of the reference population. The results were used to estimate genetic gain in the ini...
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Funding information Bundesministerium für Ernährung und Landwirtschaft, Grant/Award Number: 742 397; European Commission, Grant/Award Number: 613960 Abstract The inbreeding coefficients are considered in breeding decisions, and the... more
Funding information Bundesministerium für Ernährung und Landwirtschaft, Grant/Award Number: 742 397; European Commission, Grant/Award Number: 613960 Abstract The inbreeding coefficients are considered in breeding decisions, and the inverse numerator relationship matrix A is a prerequisite for breeding value estimation. Polyandry and haploid males are among the specifics of relationships between honey bees. Brascamp and Bijma (2014) averaged out the manifold possible relationships among honey bees that appear to have the same parents in a pedigree and assigned a single entry in A to animals that behave as a unit, for example, the workers of a hive. Their methods of calculation connected full‐sibs in the variance matrix of the Mendelian sampling terms D, via nonzero off‐diagonal elements. This impedes the inversion of A and the closely connected calculation of inbreeding coefficients, because efficient algorithms for this task take D to be a diagonal matrix. Memory limitations necessitate their use for large data sets. We adapted the quickest of them to the block diagonal matrix D, that is postulated for the honey bee. To our knowledge, the presented algorithm is the first one that facilitates the method of Brascamp and Bijma (2014) on large data sets.
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Honeybee toxicology is complex because effects on individual bees are modulated by social interactions between colony members. In the present study, we applied high doses of the insect growth regulator fenoxycarb to honeybee colonies to... more
Honeybee toxicology is complex because effects on individual bees are modulated by social interactions between colony members. In the present study, we applied high doses of the insect growth regulator fenoxycarb to honeybee colonies to elucidate a possible interplay of individually- and colony-mediated effects regarding honey bee toxicology. Additionally, possible effects of the solvent dimethyl sulfoxide (DMSO) were assessed. We conducted studies on egg hatching and brood development to assess brood care by nurse bees as well as queen viability. Egg hatching was determined by the eclosion rate of larvae from eggs originating from colonies (i) treated with sugar syrup only, (ii) treated with sugar syrup containing DMSO and (iii) treated with sugar syrup containing fenoxycarb (dissolved in DMSO). To evaluate brood development, combs with freshly laid eggs were reciprocally transferred between colonies, and development of brood was examined in the recipient hive. Brood reared inside DMSO- and fenoxycarb-treated colonies as well as brood from DMSO- and from fenoxycarb-exposed queens showed higher mortality than brood not exposed to the chemicals. No differences were found in egg hatching among the treatments, but there was a higher variability of eclosion rates after queens were exposed to fenoxycarb. We also observed queen loss and absconding of whole colonies. Based on our results we infer that fenoxycarb has queen- as well as nurse bee-mediated effects on brood quality and development which can lead to the queen's death. There also is an effect of DMSO on the nurse bees' performance that could disturb the colony's equilibrium, at least for a delimited timespan.
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SUMMARY The ectoparasitic mite Varroa destructor and honey bee pathogenic viruses have been implicated in the recent demise of honey bee colonies. Several studies have shown that the combination of V. destructor and deformed wing virus... more
SUMMARY The ectoparasitic mite Varroa destructor and honey bee pathogenic viruses have been implicated in the recent demise of honey bee colonies. Several studies have shown that the combination of V. destructor and deformed wing virus (DWV) poses an especially serious threat to honey bee health. Mites transmitting virulent forms of DWV may cause fatal DWV infections in the developing bee, while pupae parasitised by mites not inducing or activating overt DWV infections may develop normally. Adult bees respond to brood diseases by removing affected brood. This hygienic behaviour is an essential part of the bees' immune response repertoire and is also shown towards mite-parasitised brood. However, it is still unclear whether the bees react towards the mite in the brood cell or rather towards the damage done to the brood. We hypothesised that the extent of mite-associated damage rather than the mere presence of parasitising mites triggers hygienic behaviour. Hygienic behaviour assa...
Research Interests: Animal Behavior, Principal Component Analysis, Mass Spectrometry, RNA viruses, Applied Animal Behavior, and 13 moreBiological Sciences, Germany, Bees, Volatile Organic Compounds, Female, Animals, Smell, Polymerase Chain Reaction, The, Odors, Experimental Biology, Pupa, and Medical and Health Sciences
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Abstract High‐throughput high‐density genotyping arrays continue to be a fast, accurate, and cost‐effective method for genotyping thousands of polymorphisms in high numbers of individuals. Here, we have developed a new high‐density SNP... more
Abstract High‐throughput high‐density genotyping arrays continue to be a fast, accurate, and cost‐effective method for genotyping thousands of polymorphisms in high numbers of individuals. Here, we have developed a new high‐density SNP genotyping array (103,270 SNPs) for honey bees, one of the most ecologically and economically important pollinators worldwide. SNPs were detected by conducting whole‐genome resequencing of 61 honey bee drones (haploid males) from throughout Europe. Selection of SNPs for the chip was done in multiple steps using several criteria. The majority of SNPs were selected based on their location within known candidate regions or genes underlying a range of honey bee traits, including hygienic behavior against pathogens, foraging, and subspecies. Additionally, markers from a GWAS of hygienic behavior against the major honey bee parasite Varroa destructor were brought over. The chip also includes SNPs associated with each of three major breeding objectives—honey yield, gentleness, and Varroa resistance. We validated the chip and make recommendations for its use by determining error rates in repeat genotypings, examining the genotyping performance of different tissues, and by testing how well different sample types represent the queen's genotype. The latter is a key test because it is highly beneficial to be able to determine the queen's genotype by nonlethal means. The array is now publicly available and we suggest it will be a useful tool in genomic selection and honey bee breeding, as well as for GWAS of different traits, and for population genomic, adaptation, and conservation questions.
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Additional file 2. Formula for the prediction accuracy for replacement queens. We derive our Eq. (16) for the accuracy of the replacement queens in year 8 from formulas of Brascamp and Bijma [27].
Simple summary Parasitic mites are among the main causes of honeybee colony losses worldwide. Long-term selection has led to bees that are, in part, resistant to one specific mite, Varroa destructor. We investigated whether an important... more
Simple summary Parasitic mites are among the main causes of honeybee colony losses worldwide. Long-term selection has led to bees that are, in part, resistant to one specific mite, Varroa destructor. We investigated whether an important Varroa resistance trait, “hygienic behavior”, is also effective against Tropilaelaps mercedesae. T. mercedesae is another bee-parasitic mite of great economic importance and a lifecycle similar to that of V. destructor. “Hygienic behavior” means the ability of bees to recognize and destroy mite-infested bee brood, interrupting reproduction of the parasite. We also compared the expression of the behavior in two species of bees, one of which (Apis cerana) is thought to be resistant to T. mercedesae, while the other (Apis mellifera) is sensitive to it. We confirmed that both bees were able to express hygienic behavior also towards T. mercedesae. Moreover, we found that specialist bees destroying V. destructor-infested brood often also destroyed brood in...
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Research Interests: Zoology and Apidologie
Here we cover a wide range of methods currently in use and recommended in modern queen rearing, selection and breeding. The recommendations are meant to equally serve as standards for both scientific and practical beekeeping purposes. The... more
Here we cover a wide range of methods currently in use and recommended in modern queen rearing, selection and breeding. The recommendations are meant to equally serve as standards for both scientific and practical beekeeping purposes. The basic conditions and different management techniques for queen rearing are described, including recommendations for suitable technical equipment. As the success of breeding programmes strongly depends on the selective mating of queens, a subchapter is dedicated to the management and quality control of mating stations. Recommendations for the handling and quality control of queens complete the queen rearing section. The improvement of colony traits usually depends on a comparative testing of colonies. Standardized recommendations for the organization of performance tests and the measurement of the most common selection characters are presented. Statistical methods and data preconditions for the estimation of breeding values which integrate pedigree and performance data from as many colonies as possible are described as the most efficient selection method for large populations. Alternative breeding programmes for small populations or certain scientific questions are briefly mentioned, including also an overview of the young and fast developing field of molecular selection tools. Because the subject of queen rearing and selection is too large to be covered within this paper, plenty of references are given to facilitate comprehensive studies. Métodos estándar para la cría y selección de reinas de Apis mellifera Resumen Se describe una amplia gama de métodos actualmente en uso y recomendables sobre la cría actual de reinas, su selección y cruzamiento. Las recomendaciones tienen el propósito de servir de igual forma como estándares para fines apícolas tanto científicos como prácticos. Se describen las condiciones básicas y las diferentes técnicas de manejo para la cría de reinas, incluyendo recomendaciones para el equipo técnico adecuado. Dado que el éxito de los programas de mejora depende en gran medida el apareamiento selectivo de reinas, se dedica un subcapítulo a la gestión y control de calidad de las estaciones de apareamiento. Las recomendaciones para el manejo y control de calidad de las reinas completan la sección de cría de reinas. La mejora de las características de colonias por lo general, depende de ensayos comparativos entre colonias. Se presentan recomendaciones normalizadas para la organización de pruebas de rendimiento y la medición de los caracteres de selección más comunes. Aquellos métodos estadísticos y condiciones previas de datos para la estimación de valores de cruzamiento que integren los datos genealógicos y de rendimiento de tantas colonias como sea posible, se describen como los métodos de
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We report on an image classification task originated from the video observation of beehives. Biologists desire to have an automatic sup- port to identify so called hygienic bees. For this it is important to know which brood cells are in a... more
We report on an image classification task originated from the video observation of beehives. Biologists desire to have an automatic sup- port to identify so called hygienic bees. For this it is important to know which brood cells are in a stadium of initial opening. To find these cells a prescreening process is necessary which distinguishes between three types of
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Results for the application of an adaptive background model to the problem of detecting changes on a combs surface are reported. It is demonstrated that the combined search for uncapped brood cells in the current image and the background... more
Results for the application of an adaptive background model to the problem of detecting changes on a combs surface are reported. It is demonstrated that the combined search for uncapped brood cells in the current image and the background image increases the overall detection rate of the system.
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Honeybee biodiversity is under massive threat, and improved methods for gamete cryopreservation could be a precious tool for both the in situ- and ex situ-conservation of subspecies and ecotypes. Recent cryoprotocols for drone semen have... more
Honeybee biodiversity is under massive threat, and improved methods for gamete cryopreservation could be a precious tool for both the in situ- and ex situ-conservation of subspecies and ecotypes. Recent cryoprotocols for drone semen have improved the viability and fertility of frozen-thawed semen by using increased diluent:semen-ratios, but there is still much room for progress. As semen cryopreserved after dilution often appeared hyperactive, we speculated that the disruption of sperm-sperm interactions during dilution and cryopreservation could reduce the fertile lifespan of the cells. We therefore developed protocols to reduce admixture, or abolish it altogether by dialyzing semen against a hypertonic solution of cryoprotectant. Additionally, we tested methods to reduce the cryoprotectant concentration after thawing. Insemination of queens with semen cryopreserved after dialysis yielded 49%, 59% and 79% female (= stemming from fertilized eggs) pupae in three separate experiments,...
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Research Interests: Zoology and Apidologie
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Research Interests: Physiology, Zoology, Insect Physiology, Oogenesis, Bees, and 9 moreApis mellifera, Female, Animals, Honey bee, Sterilization, Insect, Hemolymph, Ovary, and ECDYSTEROIDS
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Research Interests: Physiology, Zoology, Reproduction, Insect Physiology, Bees, and 9 moreFemale, Animals, Male, Juvenile Hormone, Hemolymph, Spermatozoa, Ovary, Dimorphism, and ECDYSTEROIDS
Centrifugation of Apis mellifera L. drone semen is a necessary step in the homogenization of semen pools for the enlargement of the effective breeding population, as well as in the collection of semen by the so-called washing technique.... more
Centrifugation of Apis mellifera L. drone semen is a necessary step in the homogenization of semen pools for the enlargement of the effective breeding population, as well as in the collection of semen by the so-called washing technique. It is also of interest for the removal of cryoprotectants after cryopreservation. The adoption of methods involving semen centrifugation has been hampered by their damaging effect to sperm. Here, we tested four new diluents as well as three additives (catalase, hen egg yolk, and a protease inhibitor), using sperm motility and dual fluorescent staining as indicators of semen quality. Three of the new diluents significantly reduced motility losses after centrifugation, as compared with the literature standard. Values of motility and propidium iodide negativity obtained with two of these diluents were not different from those measured with untreated semen. The least damaging diluent, a citrate-HEPES buffer containing trehalose, was then tested in an insemination experiment with centrifuged semen. Most queens receiving this semen produced normal brood, and the number of sperm reaching the storage organ of the queen was not significantly different from that in queens receiving untreated semen. These results could improve the acceptance of techniques involving the centrifugation of drone semen. The diluent used in the insemination experiment could also serve as semen extender for applications not involving centrifugation.
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... For the measurement of early embryonic mortality (EEM), in 2005 and 2006, empty combs were introduced into the mating nuclei, and eggs ... of literature exists with respect to the impact of maternal investment on the body size of... more
... For the measurement of early embryonic mortality (EEM), in 2005 and 2006, empty combs were introduced into the mating nuclei, and eggs ... of literature exists with respect to the impact of maternal investment on the body size of offspring of various species (Bernardo 1996, and ...