Kaspar Bienefeld - Academia.edu (original) (raw)

Papers by Kaspar Bienefeld

Genetics, Selection, Evolution : GSE, 2021

Background With the completion of a single nucleotide polymorphism (SNP) chip for honey bees, the... 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...

Journal of Animal Breeding and Genetics

Funding information Bundesministerium für Ernährung und Landwirtschaft, Grant/Award Number: 742 3... 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.

Journal of Apicultural Research, 1996

Ecotoxicology, 2016

Honeybee toxicology is complex because effects on individual bees are modulated by social interac... 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&amp;amp;amp;amp;amp;amp;amp;#39;s death. There also is an effect of DMSO on the nurse bees&amp;amp;amp;amp;amp;amp;amp;#39; performance that could disturb the colony&amp;amp;amp;amp;amp;amp;amp;#39;s equilibrium, at least for a delimited timespan.

Journal of Experimental Biology, 2012

SUMMARY The ectoparasitic mite Varroa destructor and honey bee pathogenic viruses have been impli... 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...

Journal of Entomology, 2013

Ecology and Evolution

Abstract High‐throughput high‐density genotyping arrays continue to be a fast, accurate, and cost... 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.

Additional file 2. Formula for the prediction accuracy for replacement queens. We derive our Eq. ... more 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. Lon... 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...

Apidologie, 2006

The estimation of breeding value for the honey bee is markedly more difficult than for other agri... more The estimation of breeding value for the honey bee is markedly more difficult than for other agricultural animals as colony traits in honey bees are the expression of the combined activities of the queen and workers. Recent studies have shown strong negative genetic correlations between the contributions of both queens and workers to economically important traits (e.g. honey production). The most advantageous method currently available for evaluating breeding values in other animals, the Best Linear Unbiased Prediction (BLUP)-Animal Model, has been adapted to the peculiarities of honey bee genetics and reproduction. This method considers maternal (queen) effects using all available records of relatives and weights these so as to obtain the most accurate prediction of the genotype. It simultaneously considers environmental effects, genetic merit of mates and contemporarily tested colonies, and estimates the breeding values for queen and worker effects on colony traits for each queen.

Apidologie, 2002

Fourier-transform infrared spectroscopy (FT-IR) was used as a rapid, simple and reliable method f... more Fourier-transform infrared spectroscopy (FT-IR) was used as a rapid, simple and reliable method for quality analysis of honey. More than 1600 samples of honey were analysed using FT-IR and reference methods to develop a partial least-square regression based calibration model for the major components of honey (sugars, proline, free acids, invertase, moisture, hydroxymethylfurfural, pH and electrical conductivity). The coefficient of determination R 2 ranging from 0.84-0.98 indicates an acceptable calibration for most of the parameters. Statistical verification of the spectral analysis in routine analysis showed a high correlation (0.81-0.99), good repeatability (0.84-0.99), no environmental influences (P > 0.05) and no significant statistical differences to the reference methods. This study shows that not only chemical composition but also the physical properties can be determined by FT-IR. The calibrations can be adapted to different analytical standards and honey sources.

Apidologie, 1989

— Inbreeding coefficients of queens and workers of 5581 controlled mated colonies were esti... more — Inbreeding coefficients of queens and workers of 5581 controlled mated colonies were estimated. During a period of over 30 years inbreeding increased by 0.15% in queens and 0.06% in workers per year. The highest inbreeding coefficients were 44% in individual queens and 45% in individual worker groups, respectively. Using partial regression, the importance and consequences of inbreeding on colony traits were ascertained. Inbreeding seems to affect the two castes differently. Colony performance with regard to honey and wax is significantly depressed (-6% and -8%, respectively, per 1 % inbreeding) by the inbreeding of the workers. In our material, inbreeding of queens did not affect colony efficiency except when workers were also inbred. Workers can compensate for inbreeding depression of queens, but the reverse is not true. Inbreeding of workers leads to calmer and less aggressive colony behaviour, whereas inbreeding of queens has the opposite effect. Swarming tendency increased with increased inbreeding of workers. In contrast, queens with moderate inbreeding have colonies with the highest swarming tendency. Honey production, calmness during examination and swarming tendency show significant interactions between the inbreeding level of queens and workers.

Here we cover a wide range of methods currently in use and recommended in modern queen rearing, s... 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

Journal of Invertebrate Pathology, 2006

Honeybees (Apis mellifera) can be attacked by many eukaryotic parasites, and bacterial as well as... more Honeybees (Apis mellifera) can be attacked by many eukaryotic parasites, and bacterial as well as viral pathogens. Especially in combination with the ectoparasitic mite Varroa destructor, viral honeybee diseases are becoming a major problem in apiculture, causing economic losses worldwide. Several horizontal transmission routes are described for some honeybee viruses. Here, we report for the Wrst time the detection of viral sequences in semen of honeybee drones suggesting mating as another horizontal and/or vertical route of virus transmission. Since artiWcial insemination and controlled mating is widely used in honeybee breeding, the impact of our Wndings for disease transmission is discussed.

Journal of Animal Breeding and Genetics, 2000

The hygienic behaviour of the honey bees is considered to be a potential characteristic associate... more The hygienic behaviour of the honey bees is considered to be a potential characteristic associated with resistance to Varroa destructor n.sp. In this study the heritability of the hygienic behaviour of Apis mellifera L. bees was estimated on the basis of the mother±daughter regression. Data were obtained from measurements of the bees' hygienic behaviour towards V. destructor-infested cells and towards pin-killed sealed brood. The heritability for the hygienic behaviour towards V. destructorinfested brood cells was h 2 0.18 (+ 0.27) and h 2 0.36 (+ 0.30) for the hygienic behaviour towards dead brood cells. The repeatability was likewise higher for the pin-killed brood assay (W 0.46) compared with the assay using living mites-infested brood cells (W 0.24). The genetic correlation between the behavioural responses to either the mite-infested or pin-killed brood cells was calculated to be r g 0.61 (+ 0.51) and the phenotypic correlation to be r p 0.11 (p 0.28, n 100). Since hygienic colonies demonstrate resistance to brood diseases such as American foulbrood and chalkbrood, it may be worthwhile to intensify the expression of the hygienic behaviour through selective breeding and thus strengthen these potential characteristics associated with resistance to V. destructor in honey bee stock.

We report on an image classification task originated from the video observation of beehives. Biol... 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

Results for the application of an adaptive background model to the problem of detecting changes o... 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.

Apidologie, 2009

In this study, we investigated whether differences in the reproductive biology of honey bee (Apis... more In this study, we investigated whether differences in the reproductive biology of honey bee (Apis mellifera) queens and laying workers are reflected in their eggs. We first tested the capacity of queen-and worker-laid male eggs to withstand dry conditions, by incubating samples at 30.0, 74.9, and 98.7% relative humidity. We found that worker-laid eggs were more sensitive to desiccation. Secondly, we measured the weight and quantities of vitellin, total protein, lipid, glycogen, and free carbohydrate in queen-and workerlaid eggs. Although worker-laid eggs were found to be heavier than queen-laid eggs in two of the four replicates, no systematic differences were found regarding nutrient content. Finally, we compared the duration of embryo development in the two egg types. Worker-laid eggs developed more slowly than queen-laid eggs in two out of three replicates, suggesting that they may only be partly mature at the moment they are laid. Possible causes and consequences of the observed differences are discussed.