Health Status of Honeybee Colonies Differing in Genetic Intra-Colonial Diversity

Two different levels of diversity within a colony were compared for the prevalence of pathogens and diseases. Lower genetic diversity was obtained in the colonies in which the queens were inseminated with semen collected from drones originating from a single colony, while greater was obtained in the colonies with queens inseminated with semen from drones of thirty different colonies. Bees were tested for Varroa destructor infestation, microsporidia Vairimorpha spp. infection, acute bee paralysis virus (ABPV) and deformed wing virus (DWV). Colonies with a greater genetic diversity of workers in colonies were more infested with Varroa mites than genetically uniform colonies. Varroa infestation was not found to be associated directly with the weakening of bee colonies after winter. The two experimental groups had a similar number of colonies infected with Vairimorpha, and viruses. Intensity of Varroa infestation and Vairimorpha infection did not significantly affect the overwintering of bee colonies. Colonies in which DWV was detected significantly weakened during overwintering

Causes and Scale of Winter Flights in Honey Bee (Apis Mellifera Carnica ) Colonies

Winter honey bee losses were evaluated during the two overwintering periods of 2009/2010 and 2010/2011. The research included dead bee workers that fell on the hive bottom board (debris) and the ones that flew out of the hive. Differences were observed in the number of bees fallen as debris between the two periods, whereas the number of bees flying out was similar in both years. No differences were found between the numbers of dead bees in strong and weak colonies. The percentage of bees flying out of the colony increased in the presence of Nosema spores, Varroa infestation, increased average air temperature, and insolation during the day. In addition, both the presence of Nosema and insolation during the day had an impact on the number of bees that died and fell on the hive board

Balling Behavior of Workers Toward Honey Bee Queens Returning from Mating Flights

During natural mating honeybee queens can get lost due to drifting, predators or other cases. In this work, the balling of queens returning from flights by worker bees originating from the same colony was observed. Three subspecies of bees Carniolan, Caucasian and European Black Bee were tested. Research was conducted in both spring and summer, but in the former in newly created colonies, while in the latter in new and earlier used ones. Generally 15.2% of queens were balled and in total 30.2% of queens were lost during mating flights. 269 queens performed 785 mating flights, and 5.2% of those finished with balling. Three times more queens were balled when returning from mating flight rather than orientation flight. Subspecies matches or mismatches of queens and workers in nucleuses did not significantly affect the balling or its frequency. Additionally, no bee subspecies characterized stronger tendencies to ball a queen. Worker bees from newly created nucleuses treated queens similarly to the ones in nucleuses earlier used. However, significantly more queens had been balled during the spring in comparison to summer. There were days with higher balling of queens. During some days the weather was very unstable and unpredictable with such anomalies as heat waves, thunderstorms or sudden drops in insolation. Most of the queens were balled at the entrance while returning from flight and only a few inside the hive. In the research, clear causes of balling were not found, but some factors can be excluded

Susceptibility of Bee Larvae to Chalkbrood in Relation to Hygienic Behaviour of Worker Bees in Colonies of Chosen Races of Honeybee (Apis Mellifera )

The susceptibility of bee larvae to Ascosphaera apis infestation and the hygienic behaviour of worker bees in relation to A. apis infected and freeze-killed brood were evaluated in three races of bees: Apis mellifera carnica, Apis mellifera caucasica, and Apis mellifera mellifera. Experimental bee colonies were evaluated in field conditions during the three beekeeping seasons. The lowest percentage of infected larvae was observed in car GR1 and mel A colonies (8.5% and 15%, respectively) and the highest in car Mr and cau P colonies (21% and 24.3%, respectively). Bees in the car GR1 and mel A colonies removed mummified brood in a shorter period of time (6.5 and 7.1 days on average, respectively) than car Mr and cau P colonies (above 8 days). Bees in the mel A and car GR1 colonies cleaned significantly more cells with freeze-killed brood within 24 and 48 hours (above 70% and 80% on average, respectively) than car Mr and cau P colonies (on average 10 - 20% lower cleaning rate). A low correlation coefficient was found for the susceptibility of larvae to A. apis infection and hygienic behaviour

Performance of Bee Colonies Headed by Queens Instrumentally Inseminated with Semen of Drones Who Come from a Single Colony or Many Colonies

The aim of the study was to determine the effect of honey bee worker diversity within the colony on: development, honey productivity, and wintering. Two different levels of diversity within the colony were tested. The appropriate levels of diversity within the colony were obtained by selecting drones for inseminating the queens. Lower genetic diversity was obtained in the colonies headed by a queen inseminated with semen collected from drones originating from a single colony. Higher genetic diversity was obtained in the colonies with queens inseminated with semen from drones of 30 different colonies. Colonies with a higher genetic variation of workers in the colonies had greater levels of functional characteristics. However, apart from the number of dead bees in winter, the genetic diversity level of the workers on the colony development and honey production, did not have a significant influence. There was an averaging effect observed concerning that male component in the colonies with a higher genetic variation of workers - on honey yield, when compared to the non-additive effect of the best drones

Maternal Inheritance in Hybrids of Three Honey Bee Subspecies

The identification of honey bee (Apis mellifera) subspecies is often based on the measurements of workers’ fore-wings. The interpretation of the measurements can be difficult because the phenotype of workers is affected by both genetic and environmental factors. Moreover, it is not clear how the phenotype is affected by maternal inheritance. We have used the methodology of geometric morphometrics to verify if hybrids of honey bee subspecies and their backcrosses are more similar to either the father or mother colony. The comparison was based on fore-wing venation of three honey bee subspecies: A. m. carnica, A. m. caucasica, A. m. mellifera. First generation hybrids and backcrosses of those subspecies were obtained through instrumental insemination. Workers of the hybrids were compared with their parental colonies. The shape of wing venation was more similar to the maternal than to parental colony. This phenomenon was particularly visible in first generation of hybrids but it was also present in backcrosses. There were also symptoms of genetic dominance of some subspecies but this effect interacted with maternal inheritance and was difficult to interpret

Microsatellite DNA polymorphism in selectively controlled Apis mellifera carnica and Apis mellifera caucasica populations from Poland

Genetic polymorphism in selectively controlled honeybee populations of A. m. carnica and A. m. caucasica in Poland, was characterized by microsatellite DNA analysis. All honeybee samples were analyzed for nine microsatellite loci: Ac011; A024; A043; A088; Ap226; Ap238; Ap243; Ap249 and Ap256, which were found to be polymorphic in both populations. The mean number of alleles per locus was 6.222 for A. m. carnica and 4.556 for A. m. caucasica. Average observed and expected heterozygosity values were calculated as 0.976 and 0.734 in A. m. carnica and as 0.933 and 0.603 in A. m. caucasica, respectively. For the nine microsatellite loci, a total of 76 alleles were found in both populations. Thirty-five private alleles were observed in A. m. carnica and 20 in A. m. caucasica. Information about allele frequencies, FST values and genotypic differentiation is given. Nei’s genetic distance between studied populations of A. m. carnica and A. m. caucasica was calculated as 0.384

Hygienic Behaviour of Honeybee Colonies with Different Levels of Polyandry and Genotypic Composition

Honey bee queens were inseminated with diluted, homogenised semen collected from a few dozen drones. This procedure was carried out to increase the diversity of the queens’ offspring, which is in comparison to the offspring of queens inseminated with semen from only a few drones coming from one colony. Queens and drones were mated within carniolan bee (Apis mellifera carnica) subspecies, but 3 selected lines were used. Queens were reared from one line and drones from the same line, and two additional lines differing in hygienic behaviour wherein in one of them that trait was strongly evident. The aim of this study was to examine whether the level of enhanced genetic variability in colonies and simultaneously the participation of hygienic bees, would increase the performance of hygienic behaviour. Overall hygienic behaviour of colonies with a lower and greater genetic variability did not differ significantly and amounted to 52.1 and 47.0%, respectively. Colonies within the lower variability group, in which drones from line selected in hygienic behaviour performance were used for inseminating queens, had a significantly greater percent of cleaned pupae than other colonies (63.2%). Hygienic behaviour in other colonies was more dependent on the gene quotas of hygienic bees in the colonies rather than on the level of polyandry

Swarming, defensive and hygienic behaviour in honey bee colonies of different genetic origin in a pan-European experiment

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Population dynamics of European honey bee genotypes under different environmental conditions

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