The survival and performance of 597 honey bee colonies, representing five subspecies and 16 different genotypes, were comparatively studied in 20 apiaries across Europe. Started in October 2009, 15.7% of the colonies survived without any therapeutic treatment against diseases until spring 2012. The survival duration was strongly affected by environmental factors (apiary effects) and, to a lesser degree, by the genotypes and origin of queens. Varroa was identified as a main cause of losses (38.4%), followed by queen problems (16.9%) and Nosema infection (7.3%). On average, colonies with queens from local origin survived 83 days longer compared to non-local origins (p < 0.001). This result demonstrates strong genotype by environment interactions. Consequently, the conservation of bee diversity and the support of local breeding activities must be prioritised in order to prevent colony losses, to optimize a sustainable productivity and to enable a continuous adaptation to environmental changes.

Adaptation of honey bees to their environment is expressed by the annual development pattern of the colony, the balance with food sources and the host - parasite balance, all of which interact among each other with changes in the environment. In the present study, we analyse the development patterns over a period of two years in colonies belonging to 16 different genotypes and placed in areas grouped within six environmental clusters across Europe. The colonies were maintained with no chemical treatment against varroa mites. The aim of the study was to investigate the presence of genotype - environment interactions and their effects on colony development, which we use in this study as a measure of their vitality. We found that colonies placed in Southern Europe tend to have lower adult bee populations compared to colonies placed in colder conditions, while the brood population tends to be smaller in the North, thus reflecting the shorter longevity of bees in warmer climates and the shorter brood rearing period in the North. We found that both genotype and environment significantly affect colony development, and that specific adaptations exist, especially in terms of adult bee population and overwintering ability.

Diseases are known to be one of the major contributors to colony losses. Within a Europe-wide experiment on genotype - environment interactions, an initial 621 colonies were set up and maintained from 2009 to 2012. The colonies were monitored to investigate the occurrence and levels of key pathogens. These included the mite Varroa destructor (mites per 10 g bees), Nosema spp. (spore loads and species determination), and viruses (presence/absence of acute bee paralysis virus (ABPV) and deformed wing virus (DWV)). Data from 2010 to the spring of 2011 are analysed in relation to the parameters: genotype, environment, and origin (local vs. non-local) of the colonies in the experiment. The relative importance of different pathogens as indicators of colony death within the experiment is compared. In addition, pathogen occurrence rates across the geographic locations are described.

Summary Honey bee colonies exhibit a wide range of variation in their behaviour, depending on their genetic origin and environmental factors. The COLOSS Genotype-Environment Interactions Experiment gave us the opportunity to investigate the phenotypic expression of the swarming, defensive and hygienic behaviour of 16 genotypes from five different honey bee subspecies in various environmental conditions. In 2010 and 2011, a total of 621 colonies were monitored and tested according to a standard protocol for estimation of expression of these three behavioural traits. The factors: year, genotype, location, origin (local vs. non-local) and season (only for hygienic behaviour) were considered in statistical analyses to estimate their effect on expression of these behaviours. The general outcome of our study is that genotype and location have a significant effect on the analysed traits. For all characters, the variability among locations was higher than the variability among genotypes. We also detected significant variability between the genotypes from different subspecies, generally confirming their known characteristics, although great variability within subspecies was noticed. Defensive and swarming behaviour were each positively correlated across the two years, confirming genetic control of these characters. Defensive behaviour was lower in colonies of local origin, and was negatively correlated with hygienic behaviour. Hygienic behaviour was strongly influenced by the season in which the test was performed. The results from our study demonstrate that there is great behavioural variation among different subspecies and strains. Sustainable protection of local genotypes can be promoted by combining conservation efforts with selection and breeding to improve the appreciation by beekeepers of native stock.

As part of the COLOSS GEI experiment, one apiary in Chalkidi, Greece was continuously monitored for various pests and pathogens including V. destructor mites, Nosema spp. spores, and quantitative titers of five viruses from late summer 2009 until March 2012. The apiary was established with 39 colonies which included ten A. m. carnica (CarV) colonies from Germany, ten A. m. ligustica (LigI) colonies from Italy, ten A. m. macedonica (MacB) colonies from Bulgaria and nine local A. m. macedonica (MacG) colonies from Greece. At the end of the monitoring period, eight colonies survived: six local MacG, one MacB and one LigI. The local MacG colonies consistently showed comparatively lower V. destructor infestation levels and, consequently, also low DWV titres. In contrast, LigI colonies had the highest Nosema spp. and BQCV titres. It is, however, difficult to attribute the low survival rate of non-local colonies to any single factor. Since all colonies were located in close proximity in a single apiary, and the local bees were in better health than non-local bees, we assume that the local bees were better adapted to the local environmental conditions, and handled environmental stressors better to avoid disease outbreak.

The objective of this study was to compare the colony development cycle (unsealed and sealed worker brood, drone brood, pollen and colony strength) of two Apis mellifera carnica subpopulations in two distinct environments (alpine and continental). At each test location were two sub groups of 12 colonies headed by naturally mated sister queens from either the Institute of Apiculture Lunz am See, Austria (AT) or from the Faculty of Agriculture University of Zagreb, Croatia (HR). Colony development was monitored every 14 days. The HR genotype, adapted to a continental climate, had faster spring brood development in both environments. During spring and early summer the AT genotype maintained the number of sealed brood cells at a constant level in the more favourable conditions, although the amount of unsealed brood reached its maximum in early June. The environment influenced colony development, food stores and colony strength. Interaction between genotype and environment did not affect the number of unsealed brood cells, but the difference was statistically significant for the number of sealed brood cells. The study indicated the presence of a number of genotype and environment interactions between the two honey bee genotypes and their colony traits.

The drifting of honey bees often occurs in apiaries where numbers of hives are kept close together and it is an important vector in the spreading of honey bee diseases. It occurs in high numbers, frequently and over long distances. Within this work, it was investigated whether drifting might play a role in the epidemiology of American foulbrood. To determine the presence and the number of P. larvae spores in samples of honey, pollen and honey sacs, three different methods were used: modified Ritter-Kiefer (1993) method, Columbia blood agar test (Plagemann, 1985) and catalase tests (Haynes, 1972). Although the level of drifting within the colonies with clinical symptoms of AFB was slightly higher than the one within the colonies without clinical symptoms, AFB infection did not significantly influence the drifting frequency. Even when drifting was compared between two groups of young bees at the age of orientation flights, AFB infection did not significantly influence the level of drifting. However, as the level of P. larvae spores detected both in the pollen and honey stored in the hives, as well as in the pollen found on the legs of the bees from infected colonies, was significantly higher compared with the one in colonies with no clinical symptoms of AFB, it can be concluded that drifting plays a role in the spreading of AFB, especially during the orientation flights of young bees.

Colony development of two Carniolan genotypes (Apis mellifera carnica) in relation to environment Marica Maja Dražić, Janja Filipi, Saša Prđun, Dragan Bubalo, Marija Špehar, Denis Cvitković, Dubravko Kezić, Hermann Pechhacker and Nikola Kezić Croatian Agricultural Agency, Ilica 101, 10000 Zagreb, Croatia. Department of Karst Agriculture, Polytechnic of Applied Sciences Marko Marulić, Knin, Croatia. Faculty of Agriculture, University of Zagreb, Svetošimunska 25, 10000 Zagreb, Croatia. Veterinary Faculty University of Zagreb, Heinzelova 55, 10000 Zagreb, Croatia. Austrian Carnica Association, Kleine Seeaustrasse 10, 3293 Lunz am See, Austria.

The COLOSS GEI (Genotype-Environment Interactions) Experiment was setup to further our understanding of recent honey bee colony losses. The main objective of the GEI experiment was to understand the effects of environmental factors on the vitality of European honey bee genotypes. This paper aims to describe the genetic background and population allocation of the bees used in this experiment. Two wing morphometric and two genetic methods were employed to discriminate bee populations. Classical morphometry of 11 angles on the wings were carried out on 350 bees. Geometric morphonnetry on 19 wing landmarks was carried out on 381 individuals. DNA microsatellite analysis was carried out on 315 individuals using 24 loci. Allozyme analysis was performed on 90 individuals using six enzyme systems. DNA microsatellite markers produced the best discrimination between the subspecies (Apis mellifera carnica, A. m. ligustica, A. m. macedonica, A. m. mellifera and A. m. siciliana) used in the experiment. Morphometric methods generally showed an intermediate level of discrimination, usually best separating A. m. siciliana and A. m. ligustica from the remaining populations. Allozyme markers lack power to discriminate at the level of individual bees, and given our sample size, also fail to differentiate subspecies. Based on DNA microsatellites, about 69% of the individuals were assigned to the same subspecies as originally declared, and 17% were found to belong to a different subspecies. Fourteen percent of the samples were found to be of mixed origin and could not be assigned to any subspecies with certainty. We further discuss the caveats of the methods and details of the sampled bees, their origins and breeding programmes in their respective locations.

American foulbrood is a widely distributed, very persistent honeybee disease, caused by the spore forming bacterium Paenibacillus larvae. The disease is highly contagious and unless recognized at an early phase, can give rise to significant losses for beekeepers. The purpose of this study was to investigate what would happen with the level of P. larvae spores concentration in honey sacs during the transmission of food through social contacts and during various times of digestion of the spore contaminated food. A method described by Ritter and Kiefer (1993) for determining the presence and the number of P. larvae spores in honey samples was modified in a way that through the number of the grown P. larvae colonies on MYP agar it was possible to determine the concentration of P. larvae spores in the honey sac of individual bees. Regardless of the quantity of food delivered through social contacts, the known concentration of P. larvae spores remained unchanged. After various times of digestion, the concentration of P. larvae spores was also constant. Therefore, the ability of honeybees to reduce the number of P. larvae spores from their honey sac by filtration was not proven.

A Europe-Wide Experiment for Assessing the Impact of Genotype-Environment Interactions on the Vitality and Performance of Honey Bee Colonies: Experimental Design and Trait EvaluationAn international experiment to estimate the importance of genotype-environment interactions on vitality and performance of honey bees and on colony losses was run between July 2009 and March 2012. Altogether 621 bee colonies, involving 16 different genetic origins of European honey bees, were tested in 21 locations spread in 11 countries. The genetic strains belonged to the subspeciesA. m. carnica, A. m. ligustica, A. m. macedonica, A. m. mellifera, A. m. siciliana.At each location, the local strain of bees was tested together with at least two "foreign" origins, with a minimum starting number of 10 colonies per origin. The common test protocol for all the colonies took into account colony survival, bee population in spring, summer and autumn, honey production, pollen collection, swarming, gentleness, hygienic behaviour,Varroa destructorinfestation,Nosemaspp. infection and viruses. Data collection was performed according to uniform methods. No chemical treatments against Varroa or other diseases were applied during the experiment. This article describes the details of the experiment set-up and the work protocol.

Quercus frainetto Ten. is species oak of the Southeast Europe, part of Italy and the west part of Asia. Western border is in Požega valley region in Croatia, and South Peloponnesus, Greece. Beekeepers from Požega region record that bees readily collect the plant sap on oak. In this area of distribution of the Q. frainetto is recognized as a specific source of honeydew. Growth process of oak fruits is extremely rich in cycles of 5-8 years, and during other years fruit production is standard. process of balance of the number of fruits on each tree is specific. At the natural reduction of overproduction of fruits, the sweet sap from fruits is noticed. Fruit sap starts to flow over cuticle of the fruit often with the foam appearance. Single fruit produces sap for several days, then process starts on another fruit. occurrence of fruit sap in wood area can last up to two month. During honeyflow season in 2003 and 2004 year, with medium to low honeydew honey production in Požega basin, 10 samples of honey were taken for the analysis. According to the results these honeys are not typical honeydew honeys. There are no special honeydew sugars and also electrical conductivity is low. There are also only quite less amounts of honeydew elements in the sediment. The sugar spectra of the oak fruits show high amounts of fructose (30, 4%), glucose (17, 9%), trehalose (26, 9%) and one not identified oligosaccharide (24, 9%). So the high fructose/glucose ratio seems to come from these oak fruit excretions. Histological analysis confirmed that mediation of plant sucking insects do not take part in process of honeydew generating. Probably the physiological process of the plant induces this specific honeydew.

Honeybees originating from 10 different countries (Austria, Poland, Germany, Hungary, Slovenia, Nepal, Sri Lanka, the United Arab Emirates, Canada, and New Zealand) located on four continents were analyzed for the presence of deformed wing virus (DWV) nucleic acid by reverse transcription-PCR. Two target regions within the DWV genome were selected for PCR amplification and subsequent sequencing, i.e., a region within the putative VP2 and VP4 structural-protein genes and a region within the RNA helicase enzyme gene. DWV nucleic acid was amplified from 34 honeybee samples representing all the above-mentioned countries with the notable exception of New Zealand. The amplification products were sequenced, and phylogenetic analyses of both genomic regions were performed independently. The phylogenetic analyses included all sequences determined in this study as well as previously published DWV sequences and the sequences of two closely related viruses, Kakugo virus (KGV) and Varroa destructor virus 1 (VDV-1). In the sequenced regions, the DWV genome turned out to be highly conserved, independent of the geographic origins of the honeybee samples: the partial sequences exhibited 98 to 99% nucleotide sequence identity. Substitutions were most frequently observed at the same positions in the various DWV sequences. Due to the high level of sequence conservation, no significant clustering of the samples in the phylogenetic trees could be identified. On the other hand, the phylogenetic analyses support a genetic segregation of KGV and VDV-1 from DWV.

A single-step multiple-target (multiplex) reverse transcription-PCR (RT-PCR) was developed for the simultaneous detection and differentiation of three economically important viruses of the honeybee Apis mellifera L.: Acute bee paralysis virus (ABPV), Black queen cell virus (BQCV) and Sacbrood virus (SBV). Three compatible sets of primers, specific for each virus, were designed in conserved regions of the viral genomes for use in a one-step (single tube) RT-PCR assay. The individual RT-PCR assays and the combined multiplex assay were optimized for highest sensitivity and specificity. The multiplex RT-PCR assay was tested on field samples collected from Austrian honeybee colonies. All three viruses were detected, and their identity was confirmed by sequencing of the PCR products. The described multiplex RT-PCR proved to be an accurate tool for rapid simultaneous detection of ABPV, BQCV and SBV directly in honeybee specimens.

At 2 drone congregation areas (DCA) the relation between drone presence and distance to the apiary of origin was studied. Two methods were applied. First, drones were caught and marked on the DCA and later recovered in the colonies. Second, drones which were marked before at the apiary (in the colonies) were subsequently recaptured on both DCA’s. The 2 methods led to identical conclusions. Consistently in each of 3 years the majority of the drones from each of the 3 apiaries was found at the nearer DCA. There was, however, no direct correlation between the flight distances and the ratio of drones visiting from each apiary. Thus some other factors (“attractiveness” of the DCA) may also have influenced the choice of the drones. Our findings support the idea that there is an orientation phase during which drones explore several DCA’s before each drone stays at 1 DCA, and energetic choices made by drones in relation to flight distances seem to be important. The choice of the nearer DCA would permit the drone to prolong his presence at the DCA and increase his chances to mate: “the nearer the better”!

The mating efficiency, flight activity, and sperm numbers of drones from 10 colonies each of 3 different groups-inbred with light Varroa mite infestation (group 1); non-inbred, heavily infested (group 2); and non-inbred, lightly infested (group 3)-were observed.In the drone congregation area (DCA), drones from the heavily infested group were significantly underrepresented. Also, their flight activity was significantly reduced.Drones from the inbred, lightly infested group had a lower number of sperm than the non-inbred, lightly infested group but a significantly higher number than the heavily infested group.In all activities, drones from the heavily infested group showed reduced mating efficiency compared to the non-inbred and inbred, lightly infested groups.

The biology of the mite Varroa destructor, the social structure and seasonal changes of the bee colony, where the mite spends its whole life cycle are described. Epidemiology and symptoms of this parasitosis are given. The most usual measures in bee management and medical and chemical products approved or permitted for mite control in Austria are listed and some reasons of therapeutic failure are described.

Varroa destructor, an ectoparasitic mite, is one of the major pests of honeybees in many parts of the world. In order to keep bee colonies alive and productive, effective biological, biotechnical, or acaricidal control measures are necessary. Oxalic acid is one substance under discussion to replace synthetic acaricides (e.g. pyrethroids, organophosphates) to minimize the risk of residues in bee products. The application of oxalic acid based solutions (Bienenwohl or a self-prepared oxalic acid solution with sugar) to control Varroa destructor resulted in no relevant changes in the oxalic acid content of honey produced the following year, compared with honey samples from untreated colonies from the same location. The range of oxalic acid content in honey was 5–68 mg/kg in oxalic acid treated and 5–65 mg/kg in untreated colonies. The oxalic acid content of the honey was positively correlated with its electrical conductivity and thus with its original nectar or honeydew source.