Honeybee health and the species' gut microbiota are interconnected. Also noteworthy are the multiple niches present within hives, each with distinct microbiotas and all coexisting, which we termed ..."apibiome". External stressors (e.g. anthropization) can compromise microbial balance and bee resilience. We hypothesised that (1) the bacterial communities of hives located in areas with different degrees of anthropization differ in composition, and (2) due to interactions between the multiple microbiomes within the apibiome, changes in the community of a niche would impact the bacteria present in other hive sections. We characterised the bacterial consortia of different niches (bee gut, bee bread, hive entrance and internal hive air) of 43 hives from 3 different environments (agricultural, semi-natural and natural) through 16S rRNA amplicon sequencing. Agricultural samples presented lower community evenness, depletion of beneficial bacteria, and increased recruitment of stress related pathways (predicted via PICRUSt2). The taxonomic and functional composition of gut and hive entrance followed an environmental gradient. Arsenophonus emerged as a possible indicator of anthropization, gradually decreasing in abundance from agriculture to the natural environment in multiple niches. Importantly, after 16 days of exposure to a semi-natural landscape hives showed intermediate profiles, suggesting alleviation of microbial dysbiosis through reduction of anthropization.
Infestation with Varroa destructor is a serious cause of bee colony (Apis mellifera) losses on a global level. However, the presence of untreated survivor populations in many different regions ...supports the idea that selection for resistance can be successful. As colony survival is difficult or impossible to measure, differences in mite infestation levels and tests for specific behavioral traits are used for selective breeding for Varroa resistance. In this paper we looked into different definitions of mite infestation and linked these with brood hygiene (pin test), brood recapping and suppressed mite reproduction. We based our analyses on datasets of Apis mellifera carnica from three countries: Austria (147 records), Croatia (135) and Germany (207). We concluded that bee infestation in summer, adjusted for the level of natural mite fall in spring, is a suitable trait in the breeding objective, and also suggested including brood infestation rate and the increase rate of bee infestation in summer. Repeatability for bee infestation rate was about 0.55, for cells opened in pin test about 0.33, for recapping 0.35 and for suppressed mite reproduction (SMR) virtually zero. Although in most cases we observed correlations with the expected sign between infestation parameters and behavioral traits, the values were generally low (<0.2) and often not significantly different from zero.
The purpose of our study was to investigate methods of short-term storage that allow preservation, transport and retrieval of genetic information contained in honeybee queen's spermatheca. Genotyping ...of the honeybee colony requires well ahead planned sample collection, depending on the type of data to be acquired. Sampling and genotyping of spermatheca's content instead of individual offspring is timesaving, allowing answers to the questions related to patriline composition immediately after mating. Such procedure is also cheaper and less error prone. For preservation either Allprotect Tissue Reagent (Qiagen) or absolute ethanol were used. Conditions during transportation were simulated by keeping samples 6-8 days at room temperature. Six different storing conditions of spermathecas were tested, complemented with two DNA extraction methods. We have analysed the concentration of DNA, RNA, and proteins in DNA extracts. We also analysed how strongly the DNA is subjected to fragmentation (through amplification of genetic markers ANT2 and tRNA
-COX2) and whether the quality of the extracted DNA is suitable for microsatellite (MS) analysis. Then, we tested the usage of spermatheca as a source of patriline composition in an experiment with three instrumentally inseminated virgin queens and performed MS analysis of the extracted DNA from each spermatheca, as well as queens' and drones' tissue. Our results show that median DNA concentration from spermathecas excised prior the storage, regardless of the storing condition and DNA extraction method, were generally lower than median DNA concentration obtained from spermathecas dissected from the whole queens after the storage. Despite the differences in DNA yield from the samples subjected to different storing conditions there was no significant effect of storage method or the DNA extraction method on the amplification success, although fewer samples stored in EtOH amplified successfully in comparison to ATR storing reagent. However, we recommend EtOH as a storing reagent due to its availability, low price, simplicity in usage in the field and in the laboratory, and capability of good preservation of the samples for DNA analysis during transport at room temperature.
The positive effects of honey bee venom on human health and the high market price are the main reasons for beekeepers' increasing interest in its production. However, until today there is no ...standardized technology for honey bee venom collection. Today's methods are mainly based on collectors placed at the hive entrance. The main problems with this method are the application of the collector, and the contamination that collected venom may contain which consequently reduces its quality. The disadvantages of this technology can at least partially be eliminated by the use of collectors placed inside the hive. Therefore, this study aimed to evaluate the effect of the collection method on the honey bee venom quality and quantity. The results of the study showed that significantly higher amounts of venom could be collected with collectors within the hive, while at the same time the quality of the venom, considering the melittin content, remained equal. Having in mind that honey bee venom collection has not had a significant impact on strength of the colonies (in comparison to control colonies that were not subjected to venom collection), collection technology with collectors placed inside the hive is a better option.
Agrochemicals and biocides are suspected to cause a dysbiosis of honey bee microbiota, decreasing colonies ability to respond to the environment. As a first step to investigate agriculture and ...beekeeping impact, hives bacteriomes from an anthropized environment (Agri-env) were compared to that of pristine’s (Prist-env). 16S rRNA sequencing evidenced differences in richness and composition between sample types (Gut (G), Brood (B), Bee-bread (BB)) and environments. Higher opportunist loads and shifts toward taxa capable of metabolizing insecticides were observed in G and B at Agri-env, while beneficial bacteria were enriched in Prist-env. Bacteria in BB did not differ, the acidity of the niche outweighing the influence of external factors. Results showed the environment plays a major role in shaping honey bee microbiota, the agricultural realm inducing a bacterial disruption that would let to colonies vulnerability. In contrast, a less susceptible bee will be promoted in less anthropized locations.
Zbog povećanih gubitaka pčelinjih zajednica, potražnja za njima raste iz godine u godinu. Kako bi nadoknadili izgubljene pčelinje zajednice ili povećali veličinu pčelinjaka, pčelari moraju kupiti ...nove zajednice ili ih mogu sami proizvesti tijekom sezone. Cilj ovoga rada bio je ispitati tehnološku i ekonomsku učinkovitost triju različitih metoda proizvodnje pčelinjih zajednica: korištenjem jednoga, dvaju i četiriju okvira saća s poklopljenim leglom i pripadajućim pčelama kojima je dodana sparena matica. Istraživanje je provedeno u sjeveroistočnoj Hrvatskoj od svibnja 2019. do travnja 2020. Na kraju prve sezone nije bilo značajnih razlika između skupina u broju okvira zauzetih leglom i pčelama. Proizvodnja zajednica s jednim okvirom poklopljenoga legla omogućuje pčelaru proizvodnju većega broja pčelinjih zajednica, dok su se pčelinje zajednice proizvedene na početku sezone s pomoću četiriju okvira poklopljenoga legla dovoljno razvile i proizvodile med tijekom glavne ljetne pčelinje paše. Sva tri načina proizvodnje pčelinjih zajednica pokazala su pozitivan ekonomski rezultat i stopu isplativosti.
Due to the increased honeybee colony losses, the demands for honeybee colonies are growing annually. To regain the lost colonies or to increase the apiary size, the beekeepers need to purchase the new colonies or to prepare the new ones during the season. The aim of this study was to investigate the technological and economic efficiency of the three different methods of honeybee colony production, deploying one, two, or four combs of capped brood with the adhering bees and a mated queen. The study was conducted in northeastern Croatia from May 2019 to April 2020. At the end of the first season, there were no significant differences between the groups in the number of combs occupied with the brood and the bees. The production of colonies with one brood comb provides the beekeeper with an opportunity to multi ply more colonies, while the colonies established using four brood combs during an early season produced honey during the main summer nectar flow. All three methods of colony production have scored a positive economic result and have demonstrated positive profitability rates.
•Concentrations of macro-, micro- and toxic elements were measured in 10 honey types.•Honeys were collected in four regions of Croatia in three beekeeping seasons.•Significant differences were found ...in the element levels between different honeys.•Element content differences in honeys were measured between seasons.•Regional element content differences of the same honey types were established.
Concentrations of 20 elements were measured in ten honey types collected from four main geographical regions of Croatia during three beekeeping seasons. The four regions differ by their geography, ecology and climate. Significant differences in the element concentrations between honeys of different botanical origin were found for Al, Ba, Ca, Cu, Fe, K, Mg, Mn, Mo, Na, Pb and Zn (p<0.05). The highest mean concentrations of elements were found in honeys: floral Cd, Cr; acacia Mo; honeydew Al, Cu, K, Ni; chestnut Ba, Ca, Mn, Na; forest Fe, Mg; sunflower Cu; linden Pb, Co; sage Se; lacy phacelia Zn. Differences in the element content of honeys originating from the same region collected in different seasons was found for the honeys: floral Al, Ca, K, Zn; acacia Ba, Ca, Cu, Mg, Mn, Na, Zn; honeydew Cu, K, Mn, Pb; chestnut Al, Ba, Cu, K, Mn, Na, Pb; sunflower Cu; linden Ba, Ca, Mn. Also, regional differences in the element content of honeys collected within the same season was found for: floral Al, Ca, K, Mg; acacia Ca, K, Mg, Mn, Na, Zn; honeydew Cu, K, Mn, Pb; sage Ba, Ca, K, Mg, Mn; chestnut Ba.
In this study, we investigated the effect of queen caging on honey bee colonies’ post-treatment development and the optimal timing of method application on honey production during the main summer ...nectar flow. We conducted the study in nine apiaries (N = 9) across six Mediterranean countries, with a total of 178 colonies. The colonies were divided into three test groups: QC1, QC2, and C. The QC1 group involved queens caged for a total of 28 days before the expected harvesting day. In the QC2 group, queens were caged for 28 days, but only 14 days before the expected harvesting day. The C group consisted of queens that were not caged, and the colonies received common local treatments. In both the QC1 and QC2 groups, the colonies were treated with a 4.2% oxalic acid (OA) solution by trickling after the queen release. Our findings revealed no significant adverse effects (p > 0.05) on colony strength at the end of the study resulting from queen caging. However, significantly lower amounts of honey were extracted from the QC1 group compared to both the QC2 group (p = 0.001) and the C group (p = 0.009). Although there were no initial differences in Varroa destructor infestation between the groups, ten weeks later, a significantly higher infestation was detected in the C group compared to both the QC1 group (p < 0.01) and the QC2 group (p = 0.003). Overall, our study demonstrates that queen caging, in combination with the use of OA, is an effective treatment for controlling V. destructor. However, the timing of caging plays a crucial role in honey production outcomes.
The Carniolan honey bee (Apis mellifera carnica) is an indigenous subspecies of the Western honey bee in Central Europe. Croatia represents a large part of its native range. Hybridization and ...introgression is a realistic possibility due to unmonitored imports by beekeepers. In this study, we focused on honey bee colonies managed by beekeepers from all over Croatia and Slovenia. The identification of the subspecies was based on wing geometric morphometrics. The similarity of all investigated colonies to A. m. carnica was substantial, which indicates that the native subspecies continues to be present in the study area. However, some of the colonies differed markedly from the currently available reference of this subspecies. The low similarity with reference samples can be related both to hybridization with non-native subspecies and to natural geographical variation within A. m. carnica. The data and results obtained from this morphometric analysis will provide a deeper insight into the phenotypic characterization of the studied honey bee populations and directions for future conservation strategies.
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