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Abstract: Bees are the major pollinators in natural ecosystems and in the agricultural production of several crops used for human consumption. However, they are exposed to multiple stressors that are causing a serious decline in their population. We highlight a major one among them, the Varroa destructor mite (Varroa) that causes severe impacts on the health of honey bee colonies, transmitting a variety of viruses that can affect the survival ability of individual bees and entire colonies. Diagnosis and mite control methods have been intensively studied in recent decades, with many studies in different areas of knowledge having been conducted. This overview summarizes these studies with a focus on colony defense systems, biological characteristics of the parasite Varroa, diagnostic methods used to establish the infestation level of colonies, and currently used control methods.
Keywords: diagnosis, honey bee disease, mite, parasite, Varroa destructor
Published in DKUM: 18.07.2024; Views: 144; Downloads: 8
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Abstract: Honey bee subspecies originate from specific geographical areas in Africa, Europe and the Middle East, and beekeepers interested in specific phenotypes have imported genetic material to regions outside of the bees' original range for use either in pure lines or controlled crosses. Moreover, imported drones are present in the environment and mate naturally with queens from the local subspecies. The resulting admixture complicates population genetics analyses, and population stratification can be a major problem for association studies. To better understand Western European honey bee populations, we produced a whole genome sequence and single nucleotide polymorphism (SNP) genotype data set from 870 haploid drones and demonstrate its utility for the identification of nine genetic backgrounds and various degrees of admixture in a subset of 629 samples. Five backgrounds identified correspond to subspecies, two to isolated populations on islands and two to managed populations. We also highlight several large haplotype blocks, some of which coincide with the position of centromeres. The largest is 3.6 Mb long and represents 21% of chromosome 11, with two major haplotypes corresponding to the two dominant genetic backgrounds identified. This large naturally phased data set is available as a single vcf file that can now serve as a reference for subsequent populations genomics studies in the honey bee, such as (i) selecting individuals of verified homogeneous genetic backgrounds as references, (ii) imputing genotypes from a lower-density data set generated by an SNP-chip or by low-pass sequencing, or (iii) selecting SNPs compatible with the requirements of genotyping chips.
Keywords: genome, haplotype, honey bee, population genetics, SNP
Published in DKUM: 08.07.2024; Views: 101; Downloads: 7
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Abstract: Beekeepers have various options to control the parasitic mite Varroa destructor in honey bee colonies, but no empirical data are available on the methods they apply in practice. We surveyed 28,409 beekeepers maintaining 507,641 colonies in 30 European countries concerning Varroa control methods. The set of 19 different Varroa diagnosis and control measures was taken from the annual COLOSS questionnaire on honey bee colony losses. The most frequent activities were monitoring of Varroa infestations, drone brood removal, various oxalic acid applications and formic acid applications. Correspondence analysis and hierarchical clustering on principal components showed that six Varroa control options (not necessarily the most used ones) significantly contribute to defining three distinctive clusters of countries in terms of Varroa control in Europe. Cluster I (eight Western European countries) is characterized by use of amitraz strips. Cluster II comprises 15 countries from Scandinavia, the Baltics, and Central-Southern Europe. This cluster is characterized by long-term formic acid treatments. Cluster III is characterized by dominant usage of amitraz fumigation and formed by seven Eastern European countries. The median number of different treatments applied per beekeeper was lowest in cluster III. Based on estimation of colony numbers in included countries, we extrapolated the proportions of colonies treated with different methods in Europe. This suggests that circa 62% of colonies in Europe are treated with amitraz, followed by oxalic acid for the next largest percentage of colonies. We discuss possible factors determining the choice of Varroa control measures in the different clusters.
Keywords: Apis mellifera, COLOSS, beekeeping, acaricide, varroa control, survey results
Published in DKUM: 18.08.2023; Views: 786; Downloads: 31
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Abstract: V diplomskem delu smo se osredotočili na problem prepoznavanja različnih vrst medu in senzoričnih lastnosti posameznih vrst medu. V okviru poskusa smo v oktobru 2020 izvedli senzorično ocenjevanje medu po hedonski lestvici. Pri tem smo vključili naslednje vrste medu: lipov, cvetlični, hojev in kostanjev. Vrste medu smo izbrali glede na raznolikost njihovih senzoričnih lastnosti. Zanimalo nas je, kako bo pri pokuševalcih potekala prepoznava medu in kakšno vlogo bosta pri oceni všečnosti posameznih lastnosti medu imela spol in starost pokuševalca. Rezultati so pokazali, da so bili mlajši pokuševalci (stari od 21 do 40 let) uspešnejši pri prepoznavanju vrste medu. Prav tako je imela starost pokuševalcev vpliv na oceno všečnost bistrosti, konsistence in pookusa medu, medtem ko na barvo, vonj, okus in skupni vtis medu ni imela vpliva. Pokazalo se je, da spol pokuševalcev ni vplival na všečnost posameznih parametrov. Rezultati so pokazali, da je največ najnižjih ocen prejel hojev med, kar lahko povežemo z njegovimi posebnostmi, kot sta npr. smolnat okus in pookus po zeliščih, kar očitno našim pokuševalcem ni ustrezalo. Največ najvišjih ocen pa je prejel kostanjev med, ki je rjavordečkaste barve, z izrazitim, nekoliko grenkim okusom in pookusom. Pri oceni skupnega vtisa razlik med vzorci nismo potrdili.
Keywords: med, prepoznavanje, senzorične lastnosti, pokuševalec
Published in DKUM: 20.07.2022; Views: 931; Downloads: 124
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Abstract: The socio-economic impacts of COVID-19 on society have yet to be truly revealed; there is no doubt that the pandemic has severely affected the daily lives of most of humanity. It is to be expected that the research activities of scientists could be impacted to varying degrees, but no data exist on how COVID-19 has affected research specifically. Here, we show that the still ongoing COVID-19 pandemic has already diversely and negatively affected bee research at a global level. An online survey disseminated through the global COLOSS honey bee research association showed that every participant (n = 230 from 56 countries) reported an impact on one or more of their activities. Activities that require travelling or the physical presence of people (meetings and conferences, teaching and extension) were affected the most, but also laboratory and field activities, daily operations, supervision and other activities were affected to varying degrees. Since the basic activities are very similar for many research fields, it appears as if our findings for bee research can be extrapolated to other fields. In the light of our data, we recommend that stakeholders such as governments and funding bodies who support research should facilitate the wide implementation of web-based information technology required for efficient online communication for research and education, as well as adequately loosened restriction measures with respect to field and laboratory work. Finally, increased flexibility in administration and extension of research grants and fellowships seem to be needed. It is apparent that adequate responses by all stakeholders are required to limit the impact of COVID-19 and future pandemics on bee science and other research fields.
Keywords: COLOSS, Apis mellifera, coronavirus, COVID-19, honey bee, pandemic, research, extension
Published in DKUM: 12.11.2020; Views: 1013; Downloads: 198
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