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FFL-JA-Forskningsmidlene for jordbruk og matindustri

Friske varroaresistente honningbier

Alternative title: Healthy varroa resistant honeybees

Awarded: NOK 1.5 mill.

Honeybees are important crop pollinators, but like wild pollinating insects, they are subject to a number of stressors. For honeybees, the single most important stressor is the parasitic mite Varroa destructor and the viruses it vectors. Honeybee colonies left untreated against varroa mites usually die within 1-3 years. At the same time, the varroa mite has developed resistance against several miticides used to combat them, resulting in severe colony losses. In Norway some beekeepers do not treat their honeybee colonies with miticides and this population of honeybees expresses resistance (and tolerance) towards the mite. We have identified some mechanisms involved in this resistance in previous research. In 2019 we established 2 apiaries that will be used for experiments in 2020 and 2021 to evaluate the role of honeybee genetics, behaviour and management practices on the Varroa resistance expressed by these honeybees. Further, we have started the work with identifying beekeepers that do not combat varroa mites by the use of miticides. A handful of these beekeepers were visited to collect data on their management practices and to collect bee samples to measure the level of Varroa infestations and virus infections. This work will continue in 2020. These data will be used to identify common management practices and honeybee genetics associated with honeybees surviving without the use of miticides. To assist beekeepers in breeding Varroa resistant bees we established cooperation with beekeepers in the Hurdal Municipality with a closed population of honeybees. Our aim is to develop and test a model for breeding of bees that are less dependent on regular varroa treatment. We have collected bee samples and data on mite infestation that will be used as selection criteria for breeding queens in 2020. Such an approach relies on knowledge about the varroa damage threshold, i.e the infestation level of varroa mites that are likely to have substantial negative effects on the honeybee colonies. To collect such data, we will invite beekeepers to participate in a citizen science investigation. In summary, the project will contribute to make the Norwegian beekeeping less dependent upon the use of miticides and secure a sustainable production of honeybee products without residues from mite treatments and contribute to continued delivery of pollination services. 2020 This year our work in the 2 apiaries to explore the effects of management, behaviour and genetics on Varroa resistance has yielded complete data for the first phase of the project: We have obtained weekly mite population measurements, colony health parameters and obtained brood samples with which to measure Varroa reproductive success. In order to separate the behavioural component from the Varroa resistance investigation we have exchanged the queens between half the resistant bees and half the susceptible colonies, exchanging queens in the other half of the apiaries with queens from the same stock to eliminate biases from the swap. The next year we will monitor the colonies in the same way and examine what changes occur. The breeding program in Hurdal has finished its first year with over 80% of the beekeepers providing all required data. We now have enough data to make recommendations for queen rearing in the following year and will continue to take colony data and monitor Varroa population changes. We continue to grow our list of volunteers for the citizen science project and varroa survivors survey. We are refining the survey questions to improve the quality of the data collected. Due to the effects of covid and more time required for the completion of other parts, we were unable to launch the surveys this year, however we will contribute more time in the future to rolling out this part of the project. 2021 This year we collected the final data from the original colonies in WP3, the social transference. Due to high losses over the winter in the region, we purchased 10 new colonies to contribute to the data pool. The final data measurements for these 10 colonies will be collected in 2022. The Hurdal breeding program (WP5) has yielded the first queens bred from mothers chosen by the selection algorithm invented especially for this project. Data show a slight decrease in the mite loads between summer and autumn, though conclusions surrounding the success of the breeding must wait until the summer of 2022. Beekeepers continue to be motivated and interested in the project and continue to provide consistent data. This data can also be used to augment the varroa threshold survey (WP1) and the varroa-resistant bee investigations (WP2). Frames for the investigation of cell size have been successfully collected and dissections should be complete this December (2021), analysis for this WP should be complete in late March.

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Den parasittiske midden Varroa destructor (varroamidd) og de virus den sprer er den viktigste enkelt-trusselen mot birøkt. Bisamfunn som ikke behandles mot parasitten dør normalt i løpet av 1-3 år, og varroamidden utvikler resistens mot stadig flere medikament som brukes i bekjempelsen. Selv ved medikamentell bekjempelse opplever mange birøktere økte tap og svekkelse av bisamfunn som følge av varroamidden. Det finnes imidlertid honningbier i Norge som klarer seg godt uten medikamentell varroabekjempelse. Vi har tidligere påvist resistensmekanismer mot varroa hos disse biene, men vi mangler avgjørende kunnskap om i hvilken grad driftstekniske metoder spiller inn for bienes framviste resistens. Prosjektet vil gjennomføre eksperimenter for å undersøke dette elementet. Videre vil prosjektet arbeide med en rekke andre birøktere som oppgir at de ikke behandler medikamentelt mot varroa for å dokumentere om biene faktisk er varroaresistente og vi vil finne fellesnevnere i miljø, driftsteknikk og bier som kan forklare hvorfor biene framviser varroaresistens. Gjennom prosjektet vil vi også utvikle og teste en modell for hvordan birøkterne selv kan avle fram honningbier som i større grad klarer seg uten medikamentell varoabekjempelse. Et sentralt element i dette arbeidet med behovsprøvd varroabekjempelse er å dokumentere en ny terskelverdi for hvor mye varroamidd et bisamfunn tåler før det oppstår skader med økonomiske konsekvenser. Totalt sett skal prosjektet gi grunnlag for at norsk birøkt i større grad kan drives uten medikamentelll varroabekjempelse samtidig som skadevirkninger av varroamidden blir redusert. Dette vil sikre produksjon av norske biprodukter av god kvalitet og uten fremmedstoffer.

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Funding scheme:

FFL-JA-Forskningsmidlene for jordbruk og matindustri