Collective action is one of the best ways for New Zealand beekeepers to win against varroa say those behind a new concept to bring beekeepers together to share knowledge about bee breeding programmes and make improvement in the genetic makeup of honeybee stocks, chiefly to include more varroa sensitive hygiene (VSH). The New Zealand Bee Breeding Association (NZBBA) is the brainchild of long time VSH queen breeder Rae Butler, and botanist Dr Linda Newstrom-Lloyd. They explain why the Association is needed and why beekeepers should join up.
Recognizing the urgent need to address the growing and intractable varroa mite infestations and their impact on New Zealand's beekeeping industry, passionate beekeepers and researchers have come together to establish the NZBBA. It serves as a dynamic platform for everyone to exchange ideas based on scientific data and local experiences at the grassroots level. Its inception is driven by the collective vision of fostering collaboration among beekeepers, commercial beekeepers, queen breeders, and researchers with the goal of improving their understanding and skills needed to increase the levels of the VSH trait throughout the country, within the context of local multi-trait selection programmes.
A Focus on VSH – but why?
The initial focus is on VSH testing because this trait is well-known to predictably produce an increase of the bee’s resistance to varroa by interrupting the reproductive cycle of the mite. This work is not restricted to specialised queen breeders using instrumental insemination (ii). Once initial levels of VSH are achieved, many overseas beekeepers and queen producers use simplified test and selection practices that are straightforward for anyone to learn to maintain a level of VSH in their own beekeeping outfits. Selecting queens based on high VSH (with or without the support of queen breeders using ii) has been shown to make a difference in the survival of bee colonies from varroa infestations (Harbo and Harris 2001).
Expanding widespread levels of the VSH trait in bee colonies adds a promising tool to tackle the problem of varroa infestations and reduce reliance on chemical treatments. Breeding for this trait is well developed in the USA and other regions of the world (Mondet et al. 2020). The most predictable test for breeders to use for selecting VSH has been developed primarily at the United States Department of Agriculture in Baton Rouge (Danka et al. 2011, O’Shea-Wheller et al. 2022). This is a two-part test which includes, firstly, a bioassay to test for reduced infestation levels due to bee hygienic behaviour and, secondly, a measure of the increase in the proportion of non-reproductive varroa mites in brood cells. The bioassay involves inoculation with varroa and therefore is targeted specifically to varroa sensitivity in the bees. Other types of tests for general hygienic bee behaviour, such as freeze killed brood or pin killed brood, are not as predictable in detecting high performing VSH bees (Danka et al. 2013; Leclercq et al. 2018) and can therefore compromise a breeding program.
With consistent and informed efforts, the benefits of ever increasing VSH levels will be realised over time as has been achieved in the last two decades overseas (Mondet et al. 2020; O’Shea-Wheller et al. 2022). We do not need to re-invent the wheel, the methods are already available and the NZBBA will be disseminating information on methods for testing VSH soon.
The Role of Beekeepers in Building VSH Levels
Beekeepers are crucial players in the endeavour to build VSH levels in New Zealand. In general, they have about a 10% chance of finding the VSH trait in their own bee populations. Although hygienic behaviour in honey bees is natural, it is not common but can be found by testing (Bigio 2014). By learning how to test and select for VSH (while preserving other desirable beekeeping traits), beekeepers can contribute significantly to the proliferation of varroa-resistant bees in their own stock. Alternatively, if they do not find the VSH trait in their own bee stock, they can introduce the VSH trait by obtaining VSH queens from queen breeders who have used the specific VSH trait test. With widespread adoption of testing and selecting for VSH, New Zealand bee populations can gradually gain higher and higher levels of VSH which means that the bees do much of the work defending the colony against varroa.
Purpose and Methods of the NZBBA
The NZBBA stands as a platform with a clear and ambitious purpose: to breed varroa-resistant bees while maintaining high productivity and other desirable beekeeping traits. Members of the NZBBA should be committed to combining science with practical applications to empower all beekeepers to actively participate in efforts to combat varroa infestations through selection and breeding in their own bee stock. The association's objective is to focus on promoting varroa resistance breeding through research, education, and collaboration with all industry stakeholders.
Technology transfer workshops are a key part of the NZBBA, to disseminate knowledge and share experiences to help develop best practices. The association is open to interested beekeepers, commercial beekeepers, queen breeders and researchers. We have presented one workshop at the Apiculture New Zealand national conference in Rotorua on June 30 to introduce the topic of testing for the VSH trait.
The NZBBA has a website with educational information on scientific research and practical applications. We are building this site as a source of trusted information from scientific literature and experiences of participants working on the ground. The association is informal and evolving, with the aim to foster nationwide public good cooperation among all industry participants while respecting commercial sensitivity. By creating a unified network, NZBBA members can share valuable data and insights, leading to a collective and highly efficient approach to combat varroa infestations.
By prioritizing varroa resistance breeding focusing on what we see as the most important trait – the VSH trait – we can develop a valuable tool to add to the ongoing efforts to improve and implement Integrated Pest Management (IPM) strategies for varroa (Taylor and Goodwin 2021, Jack and Ellis2021). With concerted and persistent application of methods proven to increase the population levels of VSH bees, we can secure a sustainable and cost-effective future for beekeeping, honey production and pollination services in New Zealand.
We welcome and encourage everyone to join up for free as members of the NZBBA and help us to develop this resource for sharing new research and ideas on how we can achieve victory over varroa – wouldn’t that be something!
For more information, and to register as a member of the NZBBA, visit www.nzbba.co.nz.
Bigio, Gianluigi (2014). Hygienic behaviour in honey bees. University of Sussex. Thesis. https://hdl.handle.net/10779/uos.23410694.v1
Danka, R.G., Harris, J.W., Villa, J.D. 2011. Expression of Varroa Sensitive Hygiene (VSH) in Commercial VSH Honey Bees (Hymenoptera: Apidae). Journal of Economic Entomology 104(3): 745–749 (2011); Doi: 10.1603/EC10401.
Danka, R.G., Harris, J.W., Villa, J.D., Dodds, G.E. 2013. Varying congruence of hygienic responses to Varroa destructor and freeze-killed brood among different types of honeybees. Apidologie 44:447–457. Doi: 10.1007/s13592-013-0195.
Harbo, J. R., & Harris, J. W. 2001. Resistance to Varroa destructor (Mesostigmata: Varroidae) when mite-resistant queen honey bees (Hymenoptera: Apidae) were free-mated with unselected drones. Journal of Economic Entomology, 94(6), 1319-1323.
Jack, C.J., Ellis, J.D. 2021. Integrated Pest Management Control of Varroa destructor (Acari: Varroidae, the Most Damaging Pest of (Apis mellifera L. (Hymenoptera: Apidae)) Colonies. Journal of Insect Science 21(5): 6; 1–32, Doi: 10.1093/jisesa/ieab058.
Leclercq, G., Francis, F., Gengler, N. Blacquière, T. 2018. Bioassays to quantify hygienic behavior in honey bee (Apis mellifera L.) colonies: a review. Journal of Apicultural Research 57(5): 663-673, Doi: 10.1080/00218839.2018.1494916.
Mondet, F., Beaurepaire, A., McAfee, A., Locke, B., Alaux, C., Blanchard, S., Danka, R., Le Conte, Y. 2020a. Honey bee survival mechanisms against the parasite Varroa destructor: a systematic review of phenotypic and genomic research effort. International Journal for Parasitology 50: 433–447. Doi.org/10.1016/j.ijpara.2020.03.005.
O’Shea-Wheller, T.A., Rinkevich, F. D., Danka, R. G., Simone-Finstrom, M., Tokarz, P. G., & Healy, K. B. 2022. A derived honey bee stock confers resistance to Varroa destructor and associated viral transmission. Scientific Reports 12. Doi.org/10.1038/s41598-022-08643-w.
Taylor, M.A., Goodwin, R.M. 2021. Control of Varroa: A Guide for New Zealand Beekeepers. Third Edition. Ministry of Primary Industries. Wellington.