Varroa resistance is simpel or complicated

Varroa resistance is simple for the beekeeper

For the researcher, however, varroa resistance is complicated. This was the point made by Prof. Stephen Martin at the Hallsberg Conference on November 9, 2024. The well-known naturalist/researcher Charles Darwin emphasized the importance of natural selection for the adaptation of creatures to their environment in his book “The Origins of Species…” in 1859. He also mentioned honey bees in particular. For this reason, two authors have placed him on the cover of their books on varroa resistance. 

“The Honey Bee Solution to Varroa” by Steve Riley, 131 pages, describes how varroa-resistant bees were developed in the UK. Prof. Stephen Martin wrote the foreword to the book. Today, 25% of bee colonies in the UK are treatment-free. Buy the book from Northern Bee Books: https://www.northernbeebooks.co.uk/products/the-honey-bee-solution-to-varroa-riley

The second book, “Beekeeping in harmony with nature” by Bartolomiej Maleta, has been translated from Polish into English by Prof. Stephen Martin, 391 pages. The book is a compilation of beekeepers’ various methods of resulting invarroa-resistant bees. It can be purchased from Northern Bee Books:https://www.northernbeebooks.co.uk/products/beekeeping-in-harmony-with-nature-maleta

The books can be a great help to those who want to breed treatment-free bees. Both are published by Northern Bee Books in the UK. They contain a wealth of useful information and many valuable illustrations. Riley’s book primarily describes the use of natural mite fall to assess the mite population. And also other important traits observed. This was the method used in the UK to achieve treatment-free beekeeping. Maleta’s book also contains descriptions of bee characteristics that are important for their resistance to mites. A prominent method in Maleta’s book for estimating the mite population is alcohol washing of 1 dl/300 bees to calculate the so-called infestation rate on adult bees during the breeding season. If the rate exceeds 3%, the colony is treated within a week. Page 351.

Neither of the two authors, nor many of those described and their methods, have been noticed by university researchers! One exception is Prof. Stephen Martin in the UK, who collaborates with university researchers, independent researchers, and beekeepers on this important topic. 

Few university researchers are today able to assist beekeepers in their efforts to achieve treatment-free bees, and few have seemingly taken note of beekeepers’ successes. Many independent researchers/beekeepers have been successful in different countries! One wonders whether university researchers in general are truly interested in collaborating with beekeepers, or whether they prefer to pursue their own (and other university researchers’) programs and focus primarily on their own research.

When Stephen Martin visited Hallsberg in 2024, he said that a safe and simple way to achieve success is to calculate the mite population in a comparative manner between bee colonies. The colonies with the lowest mite populations are used to breed queens, and those with the highest mite populations have their queens replaced. That’s what successful beekeepers have done.

Plus, keep an eye out for eventual presence bees with wing damaged wings (bees with DWV, deformed wing virus).

University researchers’ studies can be helpful to independent researchers/beekeepers. The following study estimates the growth of varroa populations over 16 weeks from mid-May:

Selective Breeding for Low and High Varroa destructor Growth in Honey Bee (Apis mellifera) Colonies: Initial Results of Two Generations. Link to the study: https://www.mdpi.com/2075-4450/11/12/864

The study supports the idea that success in breeding for varroa resistance can be achieved simply by taking into account the size of the varroa population (in this case, its growth over a limited period). Beekeepers do not need to define a sufficient number of varroa resistance traits before recommending a selection method aimed at varroa resistance, as university researchers often want to do.

As far as I know, no one has achieved treatment-free bee populations using this strategy. However, using the simpler strategy of calculating the size of varroa populations, or simply stopping the use of varroa control agents (to which there may be various objections, see for example the Cuba study below), several beekeepers have achieved success.

The emergence of treatment-free populations is described in the two books mentioned above.

Nor is it necessary to have access to at least 100 bee colonies in a project in order to achieve treatment-free status. In fact, there is no defined minimum number of bee colonies required to achieve success in breeding. A certain degree of isolation is beneficial, but does not appear to be an absolute prerequisite, according to experience in the UK.

The use of natural selection to achieve Varroa resistance in a very large population is described in a study in which Prof. Stephen Martin participated:

Recapping and mite removal behavior in Cuba: home to the world’s largest population of Varroa-resistant European honeybees. Link: https://www.nature.com/articles/s41598-022-19871-5

Varroa control agents have not been used against Varroa for over 20 years in Cuba. When the use of varroa control agents was initially discontinued, the loss of bee colonies across the country was just under 40% of bee colonies before sufficient varroa resistance developed, and the number of bee colonies rose again from 126,000 (2003) to 221,000 (2021).