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ARS Home » Southeast Area » Baton Rouge, Louisiana » Honey Bee Lab » Research » Publications at this Location » Publication #399381
Research Project: Using Genetics to Improve the Breeding and Health of Honey Bees

Location: Honey Bee Breeding, Genetics, and Physiology Research

Title: Confirmation of the Y215H mutation in the ß2-octopamine receptor in Varroa destructor is associated with contemporary cases of amitraz resistance in United States

Author
item Rinkevich, Frank
item MORENO-MARTI, SARA - University Of Valencia
item HERNANDEZ-RODRIGUEZ, CARMEN - University Of Valencia
item GONZALEZ-CABRERA, JOEL - University Of Valencia

Submitted to: Pest Management Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/18/2023
Publication Date: 3/22/2023
Citation: Rinkevich Jr, F.D., Moreno-Marti, S., Hernandez-Rodriguez, C.S., Gonzalez-Cabrera, J. 2023. Confirmation of the Y215H mutation in the ß2-octopamine receptor in Varroa destructor is associated with contemporary cases of amitraz resistance in United States. Pest Management Science. pp.1-6. https://doi.org/10.1002/ps.7461.
DOI: https://doi.org/10.1002/ps.7461

Interpretive Summary: This article deals with the confirmation that a mutation in the target site for amitraz is responsible for amitraz resistance in Varroa from the US. Previous work has identified this mutation in Varroa, but its association with resistance was not strong since the Varroa were not classified as resistant or susceptible in an amitraz resistance test. To address this issue, Varroa samples that were collected in 2020 and 2021 were classified as resistant or susceptible using an amitraz resistance test. These samples were genotyped for the resistance mutation in the target site. Results show a strong association of the resistant phenotype and resistant genotype, demonstrating the results of the test are reliable indicators of resistant Varroa. However, results showed that the resistance test may understate resistance levels due to the influence of temperature. These results confirm the association of the amitraz resistance mutation with amitraz resistance phenotype. The utility of using a molecular test to diagnose amitraz resistance is discussed.

Technical Abstract: Amitraz is a widely used miticide to control the parasite, Varroa desctructor, in honey bee colonies. Resistance has evolved to the point where there are instances of treatment failure when amitraz is used to control Varroa. In the US, a mutation in the beta2-octopamine receptor, which is the target site for amitraz, was previously identified. However, the association of this particular mutation with the amitraz resistance phenotype was not particularly strong due to the lack of amitraz resistance data from bioassays from Varroa in the USA. This work looked at the association of this mutation in Varroa that were phenotyped with the Apivar efficacy test as a measure of amitraz resistance. Varroa samples were collected in 2020 and 2021 from Varroa populations in the US that were evaluated for amitraz resistance. Individuals from these collections were subsampled across a range of amitraz resistance levels and genotyped for the mutation in the beta2-octopamine receptor. The results show a strong association of the amitraz resistance phenotype with the amitraz resistance genotype. The susceptible genotype was strongly associated with the susceptible phenotype. However, the resistant genotype was not a reliable indicator of resistance phenotype due to high natural Varroa fall at high temperatures which would cause genotypically resistant Varroa to appear susceptible in this test. The utility of the molecular diagnostic as well as the influence of temperature on bioassay results are discussed.