Varroa destructor haplotypes in the United Arab Emirates exhibit pyrethroid resistance-linked point mutations but lack amitraz resistance markers

The mite Varroa destructor is the primary driver of global declines in managed Apis mellifera colonies. Although synthetic acaricides initially controlled varroosis effectively, their efficacy has waned following the proliferation of resistant mite populations. We investigated V. destructor haplotype diversity in the United Arab Emirates (UAE) using mitochondrial cytochrome c oxidase subunit 1 ( cox 1) and cytochrome b ( cytb ) gene sequences. Concurrently, we screened for point mutations in the voltage-gated sodium channel ( VGSC ) and the β2-adrenergic-like octopamine receptor ( Octβ2R ) genes, which confer resistance to pyrethroids and amitraz, respectively. While all cox 1 sequences matched the wild K haplotype, we identified three coexisting cytb variants: the predominant wild K haplotype (81.4%), the mutant P1 haplotype (6.8%), and heteroplasmic KP1 mites (11.8%). Notably, 55.3% of mites were homozygous for the L925V allele, a VGSC genotype conferring pyrethroid resistance. The K haplotype predominated among susceptible VGSC homozygotes (93.2%), whereas the P1 and KP1 haplotypes peaked in resistant homozygotes (10.1%) and susceptible heterozygotes (23.1%), respectively. Conversely, no mites exhibited Octβ2R mutations associated with amitraz resistance, independent of their VGSC genotype. These findings inform future Varroa management programmes by guiding the selection of effective synthetic miticides. Furthermore, they underscore the need to evaluate the relationship between cytb mutations and acaricide susceptibility.