High-Resolution Linkage Analyses to Identify Genes That Influence Varroa Sensitive Hygiene Behavior in Honey Bees

Abstract

Varroa mites (V. destructor) are a major threat to honey bees (Apis melilfera) and beekeeping worldwide and likely lead to colony decline if colonies are not treated. Most treatments involve chemical control of the mites; however, Varroa has evolved resistance to many of these miticides, leaving beekeepers with a limited number of alternatives. A non-chemical control method is highly desirable for numerous reasons including lack of chemical residues and decreased likelihood of resistance. Varroa sensitive hygiene behavior is one of two behaviors identified that are most important for controlling the growth of Varroa populations in bee hives. To identify genes influencing this trait, a study was conducted to map quantitative trait loci (QTL). Individual workers of a backcross family were observed and evaluated for their VSH behavior in a mite-infested observation hive. Bees that uncapped or removed pupae were identified. The genotypes for 1,340 informative single nucleotide polymorphisms were used to construct a high-resolution genetic map and interval mapping was used to analyze the association of the genotypes with the performance of Varroa sensitive hygiene. We identified one major QTL on chromosome 9 (LOD score = 3.21) and a suggestive QTL on chromosome 1 (LOD = 1.95). The QTL confidence interval on chromosome 9 contains the gene ‘no receptor potential A’ and a dopamine receptor. ‘No receptor potential A’ is involved in vision and olfaction in Drosophila, and dopamine signaling has been previously shown to be required for aversive olfactory learning in honey bees, which is probably necessary for identifying mites within brood cells. Further studies on these candidate genes may allow for breeding bees with this trait using marker-assisted selection.

Selection for resistance to Varroa destructor under commercial beekeeping conditions

“…They agreed with Rothenbuhler's (1964) conclusion that independent genetic loci regulate each component of hygienic behavior. Tsuruda, Harris, Bourgeois, Danka, and Hunt (2012) located candidate genes associated with the removal of mite-infested pupae observed in the resistance trait varroa sensitive hygiene (VSH). Studies on the heritability of VSH concluded that selective breeding can probably intensify its expression (Boecking, Bienefeld, & Drescher, 2000).…”

The architecture of the pollen hoarding syndrome in honey bees: implications for understanding social evolution, behavioral syndromes, and selective breeding

“…In order to enable marker assisted selection (Rinderer, Harris et al, 2010), QTL studies of the hygienic behavior of the Minnesota Hygienic (Lapidge, Oldroyd et al, 2002; Oxley, Spivak et al, 2010) and the Varroa Sensitive Hygiene stocks (Tsuruda, Harris et al, 2012) have been conducted. Additional QTL studies have targeted mite grooming behavior (Arechavaleta-Velasco, Alcala-Escamilla et al, 2012) and mite reproductive success (Behrens, Huang et al, 2011).…”

“…However, the QTL studies of Varroa resistant stocks have not yielded consistent QTL and show no overlap with transcriptome analyses (Le Conte, Alaux et al, 2011; Tsuruda, Harris et al, 2012). A tighter control of breeding and the identification of causative SNPs may increase the prospects for consistent findings in honey bee health research and enable marker assisted selection.…”

Transcriptional responses in eastern honeybees (Apis cerana) infected with mites, Varroa destructor

“…The mechanisms underlying the genetic differences in the eastern Varroa-resistant bees remain unclear. Quantitative trait loci mapping techniques have been used to study gene expression, identify resistance genes (Parker et al, 2012), and identify chromosomal regions that contain genes influencing specific traits in resistant and susceptible A. mellifera lines (Behrens et al, 2012;Tsuruda et al, 2012). However, these studies used different breeding lines.…”