Expression of Varroa Sensitive Hygiene (VSH) in Commercial VSH Honey Bees (Hymenoptera: Apidae)

Abstract

We tested six commercial sources of honey bees, Apis mellifera L. (Hymenoptera: Apidae), whose breeding incorporated the trait of Varroa sensitive hygiene (VSH). VSH confers resistance to the parasitic mite Varroa destructor Anderson & Trueman by enhancing the ability of the bees to hygienically remove mite-infested brood. VSH production queens (i.e., queens commercially available for use in beekeepers' production colonies) from the six sources were established in colonies which later were measured for VSH. Their responses were compared with those of colonies with three other types of queens, as follows: VSH queens from the selected closed population maintained by USDA-ARS for research and as a source of breeding germplasm, queens from the cooperating commercial distributor of this germplasm, and queens of a commercial, mite-susceptible source. The reduction of mite infestation in brood combs exposed to test colonies for 1 wk differed significantly between groups. On average, colonies with VSH production queens reduced infestation by 44%. This group average was intermediate between the greater removal by pure ARS VSH (76%) and the cooperators' breeding colonies (64%), and the lesser removal by susceptible colonies (7%). VSH production colonies from the different sources had variable expression of hygiene against mites, with average reduced infestations ranging from 22 to 74%. In addition, infertility was high among mites that remained in infested cells in VSH breeder colonies from ARS and the commercial distributor but was lower and more variable in VSH production colonies and susceptible colonies. Commercial VSH production colonies supply mite resistance that generally seems to be useful for beekeeping. Resistance probably could be improved if more VSH drones sources were supplied when VSH production queens are being mated.

Selection of VSH-derived “Pol-line” honey bees and evaluation of their Varroa-resistance characteristics

“…Infertility of mites in VSH and Pol-line colonies here (43 and 29 %, respectively) is similar to that in two reports (Villa et al 2009;Danka et al 2013b). less than in two others (55, 76 %; Harbo and Harris 2005;Danka et al 2011), and greater than in another (∼10-30 %; Harris and Harbo 1999). Recent selection of VHS bees at our laboratory has been based largely on removal of mite-infested pupae rather than on the original criterion of the percentage of non-reproducing mites .…”

“…Removal of pupae from naturally mite-infested cells by VSH and Pol-line bees here (84 and 78 %, respectively) is greater than that found for VSH bees in most reports (67-76 % in Harbo and Harris 2009;Villa et al 2009;Danka et al 2011;Harris et al 2012 andDanka et al 2013b;91 % in Danka et al 2010). Non-reproduction by mites in VSH and Pol-line colonies here (53 and 47 %, respectively) is much less than for VSH bees in two reports (80-100 %; Harbo and Harris 2001;Harbo and Harris 2005) but greater than in another (∼40 %; Harris and Harbo 1999).…”

“…The average mite resistance of randomly selected colonies with outcrossed queens would be expected to lie midway between the VSH and Control parents, as has been seen in prior studies (Harbo and Harris 2001;Danka et al 2011). However, mite resistance in Pol-line bees was much closer to that of the VSH parent.…”

Grooming behavior and gene expression of the Indiana “mite-biter” honey bee stock

“…Two bee behavioral traits that restrain V. destructor population growth in colonies are grooming behavior (Rinderer et al 2010;Arechavaleta-Velasco and Guzmán-Novoa 2001), the removal of mites from the bees' bodies, and the Varroa sensitive hygiene (VSH) trait, which involves the ability of bees to detect and remove infested brood where V. destructor reproduces (Ibrahim and Spivak 2006;Harbo and Harris 2009). Stocks selected for increased VSH by researchers from the United States Department of Agriculture (USDA) have been made available to North American queen breeders (Danka et al 2011).…”

Diagnosis of Varroa Mite (Varroa destructor) and Sustainable Control in Honey Bee (Apis mellifera) Colonies—A Review

“…Some bee resistance traits show potential for reducing varroa mite populations in colonies and can be used in a selective breeding program. Mite infestation may be reduced by enhancing the ability of bees to hygienically remove varroa mites from brood (i.e., Varroa sensitive hygiene (VSH)) [70,71].…”