Simplified methods of evaluating colonies for levels of Varroa Sensitive Hygiene (VSH)

TLDR: Varroa Sensitive Hygiene is a trait of honey bees, Apis mellifera, that supports resistance to Varroa destructor mites and simpler and shorter-term measures of uncapping, recapping, and reductions in infestation and mite fertility may facilitate selection of VSH by more bee breeders.

Abstract: SummaryVarroa Sensitive Hygiene (VSH) is a trait of honey bees, Apis mellifera, that supports resistance to Varroa destructor mites. Components of VSH were evaluated to identify simple methods for selection of the trait. Mite population growth was measured in colonies with variable levels of VSH in two field trials using 24 and 16 colonies. Mite population growth was significantly lower in VSH and hybrid colonies than in control (i.e., unselected) colonies. In resident brood with mite infestations below 5%, the percentage of uncapped pupal cells did not differ significantly among VSH, hybrid and control colonies, but the percentage of recapped cells was highest in VSH colonies (P = 0.03). When brood from more highly infested colonies (9–49% of pupae infested) was introduced for forty hours, VSH colonies reduced infestation more than control colonies (P< 0.01) but final mite fertility was similar (P= 0.12). When infested brood was exposed in colonies for one week, VSH colonies reduced both mite fertility (...