Diagram depicting honey bee disease tolerant traits and infestation dynamics. (a) Hygienic behavior (HB) is composed of two component behaviors, 'uncapping' (uncapped, U) which involves the opening of the cell containing a dead pupa and 'removal' (removed, R) which involves the removal of the dead pupa from the cell after uncapping has occurred. These behaviors are not always performed by the same bee. HB was recorded over 24 hour (rapid) and 48 hour (slow) periods. (b) Varroa sensitive hygiene (VSH) was defined by determining the proportion of Varroa-infested cells in which no reproductively viable Varroa mite daughters were produced. Increases in this measure infer that greater proportions of mites remaining in the brood have had their reproduction suppressed because of infertility, death, the production of only males, or have had their reproduction delayed preventing sexual maturation of females. (c) Brood infestation (BI) is the percentage of brood cells infested by one or more mites regardless of the mite's reproductive status. (d) Phoretic infestation (PI) is an estimate of the density of mite phoresy on adult bees, and (e) natural drop (ND) is a normalized measure of the number of mites falling from the adult bees onto an adhesive board on the bottom board of colonies.
Parker et al. Genome Biology 2012 13:R81 doi:10.1186/gb-2012-13-9-r81