Hygienic behavior in honey bees and prediction of Varroa non-reproduction in single-drone inseminated (SDI) colonies

Abstract

The two standardized assays for testing hygienic behavior in Apis mellifera in the field are the freeze-killed brood (FKB) and the pin-killed brood (PKB) assays. Correlation between the two tests is still in debate. It has been argued that the PKB assay was predictive of Varroa nonreproduction. We measured the agreement between the two methods in two apiaries with 36 and 59 colonies, respectively. The agreement between the two assays was very poor with a 95% limit of agreement greater than 100%. These assays and the SMR (Suppression of Mite Reproduction) trait were also measured in 21 single drone inseminated colonies infested with Varroa and with varying SMR efficacy. A PKB assay result of >46% at 24 h predicted an SMR trait >40% with a sensitivity and a specificity of 0.727 and 0.90, respectively, whereas the FKB assay did not exhibit any predictive value. In conclusion, the PKB and FKB assays are not correlated, but the PKB assay predicted SMR with a good accuracy.