Morphometric Techniques Do Not Detect Intermediate and Low Levels of Africanization in Honey Bee (Hymenoptera: Apidae) Colonies

We tested three different morphometric methods used to identify Africanized honey bee (Apis mellifera L.) colonies and determined the correlative relationships of their associated discriminant scores and colony defensive behavior. Workers within and between experimental colonies varied in the percentage of their genotype that was of African origin. Morphometric scores of colonies were compared with two defensive behavior traits: the time it took for the first worker in a colony to respond to, and sting, a moving leather-patch target, and the total number of stings received in the target during a 60-s interval following the first sting. All identification methods correctly classified all of the colonies that were presumed to be 100% Africanized or European. However, <45% of the hybrid samples were scored as Africanized. In all cases, as the level of Africanization decreased, so did the sensitivity and accuracy of the method. Correlations between morphometric scores and defensive behavior were significant when extreme genotypes were included in the analyses, but no method correlated with samples ranging in the interval >0 but <50% Africanized. Implications are discussed of using these and alternative identification methods in regulatory programs.