Heritability of morphological characters used to distinguish European and Africanized honeybees

Abstract

Identification of "Africanized" honeybees (Apis mellifera) is usually achieved by measuring an array of morphological characters. Discriminant functions exist that allow determination of subspecies similarity on the basis of these measurements. Here we compute the heritabilities of the standard character set for ten eco-types (Table 1) of bees. Heritability is extremely high for body size characters and there is greater genetic variance among ecotypes than within. Heritability is lower, but still very high, for the vein angle characters and hamuli number (Table 3). Heritability was also computed for the same character set for a group of 20 colonies in Venezuela (Table 4). Heritabilities declined by an average of 41% when specimens were reared in nonmaternal environments, but were still extremely high for the body size characters. These results support the continued use of morphological characters as a tool for identifying Africanized bees. They also suggest that multivariate analysis of morphology is useful in evaluating changes in the honeybee genome, and is therefore an effective means of studying the population genetics of honeybees.