Rapid morphological changes in populations of hybrids  between Africanized and European honey bees.
African honey bees, introduced to Brazil in 1956,  rapidly dominated the previously introduced European subspecies. To better  understand how hybridization between these different types of bees proceeded,  we made geometric morphometric analyses of the wing venation patterns of  specimens resulting from crosses made between Africanized honey bees  (predominantly Apis mellifera scutellata) and Italian honey bees (A.  mellifera ligustica) from 1965 to 1967, at the beginning of the  Africanization process, in an apiary about 150 km from the original  introduction site. Two virgin queens reared from an Italian parental were  instrumentally inseminated with semen from drones from an Africanized parental.  Six F(1) queens from one of these colonies were open  mated with Africanized drones. Resultant F(1) drones were backcrossed to 50 Italian and 50  Africanized parental queens. Five backcross workers were collected from each of  eight randomly selected colonies of each type of backcross (N = 5 bees x 8  colonies x 2 types of backcrosses). The F1 progeny (40 workers and 30 drones) was found to be  morphologically closer to the Africanized than to the European parental (N = 20  drones and 40 workers, each); Mahalanobis square distances = 21.6 versus 25.8,  respectively, for the workers, and 39.9 versus 46.4, respectively, for the  drones. The worker progenies of the backcrosses (N = 40, each) were placed  between the respective parental and the F(1) progeny, although closer to the Africanized than to  the Italian parentals (Mahalanobis square distance = 6.2 versus 12.1,  respectively). Consequently, the most common crosses at the beginning of the  Africanization process would have generated individuals more similar to  Africanized than to Italian bees. This adds a genetic explanation for the rapid  changes in the populational morphometric profile in recently colonized areas.  Africanized alleles of wing venation pattern genes are apparently dominant and  epistatic.
Escola de Artes, Ciências e Humanidades, Universidade de São Paulo, São Paulo, SP, Brasil. tfrancoy@usp.br
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Francoy
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Gonçalves
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De Jong
D000349:Africa; D000818:Animals; D001516:Bees / Q000033:anatomy & histology* / Q000235:genetics*; D003433:Crosses, Genetic; D016002:Discriminant Analysis; D005260:Female; D005828:Genetics, Population; D006608:Hierarchy, Social; D006722:Honey; D006824:Hybridization, Genetic; D007558:Italy; D008297:Male; D010375:Pedigree; D011157:Population Dynamics; D014921:Wings, Animal / Q000033:anatomy & histology