Genetic and morphological variability in Neotropical populations of Apis mellifera / Variabilidade genético-morfológica em populações neotropicais de Apis mellifera

AUTOR(ES)
DATA DE PUBLICAÇÃO

2007

RESUMO

Since the release of the African bee Apis mellifera scutellata in Brazil in 1957, Africanized honey bees have been widely studied, though there are still unresolved questions about population variability. We examined the temporal and spatial variability of Apis mellifera populations from Brazil and Panama, using mitochondrial DNA, traditional morphometrics, geometric morphometrics and an Automatic Bee Identification System (ABIS). The populations from Ribeirão Preto, Brazil and Panamá were examined for temporal changes in their morphometric profiles and in mitochondrial DNA patterns. Bees from south Brazil were found to be significantly larger than those from the north and northeast. Bees collected at the beginning of the Africanization process were also found to be bigger than those collected recently. These differences in size may reflect different degrees of admixture of the founder subspecies and also environmental and ecological factors. No significant correlation was observed between the size of the wings and the altitude where the bees were sampled. When the patterns of wing venation were compared among the Africanized populations, we found little variation; though Africanized bees were found to be distinct from (African) A. m. scutellata, this group was most similar to the African pattern. The mtDNA of the Africanized populations was found to be almost completely of African origin, except for three of 394 colonies, which had the east European pattern. This nearly complete displacement may have been caused by nest usurpation by Africanized bees or due to a competitive disadvantage of hybrids with European maternity. We did not get good discrimination or identifications of the populations with ABIS and geometric morphometrics, probably due to the high rates of gene flow among the groups. However, when tested in more distinct groups, for example, subspecies and isolated populations, such as the Italian bees on Fernando de Noronha island, these two methods were very efficient, with identification rates of around 85% and 100%, respectively. The population of Italian bees (A.m. ligustica) on Fernando de Noronha presented a morphometric profile very different from that of A. m. ligustica, the subspecies introduced to the island in 1984. These differences could be a result of inbreeding, environmental adaptations or bottleneck effects. The two new morphometric methodologies, though they did not provide good discrimination of the Africanized populations, are very promising for studies of Apis mellifera subspecies and for identification of other bee species.

ASSUNTO(S)

morfometria of wing population variability apis mellifera variabilidade populacional identificação indi morfometria de asa individual and population identification apis mellifera dna mitocondrial

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