Divergência genética por marcadores RAPD em Tetragonisca angustula Latreille, 1811 (Hymenoptera, Apidae, Meliponidae)

Abstract

Tetragonisca angustula (Latreille, 1811) popularly known as ‘jatai’, is one of the most common stingless bees of the Neotropical region. It presents well varied nidification sites and it is found from México to Argentina. This research determined the genetic distance through RAPD markers among 29 bee populations comprising: 26 samples of T. angustula from 26 different places in three Latin America countries; two samples of T. buchwaldi (‘jatai’ from Acre) and one sample of Apis mellifera as the outgroup. Eieven short and seven long primers were used in this analysis. They produced 218 bands with an average number of polimorfism per primer of 3,8 for the ‘jatai’ group. The genetic distance as Percent Disagreement (PD) divided the T. angustula population in two groups at the levei of 0,139. Group 1 was formed by the samples: Panamá, Mirador, Barra do Corda, Domingos Martins, São Francisco, Araxá, Canaã, Pedreira, Curitiba, Blumenau, Maricá and Bocaiuva. Group 2 comprised: Porangatu, Rio Verde, Uberlândia 1 and 2, Ribeirão Preto, Pilar do Sul, Prudentópolis, Campinápolis, Campina Verde, Grupiara, Ladário, Cerro Azul, Posadas and Aristóbulo dei Valle. Panamá was the most different genotype within group 1, with a genetic distance of 0,121 from the outhers, while the maximum distance within group 2 was 0,072 for the Argentinian group (Posadas, Aristóbulo dei Valle and Cerro Azul) in relation to the others in the same group. The genotype of Pilar do Sul obtained by the cluster analysis (group 2) apparently does not correspond to its geographic distribution. This may have ocurred due to the fact that this sample, and also the one from Prudentópolis, were collected in a meliponary in Ribeirão Preto which were kept there since 1993 and 1992, respectively. The long primerswere more efficient in the distinction of more distant groups, while short primers were more efficient in the distinction of closer genotypes. The genetic distance (0,159) between T. angustula and T. buchwaldi which belongs to the same genus was larger than between T. angustula and A. mellifera (0,525) which are from different sub-families. Four suppositions were raised: 1): the number of samples of A. mellifera and T. buchwaldi used in this study was small; 2): the number of long primers was small; 3): the efficiency of the RAPD technique was endangered in higher hierarchical groups. 4). T. buchwaldi is more distant from T. angustula than it is observed morphologically. To elucidate this question, new RAPD experiments using more T. buchwaldi samples and a large number of long primers, besides further biology and systematic research are needed. Five molecular markers (from two primers) were able to distinguish the two T. angustula groups. A larger pattern of distribution for cluster 2 (corresponding to T. a. fiebrigi) was found, corresponding to Northeast Argentina, West Paraná, Santa Catarina, São Paulo, Minas Gerais, Goiás, Mato Grosso and Mato Grosso do Sul. Group 1 (corresponding to T. a. angustula) was distributed in Panamá, Maranhão, North Minas Gerais and through the Atlantic forest reached the state of Santa Catarina. Except for the samples of North Minas Gerais (Bocaiúva and São Francisco) and Araxá, cluster 1, in a general manner, was found distributed throughout rain forests. It was not possible to establish limits between groups in the Northern Mato Grosso, Goiás, Tocantins and the Amazon region, due to the lack of collectings in such areas. RAPD markers were considered to be an efficient molecular tool for the study of populations in meliponines.