For a study of diversity and genetic structuring in Melipona quadrifasciata, 61 colonies were collected in eight locations in the state of Minas Gerais, Brazil. By means of PCR analysis, 119 ISSR bands were obtained, 80 (68%) being polymorphic. He and H B were 0.20 and 0.16, respectively. Two large groups were obtained by the UPGMA method, one formed by individuals from Januária, Urucuia, Rio Vermelho and Caeté and the other by individuals from São João Del Rei, Barbacena, Ressaquinha and Cristiano Otoni. The Φst and θB values were 0.65 and 0.58, respectively, thereby indicating high population structuring. UPGMA grouping did not reveal genetic structuring of M. quadrifasciata in function of the tergite stripe pattern. The significant correlation between dissimilarity values and geographic distances (r = 0.3998; p < 0.05) implies possible geographic isolation. The genetic differentiation in population grouping was probably the result of an interruption in gene flow, brought about by geographic barriers between mutually close geographical locations. Our results also demonstrate the potential of ISSR markers in the study of Melipona quadrifasciata population structuring, possibly applicable to the studies of other bee species.

Melipona quadrifasciata Lepeletier, 1836, regionally known as "mandaçaia", has been traditionally divided in two distinct subspecies: M. quadrifasciata anthidioides and M. quadrifasciata quadrifasciata. The main difference between the subspecies refers to the yellow metasomal stripes which are continuous in M. q. quadrifasciata and discontinuous in M. q. anthidioides. This study investigated the geographic differentiation in the metasomal stripes and characterized the restriction sites in the mtDNA of both chromatic types. Specimens from 198 localities were examined, and the variation observed in the pattern of stripes was grouped into distinct classes. The distribution pattern found in the present work agrees with the previously reported pattern: M. q. quadrifasciata inhabits the southern portion of the distribution, from Misiones, Argentina, southeastern Paraguay and Rio Grande do Sul to southern São Paulo, and M. q. anthidioides ranges from northeastern São Paulo to the northern Diamantina Plateau, Bahia, and westwards to the central portion of the Goiás state. It is documented for the first time the occurrence of two populations with continuous stripes inhabiting disjunct areas in relation to M. q. quadrifasciata - one in northern Minas Gerais and another in northeastern Bahia and Sergipe. The data of RFLP showed two restriction patterns, one present in M. q. quadrifasciata, and another in M. q. anthidioides and in populations with continuous metasomal stripes from northern Minas Gerais and northeastern Bahia and Sergipe. The observed patterns of geographic differentiation of M. quadrifasciata suggests the occurrence of repeated events of geographical isolation, followed by range expansion, that occurred probably during the cycles of climatic changes in the Pleistocene.

A espécie de abelha sem ferrão Melipona quadrifasciata apresenta duas subespécies, Melipona quadrifasciata quadrifasciata Lep. e Melipona quadrifasciata anthidioides Lep. A diferença morfológica entre as duas subespécies é a presença de três a cinco bandas tergais amarelas do 3º ao 6º segmentos em operárias e machos de M. q. quadrifasciata e duas a cinco bandas interrompidas em M. q. anthidioides. Nós identificamos um marcador de DNA que está presente em M. q. quadrifasciata e ausente em M. q. anthidioides. Este marcador está ausente em abelhas coletadas no norte do Estado de Minas Gerais (Brasil), embora esses indivíduos apresentem morfologia similar à de M. q. quadrifasciata. Este marcador poderá ser utilizado em estudos da zona de hibridação entre as subespécies.

The stingless bee species Melipona quadrifasciata includes two subspecies, Melipona quadrifasciata anthidioids and Melipona quadrifasciata quadrifasciata. The morphological difference between the two subspecies is the presence of three to five continuous yellow stripes on the terga on the 3rd to 6th segments in workers and males of M. q. quadrifasciata, and two to five interrupted bands in M. q. anthidioides. We identified a DNA marker which is present in M. q. quadrifasciata and absent in M. q. anthidioides. Only one among the M. q. quadrifasciata colonies did not present the marker. It was also absent in bees collected in northern Minas Gerais State (Brazil), despite their morphological resemblance to M. q. quadrifasciata. The marker can be used for studying the genetic structure of the hybridization zone formed by the intercrossing of the two subspecies.