Variation and genetic structure of Melipona quadrifasciata Lepeletier (Hymenoptera, Apidae) populations based on ISSR pattern

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

Handling sticky Resin by Stingless Bees: Adhesive Properties of Surface Structures

Many Stingless Bees (Hymenoptera: Meliponini) like Tetragonisca angustula collect resin to defend their nests against intruders like ants or Robber Bees. Small portions of resin are attached to intruders bodies and extremities causing their immobilization. It has been observed that resin is removed easily from the bee's mandible but adheres strongly to the intruder's cuticle. We tested the hypothesis that resin sticks lesser to the mandibles of Stingless Bees than to the surface of intruders due to special surface structures or adhesive properties of these structures. The surface structures of the mandible of T. angustula and the trochanter of Camponotus sericeiventris were studied by scanning electron microscopy. To measure adhesion properties, selected surfaces were fixed on a fine glass pin and withdrawn from a glass tip covered with resin. The deformation of the glass pin indicates adhesion forces operating between the resin and the selective surface. The absolute value of the forces is computed from the glass pin's stiffness. It has been shown that resin sticks more to the smooth mandible of the bee than to the structured trochanter of the ant. A new hypothesis to be tested says that the bees might lubricate their mandibles with nectar or honey to reduce the resin's adhesion temporarily

Ovarian activation in Melipona quadrifasciata queens triggered by mating plug stimulation (Hymenoptera, Apidae)

The effect of the detached male genital capsule on ovarian activation in queens of the stingless bee Melipona quadrifasciata, and the amount of time the genital capsule remains attached to the queen genital chamber after mating, were investigated. Twenty-four controlled matings were carried out and the male capsules were manually removed at preset time intervals. The results indicate that the experimental removal of the mating plug on the first three days after mating inhibits ovarian activation or strongly decreases the chances that it will happen. After this period it would not affect ovarian activation, despite continuing to be attached to the queen for a few more days. It is suggested that the male genital capsule provides mechanical stimulation only

Honey physicochemical properties of three species of the brazilian Melipona

Physicochemical analyses were carried out to evaluate 27 samples of honeys from three species of the Brazilian genus Melipona (M. capixaba, M. rufiventris and M. mondury) from Espírito Santo and Minas Gerais States. The parameters water activity (Aw), percentage of soluble solids (Brix %), pH, acidity (meq/Kg) and moisture (%) were evaluated. The honey characteristics obtained from these samples were very similar to the ones from other Melipona species. However, regarding the honey from Apis (honey bee), only the pH values were similar. The low pH value and the high acidity detected in Melipona honey are potential factors for increasing the honey shelf life because they do not provide favorable conditions for the microbial development. On the other hand, the high level of water activity favors the growth of microorganisms, especially yeast, which demands a more careful handled and storage. The observed differences between Melipona and Apis honey reinforce the need for specific quality settings for stingless bee honey

Possible introgression of B chromosomes between bee species (Genus Partamona )

The origin of supernumerary (B) chromosomes is still a de- bated topic, with intra- and interspecific origins being the most plausible options. In the bee Partamona helleri, a se- quence-characterized amplified region (SCAR) marker being specific to B chromosomes suggested the possibility of inter- specific origin. Here, we search for this marker in 3 close rela- tive species and perform DNA sequence comparison be- tween species. The SCAR sequence does not show homolo- gy with other sequences in the databases, but does contain an open reading frame with sequence homology with a re- verse transcriptase. Dot-blot hybridization using the SCAR marker as a probe confirmed that it is present in B-carrying, but not B-lacking larvae of P. helleri, and indicated its pres- ence in adult individuals of P. cupira and P. criptica. Addition- ally, PCR amplification of the SCAR marker was successful on genomic DNA obtained from P. helleri and P. rustica larvae carrying B chromosomes, and on genomic DNA obtained from adult individuals of P. cupira, P. criptica and P. rustica. Finally, a comparison of the DNA sequence of the SCAR markers amplified from these 4 species showed very few nu- cleotide differences between the species. The complete as- sociation between B chromosome and SCAR presence and the scarce divergence observed for this DNA sequence be- tween the 4 species analyzed suggest the possibility that this B chromosome has recently been transferred between spe- cies through several episodes of interspecific hybridization

A molecular marker distinguishes the subspecies Melipona quadrifasciata quadrifasciata and Melipona quadrifasciata anthidioides (Hymenoptera: Apidae, Meliponinae)

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.<br>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