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SummaryThe effective reproductive capacity of Varroa destructor in honey bee colonies is currently calculated on the basis of the number of female deutonymphs found in singly infested worker brood cells at 17–18 days (two to three days before the bee emerges). This calculation presumes that the deutonymphs will reach the adult stage by the time that the adult bee ecloses. Some deutonymphs may not, however, reach the adult phase and there also could be mortality. In order to examine this possibility, we studied mite reproduction in worker brood of Africanized honey bee colonies at 17–18 days and then selected eight colonies in which over 90% of the infested brood cells contained a single original female mite. The mean proportion of singly infested worker brood cells in these colonies was 96.3%. Consequently, by subtracting one from the total number of adult female mites found at the time the bee emerged we would be able to estimate the effective reproductive capacity of the original mites, with little erro...

Melipona quadrifasciata quadrifasciata and M. quadrifasciata anthidioides are subspecies of M. quadrifasciata, a stingless bee species common in coastal Brazil. These subspecies are discriminated by the yellow stripe pattern of the abdominal tergites. We found Vsp I restriction patterns in the cytochrome b region closely associated to each subspecies in 155 M. quadrifasciata colonies of different geographical origin. This mitochondrial DNA molecular marker facilitates diagnosis of M. quadrifasciata subspecies matrilines and can be used to establish their natural distribution and identify hybrid colonies.

International audience; The stingless bee Tetragonisca angustula is a meliponini bee naturally distributed from Argentina to Mexico. Morphologically, based on the mesepisternum color, it is separated into T. angustula angustula and T. angustula fiebrigi subspecies. The objective of this study was to characterize the restriction site variation in the mitochondrial DNA of each subspecies. Samples of worker bees were collected from two regions of Santa Catarina state, known as having a natural distribution of each subspecies. Each of the 138 colonies collected in the distribution region of T. a. angustula and of 72 colonies from the region of T. a. fiebrigi was individually analyzed. The ATPases 8, 6 and COIII mitochondrial genes were amplified and digested with seven restriction enzymes (PCR + RFLP). Large genetic differences were observed among bees collected in both geographical areas of natural distribution for the T. angustula subspecies. Four enzymes showed different restriction patterns that allowed separation of the subspecies.

Different levels of infestation with the mite Varroa jacobsoni have been observed in the various Apis mellifera races. In general, bees of European races are more susceptible to the mite than African honey bees and their hybrids. In Brazil honey bee colonies are not treated against the mite, though apparently both climate and bee race influence the mite infestation. Six mixed colonies were made with Italian and Africanized honey bees. The percentage infestation by this parasite was found to be significantly lower in adult Africanized (1.69 ± 0.44) than Italian bees (2.79 ± 0.65). This ratio was similar to that found in Mexico, even though the Africanized bees tested there had not been in contact with varroa, compared to more than 20 years of the coexistence in Brazil. However, mean mite infestation in Brazil on both kinds of bees was only about a third of that found in Mexico.Desde o contato inicial entre o ácaro Varroa jacobsoni e a abelha Apis mellifera, diferentes níveis de infestação foram verificados entre as diversas raças dessa espécie de abelhas. O presente trabalho teve como objetivo verificar o grau de infestação determinado pelo acaro Varroa jacobsoni em abelhas Apis mellifera, africanizadas e italianas puras, quando criadas numa mesma colméia. Para isso, o grau de infestação foi obtido em seis colônias de abelhas constituídas de operárias de ambas as raças. O resultado de dezesseis repetições mostrou que as abelhas africanizadas foram menos infestadas que as abelhas italianas. Esse resultado sugere que, nas condições naturais de infestação, as abelhas africanizadas são mais defensivas ao parasita Varroa jacobsoni, garantindo a essa raça de abelhas a resistência à praga varroosis.