Varroa jacobsoni infestation of adult Africanized and Italian honey bees (Apis mellifera) in mixed colonies in Brazil

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.