Abstract
Besides the individual mechanical, physiological and immunological defenses that social insects such as Apis mellifera have against pathogens, some group behaviors exist that can limit the spread of diseases among within the colony. Among these is hygienic behavior, more recently considered to be one of the forms of "social immunity". Hygienic behavior in honey bees can be defined as their ability to detect and uncap cells containing sick or dead brood and remove them from the hive. For several decades this has been considered an important natural defense mechanism against various diseases. Therefore, the disease resistance of A. mellifera is directly related to their hygienic or colony-cleaning behavior, since the fewer infectious foci exist in the colony, the healthier the bees will be. Despite being studied for many years, there are still questions to be clarified about the hygienic behavior of bees. Modern molecular techniques such transcriptome analysis can be useful to shed more light on the subject, since that behavioral trait can present age-related plasticity, besides being highly polygenic. In Brazil there is a lack of investments in genetic improvement programs involving apiculture, despite the existence of powerful genomic tools that can assure the success of such programs, with savings of time and labor, particularly in field tests. In the specific case of hygienic behavior, it might be possible to identify some specific loci and perform marker-assisted selection. This can be a first step toward the development of new studies to enable implementation of genomic selection in this species. Furthermore, it is important to find disease-resistant bee strains to reduce or avoid the need for drug treatments, which can leave harmful residues in bee products, and to increase pollinating efficiency. Hence, studies of the genetic base for such behavior, by using genomic tools, are important to obtain resistant strains. The aims of this study are to identify genes associated with the hygienic behavior of A. mellifera by means of RNA-seq technique, to validate the technique by qRT-PCR, and to analyze the expression of those genes in specific tissues, despite the technological differences, since they can be complementary. Another goal is to obtain new knowledge for marker-assisted selection, to raise the productivity of beekeepers, not only in the state of São Paulo, but throughout Brazil. If successful, genetically improved queens (disease-resistant) will be available through a São Paulo Public Research Institute (Agência Paulista de Tecnologia dos Agronegócios - APTA/SAA-SP), to avoid the need for chemicals the consequent risk of contamination of bee products or generate resistance by bees.
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