Influência do farnesol exógeno sobre aspectos fisiológicos de abelhas Apis mellifera

Abstract

Humans and other animals frequentely get in contact with other molecules produced by plants that can regularize direct ou indirectly their physiology. In the case study Apis mellifera, the foraging workers collect the nectar, pollen and vegetable resins. In the South of Minas Gerais, the plant Baccharis dracunculifolia show in its resins the farnesol, importante precursor of the synthetic pathway of the Juvenile Hormone (JH) that commands many of the bug’s life aspects. We hypothesize that, during the foraging, the workers get in touch with significant amounts of JH precursors that, once inside the body, can be modified and converted in JH. This interference with the endogenous synthetic pathway of JH on these insects can cause physiological and behavioral changes with biological, ecological and agricultural implications. To test this hypothesis, we evalucited the influence of exogenus farnesol under physiological parameters of young working bees. To do that, we have dissected corpora allata (CA), organ responsible for the synthesis of JH, in two groups of bees, treated for three days: (I) 50 bees that received 1 g of food containing honey, sugar and farnesol dilluted in canola oil, and (II) 50 bees that received 1 g of honey, sugar and canola oil (control). Through the RT-qPCR we have determined the transcription profile of the methyl farnesoate epoxidase (mfe), methyl transferase (mt) and farnesyl diphosphate synthase (fpps3) genes, involved in the JH synthesis pathway, and the juvenile hormone esterase (jhe) gene, responsible for the JH’s degradation. Our results show that the mfe gene is more expressed in control individuals compared to the ones supplemented with exogenous farnesol; on the other hand, to the gene jhe it was found the opposite. This shows us that the more farnesol a bee consumes the lower will be the synthesis of direct precursor of JH and higher degradation of JH. Furthermore, bees treated with farnesol have had their CA volumes, including area and diameter of the nuclei, bigger in relation to the control bees. We’ve also analyzed the behavior in both groups for 72 h and observed that bees with 48 h of life supplemented with farnesol move more active compared to the control group. These findings demonstrate that exogenous agents, such as farnesol synthesized by plants, alter the physiology, metabolism and behavior of honey bees.