Effect of the exposure with sublethal dosis to the insecticides Imidacloprid. Bifenthrin andChlorpyrifos or its combination on the total amount of body proteins and mRNA expression levels ofVitelogenin on Apis mellifera workers bees

Abstract

Agrochemicals, and particularly insecticides in sublethal doses, are widely recognized as being among the group of stressorsthat drastically reduce the fitness of insects. Particularly, Apis mellifera is known for its association with agriculture to sublethalcontact with a wide range of this group of stressors that trigger different types of stress, such as nutritional stress. Based onthis, the aim of this research is to determine if the level of total body proteins and the expression of the Vitellogenin gene inthree days emerged bees varies before the topical exposure to a sublethal dose (LD10) of the pesticides Imidacloprid.Bifenthrin and Chlorpyrifos or a combination of pairs of them. The bioassay was performed on a total of 30 A mellifera workersper treatment, which were contaminated with each pesticide or combination of them and after 24 hours were sacrificed withliquid nitrogen. Total protein content was obtained according to Bradford (1976) while Vitelogenin mRNA levels weredetermined by RT-qPCR. No significant differences were observed in the total protein content between the control group andthe individual treatment groups with bifenthrin and chlorpyrifos, however in the rest of the treatments the total protein contentwas significantly lower than the control. A significantly difference in mRNA levels was also found between individuals in theuntreated group and all of the treated groups. Within the treated groups, the mRNA expression in the group in contact withbifenthrin was significantly higher than among all other groups. It was concluded that the individuals that were in contact withthe agrochemicals studied presented a lower synthesis of vitellogenin mRNA, which may coincide with studies in other insectspecies. While it was postulated that this type of agrochemicals to a greater or lesser degree, depending on the familystimulates the corpora allata generating an increase in the juvenile hormone and therefore, in the case of bees, an inhibition ofthe synthesis of vitellogenin.