RESUMO

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RESUMO

Understanding the effect of pesticides on the survival of honeybee colonies is important because these pollinators are reportedly declining globally. In the present study, we examined the changes in the head proteome of nurse honeybees exposed to individual and combined pesticides (the fungicide pyraclostrobin and the insecticide fipronil) at field-relevant doses (850 and 2.5 ppb, respectively). The head proteomes of bees exposed to pesticides were compared with those of bees that were not exposed, and proteins with differences in expression were identified by mass spectrometry. The exposure of nurse bees to pesticides reduced the expression of four of the major royal jelly proteins (MRJP1, MRJP2, MRJP4, and MRJP5) and also several proteins associated with carbohydrate metabolism and energy synthesis, the antioxidant system, detoxification, biosynthesis, amino acid metabolism, transcription and translation, protein folding and binding, olfaction, and learning and memory. Overall, when pyraclostrobin and fipronil were combined, the changes in protein expression were exacerbated. Our results demonstrate that vital proteins and metabolic processes are impaired in nurse honeybees exposed to pesticides in doses close to those experienced by these insects in the field, increasing their susceptibility to stressors and affecting the nutrition and maintenance of both managed and natural colonies.

Assuntos

RESUMO

Agrochemicals on crop cultivated areas is a source of contamination for bees and may cause physiological and behavioral disorders and mortality. The LD50 of the pesticides fipronil and imidacloprid was determined and their effect on the learning behavior of Apis mellifera L. honeybee evaluated. LD50 was determined by the ingestion of contaminated food with different concentrations of insecticide concentrations: Fipronil (0, 0.8, 0.4, 0.2, 0.1 and 0.05 μg bee⁻¹) and imidacloprid (0, 0.4, 0.2, 0.1, 0.05 and 0.025 μg bee-¹). The method of proboscis extension reflection (PER) and learning through citral odor evaluated their responses to food stimulation. LD50 obtained were 0.28 ± 0.11 and 0.10 ± 0.04 μg bee-¹ for fipronil and imidacloprid, respectively. The PER test showed no significant difference (p < 0.05) although agrochemicals affected the learning of bees. Insecticides fipronil and imidacloprid are extremely harmful to foraging Africanized Apis mellifera bees.

O uso de agroquímicos nas áreas de cultivo representa uma fonte de contaminação para as abelhas, podendo ocasionar distúrbios fisiológicos, comportamentais e mortalidade. O objetivo do presente trabalho foi determinar a DL50 dos agroquímicos Fipronil e Imidaclopride e avaliar o efeito destes no aprendizado de abelhas Apis mellifera L. adultas. A DL50 foi determinada por meio de teste de ingestão de alimento contaminado, com diferentes concentrações dos inseticidas Fipronil (0; 0,8; 0,4; 0,2; 0,1 e 0,05 μg abelha-¹) e Imidaclopride (0; 0,4; 0,2; 0,1; 0,05 e 0,025 μg abelha-¹). Para avaliar as respostas ao estímulo do alimento foi utilizado o método de reflexão de extensão da probóscide (REP) e aprendizado, utilizando odor citral. As DL50 obtidas foram 0,28 ± 0,11 e 0,10 ± 0,04 μg abelha-1 para o Fipronil e Imidaclopride, respectivamente. O teste REP não apresentou diferenças significativas (p < 0,05); porém, os agroquímicos afetaram o aprendizado das abelhas. Dessa maneira, conclui-se que os inseticidas Imidaclopride e Fipronil são nocivos às abelhas campeiras de Apis mellifera.

Assuntos

RESUMO

Agrochemicals on crop cultivated areas is a source of contamination for bees and may cause physiological and behavioral disorders and mortality. The LD50 of the pesticides fipronil and imidacloprid was determined and their effect on the learning behavior of Apis mellifera L. honeybee evaluated. LD50 was determined by the ingestion of contaminated food with different concentrations of insecticide concentrations: Fipronil (0, 0.8, 0.4, 0.2, 0.1 and 0.05 μg bee⁻¹) and imidacloprid (0, 0.4, 0.2, 0.1, 0.05 and 0.025 μg bee-¹). The method of proboscis extension reflection (PER) and learning through citral odor evaluated their responses to food stimulation. LD50 obtained were 0.28 ± 0.11 and 0.10 ± 0.04 μg bee-¹ for fipronil and imidacloprid, respectively. The PER test showed no significant difference (p < 0.05) although agrochemicals affected the learning of bees. Insecticides fipronil and imidacloprid are extremely harmful to foraging Africanized Apis mellifera bees.(AU)

O uso de agroquímicos nas áreas de cultivo representa uma fonte de contaminação para as abelhas, podendo ocasionar distúrbios fisiológicos, comportamentais e mortalidade. O objetivo do presente trabalho foi determinar a DL50 dos agroquímicos Fipronil e Imidaclopride e avaliar o efeito destes no aprendizado de abelhas Apis mellifera L. adultas. A DL50 foi determinada por meio de teste de ingestão de alimento contaminado, com diferentes concentrações dos inseticidas Fipronil (0; 0,8; 0,4; 0,2; 0,1 e 0,05 μg abelha-¹) e Imidaclopride (0; 0,4; 0,2; 0,1; 0,05 e 0,025 μg abelha-¹). Para avaliar as respostas ao estímulo do alimento foi utilizado o método de reflexão de extensão da probóscide (REP) e aprendizado, utilizando odor citral. As DL50 obtidas foram 0,28 ± 0,11 e 0,10 ± 0,04 μg abelha-1 para o Fipronil e Imidaclopride, respectivamente. O teste REP não apresentou diferenças significativas (p < 0,05); porém, os agroquímicos afetaram o aprendizado das abelhas. Dessa maneira, conclui-se que os inseticidas Imidaclopride e Fipronil são nocivos às abelhas campeiras de Apis mellifera.(AU)

Assuntos