RESUMO

The aim of this study was to evaluate whether alterations in food availability compromise the metabolic homeostasis of honey bees exposed to three fungicides alone or together. Ten honey bee colonies were used, with half receiving carbohydrate-protein supplementation for 15 weeks while another five colonies had their protein supply reduced with pollen traps. Subsequently, forager bees were collected and exposed by contact to 1 or 7 µg of bixafen, prothioconazole, or trifloxystrobin, either individually or in combination. After 48 h, bee abdomens without the intestine were used for the analysis of expression of antioxidant genes (SOD-1, CAT, and GPX-1), detoxification genes (GST-1 and CYP306A1), the storage protein gene vitellogenin, and immune system antimicrobial peptide genes (defensin-1, abaecin, hymenoptaecin, and apidaecin), through real-time PCR. All fungicide treatments induced changes in gene expression, with bixafen showing the most prominent upregulation. Exposure to 1 µg of each of the three pesticides resulted in upregulation of genes associated with detoxification and nutrition processes, and downregulation of immune system genes. When the three pesticides were combined at a dose of 7 µg each, there was a pronounced downregulation of all genes. Food availability in the colonies affected the impact of fungicides on the expression of the studied genes in forager bees.

RESUMO

There is no use restriction associated with bees for many fungicides used in agriculture; however, this does not always mean that these pesticides are harmless for these nontarget organisms. We investigated whether the fungicide pyraclostrobin, which acts on fungal mitochondria, also negatively affects honey bee mitochondrial bioenergetics. Honey bees were collected from 5 hives and anesthetized at 4 °C. The thoraces were separated, and mitochondria were isolated by grinding, filtering, and differential centrifugation. An aliquot of 0.5 mg of mitochondrial proteins was added to 0.5 mL of a standard reaction medium with 4 mM succinate (complex II substrate) plus 50 nM rotenone (complex I inhibitor), and mitochondrial respiration was measured at 30 °C using a Clark-type oxygen electrode. Mitochondrial membrane potential was determined spectrofluorimetrically using safranin O as a probe, and adenosine triphosphate (ATP) synthesis was determined by chemiluminescence. Pyraclostrobin at 0 to 50 µM was tested on the mitochondrial preparations, with 3 repetitions. Pyraclostrobin inhibited mitochondrial respiration in a dose-dependent manner at concentrations of 10 µM and above, demonstrating typical inhibition of oxidative phosphorylation. Pyraclostrobin also promoted a decline in the mitochondrial membrane potential at doses of 5 µM and above and in ATP synthesis at 15 µM and above. We conclude that pyraclostrobin interferes with honey bee mitochondrial function, which is especially critical for the energy-demanding flight activity of foraging bees. Environ Toxicol Chem 2020;39:1267-1272. © 2020 SETAC.

Assuntos

RESUMO

Silkworm cocoon production has been reduced due to a number of problems other than those inherent in sericulture, such as diseases, malnutrition, and inappropriate management. The use of pesticides in areas surrounding mulberry fields can contaminate these plants and consequently harm caterpillars. The aim of this study was to evaluate whether the application of the fungicide pyraclostrobin in mulberry plants interferes with the mitochondrial bioenergetics and the productive performance of silkworms. Mulberry plants were treated with pyraclostrobin (0, 100, 200, and 300 g ha-1). After 30 d of fungicide application, fifth instar caterpillars were fed with leaves from the treated plants. We evaluated in vitro and in vivo mitochondrial bioenergetics of mitochondria from the head and intestines, as well as the feed intake and mortality rate of the caterpillars and the weight of fresh cocoons and cocoons shells. At doses of 50 µM (in vitro) and 200 g ha-1 (in vivo), pyraclostrobin inhibited oxygen consumption in state 3, dissipated membrane potential, and inhibited ATP synthesis in mitochondria. Pyraclostrobin acted as a respiratory chain inhibitor, affecting mitochondrial bioenergetics. The fungicide did not interfere with food consumption but negatively affected mortality rate and weight of cocoons. Mulberry leaves contaminated with pyraclostrobin negatively impact the mitochondrial bioenergetics of silkworms and cocoon production.

Assuntos

RESUMO

The bordeaux mixture is used as a natural agricultural fungicide, and its application in sericulture can benefit the production of silkworm cocoons, Bombyx mori (Lepidoptera: Bombycidae). The aim of this study was to verify whether the bordeaux mixture exerts a protective effect in B. mori against fungal and viral diseases. This experiment was performed during two seasons, autumn and spring, in which 7,500 caterpillars were used at the beginning of the third instar and divided into five groups, with three repetitions of 500 individuals each. In the three groups, the caterpillars were fed leaves of Mulberry (Morus spp.) that were enriched with an aqueous bordeaux mixture solution at concentrations of 5, 10 and 20%. One group was fed exclusively mulberry leaves (control), and another was fed leaves that were moistened with water. Fungal contamination was evaluated in the integumentary surface of the insect and the mulberry leaves in the bed of creation by checking the number of colony-forming units (CFU). In the analysis of viral contamination, 20 caterpillars from each group at the beginning of the fifth instar were inoculated with 10 μl of a suspension of Bombyx mori nucleopolyhedrovirus (BmNPV). Daily, from the second to the ninth day after inoculation (dai), two caterpillars of each group were anesthetized and formalin-fixed 7% for microscopic processing and viral cytopathology analysis. A completely randomized design was used, and the CFU were compared by Tukey test with 5% significance. The results showed a decrease of 55.1% in CFU present on the mulberry leaves in the fall, when the 5% bordeaux mixture solution was used. There was no significant difference between the groups based on the bordeaux mixture in this period.[...](AU)

A calda bordalesa é um produto usado como fungicida agrícola natural e sua aplicação em sericicultura pode beneficiar a produção de casulos do bicho-da-seda, Bombyx mori (Lepidoptera: Bombycidae). O objetivo deste estudo foi verificar se a calda bordalesa exerce efeito protetor em B. mori contra doenças fúngicas e virais. O experimento foi realizado em dois períodos sazonais, outono e primavera, sendo utilizadas 7.500 lagartas no início do terceiro instar, divididas em cinco grupos, com três repetições de 500 indivíduos cada. Em três grupos as lagartas foram alimentadas com folhas de amoreira (Morus spp.) enriquecidas com solução aquosa de calda bordalesa nas concentrações de 5, 10 e 20%. Um grupo foi alimentado exclusivamente com folhas de amoreira (controle) e outro com folhas umedecidas apenas com água. A contaminação fúngica foi avaliada na superfície tegumentar do inseto e nas folhas de amoreira presentes na cama de criação, através da verificação do número de unidades formadoras de colônias (UFC). Já na análise da contaminação viral, 20 lagartas de cada grupo, no início do quinto instar, foram inoculadas com 10 μl da suspensão de Bombyx mori nucleopolyhedrovirus (BmNPV). Diariamente, do segundo ao nono dia após a inoculação (dpi), duas lagartas de cada grupo foram anestesiados e fixadas em formol 7%, para o processamento microscópico e análise da citopatologia viral. Foi adotado um delineamento inteiramente casualizado e as médias de UFC foram comparadas por teste de Tukey, com 5% de significância. Os resultados revelaram uma redução de 55,1% nas UFC presentes nas folhas de amoreira no outono, quando foi utilizada a solução 5% de calda bordalesa. Não houve diferença significativa entre os grupos à base de calda bordalesa neste período.[...](AU)

Assuntos

RESUMO

The bordeaux mixture is used as a natural agricultural fungicide, and its application in sericulture can benefit the production of silkworm cocoons, Bombyx mori (Lepidoptera: Bombycidae). The aim of this study was to verify whether the bordeaux mixture exerts a protective effect in B. mori against fungal and viral diseases. This experiment was performed during two seasons, autumn and spring, in which 7,500 caterpillars were used at the beginning of the third instar and divided into five groups, with three repetitions of 500 individuals each. In the three groups, the caterpillars were fed leaves of Mulberry (Morus spp.) that were enriched with an aqueous bordeaux mixture solution at concentrations of 5, 10 and 20%. One group was fed exclusively mulberry leaves (control), and another was fed leaves that were moistened with water. Fungal contamination was evaluated in the integumentary surface of the insect and the mulberry leaves in the bed of creation by checking the number of colony-forming units (CFU). In the analysis of viral contamination, 20 caterpillars from each group at the beginning of the fifth instar were inoculated with 10 μl of a suspension of Bombyx mori nucleopolyhedrovirus (BmNPV). Daily, from the second to the ninth day after inoculation (dai), two caterpillars of each group were anesthetized and formalin-fixed 7% for microscopic processing and viral cytopathology analysis. A completely randomized design was used, and the CFU were compared by Tukey test with 5% significance. The results showed a decrease of 55.1% in CFU present on the mulberry leaves in the fall, when the 5% bordeaux mixture solution was used. There was no significant difference between the groups based on the bordeaux mixture in this period.[...]

A calda bordalesa é um produto usado como fungicida agrícola natural e sua aplicação em sericicultura pode beneficiar a produção de casulos do bicho-da-seda, Bombyx mori (Lepidoptera: Bombycidae). O objetivo deste estudo foi verificar se a calda bordalesa exerce efeito protetor em B. mori contra doenças fúngicas e virais. O experimento foi realizado em dois períodos sazonais, outono e primavera, sendo utilizadas 7.500 lagartas no início do terceiro instar, divididas em cinco grupos, com três repetições de 500 indivíduos cada. Em três grupos as lagartas foram alimentadas com folhas de amoreira (Morus spp.) enriquecidas com solução aquosa de calda bordalesa nas concentrações de 5, 10 e 20%. Um grupo foi alimentado exclusivamente com folhas de amoreira (controle) e outro com folhas umedecidas apenas com água. A contaminação fúngica foi avaliada na superfície tegumentar do inseto e nas folhas de amoreira presentes na cama de criação, através da verificação do número de unidades formadoras de colônias (UFC). Já na análise da contaminação viral, 20 lagartas de cada grupo, no início do quinto instar, foram inoculadas com 10 μl da suspensão de Bombyx mori nucleopolyhedrovirus (BmNPV). Diariamente, do segundo ao nono dia após a inoculação (dpi), duas lagartas de cada grupo foram anestesiados e fixadas em formol 7%, para o processamento microscópico e análise da citopatologia viral. Foi adotado um delineamento inteiramente casualizado e as médias de UFC foram comparadas por teste de Tukey, com 5% de significância. Os resultados revelaram uma redução de 55,1% nas UFC presentes nas folhas de amoreira no outono, quando foi utilizada a solução 5% de calda bordalesa. Não houve diferença significativa entre os grupos à base de calda bordalesa neste período.[...]

Assuntos

RESUMO

Bees have a crucial role in pollination; therefore, it is important to determine the causes of their recent decline. Fipronil and imidacloprid are insecticides used worldwide to eliminate or control insect pests. Because they are broad-spectrum insecticides, they can also affect honeybees. Many researchers have studied the lethal and sublethal effects of these and other insecticides on honeybees, and some of these studies have demonstrated a correlation between the insecticides and colony collapse disorder in bees. The authors investigated the effects of fipronil and imidacloprid on the bioenergetic functioning of mitochondria isolated from the heads and thoraces of Africanized honeybees. Fipronil caused dose-dependent inhibition of adenosine 5'-diphosphate-stimulated (state 3) respiration in mitochondria energized by either pyruvate or succinate, albeit with different potentials, in thoracic mitochondria; inhibition was strongest when respiring with complex I substrate. Fipronil affected adenosine 5'-triphosphate (ATP) production in a dose-dependent manner in both tissues and substrates, though with different sensitivities. Imidacloprid also affected state-3 respiration in both the thorax and head, being more potent in head pyruvate-energized mitochondria; it also inhibited ATP production. Fipronil and imidacloprid had no effect on mitochondrial state-4 respiration. The authors concluded that fipronil and imidacloprid are inhibitors of mitochondrial bioenergetics, resulting in depleted ATP. This action can explain the toxicity of these compounds to honeybees.

Assuntos

RESUMO

As culturas agrícolas apresentam diferentes níveis de dependência por polinizadores e essa expressão variada ocorre inclusive entre cultivares de uma espécie, como no caso das plantas de pepino (Cucumis sativus). O objetivo desse trabalho foi avaliar a atratividade das flores de pepino Japonês de três cultivares e a importância das abelhas Africanizadas (Apis mellifera), as abelhas brasileiras sem ferrão, Jataí (Tetragonisca angustula) e Iraí (Nannotrigona testaceicornis), na produção de frutos . Foram analisados vários parâmetros como a frequência de visitas de abelhas às flores, o tempo de visita utilizado para a coleta de néctar e a taxa de frutificação, considerando-se o peso, o comprimento e diâmetro dos pepinos obtidos. Foram utilizadas três casas de vegetação em Ribeirão Preto, SP, para o cultivo de três cultivares de pepino (Hokushin, Yoshinari e Soudai). Verificou-se que as flores femininas são mais atrativas que as masculinas e que as abelhas Jataí não visitaram as flores. As abelhas Africanizadas e Iraí coletaram apenas néctar, com pico de visitação entre 10h e 12h. Visita às flores femininas tiveram uma maior duração do que as visitas às flores masculinas nas três cultivares. As abelhas Africanizadas tiveram suas colônias diminuídas devido à perda de abelhas enquanto na casa de vegetação; as abelhas nativas não sofreram perdas. Com a retirada das abelhas, a frutific

Crops have different levels of dependence on pollinators; this holds true even for cultivars of the same species, as in the case of cucumber (Cucumis sativus). The aim of this research was to assess the attractiveness of flowers of three Japanese parthenocarpic cucumber cultivars and evaluate the importance of Africanized bees (Apis mellifera), and the Brazilian native stingless bees, Jataí (Tetragonisca angustula) and Iraí (Nannotrigona testaceicornis) on fruit production. Several parameters, including frequency of bee visits to flowers as well as duration of nectar collection and fruit set were examined; additionally, fruit weight, length and diameter were evaluated. Three greenhouses located in Ribeirão Preto, SP, were used for planting three cucumber cultivars (Hokushin, Yoshinari and Soudai). The female flowers were more attractive than male flowers; however, Jataí bees were not observed visiting the flowers. The Africanized and the Iraí bees collected only nectar, with a visitation peak between 10 and 12h. Visits to female flowers had a longer duration than visits to male flower visits in all three cultivars. Africanized bee colonies declined due to loss of bees while in the greenhouse; the native stingless bee colonies did not suffer these losses. When bees were excluded, fruit set was 78%; however, when bees had access to the flowers, fruit set was significantly (19.2%)

RESUMO

As culturas agrícolas apresentam diferentes níveis de dependência por polinizadores e essa expressão variada ocorre inclusive entre cultivares de uma espécie, como no caso das plantas de pepino (Cucumis sativus). O objetivo desse trabalho foi avaliar a atratividade das flores de pepino Japonês de três cultivares e a importância das abelhas Africanizadas (Apis mellifera), as abelhas brasileiras sem ferrão, Jataí (Tetragonisca angustula) e Iraí (Nannotrigona testaceicornis), na produção de frutos . Foram analisados vários parâmetros como a frequência de visitas de abelhas às flores, o tempo de visita utilizado para a coleta de néctar e a taxa de frutificação, considerando-se o peso, o comprimento e diâmetro dos pepinos obtidos. Foram utilizadas três casas de vegetação em Ribeirão Preto, SP, para o cultivo de três cultivares de pepino (Hokushin, Yoshinari e Soudai). Verificou-se que as flores femininas são mais atrativas que as masculinas e que as abelhas Jataí não visitaram as flores. As abelhas Africanizadas e Iraí coletaram apenas néctar, com pico de visitação entre 10h e 12h. Visita às flores femininas tiveram uma maior duração do que as visitas às flores masculinas nas três cultivares. As abelhas Africanizadas tiveram suas colônias diminuídas devido à perda de abelhas enquanto na casa de vegetação; as abelhas nativas não sofreram perdas. Com a retirada das abelhas, a frutific

Crops have different levels of dependence on pollinators; this holds true even for cultivars of the same species, as in the case of cucumber (Cucumis sativus). The aim of this research was to assess the attractiveness of flowers of three Japanese parthenocarpic cucumber cultivars and evaluate the importance of Africanized bees (Apis mellifera), and the Brazilian native stingless bees, Jataí (Tetragonisca angustula) and Iraí (Nannotrigona testaceicornis) on fruit production. Several parameters, including frequency of bee visits to flowers as well as duration of nectar collection and fruit set were examined; additionally, fruit weight, length and diameter were evaluated. Three greenhouses located in Ribeirão Preto, SP, were used for planting three cucumber cultivars (Hokushin, Yoshinari and Soudai). The female flowers were more attractive than male flowers; however, Jataí bees were not observed visiting the flowers. The Africanized and the Iraí bees collected only nectar, with a visitation peak between 10 and 12h. Visits to female flowers had a longer duration than visits to male flower visits in all three cultivars. Africanized bee colonies declined due to loss of bees while in the greenhouse; the native stingless bee colonies did not suffer these losses. When bees were excluded, fruit set was 78%; however, when bees had access to the flowers, fruit set was significantly (19.2%)

RESUMO

O objetivo deste trabalho foi avaliar se a suplementação da dieta do bicho-da-seda com extrato hidrossolúvel de soja (EHS) interfere na produção de casulos e no consumo de folhas de amoreira (Morus alba L.) de diferentes cultivares pelas lagartas. O delineamento experimental utilizado foi o inteiramente casualizado em esquema fatorial 4x5, com quatro cultivares de amoreira ('IZ64', 'IZ56/4', 'FM86' e 'FMSM') e cinco dietas (folhas não tratadas, folhas umedecidas com água, folhas enriquecidas com EHS, em três níveis: suplementação da dieta com 5, 10 e 20% de PB). O EHS foi aspergido sobre as folhas, tendo a água como agente dispersante. O consumo foi verificado pela diferença entre a quantidade de folhas fornecidas e a quantidade não consumida pelas lagartas. A ingestão de alimento apresentou-se de forma quadrática, diminuindo à medida que o EHS foi adicionado à dieta. Houve interação dos fatores cultivar e dieta. O fornecimento de folhas de amoreira com acréscimo proteico de 10% por meio do EHS melhorou a qualidade dos casulos do bicho-da-seda com a utilização das cultivares 'IZ56/4' e 'FMSM'. A pulverização de EHS nas folhas da cultivar 'IZ64' prejudicou a produção de casulos. Lagartas do bicho-da-seda, alimentadas com folhas de amoreira sem suplementação, produziram cascas séricas mais pesadas com folhas das cultivares 'IZ64' e 'FMSM'. A aspersão de água nas folhas incrementou o peso de cascas séricas produzidas a partir da cultivar 'FM86'. A suplementação da dieta com EHS diminui o consumo da lagarta do bicho-da-seda. A aplicação de EHS influencia a produção de casulos em função da cultivar utilizada.

The aim of this research was to assess if the supplementation of the silkworm diet with soybean water soluble extract (WSE) interferes on the consumption of mulberry leaves (Morus alba L.) by the caterpillars and on cocoon production. The experimental design was completely randomized in factorial arrangement 4x5, with four mulberry varieties ('IZ64', 'IZ56/4', and 'FMSM' 'FM86') and five diets (untreated control leaves, leaves moistened with water and leaves enriched with WSE, in three levels). The WSE was sprayed on the leaves with water as dispersing agent. The consumption was measured by the difference between the quantity of food provided and the amount that was not consumed by the larvae. The consumption was presented quadratic form, which decreased as the WSE was added on diet. There was interaction between cultivar and diets. Silkworm fed diets containing leaves of mulberry with addition of 10% of crude protein through WSE improved the quality of cocoons with utilization of 'IZ56/4' and 'FMSM' cultivars. The sprayed of WSE on leaves of 'IZ64' cultivar decreased production of cocoons. Silkworm fed with leaves without supplementation produced heavier cocoons shells of the 'IZ64' and 'FMSM' cultivars. Water sprayed on leaves provided higher weight of cocoons shells from 'FM86' cultivar. The WSE supplementation in diets decreases consumption of silkworm. The WSE sprayed influences cocoon production depending on the cultivar.

RESUMO

The aim of this research was to assess if the supplementation of the silkworm diet with soybean water soluble extract (WSE) interferes on the consumption of mulberry leaves (Morus alba L.) by the caterpillars and on cocoon production. The experimental design was completely randomized in factorial arrangement 4x5, with four mulberry varieties ('IZ64', 'IZ56/4', and 'FMSM' 'FM86') and five diets (untreated control leaves, leaves moistened with water and leaves enriched with WSE, in three levels). The WSE was sprayed on the leaves with water as dispersing agent. The consumption was measured by the difference between the quantity of food provided and the amount that was not consumed by the larvae. The consumption was presented quadratic form, which decreased as the WSE was added on diet. There was interaction between cultivar and diets. Silkworm fed diets containing leaves of mulberry with addition of 10% of crude protein through WSE improved the quality of cocoons with utilization of 'IZ56/4' and 'FMSM' cultivars. The sprayed of WSE on leaves of 'IZ64' cultivar decreased production of cocoons. Silkworm fed with leaves without supplementation produced heavier cocoons shells of the 'IZ64' and 'FMSM' cultivars. Water sprayed on leaves provided higher weight of cocoons shells from 'FM86' cultivar. The WSE supplementation in diets decreases consumption of silkworm. The WSE sprayed influences cocoon production depending on the cultivar.

O objetivo deste trabalho foi avaliar se a suplementação da dieta do bicho-da-seda com extrato hidrossolúvel de soja (EHS) interfere na produção de casulos e no consumo de folhas de amoreira (Morus alba L.) de diferentes cultivares pelas lagartas. O delineamento experimental utilizado foi o inteiramente casualizado em esquema fatorial 4x5, com quatro cultivares de amoreira ('IZ64', 'IZ56/4', 'FM86' e 'FMSM') e cinco dietas (folhas não tratadas, folhas umedecidas com água, folhas enriquecidas com EHS, em três níveis: suplementação da dieta com 5, 10 e 20% de PB). O EHS foi aspergido sobre as folhas, tendo a água como agente dispersante. O consumo foi verificado pela diferença entre a quantidade de folhas fornecidas e a quantidade não consumida pelas lagartas. A ingestão de alimento apresentou-se de forma quadrática, diminuindo à medida que o EHS foi adicionado à dieta. Houve interação dos fatores cultivar e dieta. O fornecimento de folhas de amoreira com acréscimo proteico de 10% por meio do EHS melhorou a qualidade dos casulos do bicho-da-seda com a utilização das cultivares 'IZ56/4' e 'FMSM'. A pulverização de EHS nas folhas da cultivar 'IZ64' prejudicou a produção de casulos. Lagartas do bicho-da-seda, alimentadas com folhas de amoreira sem suplementação, produziram cascas séricas mais pesadas com folhas das cultivares 'IZ64' e 'FMSM'. A aspersão de água nas folhas incrementou o peso de cascas séricas produzidas a partir da cultivar 'FM86'. A suplementação da dieta com EHS diminui o consumo da lagarta do bicho-da-seda. A aplicação de EHS influencia a produção de casulos em função da cultivar utilizada.