Modification of the head proteome of nurse honeybees (Apis mellifera) exposed to field-relevant doses of pesticides

Abstract

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.Pollination is an indispensable service provided mainly by wild insects and farmed honeybees (Apis mellifera, Linnaeus, 1758) that supports biodiversity, agriculture, and food security 1,2 . There is growing concern over the reported global reduction in these insects, which compromises this ecological service 2-8 .The maintenance of honeybee colonies is dependent upon specialised tasks performed by individuals of different roles; thus, stress-related dysfunction of specialised workers can affect entire colonies 9,10 . Pesticides, phytochemicals, pathogens, and parasites are among the main stressors for honeybees, and exposure can lead to dysfunctions that change the behaviour, anatomy, and/or physiology of these insects 10 . Previous reviews have indicated that pesticide exposure negatively affects the maintenance of wild and commercial honeybee populations 5,11,12 . Exposure of bees to field-relevant doses of pesticides that are frequently found in plants visited by these insects compromise essential functions, such as cognition, foraging, navigation, homing, and memory [13][14][15] . Exposure also causes physiologic changes in individual bees that compromises colony maintenance 9,15-18 .Nutrition is a key factor in colony maintenance 19 and caste differentiation of honeybees, and is essential for the full development and activity of mandibular and hypopharyngeal (or brood-food) glands in the head of 6-day-old worker bees 20-22 . These glands are responsible for the production of royal jelly (RJ), a secretion used to nourish all bee larvae until 3 days old, after which only the queen larvae are fed with RJ throughout larval and a...

Transcriptome responses to heat and cold stress in prepupae of Trichogramma chilonis

“…These genes are considered homologous to small hsps in D. melanogaster (Chang & Geib, 2018;Kyriakis et al, 1994). They were also found in Aedes aegypti (Runtuwene et al, 2020) and A. mellifera (Zaluski et al, 2020). In this study, we found 8 different variants in T2 versus T3 and T2 versus T1 (Table 4).…”

Beyond brood: the potential impacts of insect growth disruptors on the long-term health and performance of honey bee colonies

“…Residues of agrochemicals detected in royal jelly are typically much lower than levels in worker diet (Johnson and Percel 2013;DeGrandi-Hoffman et al 2015;Böhme et al 2018), suggesting that nurse bees are capable of efficiently metabolizing agrochemicals in a manner that protects young larvae and queens from exposure to high levels of many agrochemicals. However, even pesticides that do not persist at detectable levels in diet may pose risks to developing brood and reproductive castes through persistence in wax (Wu et al 2011) or by altering the physiology and immune function of their worker caretakers (DeGrandi-Hoffman et al 2015;Zaluski et al 2020). As reviewed here, field-and semi-field-level experiments have demonstrated that feeding colonies IGDs can result in brood loss, suggesting that they are not always adequately protected from IGD exposure by the "shared stomach" at the doses studied.…”

Bactérias fixadoras de nitrogênio no desenvolvimento de plantas Brachiaria brizantha, cultivar xaraes

“…O volume normalizado (%V) de cada spot proteico obtido nos géis do grupo controle foi utilizado para determinar diferenças significativas entre spots proteicos dos grupos expostos aos agrotóxicos por meio de análise de variância (ANOVA); o nível de significância adotado foi de p < 0,05. Posteriormente, foi realizada identificação de proteínas em spots que apresentaram redução de expressão por ESI-MS/MS (Electrospray Ionisation Tandem Mass Spectrometry) Zaluski et al, 2020).…”

“…As abelhas melíferas apresentam grande capacidade de forrageamento, o que torna esses insetos mais susceptíveis a coleta de recursos alimentares contaminados com agrotóxicos. A detecção de agrotóxicos sistêmicos em colônias de A. mellifera tem se tornado cada vez mais comum (Colwell et al, 2017;Zaluski et al, 2020) gerando impactos negativos para a manutenção das colônias. Destaca-se que para a secreção de geleia real, as abelhas nutrizes consomem grande quantidade de pólen, se tornando altamente susceptíveis a exposição de agrotóxicos presentes nesse recurso (Rortais et al, 2005;Colwell et al, 2017).…”