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TG present in honey bee brain and association with self-grooming behavior following exposure to sublethal doses of clothianidin. (A) RDA map showing the relationship between brain TG lipids and intensity in self-grooming behavior (intense, light, and no grooming) following exposure to sublethal doses of clothianidin (0, 9x10 -4 , 4.2x10 -3 , and 1x10 -2 ng/ul). (B) Pearson correlation showing the relationship between altered brain TG and changes in the intensity of self-grooming behavior following exposure to sublethal doses of clothianidin. Values in bold show significant correlations (p < 0.05). (C) Mean percentage of TG content (%nmol ± S.E.) in brains of bees exposed to sublethal doses of clothianidin (0, 9x10 -4 , 4.2x10 -3 , and 1x10 -2 ng/ul). Different letters above the bars indicate significant differences based on a one-way ANOVA and Fisher LSD tests (p < 0.05), showing the alterations in TG species.
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Introduction
Honey bees (Apis mellifera) play key roles in food production performing complex behaviors, like self-grooming to remove parasites. However, the lipids of their central nervous system have not been examined, even though they likely play a crucial role in the performance of cognitive process to perform intricate behaviors. Lipidomics ha...
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... for triglycerides (TGs) showed that the highest sublethal dose of clothianidin (1x10 -2 ng/ll) was associated with light self-grooming behavior, the low and medium doses of clothianidin (9x10 -4 and 4.2x10 -3 ng/ll) were associated with no grooming. The control (C or 0 ng/ll) and intense self-grooming behavior were located in different quadrants (Fig. 5A) of the RDA biplot and the segregation of the treatments accounted for 65.48% of the total variability in the data. A positive correlation between intense self-grooming behavior and TG 6:0/11/2/18:1, TG 4:0/18:1/18:1, TG 4:0/18:0/18:1 was found (p < 0.05; Fig. 5B). Conversely, a negative correlation between TG 6:0/11:2/18:1, TG ...
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... or 0 ng/ll) and intense self-grooming behavior were located in different quadrants (Fig. 5A) of the RDA biplot and the segregation of the treatments accounted for 65.48% of the total variability in the data. A positive correlation between intense self-grooming behavior and TG 6:0/11/2/18:1, TG 4:0/18:1/18:1, TG 4:0/18:0/18:1 was found (p < 0.05; Fig. 5B). Conversely, a negative correlation between TG 6:0/11:2/18:1, TG 6:0/8:0/11:3, TG 12:1e/12:3/12:3 and no self-grooming was noted (p < 0.05). There were no TG species significantly correlated with light self-grooming behavior. Following one-way ANOVA, we observed a significant decrease in the percentage of nine brain TG species in bees ...
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... ANOVA, we observed a significant decrease in the percentage of nine brain TG species in bees treated with sublethal doses of clothianidin compared to the control. These species include TG 18:1/18:1/18:1, TG 16:1/18:1/18:1 and TG 4:0/18:1/18:1 (F (3,11) = 9.026, p = 0.006; F (3,11) = 5.18, p = 0.028; F (3,11) = 12.47, p = 0.002, respectively) (Fig. ...
Citations
... Neonicotinoids are considered one of the most harmful groups of pesticides to pollinators (Nocelli et al., 2012), being banned in some European Union countries due to their high toxicity to bees (Blacquière et al., 2012;Decourtye et al., 2003Decourtye et al., , 2004Faucon et al., 2005;Hayasaka et al., 2012). They affect the nervous system of insects, impairing their metabolism, reproduction, foraging behaviours, memory and learning (Blacquière et al., 2012;Decourtye et al., 2004;Morfin et al., 2022;Muth et al., 2019). Neonicotinoids can compromise the bee's ability to detect flowers in crops and often their return to hives (Blacquière et al., 2012). ...
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Pesticide use affects biodiversity and ecosystem service provision. Yet, such effects may vary between pesticides, dosage, application timing and pollinator assemblage in the study area. Understanding such diversity of effects is essential to enable integrated pest management practices that minimize negative impacts on pollinators. Here, we use a controlled experiment to compare different strategies of pesticide application in tomato crops: no application, low‐intensity applications (every 7 days) and high‐intensity application (every 3–4 days) with the last being the usual practice used by farmers in the study region. We focus on imidacloprid that is a neonicotinoid insecticide commonly used in Brazil. We show the negative effects of imidacloprid on the pollinator visitation rate of tomato flowers varied between flower visitor species. While the bee Paratrigona lineata was negatively affected by the imidacloprid application, no effects were detected when analysing all other bees as a group, indicating a null net effect. Although some studies have shown this insecticide is extremely harmful to bees' health, others showed that some bees do not avoid it, which may explain our results. However, the visitation rate recovery for P. lineata was only detected in the less than the more intensive treatment after imidacloprid applications ceased. The fact that no differences in fruit production were detected between treatments (including control blocks) could result from a null net effect of the negative effects on pollinators and positive effects on pest control. Further studies would be needed to disentangle the two effects.
... We used nest bees to assess self-grooming behavior as they have been reliably assayed for this behavior in the past (26, 28). The classification system for grooming bees was based on previous studies which identified a higher proportion of intense groomers from colonies of presumably resistant genotypes to V. destructor parasitism (26, 28), and differences in gene expression and lipidome profile between bees grooming lightly and intensively (27,29). Each individual worker bee was placed inside a Petri dish (100 mm x 15 mm; Fisher Scientific, Mississauga, ON, Canada) covered with a perforated lid, and was left there for 2 min to become used to the environment. ...
... The brains of 50 randomly selected worker bees from each category (HVG-intense, HVG-light, LVG-intense, LVG-light) were pooled to extract RNA. There were three biological repetitions (three colonies of each genotype) and two technical replicates totaling 24 RNA extractions of pooled brains and 1,200 dissections (each of the 24 RNA samples consisted of the pooled RNA of 50 brains; performed as per Morfin et al. (29) (Figure 1). Total RNA was extracted using TRIzol ™ (Invitrogen, California, USA) following the manufacturer's instructions. ...
Social organisms, including honey bees (Apis mellifera L.), have defense mechanisms to control the multiplication and transmission of parasites and pathogens within their colonies. Self-grooming, a mechanism of behavioral immunity, seems to contribute to restrain the population growth of the ectoparasitic mite Varroa destructor in honey bee colonies. Because V. destructor is the most damaging parasite of honey bees, breeding them for resistance against the mite is a high priority of the beekeeping industry. A bidirectional breeding program to select honey bee colonies with low and high V. destructor population growth (LVG and HVG, respectively) was conducted. Having high and low lines of bees allowed the study of genetic mechanisms underlying self-grooming behavior between the extreme genotypes. Worker bees were classified into two categories: ‘light groomers’ and ‘intense groomers’. The brains of bees from the different categories (LVG-intense, LVG-light, HVG-intense, and HVG-light) were used for gene expression and viral quantification analyses. Differentially expressed genes (DEGs) associated with the LVG and HVG lines were identified. Four odorant-binding proteins and a gustatory receptor were identified as differentially expressed genes. A functional enrichment analysis showed 19 enriched pathways from a list of 219 down-regulated DEGs in HVG bees, including the Kyoto Encyclopedia of Genes and Genomes (KEGG) term of oxidative phosphorylation. Additionally, bees from the LVG line showed lower levels of Apis rhabdovirus 1 and 2, Varroa destructor virus -1 (VDV-1/DWV-B), and Deformed wing virus-A (DWV-A) compared to bees of the HVG line. The difference in expression of odorant-binding protein genes and a gustatory receptor between bee lines suggests a possible link between them and the perception of irritants to trigger rapid self-grooming instances that require the activation of energy metabolic pathways. These results provide new insights on the molecular mechanisms involved in honey bee grooming behavior. Differences in viral levels in the brains of LVG and HVG bees showed the importance of investigating the pathogenicity and potential impacts of neurotropic viruses on behavioral immunity. The results of this study advance the understanding of a trait used for selective breeding, self-grooming, and the potential of using genomic assisted selection to improve breeding programs.
... The fatty acyl chains of GL classes, as well as the 5 dominant GP classes, including PE, PS, PC, PI, and CL, were used for the unsaturation analysis. The above GP classes are known to account for 99% of the total brain GPs of honeybees, thus denoted as "dominant" [14]. The ratio of the abundance of the saturated fatty acid (SFA), monounsaturated fatty acids (MUFA), as well as polyunsaturated fatty acids (PUFA) to the abundance of total fatty acids in GPs and GLs, were calculated as (with "*" representing "SFA", "MUFA" or "PUFA"): ...
... Many studies in mammals revealed that brain lipid compositions correlated with memory functions and cognitive development [43][44][45]. In honeybees, it has been found that certain lipid classes or species were enriched in the brain more than in other organs [14,46]. ...
... In the present study, a total of 81 candidates featured lipids were obtained based on the OPLS-DA (VIP > 1) and t-test (p-adj < 0.05) (Table S5). In an earlier study, Morfin et al. found a positive correlation between CL(18:3/18:1/14:0/22:6), TG(6:0/11:2/18:1), and LPE 18:0e and the behavior of intense self-grooming [14]. Thus, we focus on the lipids that are stably and positively linked with specialized tasks. ...
The division of labor is a dominant characteristic of honeybees and is accompanied by behavioral specialization and cognitive enhancement. As the central nervous system to control the labor-specific behaviors of honeybee, the brain is richest in lipid in terms of both diversity and abundance. In this study, an in-depth LC-MS/MS-based lipidomic method was applied to systematically characterize the brain lipid compositions of worker bees with three labor stages: newly emerged bee (NEB), nurse bee (NB), and forager bee (FB). A total number of 337 lipid species that assigned to 20 lipid classes were analyzed. The association of the brain lipidomes with the division of labors was suggested by the results of both the unsupervised and supervised multivariate pattern recognition analysis. More than 68% of the identified lipid species were found to be significantly changed in at least one comparison between NEB, NB, and FB. A total of 81 lipid species were identified as the potential labor-featured molecules with VIP > 1 and p-adj < 0.05. The labor-featured lipids of FA(18:2), FA(18:3), FA(26:0), PC(18:0_18:3), PS(18:1_18:1), SM(d38:1), CoQ10, and CoQ9, as well as their interactions with 12 behavior-related genes, including AmEST-6, AmFABP, AmE75, AmDGAT2, AmLSD1, AmNPC1, AmABCA1, AmNMDAR1, AmHTT, AmNOS, etc., were revealed by the further IPA analysis. These findings demonstrate for the first time that the brain lipidomes of worker bees are associated with the stable differences in their labors, which help understand the function of brain lipids on the labor-dependent behaviors of honeybees.
... Besides the acute toxicity of neonicotinoids, their sublethal effects might also play a role in the decline of bees [reviewed in: (16)]. Sublethal effects by neonicotinoids include adverse effects on the immune system (17), impaired orientation and memory formation (18), reduced colony size and negative effects on larval development (19,20), altered homing flight activity (21,22), negative effects on selfgrooming (23) and changes in gene expression (24)(25)(26)(27)(28). Negative effects of neonicotinoids in terms of prolongation of flight times and flight activities of foragers are known (22,29). The radiofrequency identification (RFID) technology is a common method to analyze negative effects of neonicotinoids on homing flight performance of honey bees (30)(31)(32)(33)(34). ...
Neonicotinoids as thiamethoxam and thiacloprid are suspected to be implicated in the decline of honey bee populations. As nicotinic acetylcholine receptor agonists, they disturb acetylcholine receptor signaling in insects, leading to neurotoxicity and are therefore globally used as insecticides. Several behavioral studies have shown links between neonicotinoid exposure of bees and adverse effects on foraging activity, homing flight performance and reproduction, but the molecular aspects underlying these effects are not well-understood. In the last years, several studies through us and others showed the effects of exposure to neonicotinoids on gene expression in the brain of honey bees. Transcripts of acetylcholine receptors, hormonal regulation, stress markers, detoxification enzymes, immune system related genes and transcripts of the energy metabolism were altered after neonicotinoid exposure. To elucidate the link between homing flight performance and shifts in gene expression in the brain of honey bees after neonicotinoid exposure, we combined homing flight activity experiments applying RFID technology and gene expression analysis. We analyzed the expression of endocrine factors, stress genes, detoxification enzymes and genes linked to energy metabolism in forager bees after homing flight experiments. Three different experiments (experiment I: pilot study; experiment II: “worst-case” study and experiment III: laboratory study) were performed. In a pilot study, we wanted to investigate if we could see differences in gene expression between controls and exposed bees (experiment I). This first study was followed by a so-called “worst-case” study (experiment II), where we investigated mainly differences in the expression of transcripts linked to energy metabolism between fast and slow returning foragers. We found a correlation between homing flight duration and the expression of cytochrome c oxidase subunit 5A, one transcript linked to oxidative phosphorylation. In the third experiment (experiment III), foragers were exposed in the laboratory to 1 ng/bee thiamethoxam and 8 ng/bee thiacloprid followed by gene expression analysis without a subsequent flight experiment. We could partially confirm the induction of cytochrome c oxidase subunit 5A, which we detected in experiment II. In addition, we analyzed the effect of the feeding mode (group feeding vs. single bee feeding) on data scattering and demonstrated that single bee feeding is superior to group feeding as it significantly reduces variability in gene expression. Based on the data, we thus hypothesize that the disruption of energy metabolism may be one reason for a prolongation of homing flight duration in neonicotinoid treated bees.
Lipidomics is a rapidly expanding field of study that provides a comprehensive approach to the analysis of lipids in meat and fish food products. Lipidomics has become an important tool for evaluating the functional quality of animal and fish products as well as their potential health benefits. This review article provides an overview of the current state of the art in lipidomics for food assessment and its application in improving the quality and nutritional value of animal and fish food. This review covers a wide range of topics, including an examination of the lipid content and composition of animal and fish products, the effect of processing and storage conditions on lipid quality, and the potential health benefits of consuming lipid-rich animal and fish products. It also covers the important roles that lipids play in animal and fish products, such as their impact on flavor, texture, and stability. The article concludes with a discussion of the future directions of lipidomics research and the potential applications of this technology in the food industry. This review article provides valuable information for researchers, food scientists, and industry professionals who are interested in exploring the functional quality of animal and fish products through the lens of lipidomics.
Transient receptor potential (TRP) and PIEZO channels are known receptors for physical stimuli such as temperature and mechanical touch in sensory nerves. Since these receptors are localized in the plasma membrane, the regulation of sensory receptor activity by plasma membrane lipids has recently attracted attention. In this study, we focused on ether phospholipids (ePLs), which are abundant in neurons, and analyzed their role in somatosensation using Drosophila as a model. Reduced warmth avoidance was observed with ePL synthesizing gene knockout or knockdown in warmth-sensitive TRPA1-expressing neurons. The temperature threshold for Drosophila TRPA1 channels significantly decreased in presence of ePLs. In addition, we found that ePLs modulate the mechanosensory behavior and activation properties of the mechanosensitive channel PIEZO. Finally, we revealed that ePLs affect physicochemical properties of the plasma membrane, such as membrane tension and lipid order, in culture cells. Our study identified ePLs as crucial regulators of multiple somatosensation modalities in Drosophila. Effects due to alteration of cellular membrane properties and activity modulation of sensory receptors.
Lipids are main energy source for insects reproduction, which are becoming emerging target for pest management. Azadirachtin (AZA) is a multi-targeted and promising botanical insecticide, but its reproduction toxicity mechanism related to lipids metabolism is poorly understood. Here, we applied lipidomic and transcriptomic to provide a comprehensive resource for describing the effect of AZA on lipids remodeling in ovary of Spodoptera litura. The results showed that AZA exposure obviously altered the contents of 130 lipids subclasses (76 upregulated and 54 downregulated). In detail, AZA exposure changed the length and saturation degrees of fatty acyl chain of most glycerolipid, phospholipid and sphingolipid as well as the expression of genes related to biosynthesis of unsaturated fatty acids and fatty acids elongation. Besides, following the abnormal lipids metabolism, western blot analysis suggested that AZA induce insulin resistance-like phenotypes by inhibiting insulin receptor substrates (IRS) /PI3K/AKT pathway, which might be responsible for the ovary abnormalities of S. litura. Collectively, our study provided insights into the lipids metabolism event in S. litura underlying AZA exposure, these key metabolites and genes identified in this study would also provide important reference for pest control in future.
Environmental transport and deposition of particulate matter (PM) associated with toxic chemicals has begun to receive attention as a source of risk to pollinators. For example, dust arising from manipulations of insecticide-treated seed has potential to exert toxic effects among non-target insects. Similarly, synthetic steroid growth promoters, antibiotics and multiple insecticides and parasiticides detected in fugitive beef cattle feedyard PM may also negatively impact pollinators since many of these chemicals have been detected on wildflowers and pollinators collected near beef cattle feedyards. Therefore, there is a need to assess risk to pollinators posed by deposition of agrochemical-laden PM, both in the field and the laboratory. Unfortunately, established laboratory methods for simulating PM exposure or toxicity associated with contaminated PM are few and highly situation-specific. Herein we describe development and use of a PM circulation system that can be employed to evaluate toxicity of agrochemical-contaminated PM in the laboratory under controlled conditions. Two model organisms (honeybees (Apis mellifera) and mason bees (Osmia lignaria)) were exposed to agrochemical-free PM in the circulator system, and post-exposure mortality was compared with controls. No significant differences in mortality between exposed and control bees were observed. Next, honeybees and mason bees were exposed to PM spiked with an insecticide known to exert toxic effects to pollinators (thiamethoxam). Bees experienced significantly higher mortality when exposed to thiamethoxam-laden PM at environmentally relevant concentrations as compared to bees exposed to agrochemical-free PM. These results confirm the validity of these methods for use in controlled laboratory PM toxicity tests and offer a source of positive and negative control groups for laboratory and field experiments examining exposure of pollinators to potentially toxic agrochemical-laden PM. This method facilitates generation of more realistic toxicity data than standard contact toxicity tests when pollinator exposure scenarios involve particulate-based agrochemicals or other toxic chemicals.
Deposition of particulate matter (PM) from a variety of sources onto pollinator habitat is a largely unexplored source of risk to pollinators. Synthetic steroid growth promoters, antibiotics, and multiple pesticides have been detected in fugitive beef cattle feedyard PM. Subsequently, many of these chemicals determined to be associated with PM have been detected on flowers near beef cattle feedyards, as well as bees visiting those flowers. Therefore, there is a need to assess risk to pollinators posed by deposition of PM and agrochemical-laden PM, both in the field and the laboratory. Unfortunately, there are no established laboratory methods for simulating PM exposure or toxicity associated with contaminated PM. Herein we describe development and utilization of a PM circulation system that can be employed in the laboratory under controlled conditions. Two model organisms (honeybees ( Apis mellifera ) and mason bees ( Osmia lignaria )) were exposed to agrochemical-free PM in the circulator system, and post-exposure mortality was compared with controls. No significant differences in mortality between exposed and control bees were observed. These results confirm the validity of these methods for use in laboratory-controlled PM exposure experiments, and offer a source of positive and negative control groups for laboratory and field experiments examining exposure of pollinators to potentially toxic chemical-laden PM.
