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Szymański S, Baracchi D, Dingle L, Bowman AS, Manfredini F. Learning performance and GABAergic pathway link to deformed wing virus in the mushroom bodies of naturally infected honey bees. J Exp Biol 2024; 227:jeb246766. [PMID: 38894668 DOI: 10.1242/jeb.246766] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2023] [Accepted: 06/07/2024] [Indexed: 06/21/2024]
Abstract
Viral infections can be detrimental to the foraging ability of the western honey bee, Apis mellifera. The deformed wing virus (DWV) is the most common honey bee virus and has been proposed as a possible cause of learning and memory impairment. However, evidence for this phenomenon so far has come from artificially infected bees, while less is known about the implications of natural infections with the virus. Using the proboscis extension reflex (PER), we uncovered no significant association between a simple associative learning task and natural DWV load. However, when assessed through a reversal associative learning assay, bees with higher DWV load performed better in the reversal learning phase. DWV is able to replicate in the honey bee mushroom bodies, where the GABAergic signalling pathway has an antagonistic effect on associative learning but is crucial for reversal learning. Hence, we assessed the pattern of expression of several GABA-related genes in bees with different learning responses. Intriguingly, mushroom body expression of selected genes was positively correlated with DWV load, but only for bees with good reversal learning performance. We hypothesise that DWV might improve olfactory learning performance by enhancing the GABAergic inhibition of responses to unrewarded stimuli, which is consistent with the behavioural patterns that we observed. However, at higher disease burdens, which might be induced by an artificial infection or by a severe, natural Varroa infestation, this DWV-associated increase in GABA signalling could impair associative learning as previously reported by other studies.
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Affiliation(s)
- Szymon Szymański
- School of Biological Sciences, University of Aberdeen, Zoology Building, Tillydrone Avenue, Aberdeen, AB24 2TZ, UK
| | - David Baracchi
- Department of Biology, University of Florence, Via Madonna del Piano 6, 50019 Sesto Fiorentino, Italy
| | - Lauren Dingle
- School of Biological Sciences, University of Aberdeen, Zoology Building, Tillydrone Avenue, Aberdeen, AB24 2TZ, UK
| | - Alan S Bowman
- School of Biological Sciences, University of Aberdeen, Zoology Building, Tillydrone Avenue, Aberdeen, AB24 2TZ, UK
| | - Fabio Manfredini
- School of Biological Sciences, University of Aberdeen, Zoology Building, Tillydrone Avenue, Aberdeen, AB24 2TZ, UK
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Diego S, Nolberto A, Pablo AJ, Ricardo C, Nelson Z, Marisol V. Nursing Honeybee Behavior and Sensorial-Related Genes Are Altered by Deformed Wing Virus Variant A. INSECTS 2024; 15:80. [PMID: 38392500 PMCID: PMC10889485 DOI: 10.3390/insects15020080] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2023] [Revised: 01/08/2024] [Accepted: 01/16/2024] [Indexed: 02/24/2024]
Abstract
Insect behavior is coordinated mainly by smell through the diverse odor-binding proteins (OBP) that allow them to identify and recognize their environment. Sensory information collected through smell is then analyzed and interpreted in the brain, allowing for correct insect functioning. The behavior of honeybees (Apis mellifera L.) can be affected by different pathogens, such as deformed wing virus (DWV). In particular, the DWV variant A (DWV-A) is capable of altering olfactory sensitivity and reducing the gene expression of different OBPs, including those associated with nursing behavior. The DWV is also capable of replicating itself in the sensory lobes of the brain, further compromising the processing of sensory information. This study evaluated the behavioral response of nurse honeybees exposed to a pheromone compound and the alterations in the gene expression of the pre- and post-synaptic neuronal genes neuroxins-1 and neurogilin-1 in the bee heads and OBP proteins in the antennae of nurse bees inoculated with DWV-A. The behavioral response of nurse bees exposed to the larval pheromone compound benzyl alcohol was analyzed using a Y-tube olfactometer. The viral load, the gene expression of OBP5 and OBP11 in antennae, and neuroxins-1 and neurogilin-1 in the bee heads were analyzed via qPCR. High viral loads significantly reduced the ability of 10- and 15-day-old nurse honeybees to choose the correct pheromone compound. Also, the gene expression of OBP5, OBP11, neuroxin-1, and neurogilin-1 in nurse honeybees decreased when they were highly infected with DWV-A. These results suggest that a DWV-A infection can disturb information processing and cause nursing honeybees to reduce their activity inside the hive, altering internal cohesion.
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Affiliation(s)
- Silva Diego
- Laboratorios de Virología y Patologías en Abejas, Facultad de Agronomía, Universidad de Concepción, Av. Vicente Méndez 595, Chillán 3780000, Chile
| | - Arismendi Nolberto
- Centro de Investigación Austral Biotech, Facultad de Ciencias, Universidad Santo Tomás, Av. Picarte 1130-1160, Valdivia 5090000, Chile
| | - Alveal Juan Pablo
- Laboratorio de Ecología Química, Instituto de Investigaciones Agropecuarias, INIA Quilamapu, Av. Vicente Méndez 515, Chillán 3780000, Chile
| | - Ceballos Ricardo
- Laboratorio de Ecología Química, Instituto de Investigaciones Agropecuarias, INIA Quilamapu, Av. Vicente Méndez 515, Chillán 3780000, Chile
| | - Zapata Nelson
- Laboratorio de Fitoquímica, Facultad de Agronomía, Universidad de Concepción, Av. Vicente Méndez 595, Chillán 3780000, Chile
| | - Vargas Marisol
- Laboratorios de Virología y Patologías en Abejas, Facultad de Agronomía, Universidad de Concepción, Av. Vicente Méndez 595, Chillán 3780000, Chile
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Cabirol A, Moriano-Gutierrez S, Engel P. Neuroactive metabolites modulated by the gut microbiota in honey bees. Mol Microbiol 2023. [PMID: 37718573 DOI: 10.1111/mmi.15167] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Revised: 09/04/2023] [Accepted: 09/05/2023] [Indexed: 09/19/2023]
Abstract
Honey bees have emerged as a new model to study the gut-brain axis, as they exhibit complex social behaviors and cognitive abilities, while experiments with gnotobiotic bees have revealed that their gut microbiota alters both brain and behavioral phenotypes. Furthermore, while honey bee brain functions supporting a broad range of behaviors have been intensively studied for over 50 years, the gut microbiota of bees has been experimentally characterized only recently. Here, we combined six published datasets from metabolomic analyses to provide an overview of the neuroactive metabolites whose abundance in the gut, hemolymph and brain varies in presence of the gut microbiota. Such metabolites may either be produced by gut bacteria, released from the pollen grains during their decomposition by bacteria, or produced by other organs in response to different bacterial products. We describe the current state of knowledge regarding the impact of such metabolites on brain function and behavior and provide further hypotheses to explore in this emerging field of research.
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Affiliation(s)
- Amélie Cabirol
- Department of Fundamental Microbiology, University of Lausanne, Lausanne, Switzerland
| | | | - Philipp Engel
- Department of Fundamental Microbiology, University of Lausanne, Lausanne, Switzerland
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Al Naggar Y, Shafiey H, Paxton RJ. Transcriptomic Responses Underlying the High Virulence of Black Queen Cell Virus and Sacbrood Virus following a Change in Their Mode of Transmission in Honey Bees ( Apis mellifera). Viruses 2023; 15:1284. [PMID: 37376584 DOI: 10.3390/v15061284] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2023] [Revised: 05/22/2023] [Accepted: 05/28/2023] [Indexed: 06/29/2023] Open
Abstract
BACKGROUND Over the last two decades, honey bees (Apis mellifera) have suffered high rates of colony losses that have been attributed to a variety of factors, chief among which are viral pathogens, such as deformed wing virus (DWV), whose virulence has increased because of vector-based transmission by the invasive, ectoparasitic varroa mite (Varroa destructor). A shift in the experimental mode of transmission of the black queen cell virus (BQCV) and sacbrood virus (SBV) from fecal/food-oral (direct horizontal) to vector-mediated (indirect horizontal) transmission also results in high virulence and viral titers in pupal and adult honey bees. Agricultural pesticides represent another factor that acts independently or in interaction with pathogens, and they are also thought to cause colony loss. Understanding the molecular mechanisms underlying the higher virulence following a vector-based mode of transmission provides deeper insight into honey bee colony losses, as does determining whether or not host-pathogen interactions are modulated by exposure to pesticides. METHODS Through an experimental design with controlled laboratory, we investigated the effects of the modes of transmission of BQCV and SBV (feeding vs. vector-mediated via injection) alone or in combination with chronic exposure to sublethal and field-realistic concentrations of flupyradifurone (FPF), a novel agricultural insecticide, on honey bee survival and transcription responses by using high-throughput RNA sequencing (RNA-seq) analysis. RESULTS Co-exposure to viruses via feeding (VF) or injection (VI) and FPF insecticide had no statistically significant interactive effect on their survival compared to, respectively, VF or VI treatments alone. Transcriptomic analysis revealed a distinct difference in the gene expression profiles of bees inoculated with viruses via injection (VI) and exposed to FPF insecticide (VI+FPF). The number of differentially expressed genes (DEGs) at log2 (fold-change) > 2.0 in VI bees (136 genes) or/and VI+FPF insecticide (282 genes) was very high compared to that of VF bees (8 genes) or the VF+FPF insecticide treatment (15 genes). Of these DEGs, the expression in VI and VI+FPF bees of some immune-related genes, such as those for antimicrobial peptides, Ago2, and Dicer, was induced. In short, several genes encoding odorant binding proteins, chemosensory proteins, odor receptors, honey bee venom peptides, and vitellogenin were downregulated in VI and VI+FPF bees. CONCLUSIONS Given the importance of these suppressed genes in honey bees' innate immunity, eicosanoid biosynthesis, and olfactory associative function, their inhibition because of the change in the mode of infection with BQCV and SBV to vector-mediated transmission (injection into haemocoel) could explain the high virulence observed in these viruses when they were experimentally injected into hosts. These changes may help explain why other viruses, such as DWV, represent such a threat to colony survival when transmitted by varroa mites.
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Affiliation(s)
- Yahya Al Naggar
- 1 General Zoology, Institute for Biology, Martin Luther University Halle-Wittenberg, Hoher Weg 8, 06120 Halle (Saale), Germany
- Zoology Department, Faculty of Science, Tanta University, Tanta 31527, Egypt
- Department of Community Ecology, UFZ-Helmholtz Centre for Environmental Research, Theodor-Lieser-Str. 4, 06120 Halle (Saale), Germany
| | - Hassan Shafiey
- 1 General Zoology, Institute for Biology, Martin Luther University Halle-Wittenberg, Hoher Weg 8, 06120 Halle (Saale), Germany
| | - Robert J Paxton
- 1 General Zoology, Institute for Biology, Martin Luther University Halle-Wittenberg, Hoher Weg 8, 06120 Halle (Saale), Germany
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Lin YC, Lu YH, Tang CK, Yang EC, Wu YL. Honey bee foraging ability suppressed by imidacloprid can be ameliorated by adding adenosine. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2023:121920. [PMID: 37257810 DOI: 10.1016/j.envpol.2023.121920] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Revised: 05/15/2023] [Accepted: 05/27/2023] [Indexed: 06/02/2023]
Abstract
Honey bees are important pollinators in most ecosystem, but they are currently facing many threats, which have led to a reduction in their population. Previous studies have indicated that neonicotinoid pesticide can impair the memory and learning ability of honey bees, which can eventually lead to a decline in their foraging and homing abilities. In this study, we investigated the homing ability barrier from the perspective of energy supply. We believe that when worker bees experience stress, their energy supply may shift from pro-movement to pro-resistance; this will lead to inadequate energy provision to the flight muscles, causing a reduction in wingbeat frequency and impairing the flight ability of the worker bees. To test this, the worker bees were treated with imidacloprid, and wing beats between the treatment groups were compared. Their glucose, glycogen, trehalose, and ATP contents were also measured, and their genes for energy metabolism and resistance were analyzed. The addition of adenosine improved the ATP content and helped recover the wingbeat frequency of the worker bees. The preliminary results obtained showed that wingbeat frequency and glucose content in the worker bees treated with imidacloprid were significantly lower than those in the control group. This result is consistent with our hypothesis and demonstrates that energy supply imbalances can prevent worker bees from returning to their hives.
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Affiliation(s)
- Yu-Chun Lin
- Department of Entomology, National Taiwan University, Taipei, 106, Taiwan
| | - Yun-Heng Lu
- Department of Entomology, National Taiwan University, Taipei, 106, Taiwan
| | - Cheng-Kang Tang
- Plant Health Care Master Degree Program, Academy of Circular Economy, National Chung-Hsing University, Taichung, 504, Taiwan
| | - En-Cheng Yang
- Department of Entomology, National Taiwan University, Taipei, 106, Taiwan
| | - Yueh-Lung Wu
- Department of Entomology, National Taiwan University, Taipei, 106, Taiwan.
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Kuo Y, Lu YH, Lin YH, Lin YC, Wu YL. Elevated temperature affects energy metabolism and behavior of bumblebees. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2023; 155:103932. [PMID: 36921734 DOI: 10.1016/j.ibmb.2023.103932] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Revised: 03/09/2023] [Accepted: 03/11/2023] [Indexed: 05/10/2023]
Abstract
Bumblebees (Bombus eximius) are one of the most prominent pollinators in the agricultural industry because of their adaptation to temperate climates and pollination behavior (buzz pollination). Several studies have explained the need to increase conservation efforts for bumblebees due to climate change, but studies on the impact of climate change on pollination behavior of bumblebees have been limited. The present study investigated the effect of elevated temperatures on the survival and physiology of bumblebees. The behavioral changes in flight ability and pollen collection were also determined. We found that elevated temperature affects the survival rate and appetite of bumblebees. Gene expression analysis suggested that the energy metabolic pathway tends to involve anaerobic respiration during heat stress. The energy produced is mainly used to maintain essential physiological functions, such as expression of heat shock proteins and conversion of peroxides to harmless molecules. Energy distributed to flight muscles is reduced during heat stress, resulting in lower wing beating frequency. In addition, the flight path of bumblebees is shortened during heat stress, thereby further contributing to reduced pollen collection. These results demonstrate that elevated temperatures cause detrimental effects to bumblebees and can also potentially reduce crop production.
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Affiliation(s)
- Yun Kuo
- Department of Entomology, National Taiwan University, Taipei, 106, Taiwan
| | - Yun-Heng Lu
- Department of Entomology, National Taiwan University, Taipei, 106, Taiwan
| | - Yu-Hsien Lin
- Department of Plant Physiology, Swammerdam Institute for Life Sciences, University of Amsterdam, 1098 XH, Amsterdam, the Netherlands
| | - Yu-Chun Lin
- Department of Entomology, National Taiwan University, Taipei, 106, Taiwan
| | - Yueh-Lung Wu
- Department of Entomology, National Taiwan University, Taipei, 106, Taiwan.
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Morfin N, Harpur BA, De la Mora A, Guzman-Novoa E. Breeding honey bees ( Apis mellifera L.) for low and high Varroa destructor population growth: Gene expression of bees performing grooming behavior. FRONTIERS IN INSECT SCIENCE 2023; 3:951447. [PMID: 38469529 PMCID: PMC10926520 DOI: 10.3389/finsc.2023.951447] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Accepted: 02/03/2023] [Indexed: 03/13/2024]
Abstract
Introduction 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. Methods 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. Results 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. Discussion 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.
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Affiliation(s)
- Nuria Morfin
- British Columbia Technology Transfer Program, British Columbia Honey Producers Association, Victoria, BC, Canada
- Department of Biochemistry & Molecular Biology, The University of British Columbia, Vancouver, BC, Canada
| | - Brock A. Harpur
- Department of Entomology, Purdue University, West Lafayette, IN, United States
| | - Alvaro De la Mora
- School of Environmental Sciences, University of Guelph, Guelph, ON, Canada
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