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Dessart M, Aguiar JMRBV, Tabacchi E, Guillerme S, Giurfa M. Color-advertising strategies of invasive plants through the bee eye. FRONTIERS IN PLANT SCIENCE 2024; 15:1393204. [PMID: 38841283 PMCID: PMC11150686 DOI: 10.3389/fpls.2024.1393204] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/28/2024] [Accepted: 04/30/2024] [Indexed: 06/07/2024]
Abstract
Invasive plants represent a significant global challenge as they compete with native plants for limited resources such as space, nutrients and pollinators. Here, we focused on four invasive species that are widely spread in the French Pyrenees, Buddleja davidii, Reynoutria japonica, Spiraea japonica and Impatiens glandulifera, and analyzed their visual advertisement signals with respect to those displayed by their surrounding native species using a perceptual approach based on the neural mechanisms of bee vision given that bees are regular pollinators of these plants. We collected 543 spectral reflections from the 4 invasive species, and 66 native species and estimated achromatic and chromatic similarities to the bee eye. R. japonica, S. japonica and B. davidii were inconspicuous against the foliage background and could be hardly discriminated in terms of color from their surrounding native plants. These characteristics promote generalization, potentially attracting pollinators foraging on similar native species. Two morphs of I. glandulifera were both highly salient in chromatic and achromatic terms and different from their surrounding native species. This distinctive identity facilitates detection and learning in association with rich nectar. While visual signals are not the only sensory cue accounting for invasive-plant success, our study reveals new elements for understanding biological invasion processes from the perspective of pollinator perceptual processes.
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Affiliation(s)
- Martin Dessart
- Institut de Recherche sur la Biologie de l'Insecte, Centre National de la Recherche Scientifique (CNRS), University of Tours, Tours, France
| | | | - Eric Tabacchi
- Centre de Recherche sur la Biodiversité et l'Environnement (CRBE), UMR 53000, Centre National de la Recherche Scientifique (CNRS), Institut de Recherche pour le Développement (IRD), Institut National Polytechnique, Université Paul Sabatier, Toulouse, France
| | - Sylvie Guillerme
- Laboratoire Géographie de l’Environnement (GEODE), Centre National de la Recherche Scientifique (CNRS), University Toulouse Jean-Jaurès, Toulouse, France
| | - Martin Giurfa
- Institut Universitaire de France, Paris, France
- Neuroscience Paris-Seine - Institut de Biologie Paris-Seine, Centre National de la Recherche Scientifique (CNRS), Institut National de la Santé et de la Recherche Médicale (INSERM), Sorbonne University, Paris, France
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2
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Bouchebti S, Levin E. Gamma-aminobutyric acid (GABA) in flower nectar and its possible physiological and behavioral effects on insect pollinators. CURRENT OPINION IN INSECT SCIENCE 2024:101206. [PMID: 38777150 DOI: 10.1016/j.cois.2024.101206] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2024] [Revised: 05/07/2024] [Accepted: 05/13/2024] [Indexed: 05/25/2024]
Abstract
Floral nectar, a vital nutrition source for pollinators, contains diverse chemical compounds, including γ-Aminobutyric acid (GABA), a prevalent non-proteinogenic amino acid. While GABA's physiological role is known and well-studied, its ecological significance in plant-pollinator interactions remains unclear. Recent studies on GABA's effects on pollinators' preference, consumption, survival, physiology, and behavior show varying outcomes according to the species, indicating a complex relationship. GABA consumption impacts motor function and cognitive abilities, potentially influencing pollination efficiency. Future research addressing diverse concentrations, species, and behavioral aspects is crucial for comprehensively understanding GABA's ecological role in plant-pollinator interactions.
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Affiliation(s)
- Sofia Bouchebti
- School of Zoology, Faculty of Life Sciences, Tel Aviv University, 6997801, Tel Aviv, Israel
| | - Eran Levin
- School of Zoology, Faculty of Life Sciences, Tel Aviv University, 6997801, Tel Aviv, Israel.
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Waris MI, Lei Y, Qi G, Guan Z, Rashied A, Chen J, Lyu L. The temporal-spatial expression and functional analysis of three gustatory receptor genes in Solenopsis invicta using sweet and bitter compounds. INSECT SCIENCE 2024; 31:448-468. [PMID: 38010036 DOI: 10.1111/1744-7917.13301] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Revised: 10/07/2023] [Accepted: 10/16/2023] [Indexed: 11/29/2023]
Abstract
The insect gustatory system participates in identifying potential food sources and avoiding toxic compounds. During this process, gustatory receptors (GRs) recognize feeding stimulant and deterrent compounds. However, the GRs involved in recognizing stimulant and deterrent compounds in the red imported fire ant, Solenopsis invicta, remain unknown. Therefore, we conducted a study on the genes SinvGR1, SinvGR32b, and SinvGR28a to investigate the roles of GRs in detecting feeding stimulant and deterrent compounds. In this current study, we found that sucrose and fructose are feeding stimulants and the bitter compound quinine is a feeding deterrent. The fire ant workers showed significant behavior changes to avoid the bitter taste in feeding stimulant compounds. Reverse transcription quantitative real-time polymerase chain reaction results from developmental stages showed that the SinvGR1, SinvGR32b, and SinvGR28a genes were highly expressed in fire ant workers. Tissue-specific expression profiles indicated that SinvGR1, SinvGR32b, and SinvGR28a were specifically expressed in the antennae and foreleg tarsi of workers, whereas SinvGR32b gene transcripts were also highly accumulated in the male antennae. Furthermore, the silencing of SinvGR1 or SinvGR32b alone and the co-silencing of both genes disrupted worker stimulation and feeding on sucrose and fructose. The results also showed that SinvGR28a is required for avoiding quinine, as workers with knockdown of the SinvGR28a gene failed to avoid and fed on quinine. This study first identified stimulant and deterrent compounds of fire ant workers and then the GRs involved in the taste recognition of these compounds. This study could provide potential target gustatory genes for the control of the fire ant.
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Affiliation(s)
- Muhammad Irfan Waris
- Institute of Plant Protection, Guangdong Academy of Agricultural Sciences, Guangdong Provincial Key Laboratory of High Technology for Plant Protection, Guangzhou, China
| | - Yanyuan Lei
- Institute of Plant Protection, Guangdong Academy of Agricultural Sciences, Guangdong Provincial Key Laboratory of High Technology for Plant Protection, Guangzhou, China
| | - Guojun Qi
- Institute of Plant Protection, Guangdong Academy of Agricultural Sciences, Guangdong Provincial Key Laboratory of High Technology for Plant Protection, Guangzhou, China
| | - Ziying Guan
- Institute of Plant Protection, Guangdong Academy of Agricultural Sciences, Guangdong Provincial Key Laboratory of High Technology for Plant Protection, Guangzhou, China
| | - Abdul Rashied
- Institute of Plant Protection, Guangdong Academy of Agricultural Sciences, Guangdong Provincial Key Laboratory of High Technology for Plant Protection, Guangzhou, China
- Department of Entomology, College of Plant Protection, South China Agricultural University, Guangzhou, China
| | - Jie Chen
- Institute of Plant Protection, Guangdong Academy of Agricultural Sciences, Guangdong Provincial Key Laboratory of High Technology for Plant Protection, Guangzhou, China
| | - Lihua Lyu
- Institute of Plant Protection, Guangdong Academy of Agricultural Sciences, Guangdong Provincial Key Laboratory of High Technology for Plant Protection, Guangzhou, China
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Pel AV, Van Nest BN, Hathaway SR, Fahrbach SE. Impact of odorants on perception of sweetness by honey bees. PLoS One 2023; 18:e0290129. [PMID: 38150461 PMCID: PMC10752549 DOI: 10.1371/journal.pone.0290129] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Accepted: 11/28/2023] [Indexed: 12/29/2023] Open
Abstract
Organic volatiles produced by fruits can result in overestimation of sweetness by humans, but it is unknown if a comparable phenomenon occurs in other species. Honey bees collect nectar of varying sweetness at different flowering plants. Bees discriminate sugar concentration and generally prefer higher concentrations; they encounter floral volatiles as they collect nectar, suggesting that they, like humans, could be susceptible to sweetness enhancement by odorant. In this study, limonene, linalool, geraniol, and 6-methyl-5-hepten-2-ol were tested for their ability to alter behaviors related to perception of sweetness by honey bees. Honey bees were tested in the laboratory using proboscis extension response-based assays and in the field using feeder-based assays. In the laboratory assays, 6-methyl-5-hepten-2-ol and geraniol, but neither linalool nor limonene, significantly increased responses to low concentrations of sucrose compared with no odorant conditions in 15-day and 25-day-old adult worker honey bees, but not in 35-day-old bees. Limonene reduced responding in 15-day-old bees, but not in the older bees. There was no odorant-based difference in performance in field assays comparing geraniol and limonene with a no odorant control. The interaction of the tested plant volatiles with sucrose concentration revealed in laboratory testing is therefore unlikely to be a major determinant of nectar choice by honey bees foraging under natural conditions. Because geraniol is a component of honey bee Nasonov gland pheromone as well as a floral volatile, its impact on responses in the laboratory may reflect conveyance of different information than the other odorants tested.
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Affiliation(s)
| | - Byron N. Van Nest
- Department of Biological Sciences, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Stephanie R. Hathaway
- Department of Entomology, Purdue University, West Lafayette, Indiana, United States of America
| | - Susan E. Fahrbach
- Department of Biology, Wake Forest University, Winston-Salem, North Carolina, United States of America
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Lafon G, Paoli M, Paffhausen BH, Sanchez GDB, Lihoreau M, Avarguès-Weber A, Giurfa M. Efficient visual learning by bumble bees in virtual-reality conditions: Size does not matter. INSECT SCIENCE 2023; 30:1734-1748. [PMID: 36734172 DOI: 10.1111/1744-7917.13181] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Revised: 01/17/2023] [Accepted: 01/27/2023] [Indexed: 06/18/2023]
Abstract
Recent developments allowed establishing virtual-reality (VR) setups to study multiple aspects of visual learning in honey bees under controlled experimental conditions. Here, we adopted a VR environment to investigate the visual learning in the buff-tailed bumble bee Bombus terrestris. Based on responses to appetitive and aversive reinforcements used for conditioning, we show that bumble bees had the proper appetitive motivation to engage in the VR experiments and that they learned efficiently elemental color discriminations. In doing so, they reduced the latency to make a choice, increased the proportion of direct paths toward the virtual stimuli and walked faster toward them. Performance in a short-term retention test showed that bumble bees chose and fixated longer on the correct stimulus in the absence of reinforcement. Body size and weight, although variable across individuals, did not affect cognitive performances and had a mild impact on motor performances. Overall, we show that bumble bees are suitable experimental subjects for experiments on visual learning under VR conditions, which opens important perspectives for invasive studies on the neural and molecular bases of such learning given the robustness of these insects and the accessibility of their brain.
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Affiliation(s)
- Gregory Lafon
- Centre de Recherches sur la Cognition Animale, Centre de Biologie Intégrative (CBI), University of Toulouse, CNRS, UPS, Toulouse, France
| | - Marco Paoli
- Centre de Recherches sur la Cognition Animale, Centre de Biologie Intégrative (CBI), University of Toulouse, CNRS, UPS, Toulouse, France
| | - Benjamin H Paffhausen
- Centre de Recherches sur la Cognition Animale, Centre de Biologie Intégrative (CBI), University of Toulouse, CNRS, UPS, Toulouse, France
| | - Gabriela de Brito Sanchez
- Centre de Recherches sur la Cognition Animale, Centre de Biologie Intégrative (CBI), University of Toulouse, CNRS, UPS, Toulouse, France
| | - Mathieu Lihoreau
- Centre de Recherches sur la Cognition Animale, Centre de Biologie Intégrative (CBI), University of Toulouse, CNRS, UPS, Toulouse, France
| | - Aurore Avarguès-Weber
- Centre de Recherches sur la Cognition Animale, Centre de Biologie Intégrative (CBI), University of Toulouse, CNRS, UPS, Toulouse, France
| | - Martin Giurfa
- Centre de Recherches sur la Cognition Animale, Centre de Biologie Intégrative (CBI), University of Toulouse, CNRS, UPS, Toulouse, France
- French Academy of Sciences for University Professors, Institut Universitaire de France (IUF), Paris, France
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Sasidharan R, Junker RR, Eilers EJ, Müller C. Floral volatiles evoke partially similar responses in both florivores and pollinators and are correlated with non-volatile reward chemicals. ANNALS OF BOTANY 2023; 132:1-14. [PMID: 37220889 PMCID: PMC10550281 DOI: 10.1093/aob/mcad064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2023] [Accepted: 05/19/2023] [Indexed: 05/25/2023]
Abstract
BACKGROUND Plants often use floral displays to attract mutualists and prevent antagonist attacks. Chemical displays detectable from a distance include attractive or repellent floral volatile organic compounds (FVOCs). Locally, visitors perceive contact chemicals including nutrients but also deterrent or toxic constituents of pollen and nectar. The FVOC and pollen chemical composition can vary intra- and interspecifically. For certain pollinator and florivore species, responses to these compounds are studied in specific plant systems, yet we lack a synthesis of general patterns comparing these two groups and insights into potential correlations between FVOC and pollen chemodiversity. SCOPE We reviewed how FVOCs and non-volatile floral chemical displays, i.e. pollen nutrients and toxins, vary in composition and affect the detection by and behaviour of insect visitors. Moreover, we used meta-analyses to evaluate the detection of and responses to FVOCs by pollinators vs. florivores within the same plant genera. We also tested whether the chemodiversity of FVOCs, pollen nutrients and toxins is correlated, hence mutually informative. KEY RESULTS According to available data, florivores could detect more FVOCs than pollinators. Frequently tested FVOCs were often reported as pollinator-attractive and florivore-repellent. Among FVOCs tested on both visitor groups, there was a higher number of attractive than repellent compounds. FVOC and pollen toxin richness were negatively correlated, indicating trade-offs, whereas a marginal positive correlation between the amount of pollen protein and toxin richness was observed. CONCLUSIONS Plants face critical trade-offs, because floral chemicals mediate similar information to both mutualists and antagonists, particularly through attractive FVOCs, with fewer repellent FVOCs. Furthermore, florivores might detect more FVOCs, whose richness is correlated with the chemical richness of rewards. Chemodiversity of FVOCs is potentially informative of reward traits. To gain a better understanding of the ecological processes shaping floral chemical displays, more research is needed on floral antagonists of diverse plant species and on the role of floral chemodiversity in visitor responses.
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Affiliation(s)
- Rohit Sasidharan
- Department of Chemical Ecology, Bielefeld University, Universitätsstraße 25, 33615 Bielefeld, Germany
| | - Robert R Junker
- Department of Biology, Evolutionary Ecology of Plants, University of Marburg, Karl-von-Frisch-Straße 8, 35043 Marburg, Germany
- Department of Environment and Biodiversity, University of Salzburg, Kapitalgasse 4-6, 5020 Salzburg, Austria
| | - Elisabeth J Eilers
- Department of Chemical Ecology, Bielefeld University, Universitätsstraße 25, 33615 Bielefeld, Germany
- CTL GmbH Bielefeld, Krackser Straße 12, 33659 Bielefeld, Germany
| | - Caroline Müller
- Department of Chemical Ecology, Bielefeld University, Universitätsstraße 25, 33615 Bielefeld, Germany
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Aidlin Harari O, Dekel A, Wintraube D, Vainer Y, Mozes-Koch R, Yakir E, Malka O, Morin S, Bohbot JD. A sucrose-specific receptor in Bemisia tabaci and its putative role in phloem feeding. iScience 2023; 26:106752. [PMID: 37234092 PMCID: PMC10206433 DOI: 10.1016/j.isci.2023.106752] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Revised: 12/22/2022] [Accepted: 04/22/2023] [Indexed: 05/27/2023] Open
Abstract
In insects, specialized feeding on the phloem sap (containing mainly the sugar sucrose) has evolved only in some hemipteran lineages. This feeding behavior requires an ability to locate feeding sites buried deeply within the plant tissue. To determine the molecular mechanism involved, we hypothesized that the phloem-feeding whitefly Bemisia tabaci relies on gustatory receptor (GR)-mediated sugar sensing. We first conducted choice assays, which indicated that B. tabaci adults consistently choose diets containing higher sucrose concentrations. Next, we identified four GR genes in the B. tabaci genome. One of them, BtabGR1, displayed significant sucrose specificity when expressed in Xenopus oocytes. Silencing of BtabGR1 significantly interfered with the ability of B. tabaci adults to discriminate between non-phloem and phloem concentrations of sucrose. These findings suggest that in phloem feeders, sugar sensing by sugar receptors might allow tracking an increasing gradient of sucrose concentrations in the leaf, leading eventually to the location of the feeding site.
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Affiliation(s)
- Ofer Aidlin Harari
- Department of Entomology, The Hebrew University of Jerusalem, The Robert H. Smith Faculty of Agriculture, Food and Environment, Rehovot 76100, Israel
| | - Amir Dekel
- Department of Entomology, The Hebrew University of Jerusalem, The Robert H. Smith Faculty of Agriculture, Food and Environment, Rehovot 76100, Israel
| | - Dor Wintraube
- Department of Entomology, The Hebrew University of Jerusalem, The Robert H. Smith Faculty of Agriculture, Food and Environment, Rehovot 76100, Israel
| | - Yuri Vainer
- Department of Entomology, The Hebrew University of Jerusalem, The Robert H. Smith Faculty of Agriculture, Food and Environment, Rehovot 76100, Israel
| | - Rita Mozes-Koch
- Department of Entomology, The Hebrew University of Jerusalem, The Robert H. Smith Faculty of Agriculture, Food and Environment, Rehovot 76100, Israel
| | - Esther Yakir
- Department of Entomology, The Hebrew University of Jerusalem, The Robert H. Smith Faculty of Agriculture, Food and Environment, Rehovot 76100, Israel
| | - Osnat Malka
- Department of Entomology, The Hebrew University of Jerusalem, The Robert H. Smith Faculty of Agriculture, Food and Environment, Rehovot 76100, Israel
| | - Shai Morin
- Department of Entomology, The Hebrew University of Jerusalem, The Robert H. Smith Faculty of Agriculture, Food and Environment, Rehovot 76100, Israel
| | - Jonathan D. Bohbot
- Department of Entomology, The Hebrew University of Jerusalem, The Robert H. Smith Faculty of Agriculture, Food and Environment, Rehovot 76100, Israel
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King BH, Gunathunga PB. Gustation in insects: taste qualities and types of evidence used to show taste function of specific body parts. JOURNAL OF INSECT SCIENCE (ONLINE) 2023; 23:11. [PMID: 37014302 PMCID: PMC10072106 DOI: 10.1093/jisesa/iead018] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Revised: 02/03/2023] [Accepted: 03/10/2023] [Indexed: 06/19/2023]
Abstract
The insect equivalent of taste buds are gustatory sensilla, which have been found on mouthparts, pharynxes, antennae, legs, wings, and ovipositors. Most gustatory sensilla are uniporous, but not all apparently uniporous sensilla are gustatory. Among sensilla containing more than one neuron, a tubular body on one dendrite is also indicative of a taste sensillum, with the tubular body adding tactile function. But not all taste sensilla are also tactile. Additional morphological criteria are often used to recognize if a sensillum is gustatory. Further confirmation of such criteria by electrophysiological or behavioral evidence is needed. The five canonical taste qualities to which insects respond are sweet, bitter, sour, salty, and umami. But not all tastants that insects respond to easily fit in these taste qualities. Categories of insect tastants can be based not only on human taste perception, but also on whether the response is deterrent or appetitive and on chemical structure. Other compounds that at least some insects taste include, but are not limited to: water, fatty acids, metals, carbonation, RNA, ATP, pungent tastes as in horseradish, bacterial lipopolysaccharides, and contact pheromones. We propose that, for insects, taste be defined not only as a response to nonvolatiles but also be restricted to responses that are, or are thought to be, mediated by a sensillum. This restriction is useful because some of the receptor proteins in gustatory sensilla are also found elsewhere.
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Amat C, Marion-Poll F, Navarro-Roldán MA, Gemeno C. Gustatory function of sensilla chaetica on the labial palps and antennae of three tortricid moths (Lepidoptera: Tortricidae). Sci Rep 2022; 12:18882. [PMID: 36344566 PMCID: PMC9640605 DOI: 10.1038/s41598-022-21825-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2022] [Accepted: 10/04/2022] [Indexed: 11/09/2022] Open
Abstract
In adult Lepidoptera the labial palps are best known for their role in CO2 detection, but they can also bear sensilla chaetica which function is unknown. The number and distribution of sensilla chaetica in labial palps was studied using a bright field microscope. To determine if these sensilla have a gustatory function, we performed single sensillum electrophysiology recordings from palp and antennal sensilla of adult moths of Cydia pomonella (L.), Grapholita molesta (Busck) and Lobesia botrana (Denis and Shieffermüller). Each sensillum was stimulated with 3 doses of one of four test stimulus (sucrose, fructose, KCl and NaCl). Overall, responses (spikes/s-1) increased with dose, and were higher in the palps than in the antennae, and higher to sugars than to salts. With sugars the response increased with concentration in the palp but not in the antenna. With salts there was a drop in response at the intermediate concentration. The number and position of sensilla chaetica on labial palps was variable among individuals. Sensilla were located in the most exposed areas of the palp. Differences in sensilla distribution were detected between species. Such differences among species and between palps and antenna suggest that taste sensilla on the palps have an unforeseen role in adaptation.
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Affiliation(s)
- Carles Amat
- grid.15043.330000 0001 2163 1432University of Lleida-Agrotecnio-CERCA Center, Av. Alcalde Rovira Roure 191, 25198 Lleida, Spain
| | - Frédéric Marion-Poll
- grid.460789.40000 0004 4910 6535Université Paris-Saclay, CNRS, IRD, UMR EGCE, 12 rue 128, 91190 Gif-sur-Yvette, France ,grid.417885.70000 0001 2185 8223Université Paris-Saclay, AgroParisTech, 22 place de l’Agronomie, 91120 Palaiseau, France
| | - Miguel A. Navarro-Roldán
- grid.15043.330000 0001 2163 1432University of Lleida-Agrotecnio-CERCA Center, Av. Alcalde Rovira Roure 191, 25198 Lleida, Spain
| | - César Gemeno
- grid.15043.330000 0001 2163 1432University of Lleida-Agrotecnio-CERCA Center, Av. Alcalde Rovira Roure 191, 25198 Lleida, Spain
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Monchanin C, Gabriela de Brito Sanchez M, Lecouvreur L, Boidard O, Méry G, Silvestre J, Le Roux G, Baqué D, Elger A, Barron AB, Lihoreau M, Devaud JM. Honey bees cannot sense harmful concentrations of metal pollutants in food. CHEMOSPHERE 2022; 297:134089. [PMID: 35240159 DOI: 10.1016/j.chemosphere.2022.134089] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2021] [Revised: 02/02/2022] [Accepted: 02/21/2022] [Indexed: 06/14/2023]
Abstract
Whether animals can actively avoid food contaminated with harmful compounds through taste is key to assess their ecotoxicological risks. Here, we investigated the ability of honey bees to perceive and avoid food resources contaminated with common metal pollutants known to impair behaviour at low concentrations. In laboratory assays, bees did not discriminate food contaminated with arsenic, lead or zinc and ingested it readily, up to estimated doses of 929.1 μg g-1 As, 6.45 mg g-1 Pb and 72.46 mg g-1 Zn. A decrease of intake and appetitive responses indicating metal detection was only observed at the highest concentrations of lead (3.6 mM) and zinc (122.3 mM) through contact with the antennae and the proboscis. Electrophysiological analyses confirmed that only high concentrations of the three metals in a sucrose solution induced a consistently reduced neural response to sucrose in antennal taste receptors (As: >0.1 μM, Pb: >1 mM; Zn: >100 mM). Overall, cellular and behavioural responses did not provide evidence for specific mechanisms that would support selective detection of toxic metals (arsenic, lead), as compared to zinc, which has important biological functions. Our results thus show that honey bees can avoid metal pollutants in their food only at high concentrations unlikely to be encountered in the environment. By contrast, they appear to be unable to detect low, yet harmful, concentrations found in flowers. Metal pollution at trace levels is therefore a major threat for pollinators.
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Affiliation(s)
- Coline Monchanin
- Centre de Recherches sur La Cognition Animale (CRCA), Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, France; Department of Biological Sciences, Macquarie University, NSW, Australia
| | - Maria Gabriela de Brito Sanchez
- Centre de Recherches sur La Cognition Animale (CRCA), Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, France
| | - Loreleï Lecouvreur
- Centre de Recherches sur La Cognition Animale (CRCA), Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, France
| | - Océane Boidard
- Centre de Recherches sur La Cognition Animale (CRCA), Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, France
| | - Grégoire Méry
- Centre de Recherches sur La Cognition Animale (CRCA), Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, France
| | - Jérôme Silvestre
- Laboratoire Ecologie Fonctionnelle et Environnement, Université de Toulouse, CNRS, Toulouse, France
| | - Gaël Le Roux
- Laboratoire Ecologie Fonctionnelle et Environnement, Université de Toulouse, CNRS, Toulouse, France
| | - David Baqué
- Laboratoire Ecologie Fonctionnelle et Environnement, Université de Toulouse, CNRS, Toulouse, France
| | - Arnaud Elger
- Laboratoire Ecologie Fonctionnelle et Environnement, Université de Toulouse, CNRS, Toulouse, France
| | - Andrew B Barron
- Department of Biological Sciences, Macquarie University, NSW, Australia
| | - Mathieu Lihoreau
- Centre de Recherches sur La Cognition Animale (CRCA), Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, France
| | - Jean-Marc Devaud
- Centre de Recherches sur La Cognition Animale (CRCA), Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, France.
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11
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Lafon G, Geng H, Avarguès-Weber A, Buatois A, Massou I, Giurfa M. The Neural Signature of Visual Learning Under Restrictive Virtual-Reality Conditions. Front Behav Neurosci 2022; 16:846076. [PMID: 35250505 PMCID: PMC8888666 DOI: 10.3389/fnbeh.2022.846076] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Accepted: 01/21/2022] [Indexed: 11/22/2022] Open
Abstract
Honey bees are reputed for their remarkable visual learning and navigation capabilities. These capacities can be studied in virtual reality (VR) environments, which allow studying performances of tethered animals in stationary flight or walk under full control of the sensory environment. Here, we used a 2D VR setup in which a tethered bee walking stationary under restrictive closed-loop conditions learned to discriminate vertical rectangles differing in color and reinforcing outcome. Closed-loop conditions restricted stimulus control to lateral displacements. Consistently with prior VR analyses, bees learned to discriminate the trained stimuli. Ex vivo analyses on the brains of learners and non-learners showed that successful learning led to a downregulation of three immediate early genes in the main regions of the visual circuit, the optic lobes (OLs) and the calyces of the mushroom bodies (MBs). While Egr1 was downregulated in the OLs, Hr38 and kakusei were coincidently downregulated in the calyces of the MBs. Our work thus reveals that color discrimination learning induced a neural signature distributed along the sequential pathway of color processing that is consistent with an inhibitory trace. This trace may relate to the motor patterns required to solve the discrimination task, which are different from those underlying pathfinding in 3D VR scenarios allowing for navigation and exploratory learning and which lead to IEG upregulation.
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Affiliation(s)
- Gregory Lafon
- Research Center on Animal Cognition, Center for Integrative Biology, CNRS, University of Toulouse, Toulouse, France
| | - Haiyang Geng
- Research Center on Animal Cognition, Center for Integrative Biology, CNRS, University of Toulouse, Toulouse, France
- College of Animal Sciences (College of Bee Science), Fujian Agriculture and Forestry University, Fuzhou, China
| | - Aurore Avarguès-Weber
- Research Center on Animal Cognition, Center for Integrative Biology, CNRS, University of Toulouse, Toulouse, France
| | - Alexis Buatois
- Research Center on Animal Cognition, Center for Integrative Biology, CNRS, University of Toulouse, Toulouse, France
| | - Isabelle Massou
- Research Center on Animal Cognition, Center for Integrative Biology, CNRS, University of Toulouse, Toulouse, France
| | - Martin Giurfa
- Research Center on Animal Cognition, Center for Integrative Biology, CNRS, University of Toulouse, Toulouse, France
- College of Animal Sciences (College of Bee Science), Fujian Agriculture and Forestry University, Fuzhou, China
- Institut Universitaire de France, Paris, France
- *Correspondence: Martin Giurfa,
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Visual learning in a virtual reality environment upregulates immediate early gene expression in the mushroom bodies of honey bees. Commun Biol 2022; 5:130. [PMID: 35165405 PMCID: PMC8844430 DOI: 10.1038/s42003-022-03075-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Accepted: 01/26/2022] [Indexed: 11/08/2022] Open
Abstract
Free-flying bees learn efficiently to solve numerous visual tasks. Yet, the neural underpinnings of this capacity remain unexplored. We used a 3D virtual reality (VR) environment to study visual learning and determine if it leads to changes in immediate early gene (IEG) expression in specific areas of the bee brain. We focused on kakusei, Hr38 and Egr1, three IEGs that have been related to bee foraging and orientation, and compared their relative expression in the calyces of the mushroom bodies, the optic lobes and the rest of the brain after color discrimination learning. Bees learned to discriminate virtual stimuli displaying different colors and retained the information learned. Successful learners exhibited Egr1 upregulation only in the calyces of the mushroom bodies, thus uncovering a privileged involvement of these brain regions in associative color learning and the usefulness of Egr1 as a marker of neural activity induced by this phenomenon.
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13
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The short neuropeptide F regulates appetitive but not aversive responsiveness in a social insect. iScience 2022; 25:103619. [PMID: 35005557 PMCID: PMC8719019 DOI: 10.1016/j.isci.2021.103619] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2021] [Revised: 12/01/2021] [Accepted: 12/09/2021] [Indexed: 12/20/2022] Open
Abstract
The neuropeptide F (NPF) and its short version (sNPF) mediate food- and stress-related responses in solitary insects. In the honeybee, a social insect where food collection and defensive responses are socially regulated, only sNPF has an identified receptor. Here we increased artificially sNPF levels in honeybee foragers and studied the consequences of this manipulation in various forms of appetitive and aversive responsiveness. Increasing sNPF in partially fed bees turned them into the equivalent of starved animals, enhancing both their food consumption and responsiveness to appetitive gustatory and olfactory stimuli. Neural activity in the olfactory circuits of fed animals was reduced and could be rescued by sNPF treatment to the level of starved bees. In contrast, sNPF had no effect on responsiveness to nociceptive stimuli. Our results thus identify sNPF as a key modulator of hunger and food-related responses in bees, which are at the core of their foraging activities.
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14
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Motion cues from the background influence associative color learning of honey bees in a virtual-reality scenario. Sci Rep 2021; 11:21127. [PMID: 34702914 PMCID: PMC8548521 DOI: 10.1038/s41598-021-00630-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2021] [Accepted: 10/13/2021] [Indexed: 11/21/2022] Open
Abstract
Honey bees exhibit remarkable visual learning capacities, which can be studied using virtual reality (VR) landscapes in laboratory conditions. Existing VR environments for bees are imperfect as they provide either open-loop conditions or 2D displays. Here we achieved a true 3D environment in which walking bees learned to discriminate a rewarded from a punished virtual stimulus based on color differences. We included ventral or frontal background cues, which were also subjected to 3D updating based on the bee movements. We thus studied if and how the presence of such motion cues affected visual discrimination in our VR landscape. Our results showed that the presence of frontal, and to a lesser extent, of ventral background motion cues impaired the bees' performance. Whenever these cues were suppressed, color discrimination learning became possible. We analyzed the specific contribution of foreground and background cues and discussed the role of attentional interference and differences in stimulus salience in the VR environment to account for these results. Overall, we show how background and target cues may interact at the perceptual level and influence associative learning in bees. In addition, we identify issues that may affect decision-making in VR landscapes, which require specific control by experimenters.
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15
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Adipokinetic hormone (AKH), energy budget and their effect on feeding and gustatory processes of foraging honey bees. Sci Rep 2021; 11:18311. [PMID: 34526585 PMCID: PMC8443544 DOI: 10.1038/s41598-021-97851-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2021] [Accepted: 08/31/2021] [Indexed: 02/08/2023] Open
Abstract
The adipokinetic hormone (AKH) of insects is considered an equivalent of the mammalian hormone glucagon as it induces fast mobilization of carbohydrates and lipids from the fat body upon starvation. Yet, in foraging honey bees, which lack fat body storage for carbohydrates, it was suggested that AKH may have lost its original function. Here we manipulated the energy budget of bee foragers to determine the effect of AKH on appetitive responses. As AKH participates in a cascade leading to acceptance of unpalatable substances in starved Drosophila, we also assessed its effect on foragers presented with sucrose solution spiked with salicin. Starved and partially-fed bees were topically exposed with different doses of AKH to determine if this hormone modifies food ingestion and sucrose responsiveness. We found a significant effect of the energy budget (i.e. starved vs. partially-fed) on the decision to ingest or respond to both pure sucrose solution and sucrose solution spiked with salicin, but no effect of AKH per se. These results are consistent with a loss of function of AKH in honey bee foragers, in accordance with a social life that implies storing energy resources in the hive, in amounts that exceed individual needs.
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16
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Toh YP, Dion E, Monteiro A. Dissections of Larval, Pupal and Adult Butterfly Brains for Immunostaining and Molecular Analysis. Methods Protoc 2021; 4:53. [PMID: 34449688 PMCID: PMC8395752 DOI: 10.3390/mps4030053] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Revised: 07/28/2021] [Accepted: 07/31/2021] [Indexed: 11/21/2022] Open
Abstract
Butterflies possess impressive cognitive abilities, and investigations into the neural mechanisms underlying these abilities are increasingly being conducted. Exploring butterfly neurobiology may require the isolation of larval, pupal, and/or adult brains for further molecular and histological experiments. This procedure has been largely described in the fruit fly, but a detailed description of butterfly brain dissections is still lacking. Here, we provide a detailed written and video protocol for the removal of Bicyclus anynana adult, pupal, and larval brains. This species is gradually becoming a popular model because it uses a large set of sensory modalities, displays plastic and hormonally controlled courtship behaviour, and learns visual mate preference and olfactory preferences that can be passed on to its offspring. The extracted brain can be used for downstream analyses, such as immunostaining, DNA or RNA extraction, and the procedure can be easily adapted to other lepidopteran species and life stages.
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Affiliation(s)
- Yi Peng Toh
- Department of Biological Sciences, National University of Singapore, 14 Science Drive 4, Singapore 117543, Singapore; (Y.P.T.); (A.M.)
| | - Emilie Dion
- Department of Biological Sciences, National University of Singapore, 14 Science Drive 4, Singapore 117543, Singapore; (Y.P.T.); (A.M.)
| | - Antónia Monteiro
- Department of Biological Sciences, National University of Singapore, 14 Science Drive 4, Singapore 117543, Singapore; (Y.P.T.); (A.M.)
- Yale-NUS College, 10 College Avenue West, Singapore 138609, Singapore
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