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Değirmenci L, Rogé Ferreira FL, Vukosavljevic A, Heindl C, Keller A, Geiger D, Scheiner R. Sugar perception in honeybees. Front Physiol 2023; 13:1089669. [PMID: 36714315 PMCID: PMC9880324 DOI: 10.3389/fphys.2022.1089669] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Accepted: 12/28/2022] [Indexed: 01/14/2023] Open
Abstract
Honeybees (Apis mellifera) need their fine sense of taste to evaluate nectar and pollen sources. Gustatory receptors (Grs) translate taste signals into electrical responses. In vivo experiments have demonstrated collective responses of the whole Gr-set. We here disentangle the contributions of all three honeybee sugar receptors (AmGr1-3), combining CRISPR/Cas9 mediated genetic knock-out, electrophysiology and behaviour. We show an expanded sugar spectrum of the AmGr1 receptor. Mutants lacking AmGr1 have a reduced response to sucrose and glucose but not to fructose. AmGr2 solely acts as co-receptor of AmGr1 but not of AmGr3, as we show by electrophysiology and using bimolecular fluorescence complementation. Our results show for the first time that AmGr2 is indeed a functional receptor on its own. Intriguingly, AmGr2 mutants still display a wildtype-like sugar taste. AmGr3 is a specific fructose receptor and is not modulated by a co-receptor. Eliminating AmGr3 while preserving AmGr1 and AmGr2 abolishes the perception of fructose but not of sucrose. Our comprehensive study on the functions of AmGr1, AmGr2 and AmGr3 in honeybees is the first to combine investigations on sugar perception at the receptor level and simultaneously in vivo. We show that honeybees rely on two gustatory receptors to sense all relevant sugars.
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Affiliation(s)
- Laura Değirmenci
- Behavioral Physiology and Sociobiology, Biocenter, Julius-Maximilians-Universität Würzburg, Wuerzburg, Germany,*Correspondence: Laura Değirmenci, ; Fabio Luiz Rogé Ferreira,
| | - Fabio Luiz Rogé Ferreira
- Molecular Plant Physiology and Biophysics, Julius-von-Sachs-Institute, Julius-Maximilians-Universität Würzburg, Wuerzburg, Germany,*Correspondence: Laura Değirmenci, ; Fabio Luiz Rogé Ferreira,
| | - Adrian Vukosavljevic
- Behavioral Physiology and Sociobiology, Biocenter, Julius-Maximilians-Universität Würzburg, Wuerzburg, Germany
| | - Cornelia Heindl
- Behavioral Physiology and Sociobiology, Biocenter, Julius-Maximilians-Universität Würzburg, Wuerzburg, Germany
| | - Alexander Keller
- Organismic and Cellular Interactions, Faculty of Biology, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Dietmar Geiger
- Molecular Plant Physiology and Biophysics, Julius-von-Sachs-Institute, Julius-Maximilians-Universität Würzburg, Wuerzburg, Germany
| | - Ricarda Scheiner
- Behavioral Physiology and Sociobiology, Biocenter, Julius-Maximilians-Universität Würzburg, Wuerzburg, Germany
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Schilcher F, Hilsmann L, Rauscher L, Değirmenci L, Krischke M, Krischke B, Ankenbrand M, Rutschmann B, Mueller MJ, Steffan-Dewenter I, Scheiner R. In Vitro Rearing Changes Social Task Performance and Physiology in Honeybees. Insects 2021; 13:insects13010004. [PMID: 35055848 PMCID: PMC8779213 DOI: 10.3390/insects13010004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Revised: 12/16/2021] [Accepted: 12/17/2021] [Indexed: 11/22/2022]
Abstract
Simple Summary The rearing of honeybee larvae in the laboratory is an important tool for studying the effects of plant protection products or pathogens on developing and adult bees, yet how rearing under artificial conditions affects the later social behavior and physiology of the honeybees is mostly unknown. We, here, show that honeybees reared in the laboratory generally had a lower probability for performing nursing or foraging tasks compared to bees reared under natural conditions in bee colonies. Nursing behavior itself appeared normal in in vitro honeybees. In contrast, bees reared in the laboratory foraged for a shorter period in life and performed fewer trips compared to bees reared in colonies. In addition, in vitro honeybees did not display the typical increase in juvenile hormone titer, which goes hand-in-hand with the initiation of foraging in colony-reared bees. Abstract In vitro rearing of honeybee larvae is an established method that enables exact control and monitoring of developmental factors and allows controlled application of pesticides or pathogens. However, only a few studies have investigated how the rearing method itself affects the behavior of the resulting adult honeybees. We raised honeybees in vitro according to a standardized protocol: marking the emerging honeybees individually and inserting them into established colonies. Subsequently, we investigated the behavioral performance of nurse bees and foragers and quantified the physiological factors underlying the social organization. Adult honeybees raised in vitro differed from naturally reared honeybees in their probability of performing social tasks. Further, in vitro-reared bees foraged for a shorter duration in their life and performed fewer foraging trips. Nursing behavior appeared to be unaffected by rearing condition. Weight was also unaffected by rearing condition. Interestingly, juvenile hormone titers, which normally increase strongly around the time when a honeybee becomes a forager, were significantly lower in three- and four-week-old in vitro bees. The effects of the rearing environment on individual sucrose responsiveness and lipid levels were rather minor. These data suggest that larval rearing conditions can affect the task performance and physiology of adult bees despite equal weight, pointing to an important role of the colony environment for these factors. Our observations of behavior and metabolic pathways offer important novel insight into how the rearing environment affects adult honeybees.
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Affiliation(s)
- Felix Schilcher
- Biocentre, Department of Behavioural Physiology and Sociobiology, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany; (L.H.); (L.R.); (L.D.); (R.S.)
- Correspondence: ; Tel.: +49-931-31-85373
| | - Lioba Hilsmann
- Biocentre, Department of Behavioural Physiology and Sociobiology, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany; (L.H.); (L.R.); (L.D.); (R.S.)
| | - Lisa Rauscher
- Biocentre, Department of Behavioural Physiology and Sociobiology, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany; (L.H.); (L.R.); (L.D.); (R.S.)
| | - Laura Değirmenci
- Biocentre, Department of Behavioural Physiology and Sociobiology, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany; (L.H.); (L.R.); (L.D.); (R.S.)
| | - Markus Krischke
- Department of Pharmaceutical Biology, Julius-von-Sachs-Institute, Julius-Maximilians-Universität Würzburg, Julius-von-Sachs-Platz 2, 97082 Würzburg, Germany; (M.K.); (M.J.M.)
| | - Beate Krischke
- Biocentre, Department of Animal Ecology and Tropical Biology, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany; (B.K.); (B.R.); (I.S.-D.)
| | - Markus Ankenbrand
- Center for Computational and Theoretical Biology (CCTB), Julius-Maximilians-Universität Würzburg, Klara-Oppenheimer-Weg 32, 97074 Würzburg, Germany;
| | - Benjamin Rutschmann
- Biocentre, Department of Animal Ecology and Tropical Biology, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany; (B.K.); (B.R.); (I.S.-D.)
| | - Martin J. Mueller
- Department of Pharmaceutical Biology, Julius-von-Sachs-Institute, Julius-Maximilians-Universität Würzburg, Julius-von-Sachs-Platz 2, 97082 Würzburg, Germany; (M.K.); (M.J.M.)
| | - Ingolf Steffan-Dewenter
- Biocentre, Department of Animal Ecology and Tropical Biology, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany; (B.K.); (B.R.); (I.S.-D.)
| | - Ricarda Scheiner
- Biocentre, Department of Behavioural Physiology and Sociobiology, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany; (L.H.); (L.R.); (L.D.); (R.S.)
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Değirmenci L, Geiger D, Rogé Ferreira FL, Keller A, Krischke B, Beye M, Steffan-Dewenter I, Scheiner R. CRISPR/Cas 9-Mediated Mutations as a New Tool for Studying Taste in Honeybees. Chem Senses 2021; 45:655-666. [PMID: 32968780 DOI: 10.1093/chemse/bjaa063] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Honeybees rely on nectar as their main source of carbohydrates. Sucrose, glucose, and fructose are the main components of plant nectars. Intriguingly, honeybees express only 3 putative sugar receptors (AmGr1, AmGr2, and AmGr3), which is in stark contrast to many other insects and vertebrates. The sugar receptors are only partially characterized. AmGr1 detects different sugars including sucrose and glucose. AmGr2 is assumed to act as a co-receptor only, while AmGr3 is assumedly a fructose receptor. We show that honeybee gustatory receptor AmGr3 is highly specialized for fructose perception when expressed in Xenopus oocytes. When we introduced nonsense mutations to the respective AmGr3 gene using CRISPR/Cas9 in eggs of female workers, the resulting mutants displayed almost a complete loss of responsiveness to fructose. In contrast, responses to sucrose were normal. Nonsense mutations introduced by CRISPR/Cas9 in honeybees can thus induce a measurable behavioral change and serve to characterize the function of taste receptors in vivo. CRISPR/Cas9 is an excellent novel tool for characterizing honeybee taste receptors in vivo. Biophysical receptor characterization in Xenopus oocytes and nonsense mutation of AmGr3 in honeybees unequivocally demonstrate that this receptor is highly specific for fructose.
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Affiliation(s)
- Laura Değirmenci
- Behavioral Physiology and Sociobiology, University of Würzburg, Biocenter, Am Hubland, Würzburg, Germany
| | - Dietmar Geiger
- Julius-von-Sachs-Institute, Molecular Plant Physiology and Biophysics, University of Würzburg, Biocenter, Würzburg, Germany
| | - Fábio Luiz Rogé Ferreira
- Julius-von-Sachs-Institute, Molecular Plant Physiology and Biophysics, University of Würzburg, Biocenter, Würzburg, Germany
| | - Alexander Keller
- Department of Bioinformatics, Biocenter, Am Hubland, Würzburg, Germany
| | - Beate Krischke
- Animal Ecology and Tropical Biology, University of Würzburg, Biocenter, Am Hubland, Würzburg, Germany
| | - Martin Beye
- Evolutionary Genetics, Heinrich-Heine-Universität Düsseldorf, Düsseldorf, Germany
| | - Ingolf Steffan-Dewenter
- Animal Ecology and Tropical Biology, University of Würzburg, Biocenter, Am Hubland, Würzburg, Germany
| | - Ricarda Scheiner
- Behavioral Physiology and Sociobiology, University of Würzburg, Biocenter, Am Hubland, Würzburg, Germany
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Zanni V, Değirmenci L, Annoscia D, Scheiner R, Nazzi F. The reduced brood nursing by mite-infested honey bees depends on their accelerated behavioral maturation. J Insect Physiol 2018; 109:47-54. [PMID: 29932950 DOI: 10.1016/j.jinsphys.2018.06.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2018] [Revised: 06/04/2018] [Accepted: 06/13/2018] [Indexed: 06/08/2023]
Abstract
The parasitic mite Varroa destructor is regarded as the most important parasite of honey bees and plays a fundamental role in the decline of bee colonies observed in the last decade in the Northern hemisphere. Parasitization has a number of detrimental effects on bees, including reduced nursing, which can have important impacts on colony balance. In this work we investigated at the individual level the causes of this abnormal behavior and found that the reduced nursing activity in mite-infested workers is associated with impaired learning performance and a series of physiological traits that are typical of foragers, including reduced response to brood pheromone, limited development of hypopharyngeal glands and higher juvenile hormone titre in the haemolymph. Altogether our data confirm the premature transition to foraging already postulated based on previous genomics studies, from a physiological point of view.
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Affiliation(s)
- V Zanni
- Dipartimento di Scienze AgroAlimentari, Ambientali e Animali, Università degli Studi di Udine, via delle Scienze 206, 33100 Udine, Italy
| | - L Değirmenci
- Behavioral Physiology and Sociobiology (Zoology II), Biocenter, University of Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - D Annoscia
- Dipartimento di Scienze AgroAlimentari, Ambientali e Animali, Università degli Studi di Udine, via delle Scienze 206, 33100 Udine, Italy
| | - R Scheiner
- Behavioral Physiology and Sociobiology (Zoology II), Biocenter, University of Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - F Nazzi
- Dipartimento di Scienze AgroAlimentari, Ambientali e Animali, Università degli Studi di Udine, via delle Scienze 206, 33100 Udine, Italy.
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Değirmenci L, Thamm M, Scheiner R. Responses to sugar and sugar receptor gene expression in different social roles of the honeybee (Apis mellifera). J Insect Physiol 2018; 106:65-70. [PMID: 28935437 DOI: 10.1016/j.jinsphys.2017.09.009] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Revised: 09/11/2017] [Accepted: 09/17/2017] [Indexed: 06/07/2023]
Abstract
Honeybees (Apis mellifera) are well-known for their sophisticated division of labor with each bee performing sequentially a series of social tasks. Colony organization is largely based on age-dependent division of labor. While bees perform several tasks inside the hive such as caring for brood ("nursing"), cleaning or sealing brood cells or producing honey, older bees leave to colony to collect pollen (proteins) and nectar (carbohydrates) as foragers. The most pronounced behavioral transition occurs when nurse bees become foragers. For both social roles, the detection and evaluation of sugars is decisive for optimal task performance. Nurse bees rely on their gustatory senses to prepare brood food, while foragers evaluate a nectar source before starting to collect food from it. To test whether social organization is related to differential sensing of sugars we compared the taste of nurse bees and foragers for different sugars. Searching for molecular correlates for differences in sugar perception, we further quantified expression of gustatory receptor genes in both behavioral groups. Our results demonstrate that nurse bees and foragers perceive and evaluate different sugars differently. Both groups, however, prefer sucrose over fructose. At least part of the taste differences between social roles could be related to a differential expression of taste receptors in the antennae and brain. Our results suggest that differential expression of sugar receptor genes might be involved in regulating division of labor through nutrition-related signaling pathways.
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Affiliation(s)
- Laura Değirmenci
- University of Würzburg, Behavioral Physiology & Sociobiology, Biocenter, Am Hubland, 97074 Würzburg, Germany
| | - Markus Thamm
- University of Würzburg, Behavioral Physiology & Sociobiology, Biocenter, Am Hubland, 97074 Würzburg, Germany
| | - Ricarda Scheiner
- University of Würzburg, Behavioral Physiology & Sociobiology, Biocenter, Am Hubland, 97074 Würzburg, Germany.
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