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Sen E, El-Keredy A, Jacob N, Mancini N, Asnaz G, Widmann A, Gerber B, Thoener J. Cognitive limits of larval Drosophila: testing for conditioned inhibition, sensory preconditioning, and second-order conditioning. Learn Mem 2024; 31:a053726. [PMID: 38862170 PMCID: PMC11199949 DOI: 10.1101/lm.053726.122] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2023] [Accepted: 01/18/2024] [Indexed: 06/13/2024]
Abstract
Drosophila larvae are an established model system for studying the mechanisms of innate and simple forms of learned behavior. They have about 10 times fewer neurons than adult flies, and it was the low total number of their neurons that allowed for an electron microscopic reconstruction of their brain at synaptic resolution. Regarding the mushroom body, a central brain structure for many forms of associative learning in insects, it turned out that more than half of the classes of synaptic connection had previously escaped attention. Understanding the function of these circuit motifs, subsequently confirmed in adult flies, is an important current research topic. In this context, we test larval Drosophila for their cognitive abilities in three tasks that are characteristically more complex than those previously studied. Our data provide evidence for (i) conditioned inhibition, as has previously been reported for adult flies and honeybees. Unlike what is described for adult flies and honeybees, however, our data do not provide evidence for (ii) sensory preconditioning or (iii) second-order conditioning in Drosophila larvae. We discuss the methodological features of our experiments as well as four specific aspects of the organization of the larval brain that may explain why these two forms of learning are observed in adult flies and honeybees, but not in larval Drosophila.
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Affiliation(s)
- Edanur Sen
- Department of Genetics, Leibniz Institute for Neurobiology, 39118 Magdeburg, Germany
| | - Amira El-Keredy
- Department of Genetics, Leibniz Institute for Neurobiology, 39118 Magdeburg, Germany
- Department of Genetics, Faculty of Agriculture, Tanta University, 31111 Tanta, Egypt
| | - Nina Jacob
- Department of Genetics, Leibniz Institute for Neurobiology, 39118 Magdeburg, Germany
| | - Nino Mancini
- Department of Genetics, Leibniz Institute for Neurobiology, 39118 Magdeburg, Germany
| | - Gülüm Asnaz
- Department of Molecular Neurobiology of Behavior, University of Göttingen, 37077 Göttingen, Germany
| | - Annekathrin Widmann
- Department of Molecular Neurobiology of Behavior, University of Göttingen, 37077 Göttingen, Germany
| | - Bertram Gerber
- Department of Genetics, Leibniz Institute for Neurobiology, 39118 Magdeburg, Germany
- Otto von Guericke University Magdeburg, Institute of Biology, 39106 Magdeburg, Germany
- Center for Behavioral Brain Sciences, 39106 Magdeburg, Germany
| | - Juliane Thoener
- Department of Genetics, Leibniz Institute for Neurobiology, 39118 Magdeburg, Germany
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2
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Poe AR, Zhu L, Szuperak M, McClanahan PD, Anafi RC, Scholl B, Thum AS, Cavanaugh DJ, Kayser MS. Developmental emergence of sleep rhythms enables long-term memory in Drosophila. SCIENCE ADVANCES 2023; 9:eadh2301. [PMID: 37683005 PMCID: PMC10491288 DOI: 10.1126/sciadv.adh2301] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2023] [Accepted: 08/09/2023] [Indexed: 09/10/2023]
Abstract
In adulthood, sleep-wake rhythms are one of the most prominent behaviors under circadian control. However, during early life, sleep is spread across the 24-hour day. The mechanism through which sleep rhythms emerge, and consequent advantage conferred to a juvenile animal, is unknown. In the second-instar Drosophila larvae (L2), like in human infants, sleep is not under circadian control. We identify the precise developmental time point when the clock begins to regulate sleep in Drosophila, leading to emergence of sleep rhythms in early third-instars (L3). At this stage, a cellular connection forms between DN1a clock neurons and arousal-promoting Dh44 neurons, bringing arousal under clock control to drive emergence of circadian sleep. Last, we demonstrate that L3 but not L2 larvae exhibit long-term memory (LTM) of aversive cues and that this LTM depends upon deep sleep generated once sleep rhythms begin. We propose that the developmental emergence of circadian sleep enables more complex cognitive processes, including the onset of enduring memories.
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Affiliation(s)
- Amy R. Poe
- Department of Psychiatry, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Lucy Zhu
- Department of Psychiatry, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Milan Szuperak
- Department of Psychiatry, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | | | - Ron C. Anafi
- Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
- Chronobiology and Sleep Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Benjamin Scholl
- Department of Neuroscience, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Andreas S. Thum
- Department of Genetics, Institute of Biology, Faculty of Life Sciences, Leipzig University, Leipzig, Germany
| | | | - Matthew S. Kayser
- Department of Psychiatry, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
- Chronobiology and Sleep Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
- Department of Neuroscience, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
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3
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Zhong M, Sun C, Zhou B. Anti-Mitochondrial and Insecticidal Effects of Artemisinin against Drosophila melanogaster. Int J Mol Sci 2023; 24:ijms24086912. [PMID: 37108079 PMCID: PMC10138759 DOI: 10.3390/ijms24086912] [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: 03/04/2023] [Revised: 04/03/2023] [Accepted: 04/04/2023] [Indexed: 04/29/2023] Open
Abstract
Artemisinin (ART) is an endoperoxide molecule derived from the medicinal plant Artemisia annua L. and is clinically used as an antimalarial drug. As a secondary metabolite, the benefit of ART production to the host plant and the possible associated mechanism are not understood. It has previously been reported that Artemisia annua L. extract or ART can inhibit both insect feeding behaviors and growth; however, it is not known whether these effects are independent of each other, i.e., if growth inhibition is a direct outcome of the drug's antifeeding activity. Using the lab model organism Drosophila melanogaster, we demonstrated that ART repels the feeding of larvae. Nevertheless, feeding inhibition was insufficient to explain its toxicity on fly larval growth. We revealed that ART provoked a strong and instant depolarization when applied to isolated mitochondria from Drosophila while exerting little effect on mitochondria isolated from mice tissues. Thus, ART benefits its host plant through two distinct activities on the insect: a feeding-repelling action and a potent anti-mitochondrial action which may underlie its insect inhibitory activities.
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Affiliation(s)
- Mengjiao Zhong
- School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Chen Sun
- College of Agronomy and Biotechnology, China Agricultural University, Beijing 100193, China
| | - Bing Zhou
- Shenzhen Institute of Synthetic Biology, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen 518055, China
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4
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Drosophila melanogaster Chemosensory Pathways as Potential Targets to Curb the Insect Menace. INSECTS 2022; 13:insects13020142. [PMID: 35206716 PMCID: PMC8874460 DOI: 10.3390/insects13020142] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Revised: 01/19/2022] [Accepted: 01/25/2022] [Indexed: 11/17/2022]
Abstract
Simple Summary The perception and processing of chemosensory stimuli are indispensable to the survival of living organisms. In insects, olfaction and gustation play a critical role in seeking food, finding mates and avoiding signs of danger. This review aims to present updated information about olfactory and gustatory signaling in the fruit fly Drosophila melanogaster. We have described the mechanisms involved in olfactory and gustatory perceptions at the molecular level, the receptors along with the allied molecules involved, and their signaling pathways in the fruit fly. Due to the magnifying problems of disease-causing insect vectors and crop pests, the applications of chemosensory signaling in controlling pests and insect vectors are also discussed. Abstract From a unicellular bacterium to a more complex human, smell and taste form an integral part of the basic sensory system. In fruit flies Drosophila melanogaster, the behavioral responses to odorants and tastants are simple, though quite sensitive, and robust. They explain the organization and elementary functioning of the chemosensory system. Molecular and functional analyses of the receptors and other critical molecules involved in olfaction and gustation are not yet completely understood. Hence, a better understanding of chemosensory cue-dependent fruit flies, playing a major role in deciphering the host-seeking behavior of pathogen transmitting insect vectors (mosquitoes, sandflies, ticks) and crop pests (Drosophila suzukii, Queensland fruit fly), is needed. Using D. melanogaster as a model organism, the knowledge gained may be implemented to design new means of controlling insects as well as in analyzing current batches of insect and pest repellents. In this review, the complete mechanisms of olfactory and gustatory perception, along with their implementation in controlling the global threat of disease-transmitting insect vectors and crop-damaging pests, are explained in fruit flies.
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5
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Maier GL, Komarov N, Meyenhofer F, Kwon JY, Sprecher SG. Taste sensing and sugar detection mechanisms in Drosophila larval primary taste center. eLife 2021; 10:67844. [PMID: 34859782 PMCID: PMC8709573 DOI: 10.7554/elife.67844] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Accepted: 11/23/2021] [Indexed: 11/25/2022] Open
Abstract
Despite the small number of gustatory sense neurons, Drosophila larvae are able to sense a wide range of chemicals. Although evidence for taste multimodality has been provided in single neurons, an overview of gustatory responses at the periphery is missing and hereby we explore whole-organ calcium imaging of the external taste center. We find that neurons can be activated by different combinations of taste modalities, including opposite hedonic valence and identify distinct temporal dynamics of response. Although sweet sensing has not been fully characterized so far in the external larval gustatory organ, we recorded responses elicited by sugar. Previous findings established that larval sugar sensing relies on the Gr43a pharyngeal receptor, but the question remains if external neurons contribute to this taste. Here, we postulate that external and internal gustation use distinct and complementary mechanisms in sugar sensing and we identify external sucrose sensing neurons.
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Affiliation(s)
- G Larisa Maier
- Department of Biology, University of Fribourg, Fribourg, Switzerland
| | - Nikita Komarov
- Department of Biology, University of Fribourg, Fribourg, Switzerland
| | - Felix Meyenhofer
- Department of Biology, University of Fribourg, Fribourg, Switzerland
| | - Jae Young Kwon
- Department of Biological Sciences, Sungkyunkwan University, Suwon, Republic of Korea
| | - Simon G Sprecher
- Department of Biology, University of Fribourg, Fribourg, Switzerland
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6
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Schumann I, Berger M, Nowag N, Schäfer Y, Saumweber J, Scholz H, Thum AS. Ethanol-guided behavior in Drosophila larvae. Sci Rep 2021; 11:12307. [PMID: 34112872 PMCID: PMC8192949 DOI: 10.1038/s41598-021-91677-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2021] [Accepted: 05/27/2021] [Indexed: 11/22/2022] Open
Abstract
Chemosensory signals allow vertebrates and invertebrates not only to orient in its environment toward energy-rich food sources to maintain nutrition but also to avoid unpleasant or even poisonous substrates. Ethanol is a substance found in the natural environment of Drosophila melanogaster. Accordingly, D. melanogaster has evolved specific sensory systems, physiological adaptations, and associated behaviors at its larval and adult stage to perceive and process ethanol. To systematically analyze how D. melanogaster larvae respond to naturally occurring ethanol, we examined ethanol-induced behavior in great detail by reevaluating existing approaches and comparing them with new experiments. Using behavioral assays, we confirm that larvae are attracted to different concentrations of ethanol in their environment. This behavior is controlled by olfactory and other environmental cues. It is independent of previous exposure to ethanol in their food. Moreover, moderate, naturally occurring ethanol concentration of 4% results in increased larval fitness. On the contrary, higher concentrations of 10% and 20% ethanol, which rarely or never appear in nature, increase larval mortality. Finally, ethanol also serves as a positive teaching signal in learning and memory and updates valence associated with simultaneously processed odor information. Since information on how larvae perceive and process ethanol at the genetic and neuronal level is limited, the establishment of standardized assays described here is an important step towards their discovery.
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Affiliation(s)
- Isabell Schumann
- Department of Genetics, Leipzig University, 04103, Leipzig, Germany
| | - Michael Berger
- Department of Biology, University of Cologne, 50674, Cologne, Germany
| | - Nadine Nowag
- Department of Genetics, Leipzig University, 04103, Leipzig, Germany
| | - Yannick Schäfer
- Department of Biology, University of Cologne, 50674, Cologne, Germany
| | | | - Henrike Scholz
- Department of Biology, University of Cologne, 50674, Cologne, Germany
| | - Andreas S Thum
- Department of Genetics, Leipzig University, 04103, Leipzig, Germany. .,Department of Genetics, Institute of Biology, Faculty of Life Sciences, Leipzig University, Talstraße 33, 04103, Leipzig, Germany.
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7
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Muñoz IJ, Schilman PE, Barrozo RB. Impact of alkaloids in food consumption, metabolism and survival in a blood-sucking insect. Sci Rep 2020; 10:9443. [PMID: 32523008 PMCID: PMC7287067 DOI: 10.1038/s41598-020-65932-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Accepted: 04/27/2020] [Indexed: 02/08/2023] Open
Abstract
The sense of taste provides information about the “good” or “bad” quality of a food source, which may be potentially nutritious or toxic. Most alkaloids taste bitter to humans, and because bitter taste is synonymous of noxious food, they are generally rejected. This response may be due to an innate low palatability or due to a malaise that occurs after food ingestion, which could even lead to death. We investigated in the kissing bug Rhodnius prolixus, whether alkaloids such as quinine, caffeine and theophylline, are merely distasteful, or if anti-appetitive responses are caused by a post-ingestion physiological effect, or both of these options. Although anti-appetitive responses were observed for the three alkaloids, only caffeine and theophylline affect metabolic and respiratory parameters that reflected an underlying physiological stress following their ingestion. Furthermore, caffeine caused the highest mortality. In contrast, quinine appears to be a merely unpalatable compound. The sense of taste helps insects to avoid making wrong feeding decisions, such as the intake of bitter/toxic foods, and thus avoid potentially harmful effects on health, a mechanism preserved in obligate hematophagous insects.
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Affiliation(s)
- Ignacio J Muñoz
- Grupo de Neuroetología de Insectos Vectores, Laboratorio Fisiología de Insectos, Instituto Biodiversidad Biología Experimental Aplicada, CONICET; Departamento Biodiversidad Biología Experimental, Facultad Ciencias Exactas y Naturales, Universidad de Buenos Aires, UBA, Buenos Aires, Argentina.,Laboratorio de Ecofisiología de Insectos, Instituto de Biodiversidad y Biología Experimental y Aplicada, CONICET; Departamento de Biodiversidad y Biología Experimental, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, UBA, Buenos Aires, Argentina
| | - Pablo E Schilman
- Laboratorio de Ecofisiología de Insectos, Instituto de Biodiversidad y Biología Experimental y Aplicada, CONICET; Departamento de Biodiversidad y Biología Experimental, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, UBA, Buenos Aires, Argentina.
| | - Romina B Barrozo
- Grupo de Neuroetología de Insectos Vectores, Laboratorio Fisiología de Insectos, Instituto Biodiversidad Biología Experimental Aplicada, CONICET; Departamento Biodiversidad Biología Experimental, Facultad Ciencias Exactas y Naturales, Universidad de Buenos Aires, UBA, Buenos Aires, Argentina.
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8
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Cellular Basis of Bitter-Driven Aversive Behaviors in Drosophila Larva. eNeuro 2020; 7:ENEURO.0510-19.2020. [PMID: 32220859 PMCID: PMC7189479 DOI: 10.1523/eneuro.0510-19.2020] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2019] [Revised: 03/16/2020] [Accepted: 03/16/2020] [Indexed: 12/04/2022] Open
Abstract
Feeding, a critical behavior for survival, consists of a complex series of behavioral steps. In Drosophila larvae, the initial steps of feeding are food choice, during which the quality of a potential food source is judged, and ingestion, during which the selected food source is ingested into the digestive tract. It remains unclear whether these steps employ different mechanisms of neural perception. Here, we provide insight into the two initial steps of feeding in Drosophila larva. We find that substrate choice and ingestion are determined by independent circuits at the cellular level. First, we took 22 candidate bitter compounds and examined their influence on choice preference and ingestion behavior. Interestingly, certain bitter tastants caused different responses in choice and ingestion, suggesting distinct mechanisms of perception. We further provide evidence that certain gustatory receptor neurons (GRNs) in the external terminal organ (TO) are involved in determining choice preference, and a pair of larval pharyngeal GRNs is involved in mediating both avoidance and suppression of ingestion. Our results show that feeding behavior is coordinated by a multistep regulatory process employing relatively independent neural elements. These findings are consistent with a model in which distinct sensory pathways act as modulatory circuits controlling distinct subprograms during feeding.
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9
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Caponera V, Barrett M, Marenda DR, O'donnell S. Erythritol Ingestion Causes Concentration-Dependent Mortality in Eastern Subterranean Termites (Blattodea: Rhinotermitidae). JOURNAL OF ECONOMIC ENTOMOLOGY 2020; 113:348-352. [PMID: 31588517 DOI: 10.1093/jee/toz260] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2019] [Indexed: 06/10/2023]
Abstract
Damage from termite infestations is economically significant and control can be costly when requiring the widespread use of conventional insecticides. Erythritol, a polyalcohol sweetener that is safe for human consumption, causes increased mortality when ingested by some insects, indicating potential as a safe alternative insecticide. Here, we investigated the applicability of erythritol as a novel toxicant method of termite control. Eastern subterranean termites, Reticulitermes flavipes Kollar (Blattodea: Rhinotermitidae), were fed paper foods treated with increasing concentrations of erythritol and were assessed for mortality and bait consumption. Termite survival to 8 d (the duration of the experiment) significantly decreased as erythritol treatment concentration increased, indicating that the lethal effects of erythritol were concentration-dependent. Termites consumed erythritol-treated paper at all concentrations and did not display avoidance in choice assays, suggesting that erythritol may be practical for use as an ingestible bait. These results provide a basis for further development of erythritol as a safe alternative method of termite control.
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Affiliation(s)
- Virginia Caponera
- Department of Biodiversity Earth and Environmental Science, Drexel University, Philadelphia, PA
| | - Meghan Barrett
- Department of Biology, Drexel University, Philadelphia, PA
| | - Daniel R Marenda
- Department of Biology, Drexel University, Philadelphia, PA
- Neurobiology and Anatomy , Drexel University College of Medicine, Philadelphia, PA
| | - Sean O'donnell
- Department of Biodiversity Earth and Environmental Science, Drexel University, Philadelphia, PA
- Department of Biology, Drexel University, Philadelphia, PA
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10
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Lutz EK, Grewal TS, Riffell JA. Computational and experimental insights into the chemosensory navigation o f Aedes aegypti mosquito larvae. Proc Biol Sci 2019; 286:20191495. [PMID: 31744443 PMCID: PMC6892055 DOI: 10.1098/rspb.2019.1495] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Mosquitoes are prolific disease vectors that affect public health around the world. Although many studies have investigated search strategies used by host-seeking adult mosquitoes, little is known about larval search behaviour. Larval behaviour affects adult body size and fecundity, and thus the capacity of individual mosquitoes to find hosts and transmit disease. Understanding vector survival at all life stages is crucial for improving disease control. In this study, we use experimental and computational methods to investigate the chemical ecology and search behaviour of Aedes aegypti mosquito larvae. We first show that larvae do not respond to several olfactory cues used by adult Ae. aegypti to assess larval habitat quality, but perceive microbial RNA as a potent foraging attractant. Second, we demonstrate that Ae. aegypti larvae use chemokinesis, an unusual search strategy, to navigate chemical gradients. Finally, we use computational modelling to demonstrate that larvae respond to starvation pressure by optimizing exploration behaviour—possibly critical for exploiting limited larval habitat types. Our results identify key characteristics of foraging behaviour in an important disease vector mosquito. In addition to implications for better understanding and control of disease vectors, this work establishes mosquito larvae as a tractable model for chemosensory behaviour and navigation.
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Affiliation(s)
- Eleanor K Lutz
- Department of Biology, University of Washington, Box 351800, Seattle, WA 98195, USA
| | - Tjinder S Grewal
- Department of Biochemistry, University of Washington, Box 357350, Seattle, WA 98195, USA
| | - Jeffrey A Riffell
- Department of Biology, University of Washington, Box 351800, Seattle, WA 98195, USA
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11
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Scepanovic G, Stewart BA. Analysis of Drosophila nervous system development following an early, brief exposure to ethanol. Dev Neurobiol 2019; 79:780-793. [PMID: 31472090 DOI: 10.1002/dneu.22718] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2019] [Revised: 07/22/2019] [Accepted: 08/27/2019] [Indexed: 01/09/2023]
Abstract
The effects of ethanol on neural function and development have been studied extensively, motivated in part by the addictive properties of alcohol and the neurodevelopmental deficits that arise in children with fetal alcohol spectrum disorder (FASD). Absent from this research area is a genetically tractable system to study the effects of early ethanol exposure on later neurodevelopmental and behavioral phenotypes. Here, we used embryos of the fruit fly, Drosophila melanogaster, as a model system to investigate the neuronal defects that arise after an early exposure to ethanol. We found several disruptions of neural development and morphology following a brief ethanol exposure during embryogenesis and subsequent changes in larval behavior. Altogether, this study establishes a new system to examine the effects of alcohol exposure in embryos and the potential to conduct large-scale genetics screens to uncover novel factors that sensitize or protect neurons to the effects of alcohol.
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Affiliation(s)
- Gordana Scepanovic
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario, Canada
| | - Bryan A Stewart
- Department of Cell and Systems Biology, University of Toronto, Toronto, Ontario, Canada.,Department of Biology, University of Toronto Mississauga, Mississauga, Ontario, Canada
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12
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Kudow N, Kamikouchi A, Tanimura T. Softness sensing and learning in Drosophila larvae. ACTA ACUST UNITED AC 2019; 222:jeb.196329. [PMID: 30833462 DOI: 10.1242/jeb.196329] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2018] [Accepted: 02/23/2019] [Indexed: 11/20/2022]
Abstract
Mechanosensation provides animals with important sensory information in addition to olfaction and gustation during feeding behavior. Here, we used Drosophila melanogaster larvae to investigate the role of softness sensing in behavior and learning. In the natural environment, larvae need to dig into soft foods for feeding. Finding foods that are soft enough to dig into is likely to be essential for their survival. We report that larvae can discriminate between different agar concentrations and prefer softer agar. Interestingly, we show that larvae on a harder surface search for a softer surface using memory associated with an odor, and that they evaluate foods by balancing softness and sweetness. These findings suggest that larvae integrate mechanosensory information with chemosensory input while foraging. Moreover, we found that the larval preference for softness is affected by genetic background.
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Affiliation(s)
- Nana Kudow
- Department of Biology, Faculty of Science, Kyushu University, Motooka 744, Fukuoka 819-0395, Japan.,Division of Biological Science, Graduate School of Science, Nagoya University, Furo, Chikusa, Aichi 464-8602, Japan
| | - Azusa Kamikouchi
- Division of Biological Science, Graduate School of Science, Nagoya University, Furo, Chikusa, Aichi 464-8602, Japan
| | - Teiichi Tanimura
- Department of Biology, Faculty of Science, Kyushu University, Motooka 744, Fukuoka 819-0395, Japan .,Division of Biological Science, Graduate School of Science, Nagoya University, Furo, Chikusa, Aichi 464-8602, Japan.,Department of Genetics, Leibniz Institute for Neurobiology (LIN), Brenneckestr. 6, 39118 Magdeburg, Germany
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13
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Weiglein A, Gerstner F, Mancini N, Schleyer M, Gerber B. One-trial learning in larval Drosophila. ACTA ACUST UNITED AC 2019; 26:109-120. [PMID: 30898973 PMCID: PMC6432171 DOI: 10.1101/lm.049106.118] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2018] [Accepted: 02/25/2019] [Indexed: 01/22/2023]
Abstract
Animals of many species are capable of “small data” learning, that is, of learning without repetition. Here we introduce larval Drosophila melanogaster as a relatively simple study case for such one-trial learning. Using odor-food associative conditioning, we first show that a sugar that is both sweet and nutritious (fructose) and sugars that are only sweet (arabinose) or only nutritious (sorbitol) all support appetitive one-trial learning. The same is the case for the optogenetic activation of a subset of dopaminergic neurons innervating the mushroom body, the memory center of the insects. In contrast, no one-trial learning is observed for an amino acid reward (aspartic acid). As regards the aversive domain, one-trial learning is demonstrated for high-concentration sodium chloride, but is not observed for a bitter tastant (quinine). Second, we provide follow-up, parametric analyses of odor-fructose learning. Specifically, we ascertain its dependency on the number and duration of training trials, the requirements for the behavioral expression of one-trial odor-fructose memory, its temporal stability, and the feasibility of one-trial differential conditioning. Our results set the stage for a neurogenetic analysis of one-trial learning and define the requirements for modeling mnemonic processes in the larva.
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Affiliation(s)
- Aliće Weiglein
- Department of Genetics, Leibniz Institute for Neurobiology, 39118 Magdeburg, Germany
| | - Florian Gerstner
- Department of Genetics, Leibniz Institute for Neurobiology, 39118 Magdeburg, Germany.,Department of Animal Physiology, University Bayreuth, 95447 Bayreuth, Germany
| | - Nino Mancini
- Department of Genetics, Leibniz Institute for Neurobiology, 39118 Magdeburg, Germany
| | - Michael Schleyer
- Department of Genetics, Leibniz Institute for Neurobiology, 39118 Magdeburg, Germany
| | - Bertram Gerber
- Department of Genetics, Leibniz Institute for Neurobiology, 39118 Magdeburg, Germany.,Institute of Biology, Otto von Guericke University Magdeburg, 39106 Magdeburg, Germany.,Center for Behavioral Brain Sciences, 39106 Magdeburg, Germany
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14
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Schleyer M, Fendt M, Schuller S, Gerber B. Associative Learning of Stimuli Paired and Unpaired With Reinforcement: Evaluating Evidence From Maggots, Flies, Bees, and Rats. Front Psychol 2018; 9:1494. [PMID: 30197613 PMCID: PMC6117914 DOI: 10.3389/fpsyg.2018.01494] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2018] [Accepted: 07/30/2018] [Indexed: 12/02/2022] Open
Abstract
Finding rewards and avoiding punishments are powerful goals of behavior. To maximize reward and minimize punishment, it is beneficial to learn about the stimuli that predict their occurrence, and decades of research have provided insight into the brain processes underlying such associative reinforcement learning. In addition, it is well known in experimental psychology, yet often unacknowledged in neighboring scientific disciplines, that subjects also learn about the stimuli that predict the absence of reinforcement. Here we evaluate evidence for both these learning processes. We focus on two study cases that both provide a baseline level of behavior against which the effects of associative learning can be assessed. Firstly, we report pertinent evidence from Drosophila larvae. A re-analysis of the literature reveals that through paired presentations of an odor A and a sugar reward (A+) the animals learn that the reward can be found where the odor is, and therefore show an above-baseline preference for the odor. In contrast, through unpaired training (A/+) the animals learn that the reward can be found precisely where the odor is not, and accordingly these larvae show a below-baseline preference for it (the same is the case, with inverted signs, for learning through taste punishment). In addition, we present previously unpublished data demonstrating that also during a two-odor, differential conditioning protocol (A+/B) both these learning processes take place in larvae, i.e., learning about both the rewarded stimulus A and the non-rewarded stimulus B (again, this is likewise the case for differential conditioning with taste punishment). Secondly, after briefly discussing published evidence from adult Drosophila, honeybees, and rats, we report an unpublished data set showing that relative to baseline behavior after truly random presentations of a visual stimulus A and punishment, rats exhibit memories of opposite valence upon paired and unpaired training. Collectively, the evidence conforms to classical findings in experimental psychology and suggests that across species animals associatively learn both through paired and through unpaired presentations of stimuli with reinforcement – with opposite valence. While the brain mechanisms of unpaired learning for the most part still need to be uncovered, the immediate implication is that using unpaired procedures as a mnemonically neutral control for associative reinforcement learning may be leading analyses astray.
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Affiliation(s)
- Michael Schleyer
- Department Genetics of Learning and Memory, Leibniz Institute for Neurobiology, Magdeburg, Germany
| | - Markus Fendt
- Institute for Pharmacology and Toxicology, Otto von Guericke University Magdeburg, Magdeburg, Germany.,Center for Behavioral Brain Sciences, Magdeburg, Germany
| | - Sarah Schuller
- Department Genetics of Learning and Memory, Leibniz Institute for Neurobiology, Magdeburg, Germany
| | - Bertram Gerber
- Department Genetics of Learning and Memory, Leibniz Institute for Neurobiology, Magdeburg, Germany.,Center for Behavioral Brain Sciences, Magdeburg, Germany.,Behavior Genetics, Institute for Biology, Otto von Guericke University Magdeburg, Magdeburg, Germany
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15
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Tomasiunaite U, Widmann A, Thum AS. Maggot Instructor: Semi-Automated Analysis of Learning and Memory in Drosophila Larvae. Front Psychol 2018; 9:1010. [PMID: 29973900 PMCID: PMC6019503 DOI: 10.3389/fpsyg.2018.01010] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2018] [Accepted: 05/31/2018] [Indexed: 11/21/2022] Open
Abstract
For several decades, Drosophila has been widely used as a suitable model organism to study the fundamental processes of associative olfactory learning and memory. More recently, this condition also became true for the Drosophila larva, which has become a focus for learning and memory studies based on a number of technical advances in the field of anatomical, molecular, and neuronal analyses. The ongoing efforts should be mentioned to reconstruct the complete connectome of the larval brain featuring a total of about 10,000 neurons and the development of neurogenic tools that allow individual manipulation of each neuron. By contrast, standardized behavioral assays that are commonly used to analyze learning and memory in Drosophila larvae exhibit no such technical development. Most commonly, a simple assay with Petri dishes and odor containers is used; in this method, the animals must be manually transferred in several steps. The behavioral approach is therefore labor-intensive and limits the capacity to conduct large-scale genetic screenings in small laboratories. To circumvent these limitations, we introduce a training device called the Maggot Instructor. This device allows automatic training up to 10 groups of larvae in parallel. To achieve such goal, we used fully automated, computer-controlled optogenetic activation of single olfactory neurons in combination with the application of electric shocks. We showed that Drosophila larvae trained with the Maggot Instructor establish an odor-specific memory, which is independent of handling and non-associative effects. The Maggot Instructor will allow to investigate the large collections of genetically modified larvae in a short period and with minimal human resources. Therefore, the Maggot Instructor should be able to help extensive behavioral experiments in Drosophila larvae to keep up with the current technical advancements. In the longer term, this condition will lead to a better understanding of how learning and memory are organized at the cellular, synaptic, and molecular levels in Drosophila larvae.
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Affiliation(s)
| | - Annekathrin Widmann
- Department of Biology, University of Konstanz, Konstanz, Germany.,Department of Molecular Neurobiology of Behavior, Georg-August-University Göttingen, Göttingen, Germany
| | - Andreas S Thum
- Department of Biology, University of Konstanz, Konstanz, Germany.,Department of Genetics, University of Leipzig, Leipzig, Germany
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16
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Pavin A, Fain K, DeHart A, Sitaraman D. Aversive and Appetitive Learning in Drosophila Larvae: A Simple and Powerful Suite of Laboratory Modules for Classroom or Open-ended Research Projects. JOURNAL OF UNDERGRADUATE NEUROSCIENCE EDUCATION : JUNE : A PUBLICATION OF FUN, FACULTY FOR UNDERGRADUATE NEUROSCIENCE 2018; 16:A177-A185. [PMID: 30057500 PMCID: PMC6057766] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Subscribe] [Scholar Register] [Received: 01/11/2018] [Revised: 04/27/2018] [Accepted: 04/28/2018] [Indexed: 06/08/2023]
Abstract
A key element of laboratory courses introducing students to neuroscience includes behavioral exercises. Associative learning experiments often conducted in research laboratories are difficult to perform and time consuming. Commonly, these experiments cannot be performed without extensive instrumentation or animal care facilities. Here, we describe three distinct laboratory modules that build on simple chemosensory and memory assays in Drosophila larvae. Additionally, we describe open-ended research projects using these assays that can be developed into semester long independent research experiences. Given that Drosophila is a genetic model organism, these simple behavioral assays can be used to generate multiple hypothesis driven projects aimed at identifying a gene or class of neurons involved in appetitive and aversive learning. These lab modules are ideally suited for undergraduates at all levels to experience and can be incorporated in a lower/upper level neuroscience course or as a high school outreach exercise. Further, these modules enable students to collect their own data sets, work in groups in collating large data sets, performing statistical comparisons, and presenting results in the form of short research papers or traditional laboratory reports that include a short literature review.
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Affiliation(s)
- Austin Pavin
- Department of Psychological Sciences, College of Arts and Sciences, University of San Diego, San Diego, CA-92110
| | - Kevin Fain
- Department of Psychological Sciences, College of Arts and Sciences, University of San Diego, San Diego, CA-92110
| | - Allison DeHart
- Department of Psychological Sciences, College of Arts and Sciences, University of San Diego, San Diego, CA-92110
| | - Divya Sitaraman
- Department of Psychological Sciences, College of Arts and Sciences, University of San Diego, San Diego, CA-92110
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17
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Staats S, Lüersen K, Wagner AE, Rimbach G. Drosophila melanogaster as a Versatile Model Organism in Food and Nutrition Research. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2018; 66:3737-3753. [PMID: 29619822 DOI: 10.1021/acs.jafc.7b05900] [Citation(s) in RCA: 60] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Drosophila melanogaster has been widely used in the biological sciences as a model organism. Drosophila has a relatively short life span of 60-80 days, which makes it attractive for life span studies. Moreover, approximately 60% of the fruit fly genes are orthologs to mammals. Thus, metabolic and signal transduction pathways are highly conserved. Maintenance and reproduction of Drosophila do not require sophisticated equipment and are rather cheap. Furthermore, there are fewer ethical issues involved in experimental Drosophila research compared with studies in laboratory rodents, such as rats and mice. Drosophila is increasingly recognized as a model organism in food and nutrition research. Drosophila is often fed complex solid diets based on yeast, corn, and agar. There are also so-called holidic diets available that are defined in terms of their amino acid, fatty acid, carbohydrate, vitamin, mineral, and trace element compositions. Feed intake, body composition, locomotor activity, intestinal barrier function, microbiota, cognition, fertility, aging, and life span can be systematically determined in Drosophila in response to dietary factors. Furthermore, diet-induced pathophysiological mechanisms including inflammation and stress responses may be evaluated in the fly under defined experimental conditions. Here, we critically evaluate Drosophila melanogaster as a versatile model organism in experimental food and nutrition research, review the corresponding data in the literature, and make suggestions for future directions of research.
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Affiliation(s)
- Stefanie Staats
- Institute of Human Nutrition and Food Science , University of Kiel , Hermann-Rodewald-Strasse 6 , D-24118 Kiel , Germany
| | - Kai Lüersen
- Institute of Human Nutrition and Food Science , University of Kiel , Hermann-Rodewald-Strasse 6 , D-24118 Kiel , Germany
| | - Anika E Wagner
- Institute of Nutritional Medicine , University of Lübeck , Ratzeburger Allee 160 , D-23538 Lübeck , Germany
| | - Gerald Rimbach
- Institute of Human Nutrition and Food Science , University of Kiel , Hermann-Rodewald-Strasse 6 , D-24118 Kiel , Germany
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18
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Widmann A, Eichler K, Selcho M, Thum AS, Pauls D. Odor-taste learning in Drosophila larvae. JOURNAL OF INSECT PHYSIOLOGY 2018; 106:47-54. [PMID: 28823531 DOI: 10.1016/j.jinsphys.2017.08.004] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Revised: 08/07/2017] [Accepted: 08/16/2017] [Indexed: 06/07/2023]
Abstract
The Drosophila larva is an attractive model system to study fundamental questions in the field of neuroscience. Like the adult fly, the larva offers a seemingly unlimited genetic toolbox, which allows one to visualize, silence or activate neurons down to the single cell level. This, combined with its simplicity in terms of cell numbers, offers a useful system to study the neuronal correlates of complex processes including associative odor-taste learning and memory formation. Here, we summarize the current knowledge about odor-taste learning and memory at the behavioral level and integrate the recent progress on the larval connectome to shed light on the sub-circuits that allow Drosophila larvae to integrate present sensory input in the context of past experience and to elicit an appropriate behavioral response.
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Affiliation(s)
| | - Katharina Eichler
- Department of Biology, University of Konstanz, D-78464 Konstanz, Germany; HHMI Janelia Research Campus, 19700 Helix Drive, Ashburn, VA 20147, USA
| | - Mareike Selcho
- Department of Neurobiology and Genetics, Theodor-Boveri-Institute, Biocenter, University of Würzburg, D-97074 Würzburg, Germany
| | - Andreas S Thum
- Department of Biology, University of Konstanz, D-78464 Konstanz, Germany; Department of Genetics, University of Leipzig, D-04103 Leipzig, Germany.
| | - Dennis Pauls
- Department of Neurobiology and Genetics, Theodor-Boveri-Institute, Biocenter, University of Würzburg, D-97074 Würzburg, Germany.
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19
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Abstract
Taste allows animals to discriminate the value and potential toxicity of food prior to ingestion. Many tastants elicit an innate attractive or avoidance response that is modifiable with nutritional state and prior experience. A powerful genetic tool kit, well-characterized gustatory system, and standardized behavioral assays make the fruit fly, Drosophila melanogaster, an excellent system for investigating taste processing and memory. Recent studies have used this system to identify the neural basis for acquired taste preference. These studies have revealed a role for dopamine-mediated plasticity of the mushroom bodies that modulate the threshold of response to appetitive tastants. The identification of neural circuitry regulating taste memory provides a system to study the genetic and physiological processes that govern plasticity within a defined memory circuit.
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Affiliation(s)
- Pavel Masek
- a Department of Biology , Binghamton University , Binghamton , NY , USA
| | - Alex C Keene
- b Department of Biological Sciences , Florida Atlantic University , Jupiter , FL , USA
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20
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Almeida-Carvalho MJ, Berh D, Braun A, Chen YC, Eichler K, Eschbach C, Fritsch PMJ, Gerber B, Hoyer N, Jiang X, Kleber J, Klämbt C, König C, Louis M, Michels B, Miroschnikow A, Mirth C, Miura D, Niewalda T, Otto N, Paisios E, Pankratz MJ, Petersen M, Ramsperger N, Randel N, Risse B, Saumweber T, Schlegel P, Schleyer M, Soba P, Sprecher SG, Tanimura T, Thum AS, Toshima N, Truman JW, Yarali A, Zlatic M. The Ol1mpiad: concordance of behavioural faculties of stage 1 and stage 3 Drosophila larvae. J Exp Biol 2017; 220:2452-2475. [DOI: 10.1242/jeb.156646] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Accepted: 05/03/2017] [Indexed: 12/25/2022]
Abstract
ABSTRACT
Mapping brain function to brain structure is a fundamental task for neuroscience. For such an endeavour, the Drosophila larva is simple enough to be tractable, yet complex enough to be interesting. It features about 10,000 neurons and is capable of various taxes, kineses and Pavlovian conditioning. All its neurons are currently being mapped into a light-microscopical atlas, and Gal4 strains are being generated to experimentally access neurons one at a time. In addition, an electron microscopic reconstruction of its nervous system seems within reach. Notably, this electron microscope-based connectome is being drafted for a stage 1 larva – because stage 1 larvae are much smaller than stage 3 larvae. However, most behaviour analyses have been performed for stage 3 larvae because their larger size makes them easier to handle and observe. It is therefore warranted to either redo the electron microscopic reconstruction for a stage 3 larva or to survey the behavioural faculties of stage 1 larvae. We provide the latter. In a community-based approach we called the Ol1mpiad, we probed stage 1 Drosophila larvae for free locomotion, feeding, responsiveness to substrate vibration, gentle and nociceptive touch, burrowing, olfactory preference and thermotaxis, light avoidance, gustatory choice of various tastants plus odour–taste associative learning, as well as light/dark–electric shock associative learning. Quantitatively, stage 1 larvae show lower scores in most tasks, arguably because of their smaller size and lower speed. Qualitatively, however, stage 1 larvae perform strikingly similar to stage 3 larvae in almost all cases. These results bolster confidence in mapping brain structure and behaviour across developmental stages.
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Affiliation(s)
| | - Dimitri Berh
- Institute of Neurobiology and Behavioural Biology, University of Münster, 48149 Münster, Germany
- Department of Mathematics and Computer Science, University of Münster, 48149 Münster, Germany
| | - Andreas Braun
- EMBL/CRG Systems Biology Unit, Centre for Genomic Regulation, 08003 Barcelona, Spain
- Universitat Pompeu Fabra, 08002 Barcelona, Spain
| | - Yi-chun Chen
- Leibniz Institute for Neurobiology (Genetics), 39118 Magdeburg, Germany
| | - Katharina Eichler
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA
| | - Claire Eschbach
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA
| | | | - Bertram Gerber
- Leibniz Institute for Neurobiology (Genetics), 39118 Magdeburg, Germany
- Institute of Biology, Otto von Guericke University Magdeburg, 39118 Magdeburg, Germany
- Center for Behavioral Brain Sciences, Otto von Guericke University Magdeburg, 39106 Magdeburg, Germany
| | - Nina Hoyer
- Center for Molecular Neurobiology, University of Hamburg, 20251 Hamburg, Germany
| | - Xiaoyi Jiang
- Department of Mathematics and Computer Science, University of Münster, 48149 Münster, Germany
| | - Jörg Kleber
- Leibniz Institute for Neurobiology (Genetics), 39118 Magdeburg, Germany
| | - Christian Klämbt
- Institute of Neurobiology and Behavioural Biology, University of Münster, 48149 Münster, Germany
| | - Christian König
- Leibniz Institute for Neurobiology (Molecular Systems Biology), 39118 Magdeburg, Germany
- Institute of Pharmacology and Toxicology, Otto von Guericke University Magdeburg, 39118 Magdeburg, Germany
| | - Matthieu Louis
- EMBL/CRG Systems Biology Unit, Centre for Genomic Regulation, 08003 Barcelona, Spain
- Universitat Pompeu Fabra, 08002 Barcelona, Spain
- Department of Molecular, Cellular, and Developmental Biology, University of California, Santa Barbara, CA 93117, USA
| | - Birgit Michels
- Leibniz Institute for Neurobiology (Genetics), 39118 Magdeburg, Germany
| | | | - Christen Mirth
- Gulbenkian Institute of Science, 2780-156 Oeiras, Portugal
- School of Biological Sciences, Monash University, Melbourne, VIC 3800, Australia
| | - Daisuke Miura
- Department of Biology, Kyushu University, 819-0395 Fukuoka, Japan
| | - Thomas Niewalda
- Leibniz Institute for Neurobiology (Genetics), 39118 Magdeburg, Germany
| | - Nils Otto
- Institute of Neurobiology and Behavioural Biology, University of Münster, 48149 Münster, Germany
| | - Emmanouil Paisios
- Leibniz Institute for Neurobiology (Genetics), 39118 Magdeburg, Germany
| | | | - Meike Petersen
- Center for Molecular Neurobiology, University of Hamburg, 20251 Hamburg, Germany
| | - Noel Ramsperger
- Department of Biology, University of Konstanz, 78464 Konstanz, Germany
| | - Nadine Randel
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA
| | - Benjamin Risse
- Institute of Neurobiology and Behavioural Biology, University of Münster, 48149 Münster, Germany
- Department of Mathematics and Computer Science, University of Münster, 48149 Münster, Germany
| | - Timo Saumweber
- Leibniz Institute for Neurobiology (Genetics), 39118 Magdeburg, Germany
| | | | - Michael Schleyer
- Leibniz Institute for Neurobiology (Genetics), 39118 Magdeburg, Germany
| | - Peter Soba
- Center for Molecular Neurobiology, University of Hamburg, 20251 Hamburg, Germany
| | - Simon G. Sprecher
- Department of Biology, University of Fribourg, 1700 Fribourg, Switzerland
| | - Teiichi Tanimura
- Department of Biology, Kyushu University, 819-0395 Fukuoka, Japan
| | - Andreas S. Thum
- Department of Biology, University of Konstanz, 78464 Konstanz, Germany
| | - Naoko Toshima
- Leibniz Institute for Neurobiology (Genetics), 39118 Magdeburg, Germany
- Department of Biology, Kyushu University, 819-0395 Fukuoka, Japan
| | - Jim W. Truman
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA
- Friday Harbor Laboratories, University of Washington, Friday Harbor, WA 98250, USA
| | - Ayse Yarali
- Center for Behavioral Brain Sciences, Otto von Guericke University Magdeburg, 39106 Magdeburg, Germany
- Leibniz Institute for Neurobiology (Molecular Systems Biology), 39118 Magdeburg, Germany
| | - Marta Zlatic
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA
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21
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Paisios E, Rjosk A, Pamir E, Schleyer M. Common microbehavioral "footprint" of two distinct classes of conditioned aversion. ACTA ACUST UNITED AC 2017; 24:191-198. [PMID: 28416630 PMCID: PMC5397685 DOI: 10.1101/lm.045062.117] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2017] [Accepted: 02/28/2017] [Indexed: 12/11/2022]
Abstract
Avoiding unfavorable situations is a vital skill and a constant task for any animal. Situations can be unfavorable because they feature something that the animal wants to escape from, or because they do not feature something that it seeks to obtain. We investigate whether the microbehavioral mechanisms by which these two classes of aversion come about are shared or distinct. We find that larval Drosophila avoid odors either previously associated with a punishment, or previously associated with the lack of a reward. These two classes of conditioned aversion are found to be strikingly alike at the microbehavioral level. In both cases larvae show more head casts when oriented toward the odor source than when oriented away, and direct fewer of their head casts toward the odor than away when oriented obliquely to it. Thus, conditioned aversion serving two qualitatively different functions—escape from a punishment or search for a reward—is implemented by the modulation of the same microbehavioral features. These features also underlie conditioned approach, albeit with opposite sign. That is, the larvae show conditioned approach toward odors previously associated with a reward, or with the lack of a punishment. In order to accomplish both these classes of conditioned approach the larvae show fewer head casts when oriented toward an odor, and direct more of their head casts toward it when they are headed obliquely. Given that the Drosophila larva is a genetically tractable model organism that is well suited to study simple circuits at the single-cell level, these analyses can guide future research into the neuronal circuits underlying conditioned approach and aversion, and the computational principles of conditioned search and escape.
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Affiliation(s)
- Emmanouil Paisios
- Leibniz Institute for Neurobiology (LIN), Department of Genetics of Learning and Memory, 39118 Magdeburg, Germany
| | - Annabell Rjosk
- Leibniz Institute for Neurobiology (LIN), Department of Genetics of Learning and Memory, 39118 Magdeburg, Germany
| | - Evren Pamir
- Leibniz Institute for Neurobiology (LIN), Department of Genetics of Learning and Memory, 39118 Magdeburg, Germany
| | - Michael Schleyer
- Leibniz Institute for Neurobiology (LIN), Department of Genetics of Learning and Memory, 39118 Magdeburg, Germany
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22
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Kudow N, Miura D, Schleyer M, Toshima N, Gerber B, Tanimura T. Preference for and learning of amino acids in larval Drosophila. Biol Open 2017; 6:365-369. [PMID: 28193602 PMCID: PMC5374393 DOI: 10.1242/bio.020412] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Relative to other nutrients, less is known about how animals sense amino acids and how behaviour is organized accordingly. This is a significant gap in our knowledge because amino acids are required for protein synthesis - and hence for life as we know it. Choosing Drosophila larvae as a case study, we provide the first systematic analysis of both the preference behaviour for, and the learning of, all 20 canonical amino acids in Drosophila We report that preference for individual amino acids differs according to the kind of amino acid, both in first-instar and in third-instar larvae. Our data suggest that this preference profile changes across larval instars, and that starvation during the third instar also alters this profile. Only aspartic acid turns out to be robustly attractive across all our experiments. The essentiality of amino acids does not appear to be a determinant of preference. Interestingly, although amino acids thus differ in their innate attractiveness, we find that all amino acids are equally rewarding. Similar discrepancies between innate attractiveness and reinforcing effect have previously been reported for other tastants, including sugars, bitter substances and salt. The present analyses will facilitate the ongoing search for the receptors, sensory neurons, and internal, homeostatic amino acid sensors in Drosophila.
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Affiliation(s)
- Nana Kudow
- Department of Biology, Faculty of Science, Kyushu University, Motooka 744, Fukuoka 819-0395, Japan
| | - Daisuke Miura
- Division of Biological Science, Graduate School of Systems Life Sciences, Kyushu University, Motooka 744, Fukuoka 819-0395, Japan
| | - Michael Schleyer
- Leibniz Institute for Neurobiology (LIN), Department Genetics of Learning and Memory, Brenneckestrasse 6, Magdeburg 39118, Germany
| | - Naoko Toshima
- Division of Biological Science, Graduate School of Systems Life Sciences, Kyushu University, Motooka 744, Fukuoka 819-0395, Japan.,Leibniz Institute for Neurobiology (LIN), Department Genetics of Learning and Memory, Brenneckestrasse 6, Magdeburg 39118, Germany
| | - Bertram Gerber
- Leibniz Institute for Neurobiology (LIN), Department Genetics of Learning and Memory, Brenneckestrasse 6, Magdeburg 39118, Germany.,Center for Behavioral Brain Sciences (CBBS), Universitätsplatz 2, 39106 Magdeburg, Germany.,Otto von Guericke University Magdeburg, Institute for Biology, Universitätsplatz 2, Magdeburg 39106, Germany
| | - Teiichi Tanimura
- Department of Biology, Faculty of Science, Kyushu University, Motooka 744, Fukuoka 819-0395, Japan .,Division of Biological Science, Graduate School of Systems Life Sciences, Kyushu University, Motooka 744, Fukuoka 819-0395, Japan
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23
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Asparch Y, Pontes G, Masagué S, Minoli S, Barrozo RB. Kissing bugs can generalize and discriminate between different bitter compounds. ACTA ACUST UNITED AC 2016; 110:99-106. [PMID: 27865772 DOI: 10.1016/j.jphysparis.2016.11.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2016] [Revised: 11/09/2016] [Accepted: 11/15/2016] [Indexed: 11/25/2022]
Abstract
Animals make use of contact chemoreception structures to examine the quality of potential food sources. During this evaluation they can detect nutritious compounds that promote feeding and recognize toxins that trigger evasive behaviors. Although animals can easily distinguish between stimuli of different gustatory qualities (bitter, salty, sweet, etc.), their ability to discriminate between compounds of the same quality may be limited. Numerous plants produce alkaloids, compounds that elicit aversive behaviors in phytophagous insects and almost uniformly evoke a bitter taste for man. In hematophagous insects, however, the effect of feeding deterrent molecules has been barely studied. Recent studies showed that feeding in Rhodnius prolixus can be negatively modulated by the presence of alkaloids such as quinine (QUI) and caffeine (CAF), compounds that elicit similar aversive responses. Here, we applied associative and non-associative learning paradigms to examine under two behavioral contexts the ability of R. prolixus to distinguish, discriminate and/or generalize between these two bitter compounds, QUI and CAF. Our results show that bugs innately repelled by bitter compounds can change their behavior from avoidance to indifference or even to preference according to their previous experiences. After an aversive operant conditioning with QUI or CAF, R. prolixus modified its behavior in a direct but also in a cross-compound manner, suggesting the occurrence of a generalization process between these two alkaloids. Conversely, after a long pre-exposure to each alkaloid, bugs decreased their avoidance to the compound used during pre-exposure but still expressed an avoidance of the novel compound, proving that QUI and CAF are detected separately. Our results suggest that R. prolixus is able to discriminate between QUI and CAF, although after an associative conditioning they express a symmetrical cross-generalization. This kind of studies adds insight into the gustatory sense of a blood-sucking model but also into the learning abilities of hematophagous insects.
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Affiliation(s)
- Yamila Asparch
- Laboratorio Fisiología de Insectos, IBBEA, CONICET-UBA, DBBE, Facultad Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Gina Pontes
- Laboratorio Fisiología de Insectos, IBBEA, CONICET-UBA, DBBE, Facultad Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Santiago Masagué
- Laboratorio Fisiología de Insectos, IBBEA, CONICET-UBA, DBBE, Facultad Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Sebastian Minoli
- Laboratorio Fisiología de Insectos, IBBEA, CONICET-UBA, DBBE, Facultad Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Romina B Barrozo
- Laboratorio Fisiología de Insectos, IBBEA, CONICET-UBA, DBBE, Facultad Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina.
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24
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Widmann A, Artinger M, Biesinger L, Boepple K, Peters C, Schlechter J, Selcho M, Thum AS. Genetic Dissection of Aversive Associative Olfactory Learning and Memory in Drosophila Larvae. PLoS Genet 2016; 12:e1006378. [PMID: 27768692 PMCID: PMC5074598 DOI: 10.1371/journal.pgen.1006378] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2016] [Accepted: 09/21/2016] [Indexed: 01/01/2023] Open
Abstract
Memory formation is a highly complex and dynamic process. It consists of different phases, which depend on various neuronal and molecular mechanisms. In adult Drosophila it was shown that memory formation after aversive Pavlovian conditioning includes—besides other forms—a labile short-term component that consolidates within hours to a longer-lasting memory. Accordingly, memory formation requires the timely controlled action of different neuronal circuits, neurotransmitters, neuromodulators and molecules that were initially identified by classical forward genetic approaches. Compared to adult Drosophila, memory formation was only sporadically analyzed at its larval stage. Here we deconstruct the larval mnemonic organization after aversive olfactory conditioning. We show that after odor-high salt conditioning larvae form two parallel memory phases; a short lasting component that depends on cyclic adenosine 3’5’-monophosphate (cAMP) signaling and synapsin gene function. In addition, we show for the first time for Drosophila larvae an anesthesia resistant component, which relies on radish and bruchpilot gene function, protein kinase C activity, requires presynaptic output of mushroom body Kenyon cells and dopamine function. Given the numerical simplicity of the larval nervous system this work offers a unique prospect for studying memory formation of defined specifications, at full-brain scope with single-cell, and single-synapse resolution. Learning and memory helps organisms to predict and adapt to events in their environment. Gained experience leaves traces of memory in the nervous system. Yet, memory formation in vertebrates and invertebrates is a highly complex and dynamic process that consists of different phases, which depend on various neuronal and molecular mechanisms. To understand which changes occur in a brain when it learns, we applied a reductionist approach. Instead of studying complex cases, we analyzed learning and memory in Drosophila larvae that have a simple brain that is genetically and behaviorally accessible and consists of only about 10,000 neurons. Drosophila larvae are able to learn to associate an odor with punishing high salt concentrations. It is therefore possible to correlate changes in larval behavior with molecular events in identifiable neurons after classical olfactory conditioning. We show that under these circumstances larvae form two parallel memory phases; a short lasting component (lSTM) that is molecularly conserved throughout the animal kingdom as it depends on the classical cAMP pathway. In parallel they establish a larval anesthesia resistant memory (lARM) that relies on a different molecular signal. lARM has not been described in larvae before.
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Affiliation(s)
| | - Marc Artinger
- Department of Biology, University of Konstanz, Germany
| | | | | | | | | | - Mareike Selcho
- Department of Neurobiology and Genetics, Theodor-Boveri-Institute, Biocenter, University of Würzburg, Germany
| | - Andreas S. Thum
- Department of Biology, University of Konstanz, Germany
- Zukunftskolleg, University of Konstanz, Germany
- * E-mail:
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25
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Apostolopoulou AA, Köhn S, Stehle B, Lutz M, Wüst A, Mazija L, Rist A, Galizia CG, Lüdke A, Thum AS. Caffeine Taste Signaling in Drosophila Larvae. Front Cell Neurosci 2016; 10:193. [PMID: 27555807 PMCID: PMC4977282 DOI: 10.3389/fncel.2016.00193] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2016] [Accepted: 07/19/2016] [Indexed: 11/13/2022] Open
Abstract
The Drosophila larva has a simple peripheral nervous system with a comparably small number of sensory neurons located externally at the head or internally along the pharynx to assess its chemical environment. It is assumed that larval taste coding occurs mainly via external organs (the dorsal, terminal, and ventral organ). However, the contribution of the internal pharyngeal sensory organs has not been explored. Here we find that larvae require a single pharyngeal gustatory receptor neuron pair called D1, which is located in the dorsal pharyngeal sensilla, in order to avoid caffeine and to associate an odor with caffeine punishment. In contrast, caffeine-driven reduction in feeding in non-choice situations does not require D1. Hence, this work provides data on taste coding via different receptor neurons, depending on the behavioral context. Furthermore, we show that the larval pharyngeal system is involved in bitter tasting. Using ectopic expressions, we show that the caffeine receptor in neuron D1 requires the function of at least four receptor genes: the putative co-receptors Gr33a, Gr66a, the putative caffeine-specific receptor Gr93a, and yet unknown additional molecular component(s). This suggests that larval taste perception is more complex than previously assumed already at the sensory level. Taste information from different sensory organs located outside at the head or inside along the pharynx of the larva is assembled to trigger taste guided behaviors.
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Affiliation(s)
- Anthi A Apostolopoulou
- Department of Biology, University of KonstanzKonstanz, Germany; Department of Biomedical Science, University of SheffieldSheffield, UK
| | - Saskia Köhn
- Department of Biology, University of Konstanz Konstanz, Germany
| | - Bernhard Stehle
- Department of Biology, University of Konstanz Konstanz, Germany
| | - Michael Lutz
- Department of Biology, University of Konstanz Konstanz, Germany
| | - Alexander Wüst
- Department of Biology, University of Konstanz Konstanz, Germany
| | - Lorena Mazija
- Department of Biology, University of Konstanz Konstanz, Germany
| | - Anna Rist
- Department of Biology, University of Konstanz Konstanz, Germany
| | - C Giovanni Galizia
- Department of Biology, University of KonstanzKonstanz, Germany; Zukunftskolleg, University of KonstanzKonstanz, Germany
| | - Alja Lüdke
- Department of Biology, University of KonstanzKonstanz, Germany; Zukunftskolleg, University of KonstanzKonstanz, Germany
| | - Andreas S Thum
- Department of Biology, University of KonstanzKonstanz, Germany; Zukunftskolleg, University of KonstanzKonstanz, Germany
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26
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Choi J, van Giesen L, Choi MS, Kang K, Sprecher SG, Kwon JY. A Pair of Pharyngeal Gustatory Receptor Neurons Regulates Caffeine-Dependent Ingestion in Drosophila Larvae. Front Cell Neurosci 2016; 10:181. [PMID: 27486388 PMCID: PMC4949222 DOI: 10.3389/fncel.2016.00181] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2016] [Accepted: 07/06/2016] [Indexed: 12/16/2022] Open
Abstract
The sense of taste is an essential chemosensory modality that enables animals to identify appropriate food sources and control feeding behavior. In particular, the recognition of bitter taste prevents animals from feeding on harmful substances. Feeding is a complex behavior comprised of multiple steps, and food quality is continuously assessed. We here examined the role of pharyngeal gustatory organs in ingestion behavior. As a first step, we constructed a gustatory receptor-to-neuron map of the larval pharyngeal sense organs, and examined corresponding gustatory receptor neuron (GRN) projections in the larval brain. Out of 22 candidate bitter compounds, we found 14 bitter compounds that elicit inhibition of ingestion in a dose-dependent manner. We provide evidence that certain pharyngeal GRNs are necessary and sufficient for the ingestion response of larvae to caffeine. Additionally, we show that a specific pair of pharyngeal GRNs, DP1, responds to caffeine by calcium imaging. In this study we show that a specific pair of GRNs in the pharyngeal sense organs coordinates caffeine sensing with regulation of behavioral responses such as ingestion. Our results indicate that in Drosophila larvae, the pharyngeal GRNs have a major role in sensing food palatability to regulate ingestion behavior. The pharyngeal sense organs are prime candidates to influence ingestion due to their position in the pharynx, and they may act as first level sensors of ingested food.
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Affiliation(s)
- Jaekyun Choi
- Department of Biological Sciences, Sungkyunkwan University, Suwon South Korea
| | - Lena van Giesen
- Department of Biology, Institute of Zoology, University of Fribourg, Fribourg Switzerland
| | - Min Sung Choi
- Department of Biological Sciences, Sungkyunkwan University, Suwon South Korea
| | - KyeongJin Kang
- Department of Anatomy and Cell Biology, Samsung Biomedical Research Institute, School of Medicine, Sungkyunkwan University, Suwon South Korea
| | - Simon G Sprecher
- Department of Biology, Institute of Zoology, University of Fribourg, Fribourg Switzerland
| | - Jae Young Kwon
- Department of Biological Sciences, Sungkyunkwan University, Suwon South Korea
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27
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Metarhizium anisopliae infection alters feeding and trophallactic behavior in the ant Solenopsis invicta. J Invertebr Pathol 2016; 138:24-9. [PMID: 27234423 DOI: 10.1016/j.jip.2016.05.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2015] [Revised: 05/13/2016] [Accepted: 05/23/2016] [Indexed: 12/19/2022]
Abstract
In social insects, social behavior may be changed in a way that preventing the spread of pathogens. We infected workers of the ant Solenopsis invicta with an entomopathogenic fungus Metarhizium anisopliae and then videotaped and/or measured worker feeding and trophallactic behavior. Results showed that fungal infected S. invicta enhanced their preference for bitter alkaloid chemical quinine on 3days after inoculation, which might be self-medication of S. invicta by ingesting more alkaloid substances in response to pathogenic infection. Furthermore, infected ants devoted more time to trophallactic behavior with their nestmates on 3days post inoculation, in return receiving more food. Increased interactions between exposed ants and their naive nestmates suggest the existence of social immunity in S. invicta. Overall, our study indicates that S. invicta may use behavioral defenses such as self-medication and social immunity in response to a M. anisopliae infection.
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28
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Kim H, Choi MS, Kang K, Kwon JY. Behavioral Analysis of Bitter Taste Perception in Drosophila Larvae. Chem Senses 2015; 41:85-94. [PMID: 26512069 DOI: 10.1093/chemse/bjv061] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Insect larvae, which recognize food sources through chemosensory cues, are a major source of global agricultural loss. Gustation is an important factor that determines feeding behavior, and the gustatory receptors (Grs) act as molecular receptors that recognize diverse chemicals in gustatory receptor neurons (GRNs). The behavior of Drosophila larvae is relatively simpler than the adult fly, and a gustatory receptor-to-neuron map was established in a previous study of the major external larval head sensory organs. Here, we extensively study the bitter taste responses of larvae using 2-choice behavioral assays. First, we tested a panel of 23 candidate bitter compounds to compare the behavioral responses of larvae and adults. We define 9 bitter compounds which elicit aversive behavior in a dose-dependent manner. A functional map of the larval GRNs was constructed with the use of Gr-GAL4 lines that drive expression of UAS-tetanus toxin and UAS-VR1 in specific gustatory neurons to identify bitter tastants-GRN combinations by suppressing and activating discrete subsets of taste neurons, respectively. Our results suggest that many gustatory neurons act cooperatively in larval bitter sensing, and that these neurons have different degrees of responsiveness to different bitter compounds.
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Affiliation(s)
- Haein Kim
- Department of Biological Sciences, Sungkyunkwan University, Suwon 16419, Republic of Korea and
| | - Min Sung Choi
- Department of Biological Sciences, Sungkyunkwan University, Suwon 16419, Republic of Korea and
| | - KyeongJin Kang
- Samsung Biomedical Research Institute, Department of Anatomy and Cell Biology, School of Medicine, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Jae Young Kwon
- Department of Biological Sciences, Sungkyunkwan University, Suwon 16419, Republic of Korea and
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29
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Apostolopoulou AA, Rist A, Thum AS. Taste processing in Drosophila larvae. Front Integr Neurosci 2015; 9:50. [PMID: 26528147 PMCID: PMC4602287 DOI: 10.3389/fnint.2015.00050] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2015] [Accepted: 09/25/2015] [Indexed: 02/04/2023] Open
Abstract
The sense of taste allows animals to detect chemical substances in their environment to initiate appropriate behaviors: to find food or a mate, to avoid hostile environments and predators. Drosophila larvae are a promising model organism to study gustation. Their simple nervous system triggers stereotypic behavioral responses, and the coding of taste can be studied by genetic tools at the single cell level. This review briefly summarizes recent progress on how taste information is sensed and processed by larval cephalic and pharyngeal sense organs. The focus lies on several studies, which revealed cellular and molecular mechanisms required to process sugar, salt, and bitter substances.
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Affiliation(s)
| | - Anna Rist
- Department of Biology, University of Konstanz Konstanz, Germany
| | - Andreas S Thum
- Department of Biology, University of Konstanz Konstanz, Germany ; Zukunftskolleg, University of Konstanz Konstanz, Germany
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30
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Abstract
We examine in Drosophila a group of ∼35 ionotropic receptors (IRs), the IR20a clade, about which remarkably little is known. Of 28 genes analyzed, GAL4 drivers representing 11 showed expression in the larva. Eight drivers labeled neurons of the pharynx, a taste organ, and three labeled neurons of the body wall that may be chemosensory. Expression was not observed in neurons of one taste organ, the terminal organ, although these neurons express many drivers of the Gr (Gustatory receptor) family. For most drivers of the IR20a clade, we observed expression in a single pair of cells in the animal, with limited coexpression, and only a fraction of pharyngeal neurons are labeled. The organization of IR20a clade expression thus appears different from the organization of the Gr family or the Odor receptor (Or) family in the larva. A remarkable feature of the larval pharynx is that some of its organs are incorporated into the adult pharynx, and several drivers of this clade are expressed in the pharynx of both larvae and adults. Different IR drivers show different developmental dynamics across the larval stages, either increasing or decreasing. Among neurons expressing drivers in the pharynx, two projection patterns can be distinguished in the CNS. Neurons exhibiting these two kinds of projection patterns may activate different circuits, possibly signaling the presence of cues with different valence. Taken together, the simplest interpretation of our results is that the IR20a clade encodes a class of larval taste receptors.
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31
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Schleyer M, Miura D, Tanimura T, Gerber B. Learning the specific quality of taste reinforcement in larval Drosophila. eLife 2015; 4. [PMID: 25622533 PMCID: PMC4302267 DOI: 10.7554/elife.04711] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2014] [Accepted: 12/22/2014] [Indexed: 11/13/2022] Open
Abstract
The only property of reinforcement insects are commonly thought to learn about is its value. We show that larval Drosophila not only remember the value of reinforcement (How much?), but also its quality (What?). This is demonstrated both within the appetitive domain by using sugar vs amino acid as different reward qualities, and within the aversive domain by using bitter vs high-concentration salt as different qualities of punishment. From the available literature, such nuanced memories for the quality of reinforcement are unexpected and pose a challenge to present models of how insect memory is organized. Given that animals as simple as larval Drosophila, endowed with but 10,000 neurons, operate with both reinforcement value and quality, we suggest that both are fundamental aspects of mnemonic processing-in any brain.
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Affiliation(s)
- Michael Schleyer
- Department of Genetics of Learning and Memory, Leibniz Institute for Neurobiology, Magdeburg, Germany
| | - Daisuke Miura
- Department of Biology, Kyushu University, Fukuoka, Japan
| | | | - Bertram Gerber
- Department of Genetics of Learning and Memory, Leibniz Institute for Neurobiology, Magdeburg, Germany
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32
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Saumweber T, Cano C, Klessen J, Eichler K, Fendt M, Gerber B. Immediate and punitive impact of mechanosensory disturbance on olfactory behaviour of larval Drosophila. Biol Open 2014; 3:1005-10. [PMID: 25260919 PMCID: PMC4197435 DOI: 10.1242/bio.20149183] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
The ability to respond to and to learn about mechanosensory disturbance is widespread among animals. Using Drosophila larvae, we describe how the frequency of mechanosensory disturbance ('buzz') affects three aspects of behaviour: free locomotion, innate olfactory preference, and potency as a punishment. We report that (i) during 2-3 seconds after buzz onset the larvae slowed down and then turned, arguably to escape this situation; this was seen for buzz frequencies of 10, 100, and 1000 Hz, (ii) innate olfactory preference was reduced when tested in the presence of the buzz; this effect was strongest for the 100 Hz frequency, (iii) after odour-buzz associative training, we observed escape from the buzz-associated odour; this effect was apparent for 10 and 100, but not for 1000 Hz. We discuss the multiple behavioural effects of mechanosensation and stress that the immediate effects on locomotion and the impact as punishment differ in their frequency-dependence. Similar dissociations between immediate, reflexive behavioural effects and reinforcement potency were previously reported for sweet, salty and bitter tastants. It should be interesting to see how these features map onto the organization of sensory, ascending pathways.
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Affiliation(s)
- Timo Saumweber
- Institut für Biologie, Universität Leipzig, Tierphysiologie, 04103 Leipzig, Germany Abteilung Genetik von Lernen und Gedächtnis, Leibniz Institut für Neurobiologie (LIN), 39118 Magdeburg, Germany
| | - Carmen Cano
- Institut für Biologie, Universität Leipzig, Genetik, 04103 Leipzig, Germany Present address: Institut für Psychologie, Universität Bonn, 53111 Bonn, Germany
| | - Juliane Klessen
- Abteilung Genetik von Lernen und Gedächtnis, Leibniz Institut für Neurobiologie (LIN), 39118 Magdeburg, Germany
| | - Katharina Eichler
- Institut für Biologie, Universität Leipzig, Genetik, 04103 Leipzig, Germany Present address: Institut für Biologie, Universität Konstanz, 78457 Konstanz, Germany
| | - Markus Fendt
- Institut für Pharmakologie und Toxikologie, Medizinische Fakultät, Otto-von-Guericke-Universität Magdeburg, 39120 Magdeburg, Germany Center for Behavioral Brain Science (CBBS), 39016 Magdeburg, Germany
| | - Bertram Gerber
- Abteilung Genetik von Lernen und Gedächtnis, Leibniz Institut für Neurobiologie (LIN), 39118 Magdeburg, Germany Institut für Biologie, Universität Leipzig, Genetik, 04103 Leipzig, Germany Center for Behavioral Brain Science (CBBS), 39016 Magdeburg, Germany Institut für Biologie, Otto von Guericke Universität Magdeburg, Verhaltensgenetik, 39106 Magdeburg, Germany
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33
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Abstract
Understanding social behaviour requires a study case that is simple enough to be tractable, yet complex enough to remain interesting. Do larval Drosophila meet these requirements? In a broad sense, this question can refer to effects of the mere presence of other larvae on the behaviour of a target individual. Here we focused in a more strict sense on ‘peer pressure’, that is on the question of whether the behaviour of a target individual larva is affected by what a surrounding group of larvae is doing. We found that innate olfactory preference of a target individual was neither affected (i) by the level of innate olfactory preference in the surrounding group nor (ii) by the expression of learned olfactory preference in the group. Likewise, learned olfactory preference of a target individual was neither affected (iii) by the level of innate olfactory preference of the surrounding group nor (iv) by the learned olfactory preference the group was expressing. We conclude that larval Drosophila thus do not take note of specifically what surrounding larvae are doing. This implies that in a strict sense, and to the extent tested, there is no social interaction between larvae. These results validate widely used en mass approaches to the behaviour of larval Drosophila.
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Affiliation(s)
- Thomas Niewalda
- Leibniz Institut für Neurobiologie (LIN), Abteilung Genetik von Lernen und Gedächtnis, Brenneckestrasse 6, 39118 Magdeburg, Germany
| | - Ines Jeske
- Universität Leipzig, Institut für Biologie, Genetik, Talstrasse 33, 04103 Leipzig, Germany
| | - Birgit Michels
- Leibniz Institut für Neurobiologie (LIN), Abteilung Genetik von Lernen und Gedächtnis, Brenneckestrasse 6, 39118 Magdeburg, Germany
| | - Bertram Gerber
- Leibniz Institut für Neurobiologie (LIN), Abteilung Genetik von Lernen und Gedächtnis, Brenneckestrasse 6, 39118 Magdeburg, Germany Otto von Guericke Universität Magdeburg, Institut für Biologie, Verhaltensgenetik, Universitätsplatz 2, 39106 Magdeburg, Germany Center of Behavioural Brain Science (CBBS), Universitätsplatz 2, 39106 Magdeburg, Germany
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König C, Schleyer M, Leibiger J, El-Keredy A, Gerber B. Bitter-sweet processing in larval Drosophila. Chem Senses 2014; 39:489-505. [PMID: 24833133 DOI: 10.1093/chemse/bju016] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
"Sweet-" and "bitter-" tasting substances distinctively support attractive and aversive choice behavior, respectively, and therefore are thought to be processed by distinct pathways. Interestingly, electrophysiological recordings in adult Drosophila suggest that bitter and salty tastants, in addition to activating bitter, salt, or bitter/salt sensory neurons, can also inhibit sweet-sensory neurons. However, the behavioral significance of such a potential for combinatorial coding is little understood. Using larval Drosophila as a study case, we find that the preference towards fructose is inhibited when assayed in the background of the bitter tastant quinine. When testing the influence of quinine on the preference to other, equally preferred sweet tastants, we find that these sweet tastants differ in their susceptibility to be inhibited by quinine. Such stimulus specificity argues that the inhibitory effect of quinine is not due to general effects on locomotion or nausea. In turn, not all bitter tastants have the same potency to inhibit sweet preference; notably, their inhibitory potency is not determined by the strength of the avoidance of them. Likewise, equally avoided concentrations of sodium chloride differ in their potency to inhibit sugar preference. Furthermore, Gr33a-Gal4-positive neurons, while being necessary for bitter avoidance, are dispensable for inhibition of the sweet pathway. Thus, interactions across taste modalities are behaviorally significant and, as we discuss, arguably diverse in mechanism. These results suggest that the coding of tastants and the organization of gustatory behavior may be more combinatorial than is generally acknowledged.
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Affiliation(s)
- Christian König
- Department of Genetics, Institute of Biology, University of Leipzig, Talstr. 33, 04103 Leipzig, Germany, Research Group Molecular Systems Biology of Learning, Leibniz Institute for Neurobiology, Brenneckestr. 6, 39118 Magdeburg, Germany
| | - Michael Schleyer
- Department of Genetics, Institute of Biology, University of Leipzig, Talstr. 33, 04103 Leipzig, Germany, Department of Genetics of Learning and Memory, Leibniz Institute for Neurobiology, Brenneckestr. 6, 39118 Magdeburg, Germany
| | - Judith Leibiger
- Department of Genetics, Institute of Biology, University of Leipzig, Talstr. 33, 04103 Leipzig, Germany, Department of Genetics of Learning and Memory, Leibniz Institute for Neurobiology, Brenneckestr. 6, 39118 Magdeburg, Germany
| | - Amira El-Keredy
- Department of Genetics, Faculty of Agriculture, Tanta University, Tanta-Kafr El-Sheikh Road, Seberbay Campus, 31527 Tanta, Egypt
| | - Bertram Gerber
- Department of Genetics of Learning and Memory, Leibniz Institute for Neurobiology, Brenneckestr. 6, 39118 Magdeburg, Germany, Institute of Biology, Otto von Guericke University of Magdeburg, Universitätsplatz 2, 39106 Magdeburg, Germany and Center for Behavioral Brain Sciences, Universitätsplatz 2, 39106 Magdeburg, Germany
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35
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Babin A, Kolly S, Schneider F, Dolivo V, Zini M, Kawecki TJ. Fruit flies learn to avoid odours associated with virulent infection. Biol Lett 2014; 10:20140048. [PMID: 24598110 DOI: 10.1098/rsbl.2014.0048] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
While learning to avoid toxic food is common in mammals and occurs in some insects, learning to avoid cues associated with infectious pathogens has received little attention. We demonstrate that Drosophila melanogaster show olfactory learning in response to infection with their virulent intestinal pathogen Pseudomonas entomophila. This pathogen was not aversive to taste when added to food. Nonetheless, flies exposed for 3 h to food laced with P. entomophila, and scented with an odorant, became subsequently less likely to choose this odorant than flies exposed to pathogen-laced food scented with another odorant. No such effect occurred after an otherwise identical treatment with an avirulent mutant of P. entomophila, indicating that the response is mediated by pathogen virulence. These results demonstrate that a virulent pathogen infection can act as an aversive unconditioned stimulus which flies can associate with food odours, and thus become less attracted to pathogen-contaminated food.
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Affiliation(s)
- Aurélie Babin
- Department of Ecology and Evolution, University of Lausanne, , CH 1015 Lausanne, Switzerland
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36
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Apostolopoulou AA, Hersperger F, Mazija L, Widmann A, Wüst A, Thum AS. Composition of agarose substrate affects behavioral output of Drosophila larvae. Front Behav Neurosci 2014; 8:11. [PMID: 24478658 PMCID: PMC3904111 DOI: 10.3389/fnbeh.2014.00011] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2013] [Accepted: 01/08/2014] [Indexed: 11/17/2022] Open
Abstract
In the last decade the Drosophila larva has evolved into a simple model organism offering the opportunity to integrate molecular genetics with systems neuroscience. This led to a detailed understanding of the neuronal networks for a number of sensory functions and behaviors including olfaction, vision, gustation and learning and memory. Typically, behavioral assays in use exploit simple Petri dish setups with either agarose or agar as a substrate. However, neither the quality nor the concentration of the substrate is generally standardized across these experiments and there is no data available on how larval behavior is affected by such different substrates. Here, we have investigated the effects of different agarose concentrations on several larval behaviors. We demonstrate that agarose concentration is an important parameter, which affects all behaviors tested: preference, feeding, learning and locomotion. Larvae can discriminate between different agarose concentrations, they feed differently on them, they can learn to associate an agarose concentration with an odor stimulus and change locomotion on a substrate of higher agarose concentration. Additionally, we have investigated the effect of agarose concentration on three quinine based behaviors: preference, feeding and learning. We show that in all cases examined the behavioral output changes in an agarose concentration-dependent manner. Our results suggest that comparisons between experiments performed on substrates differing in agarose concentration should be done with caution. It should be taken into consideration that the agarose concentration can affect the behavioral output and thereby the experimental outcomes per se potentially due to the initiation of an escape response or changes in foraging behavior on more rigid substrates.
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Affiliation(s)
| | | | - Lorena Mazija
- Department of Biology, University of Konstanz Konstanz, Germany
| | | | - Alexander Wüst
- Department of Biology, University of Konstanz Konstanz, Germany
| | - Andreas S Thum
- Department of Biology, University of Konstanz Konstanz, Germany
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37
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Apostolopoulou AA, Mazija L, Wüst A, Thum AS. The neuronal and molecular basis of quinine-dependent bitter taste signaling in Drosophila larvae. Front Behav Neurosci 2014; 8:6. [PMID: 24478653 PMCID: PMC3902218 DOI: 10.3389/fnbeh.2014.00006] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2013] [Accepted: 01/06/2014] [Indexed: 12/12/2022] Open
Abstract
The sensation of bitter substances can alert an animal that a specific type of food is harmful and should not be consumed. However, not all bitter compounds are equally toxic and some may even be beneficial in certain contexts. Thus, taste systems in general may have a broader range of functions than just in alerting the animal. In this study we investigate bitter sensing and processing in Drosophila larvae using quinine, a substance perceived by humans as bitter. We show that behavioral choice, feeding, survival, and associative olfactory learning are all directly affected by quinine. On the cellular level, we show that 12 gustatory sensory receptor neurons that express both GR66a and GR33a are required for quinine-dependent choice and feeding behavior. Interestingly, these neurons are not necessary for quinine-dependent survival or associative learning. On the molecular receptor gene level, the GR33a receptor, but not GR66a, is required for quinine-dependent choice behavior. A screen for gustatory sensory receptor neurons that trigger quinine-dependent choice behavior revealed that a single GR97a receptor gene expressing neuron located in the peripheral terminal sense organ is partially necessary and sufficient. For the first time, we show that the elementary chemosensory system of the Drosophila larva can serve as a simple model to understand the neuronal basis of taste information processing on the single cell level with respect to different behavioral outputs.
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Affiliation(s)
| | - Lorena Mazija
- Department of Biology, University of Konstanz Konstanz, Germany
| | - Alexander Wüst
- Department of Biology, University of Konstanz Konstanz, Germany
| | - Andreas S Thum
- Department of Biology, University of Konstanz Konstanz, Germany
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