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Ortega-Insaurralde I, Latorre-Estivalis JM, Costa-da-Silva AL, Cano A, Insausti TC, Morales HS, Pontes G, de Astrada MB, Ons S, DeGennaro M, Barrozo RB. The pharyngeal taste organ of a blood-feeding insect functions in food recognition. BMC Biol 2024; 22:63. [PMID: 38481317 PMCID: PMC10938694 DOI: 10.1186/s12915-024-01861-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Accepted: 03/06/2024] [Indexed: 03/17/2024] Open
Abstract
BACKGROUND Obligate blood-feeding insects obtain the nutrients and water necessary to ensure survival from the vertebrate blood. The internal taste sensilla, situated in the pharynx, evaluate the suitability of the ingested food. Here, through multiple approaches, we characterized the pharyngeal organ (PO) of the hematophagous kissing bug Rhodnius prolixus to determine its role in food assessment. The PO, located antero-dorsally in the pharynx, comprises eight taste sensilla that become bathed with the incoming blood. RESULTS We showed that these taste sensilla house gustatory receptor neurons projecting their axons through the labral nerves to reach the subesophageal zone in the brain. We found that these neurons are electrically activated by relevant appetitive and aversive gustatory stimuli such as NaCl, ATP, and caffeine. Using RNA-Seq, we examined the expression of sensory-related gene families in the PO. We identified gustatory receptors, ionotropic receptors, transient receptor potential channels, pickpocket channels, opsins, takeouts, neuropeptide precursors, neuropeptide receptors, and biogenic amine receptors. RNA interference assays demonstrated that the salt-related pickpocket channel Rproppk014276 is required during feeding of an appetitive solution of NaCl and ATP. CONCLUSIONS We provide evidence of the role of the pharyngeal organ in food evaluation. This work shows a comprehensive characterization of a pharyngeal taste organ in a hematophagous insect.
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Affiliation(s)
- Isabel Ortega-Insaurralde
- Laboratorio de Neuroetología de Insectos, Departamento Biodiversidad y Biología Experimental (DBBE), Instituto Biodiversidad Biología Experimental y Aplicada (IBBEA), CONICET, Facultad Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - José Manuel Latorre-Estivalis
- Laboratorio de Insectos Sociales, Instituto de Fisiología Biología Molecular y Neurociencias (IFIBYNE), CONICET, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Andre Luis Costa-da-Silva
- Department of Biological Sciences and Biomolecular Sciences Institute, Florida International University, Miami, FL, USA
| | - Agustina Cano
- Laboratorio de Neuroetología de Insectos, Departamento Biodiversidad y Biología Experimental (DBBE), Instituto Biodiversidad Biología Experimental y Aplicada (IBBEA), CONICET, Facultad Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
| | | | - Héctor Salas Morales
- Laboratorio de Neuroetología de Insectos, Departamento Biodiversidad y Biología Experimental (DBBE), Instituto Biodiversidad Biología Experimental y Aplicada (IBBEA), CONICET, Facultad Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Gina Pontes
- Laboratorio de Ecofisiología de Insectos, Departamento Biodiversidad y Biología Experimental (DBBE), Instituto Biodiversidad Biología Experimental y Aplicada (IBBEA), CONICET, Facultad Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Martín Berón de Astrada
- Laboratorio de Fisiología de la Visión, Departamento de Fisiología Biología Molecular y Celular (FBMC), Instituto de Biociencias Biotecnología y Biología Traslacional (IB3), Facultad Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Sheila Ons
- Laboratorio de Neurobiología de Insectos, Facultad de Ciencias Exactas (CENEXA), Centro Regional de Estudios Genómicos, CONICET, Universidad Nacional de La Plata, La Plata, Buenos Aires, Argentina
| | - Matthew DeGennaro
- Department of Biological Sciences and Biomolecular Sciences Institute, Florida International University, Miami, FL, USA
| | - Romina B Barrozo
- Laboratorio de Neuroetología de Insectos, Departamento Biodiversidad y Biología Experimental (DBBE), Instituto Biodiversidad Biología Experimental y Aplicada (IBBEA), CONICET, Facultad Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina.
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King BH, Gunathunga PB. Gustation in insects: taste qualities and types of evidence used to show taste function of specific body parts. JOURNAL OF INSECT SCIENCE (ONLINE) 2023; 23:11. [PMID: 37014302 PMCID: PMC10072106 DOI: 10.1093/jisesa/iead018] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Revised: 02/03/2023] [Accepted: 03/10/2023] [Indexed: 06/19/2023]
Abstract
The insect equivalent of taste buds are gustatory sensilla, which have been found on mouthparts, pharynxes, antennae, legs, wings, and ovipositors. Most gustatory sensilla are uniporous, but not all apparently uniporous sensilla are gustatory. Among sensilla containing more than one neuron, a tubular body on one dendrite is also indicative of a taste sensillum, with the tubular body adding tactile function. But not all taste sensilla are also tactile. Additional morphological criteria are often used to recognize if a sensillum is gustatory. Further confirmation of such criteria by electrophysiological or behavioral evidence is needed. The five canonical taste qualities to which insects respond are sweet, bitter, sour, salty, and umami. But not all tastants that insects respond to easily fit in these taste qualities. Categories of insect tastants can be based not only on human taste perception, but also on whether the response is deterrent or appetitive and on chemical structure. Other compounds that at least some insects taste include, but are not limited to: water, fatty acids, metals, carbonation, RNA, ATP, pungent tastes as in horseradish, bacterial lipopolysaccharides, and contact pheromones. We propose that, for insects, taste be defined not only as a response to nonvolatiles but also be restricted to responses that are, or are thought to be, mediated by a sensillum. This restriction is useful because some of the receptor proteins in gustatory sensilla are also found elsewhere.
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Measuring foraging preferences in bumble bees: a comparison of popular laboratory methods and a test for sucrose preferences following neonicotinoid exposure. Oecologia 2021; 196:963-976. [PMID: 34250559 DOI: 10.1007/s00442-021-04979-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Accepted: 06/23/2021] [Indexed: 10/20/2022]
Abstract
Animals develop food preferences based on taste, nutritional quality and to avoid environmental toxins. Yet, measuring preferences in an experimental setting can be challenging since ecologically realistic assays can be time consuming, while simplified assays may not capture natural sampling behavior. Field realism is a particular challenge when studying behavioral responses to environmental toxins in lab-based assays, given that toxins can themselves impact sampling behavior, masking our ability to detect preferences. We address these challenges by comparing different experimental methods for measuring sucrose concentration preference in bumble bees (Bombus impatiens), evaluating the utility of two preference chamber-based methods (ad libitum versus a novel restricted-sampling assay) in replicating bees' preferences when they fly freely between artificial flowers in a foraging arena. We find that the restricted-sampling method matched a free-flying scenario more closely than the ad libitum protocol, and we advocate for expanded use of this approach, given its ease of implementation. We then performed a second experiment using the new protocol to ask whether consuming the neonicotinoid pesticide imidacloprid, known to suppress feeding motivation, interfered with the expression of sucrose preferences. After consuming imidacloprid, bees were less likely to choose the higher-quality sucrose even as they gained experience with both options. Thus, we provide evidence that pesticides interfere with bees' ability to discriminate between floral rewards that differ in value. This work highlights a simple protocol for assessing realistic foraging preferences in bees and provides an efficient way for researchers to measure the impacts of anthropogenic factors on preference expression.
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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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Masagué S, Cano A, Asparch Y, Barrozo RB, Minoli S. Sensory discrimination between aversive salty and bitter tastes in an haematophagous insect. Eur J Neurosci 2020; 51:1867-1880. [PMID: 32048391 DOI: 10.1111/ejn.14702] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Revised: 02/07/2020] [Accepted: 02/09/2020] [Indexed: 12/31/2022]
Abstract
Sensory aversion is essential for avoiding prospective dangers. We studied the chemical perception of aversive compounds of different gustatory modalities (salty, bitter) in the haematophagous bug, Rhodnius prolixus. Over a walking arena, insects avoided a substrate embedded with 1M NaCl or KCl if provided with water as an alternative. However, no preferences were expressed when both salts were opposed to each other. A pre-exposure to amiloride interfered with the repellency of NaCl and KCl equally, suggesting that amiloride-sensitive receptors are involved in the detection of both salts. Discriminative experiments were then performed to determine whether R. prolixus can distinguish between these salts. An aversive operant conditioning involving either NaCl or KCl modulated the repellency of the conditioned salt, but also of the novel salt. Repellency levels of both salts were rigid to a chemical pre-exposure to any of both salts. When gustatory modalities were crossed by presenting as a choice NaCl and a bitter molecule as caffeine (Caf), no innate preferences were expressed. Aversive operant conditionings with either NaCl or Caf rendered unspecific changes in the repellency of both compounds. A chemical pre-exposure to Caf modulated the response to Caf but not to NaCl, suggesting the existence of two independent neural pathways for the detection of salts and bitter compounds. Overall results suggest that R. prolixus cannot discriminate molecules of the same gustatory modality (i.e. salty), but can distinguish between salty and bitter tastes. The potential use of aversive gustatory stimuli as a complement of commercially available olfactory repellents is discussed.
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Affiliation(s)
- Santiago Masagué
- Laboratorio Fisiología de Insectos, Instituto Biodiversidad Biología Experimental Aplicada, CONICET - UBA, Departamento Biodiversidad Biología Experimental, Facultad Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Agustina Cano
- Laboratorio Fisiología de Insectos, Instituto Biodiversidad Biología Experimental Aplicada, CONICET - UBA, Departamento Biodiversidad Biología Experimental, Facultad Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Yamila Asparch
- Laboratorio Fisiología de Insectos, Instituto Biodiversidad Biología Experimental Aplicada, CONICET - UBA, Departamento Biodiversidad Biología Experimental, Facultad Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Romina B Barrozo
- Laboratorio Fisiología de Insectos, Instituto Biodiversidad Biología Experimental Aplicada, CONICET - UBA, Departamento Biodiversidad Biología Experimental, Facultad Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Sebastian Minoli
- Laboratorio Fisiología de Insectos, Instituto Biodiversidad Biología Experimental Aplicada, CONICET - UBA, Departamento Biodiversidad Biología Experimental, Facultad Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
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Vinauger C. Vector cognition and neurobiology. CURRENT OPINION IN INSECT SCIENCE 2019; 34:68-72. [PMID: 31247420 DOI: 10.1016/j.cois.2019.04.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2019] [Revised: 04/01/2019] [Accepted: 04/02/2019] [Indexed: 06/09/2023]
Abstract
The processing and integration of sensory information are central to the ability of disease vector insects to find their hosts, and eventually transmit diseases. Deciphering the underlying mechanisms and the modulation of their behavioral responses to host cues is likely to reveal molecular pathways and neural processes, which could then be targeted for reducing the transmission rates of pathogens. In addition, the double role of prey and predator played by hosts imposes unique challenges on vectors, making them an underexploited model to study the evolution of sensory neurobiology and of cognitive processes in miniature brains. Here, I review the most recent advances on the cognitive abilities of triatomine bugs and mosquitoes, with a particular emphasis on their ability to learn and remember information.
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Affiliation(s)
- Clément Vinauger
- Department of Biochemistry, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA.
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Barrozo RB. Food recognition in hematophagous insects. CURRENT OPINION IN INSECT SCIENCE 2019; 34:55-60. [PMID: 31247418 DOI: 10.1016/j.cois.2019.03.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2018] [Revised: 02/20/2019] [Accepted: 03/01/2019] [Indexed: 06/09/2023]
Abstract
Hematophagous insects use heat, odors, visual cues and humidity emitted by vertebrate hosts to find them in space and time. Once they reach a host, they integrate multimodal information from its skin, and decide whether to bite or not. If skin conditions fulfil the insect's expectations, it bites and pumps a small quantity of blood. Again, only if the sampled blood fulfils the insect's feeding requirements, it continues with a full ingestion. Taste is involved in both timely linked evaluation processes via contact chemoreceptors located in different parts of their bodies, driving jointly food acceptance or rejection. However, the whole picture of how blood-sucking insects evaluate the quality of a potential host is poorly understood. Here, I summarize the actual knowledge about the feeding decision-making in blood-sucking insects. Being typically involved in the transmission of diseases to humans or livestock, a deeper understanding about factors affecting an essential process as feeding in these insects could help us to find new strategies to reduce interactions.
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Affiliation(s)
- Romina B Barrozo
- Grupo de Neuroetología de Insectos Vectores, Laboratorio Fisiología de Insectos, IBBEA, CONICET - UBA, Departamento Biodiversidad y Biología Experimental, Facultad Ciencias Exactas y Naturales, Universidad de Buenos Aires, Argentina.
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Minoli S, Cano A, Pontes G, Magallanes A, Roldán N, Barrozo RB. Learning Spatial Aversion Is Sensory-Specific in the Hematophagous Insect Rhodnius prolixus. Front Psychol 2018; 9:989. [PMID: 30038588 PMCID: PMC6047214 DOI: 10.3389/fpsyg.2018.00989] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2018] [Accepted: 05/28/2018] [Indexed: 12/04/2022] Open
Abstract
Even though innate behaviors are essential for assuring quick responses to expected stimuli, experience-dependent behavioral plasticity confers an advantage when unexpected conditions arise. As being rigidly responsive to too many stimuli can be biologically expensive, adapting preferences to time-dependent relevant environmental conditions provide a cheaper and wider behavioral reactivity. According to their specific life habits, animals prioritize different sensory modalities to maximize environment exploitation. Besides, when mediating learning processes, the salience of a stimulus usually plays a relevant role in determining the intensity of an association. Then, sensory prioritization might reflect an heterogeneity in the cognitive abilities of an individual. Here, we analyze in the kissing bug Rhodnius prolixus if stimuli from different sensory modalities generate different cognitive capacities under an operant aversive paradigm. In a 2-choice walking arena, by registering the spatial distribution of insects over an experimental arena, we evaluated firstly the innate responses of bugs confronted to mechanical (rough substrate), visual (green light), thermal (32°C heated plate), hygric (humidified substrate), gustatory (sodium chloride), and olfactory (isobutyric acid) stimuli. In further experimental series bugs were submitted to an aversive operant conditioning by pairing each stimulus with a negative reinforcement. Subsequent tests allowed us to analyze if the innate behaviors were modulated by such previous aversive experience. In our experimental setup mechanical and visual stimuli were neutral, the thermal cue was attractive, and the hygric, gustatory and olfactory ones were innately aversive. After the aversive conditioning, responses to the mechanical, the visual, the hygric and the gustatory stimuli were modulated while responses to the thermal and the olfactory stimuli remained rigid. We present evidences that the spatial learning capacities of R. prolixus are dependent on the sensory modality of the conditioned stimulus, regardless their innate valence (i.e., neutral, attractive, or aversive). These differences might be given by the biological relevance of the stimuli and/or by evolutionary aspects of the life traits of this hematophagous insect.
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Affiliation(s)
- Sebastian Minoli
- Laboratorio de Fisiología de Insectos, Instituto de Biodiversidad y Biología Experimental y Aplicada-CONICET, Buenos Aires, Argentina
- Departamento de Biodiversidad y Biología Experimental-FCEN, Universidad de Buenos Aires, Buenos Aires, Argentina
| | | | - Gina Pontes
- Laboratorio de Fisiología de Insectos, Instituto de Biodiversidad y Biología Experimental y Aplicada-CONICET, Buenos Aires, Argentina
- Departamento de Biodiversidad y Biología Experimental-FCEN, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Amorina Magallanes
- Laboratorio de Fisiología de Insectos, Instituto de Biodiversidad y Biología Experimental y Aplicada-CONICET, Buenos Aires, Argentina
- Departamento de Biodiversidad y Biología Experimental-FCEN, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Nahuel Roldán
- Laboratorio de Fisiología de Insectos, Instituto de Biodiversidad y Biología Experimental y Aplicada-CONICET, Buenos Aires, Argentina
- Departamento de Biodiversidad y Biología Experimental-FCEN, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Romina B. Barrozo
- Laboratorio de Fisiología de Insectos, Instituto de Biodiversidad y Biología Experimental y Aplicada-CONICET, Buenos Aires, Argentina
- Departamento de Biodiversidad y Biología Experimental-FCEN, Universidad de Buenos Aires, Buenos Aires, Argentina
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