1
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Cheong HSJ, Boone KN, Bennett MM, Salman F, Ralston JD, Hatch K, Allen RF, Phelps AM, Cook AP, Phelps JS, Erginkaya M, Lee WCA, Card GM, Daly KC, Dacks AM. Organization of an ascending circuit that conveys flight motor state in Drosophila. Curr Biol 2024; 34:1059-1075.e5. [PMID: 38402616 PMCID: PMC10939832 DOI: 10.1016/j.cub.2024.01.071] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2023] [Revised: 12/08/2023] [Accepted: 01/29/2024] [Indexed: 02/27/2024]
Abstract
Natural behaviors are a coordinated symphony of motor acts that drive reafferent (self-induced) sensory activation. Individual sensors cannot disambiguate exafferent (externally induced) from reafferent sources. Nevertheless, animals readily differentiate between these sources of sensory signals to carry out adaptive behaviors through corollary discharge circuits (CDCs), which provide predictive motor signals from motor pathways to sensory processing and other motor pathways. Yet, how CDCs comprehensively integrate into the nervous system remains unexplored. Here, we use connectomics, neuroanatomical, physiological, and behavioral approaches to resolve the network architecture of two pairs of ascending histaminergic neurons (AHNs) in Drosophila, which function as a predictive CDC in other insects. Both AHN pairs receive input primarily from a partially overlapping population of descending neurons, especially from DNg02, which controls wing motor output. Using Ca2+ imaging and behavioral recordings, we show that AHN activation is correlated to flight behavior and precedes wing motion. Optogenetic activation of DNg02 is sufficient to activate AHNs, indicating that AHNs are activated by descending commands in advance of behavior and not as a consequence of sensory input. Downstream, each AHN pair targets predominantly non-overlapping networks, including those that process visual, auditory, and mechanosensory information, as well as networks controlling wing, haltere, and leg sensorimotor control. These results support the conclusion that the AHNs provide a predictive motor signal about wing motor state to mostly non-overlapping sensory and motor networks. Future work will determine how AHN signaling is driven by other descending neurons and interpreted by AHN downstream targets to maintain adaptive sensorimotor performance.
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Affiliation(s)
- Han S J Cheong
- Department of Biology, West Virginia University, Morgantown, WV 26505, USA; Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA; Zuckerman Institute, Columbia University, New York, NY 10027, USA
| | - Kaitlyn N Boone
- Department of Biology, West Virginia University, Morgantown, WV 26505, USA; Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA
| | - Marryn M Bennett
- Department of Biology, West Virginia University, Morgantown, WV 26505, USA
| | - Farzaan Salman
- Department of Biology, West Virginia University, Morgantown, WV 26505, USA
| | - Jacob D Ralston
- Department of Biology, West Virginia University, Morgantown, WV 26505, USA
| | - Kaleb Hatch
- Department of Biology, West Virginia University, Morgantown, WV 26505, USA
| | - Raven F Allen
- Department of Biology, West Virginia University, Morgantown, WV 26505, USA
| | - Alec M Phelps
- Department of Biology, West Virginia University, Morgantown, WV 26505, USA
| | - Andrew P Cook
- Department of Biology, West Virginia University, Morgantown, WV 26505, USA
| | - Jasper S Phelps
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA; Swiss Federal Institute of Technology Lausanne, 1015 Lausanne, Switzerland
| | - Mert Erginkaya
- Champalimaud Research, Champalimaud Centre for the Unknown, Lisbon 1400-038, Portugal
| | - Wei-Chung A Lee
- F.M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Gwyneth M Card
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, USA; Zuckerman Institute, Columbia University, New York, NY 10027, USA
| | - Kevin C Daly
- Department of Biology, West Virginia University, Morgantown, WV 26505, USA; Department of Neuroscience, West Virginia University, Morgantown, WV 26505, USA
| | - Andrew M Dacks
- Department of Biology, West Virginia University, Morgantown, WV 26505, USA; Department of Neuroscience, West Virginia University, Morgantown, WV 26505, USA.
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2
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Hoffmann A, Couzin-Fuchs E. Active smelling in the American cockroach. J Exp Biol 2023; 226:jeb245337. [PMID: 37750327 PMCID: PMC10651109 DOI: 10.1242/jeb.245337] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Accepted: 09/18/2023] [Indexed: 09/27/2023]
Abstract
Motion plays an essential role in sensory acquisition. From changing the position in which information can be acquired to fine-scale probing and active sensing, animals actively control the way they interact with the environment. In olfaction, movement impacts the time and location of odour sampling as well as the flow of odour molecules around the olfactory organs. Employing a detailed spatiotemporal analysis, we investigated how insect antennae interact with the olfactory environment in a species with a well-studied olfactory system - the American cockroach. Cockroaches were tested in a wind-tunnel setup during the presentation of odours with different attractivity levels: colony extract, butanol and linalool. Our analysis revealed significant changes in antennal kinematics when odours were presented, including a shift towards the stream position, an increase in vertical movement and high-frequency local oscillations. Nevertheless, the antennal shifting occurred predominantly in a single antenna while the overall range covered by both antennae was maintained throughout. These findings hold true for both static and moving stimuli and were more pronounced for attractive odours. Furthermore, we found that upon odour encounter, there was an increase in the occurrence of high-frequency antennal sweeps and vertical strokes, which were shown to impact the olfactory environment's statistics directly. Our study lays out a tractable system for exploring the tight coupling between sensing and movement, in which antennal sweeps, in parallel to mammalian sniffing, are actively involved in facilitating odour capture and transport, generating odour intermittency in environments with low air movement where cockroaches dwell.
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Affiliation(s)
- Antoine Hoffmann
- Department of Biology, University of Konstanz, 78457 Konstanz, Germany
- Department of Collective Behavior, Max Planck Institute of Animal Behavior, 78464 Konstanz, Germany
- IMPRS for Quantitative Behaviour, Ecology and Evolution, 78315 Radolfzell, Germany
| | - Einat Couzin-Fuchs
- Department of Biology, University of Konstanz, 78457 Konstanz, Germany
- Department of Collective Behavior, Max Planck Institute of Animal Behavior, 78464 Konstanz, Germany
- Centre for the Advanced Study of Collective Behaviour, University of Konstanz, 78464 Konstanz, Germany
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3
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Cheong HSJ, Boone KN, Bennett MM, Salman F, Ralston JD, Hatch K, Allen RF, Phelps AM, Cook AP, Phelps JS, Erginkaya M, Lee WCA, Card GM, Daly KC, Dacks AM. Organization of an Ascending Circuit that Conveys Flight Motor State. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.06.07.544074. [PMID: 37333334 PMCID: PMC10274802 DOI: 10.1101/2023.06.07.544074] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/20/2023]
Abstract
Natural behaviors are a coordinated symphony of motor acts which drive self-induced or reafferent sensory activation. Single sensors only signal presence and magnitude of a sensory cue; they cannot disambiguate exafferent (externally-induced) from reafferent sources. Nevertheless, animals readily differentiate between these sources of sensory signals to make appropriate decisions and initiate adaptive behavioral outcomes. This is mediated by predictive motor signaling mechanisms, which emanate from motor control pathways to sensory processing pathways, but how predictive motor signaling circuits function at the cellular and synaptic level is poorly understood. We use a variety of techniques, including connectomics from both male and female electron microscopy volumes, transcriptomics, neuroanatomical, physiological and behavioral approaches to resolve the network architecture of two pairs of ascending histaminergic neurons (AHNs), which putatively provide predictive motor signals to several sensory and motor neuropil. Both AHN pairs receive input primarily from an overlapping population of descending neurons, many of which drive wing motor output. The two AHN pairs target almost exclusively non-overlapping downstream neural networks including those that process visual, auditory and mechanosensory information as well as networks coordinating wing, haltere, and leg motor output. These results support the conclusion that the AHN pairs multi-task, integrating a large amount of common input, then tile their output in the brain, providing predictive motor signals to non-overlapping sensory networks affecting motor control both directly and indirectly.
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Affiliation(s)
- Han S. J. Cheong
- Department of Biology, West Virginia University, Morgantown, WV 26505, United States of America
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, United States of America
| | - Kaitlyn N. Boone
- Department of Biology, West Virginia University, Morgantown, WV 26505, United States of America
| | - Marryn M. Bennett
- Department of Biology, West Virginia University, Morgantown, WV 26505, United States of America
| | - Farzaan Salman
- Department of Biology, West Virginia University, Morgantown, WV 26505, United States of America
| | - Jacob D. Ralston
- Department of Biology, West Virginia University, Morgantown, WV 26505, United States of America
| | - Kaleb Hatch
- Department of Biology, West Virginia University, Morgantown, WV 26505, United States of America
| | - Raven F. Allen
- Department of Biology, West Virginia University, Morgantown, WV 26505, United States of America
| | - Alec M. Phelps
- Department of Biology, West Virginia University, Morgantown, WV 26505, United States of America
| | - Andrew P. Cook
- Department of Biology, West Virginia University, Morgantown, WV 26505, United States of America
| | - Jasper S. Phelps
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115, United States of America
| | - Mert Erginkaya
- Champalimaud Research, Champalimaud Centre for the Unknown, Lisbon, 1400-038, Portugal
| | - Wei-Chung A. Lee
- F.M. Kirby Neurobiology Center, Boston Children’s Hospital, Harvard Medical School, Boston, MA 02115, United States of America
| | - Gwyneth M. Card
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147, United States of America
- Zuckerman Institute, Columbia University, New York, NY 10027, United States of America
| | - Kevin C. Daly
- Department of Biology, West Virginia University, Morgantown, WV 26505, United States of America
- Department of Neuroscience, West Virginia University, Morgantown, WV 26505, United States of America
| | - Andrew M. Dacks
- Department of Biology, West Virginia University, Morgantown, WV 26505, United States of America
- Department of Neuroscience, West Virginia University, Morgantown, WV 26505, United States of America
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Daly KC, Dacks A. The self as part of the sensory ecology: how behavior affects sensation from the inside out. CURRENT OPINION IN INSECT SCIENCE 2023; 58:101053. [PMID: 37290318 DOI: 10.1016/j.cois.2023.101053] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2023] [Revised: 05/01/2023] [Accepted: 05/09/2023] [Indexed: 06/10/2023]
Abstract
Insects exhibit remarkable sensory and motor capabilities to successfully navigate their environment. As insects move, they activate sensory afferents. Hence, insects are inextricably part of their sensory ecology. Insects must correctly attribute self- versus external sources of sensory activation to make adaptive behavioral choices. This is achieved via corollary discharge circuits (CDCs), motor-to-sensory neuronal pathways providing predictive motor signals to sensory networks to coordinate sensory processing within the context of ongoing behavior. While CDCs provide predictive motor signals, their underlying mechanisms of action and functional consequences are diverse. Here, we describe inferred CDCs and identified corollary discharge interneurons (CDIs) in insects, highlighting their anatomical commonalities and our limited understanding of their synaptic integration into the nervous system. By using connectomics information, we demonstrate that the complexity with which identified CDIs integrate into the central nervous system (CNS) can be revealed.
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Talley JL, White EB, Willis MA. A comparison of odor plume-tracking behavior of walking and flying insects in different turbulent environments. J Exp Biol 2023; 226:281297. [PMID: 36354120 DOI: 10.1242/jeb.244254] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Accepted: 10/31/2022] [Indexed: 11/11/2022]
Abstract
Many animals locate food, mates and territories by following plumes of attractive odors. There are clear differences in the structure of this plume-tracking behavior depending on whether an animal is flying, swimming, walking or crawling. These differences could arise from different control rules used by the central nervous system during these different modes of locomotion or one set of rules interacting with the different environments while walking on the surface versus flying or swimming. Flow speeds and turbulence that characterize the environments where walking and flying insects track plumes may alter the structure of odor plumes in an environment-specific way that results in the same control rules generating behaviors that appear quite different. We tested these ideas by challenging walking male cockroaches, Periplaneta americana, and flying male moths, Manduca sexta, to track plumes of their species' sex pheromones in low wind speeds characteristic of cockroach experimental environments, higher wind speeds characteristic of moth experimental environments, and conditions ranging from low to high turbulence. Introducing a turbulence-generating structure into the flow significantly improved the flying plume tracker's ability to locate the odor source, and changed the structure of the behavior of both flying and walking plume trackers. Our results support the idea that plume trackers moving slowly along the substrate may use the spatial distribution of odor, while faster moving flying plume trackers may use the timing of odor encounters to steer to locate the source.
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Affiliation(s)
- Jennifer L Talley
- Department of Biology, Case Western Reserve University, Cleveland, OH 44106, USA.,Air Force Research Laboratory, Eglin Air Force Base, Eglin, FL 32542, USA
| | - Edward B White
- Department of Aerospace and Mechanical Engineering, Case Western Reserve University, Cleveland, OH 44106, USA.,Department of Aerospace Engineering, Texas A & M University, College Station, TX 77843, USA
| | - Mark A Willis
- Department of Biology, Case Western Reserve University, Cleveland, OH 44106, USA
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6
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Briggs AM, Hambly MG, Simão-Gurge RM, Garrison SM, Khaku Z, Van Susteren G, Lewis EE, Riffell JA, Luckhart S. Anopheles stephensi Feeding, Flight Behavior, and Infection With Malaria Parasites are Altered by Ingestion of Serotonin. Front Physiol 2022; 13:911097. [PMID: 35747317 PMCID: PMC9209645 DOI: 10.3389/fphys.2022.911097] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Accepted: 05/09/2022] [Indexed: 12/05/2022] Open
Abstract
Approximately 3.4 billion people are at risk of malaria, a disease caused by infection with Plasmodium spp. parasites, which are transmitted by Anopheles mosquitoes. Individuals with severe falciparum malaria often exhibit changes in circulating blood levels of biogenic amines, including reduced serotonin or 5-hydroxytryptamine (5-HT), and these changes are associated with disease pathology. In insects, 5-HT functions as an important neurotransmitter for many behaviors and biological functions. In Anopheles stephensi, we show that 5-HT is localized to innervation in the head, thorax, and midgut, suggesting a gut-to-brain signaling axis that could support the effects of ingested 5-HT on mosquito biology and behavioral responses. Given the changes in blood levels of 5-HT associated with severe malaria and the key roles that 5-HT plays in insect neurophysiology, we investigated the impact of ingesting blood with healthy levels of 5-HT (1.5 µM) or malaria-associated levels of 5-HT (0.15 µM) on various aspects of A. stephensi biology. In these studies, we provisioned 5-HT and monitored fecundity, lifespan, flight behavior, and blood feeding of A. stephensi. We also assessed the impact of 5-HT ingestion on infection of A. stephensi with the mouse malaria parasite Plasmodium yoelii yoelii 17XNL and the human malaria parasite Plasmodium falciparum. Our data show that ingestion of 5-HT associated with severe malaria increased mosquito flight velocity and investigation of visual objects in response to host odor (CO2). 5-HT ingestion in blood at levels associated with severe malaria also increased the tendency to take a second blood meal 4 days later in uninfected A. stephensi. In mosquitoes infected with P. y. yoelii 17XNL, feeding tendency was decreased when midgut oocysts were present but increased when sporozoites were present. In addition to these effects, treatment of A. stephensi with 5-HT associated with severe malaria increased infection success with P. y. yoelii 17XNL compared to control, while treatment with healthy levels of 5-HT decreased infection success with P. falciparum. These changes in mosquito behavior and infection success could be used as a basis to manipulate 5-HT signaling in vector mosquitoes for improved control of malaria parasite transmission.
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Affiliation(s)
- Anna M. Briggs
- Department of Entomology, Plant Pathology and Nematology, University of Idaho, Moscow, ID, United States
| | - Malayna G. Hambly
- Department of Entomology, Plant Pathology and Nematology, University of Idaho, Moscow, ID, United States
| | - Raquel M. Simão-Gurge
- Department of Entomology, Plant Pathology and Nematology, University of Idaho, Moscow, ID, United States
| | - Sarah M. Garrison
- Department of Entomology, Plant Pathology and Nematology, University of Idaho, Moscow, ID, United States
| | - Zainab Khaku
- Department of Entomology, Plant Pathology and Nematology, University of Idaho, Moscow, ID, United States
| | - Grace Van Susteren
- Department of Biology, University of Washington, Seattle, WA, United States
| | - Edwin E. Lewis
- Department of Entomology, Plant Pathology and Nematology, University of Idaho, Moscow, ID, United States
| | - Jeffrey A. Riffell
- Department of Biology, University of Washington, Seattle, WA, United States
| | - Shirley Luckhart
- Department of Entomology, Plant Pathology and Nematology, University of Idaho, Moscow, ID, United States
- Department of Biological Sciences, University of Idaho, Moscow, ID, United States
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Neupert S, McCulloch GA, Foster BJ, Waters JM, Szyszka P. Reduced olfactory acuity in recently flightless insects suggests rapid regressive evolution. BMC Ecol Evol 2022; 22:50. [PMID: 35429979 PMCID: PMC9013461 DOI: 10.1186/s12862-022-02005-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2021] [Accepted: 04/08/2022] [Indexed: 11/10/2022] Open
Abstract
Abstract
Background
Insects have exceptionally fast smelling capabilities, and some can track the temporal structure of odour plumes at rates above 100 Hz. It has been hypothesized that this fast smelling capability is an adaptation for flying. We test this hypothesis by comparing the olfactory acuity of sympatric flighted versus flightless lineages within a wing-polymorphic stonefly species.
Results
Our analyses of olfactory receptor neuron responses reveal that recently-evolved flightless lineages have reduced olfactory acuity. By comparing flighted versus flightless ecotypes with similar genetic backgrounds, we eliminate other confounding factors that might have affected the evolution of their olfactory reception mechanisms. Our detection of different patterns of reduced olfactory response strength and speed in independently wing-reduced lineages suggests parallel evolution of reduced olfactory acuity.
Conclusions
These reductions in olfactory acuity echo the rapid reduction of wings themselves, and represent an olfactory parallel to the convergent phenotypic shifts seen under selective gradients in other sensory systems (e.g. parallel loss of vision in cave fauna). Our study provides evidence for the hypothesis that flight poses a selective pressure on the speed and strength of olfactory receptor neuron responses and emphasizes the energetic costs of rapid olfaction.
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Rodriguez AM, Hambly MG, Jandu S, Simão-Gurge R, Lowder C, Lewis EE, Riffell JA, Luckhart S. Histamine Ingestion by Anopheles stephensi Alters Important Vector Transmission Behaviors and Infection Success with Diverse Plasmodium Species. Biomolecules 2021; 11:719. [PMID: 34064869 PMCID: PMC8151525 DOI: 10.3390/biom11050719] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2021] [Revised: 04/28/2021] [Accepted: 05/05/2021] [Indexed: 12/20/2022] Open
Abstract
An estimated 229 million people worldwide were impacted by malaria in 2019. The vectors of malaria parasites (Plasmodium spp.) are Anopheles mosquitoes, making their behavior, infection success, and ultimately transmission of great importance. Individuals with severe malaria can exhibit significantly increased blood concentrations of histamine, an allergic mediator in humans and an important insect neuromodulator, potentially delivered to mosquitoes during blood-feeding. To determine whether ingested histamine could alter Anopheles stephensi biology, we provisioned histamine at normal blood levels and at levels consistent with severe malaria and monitored blood-feeding behavior, flight activity, antennal and retinal responses to host stimuli and lifespan of adult female Anopheles stephensi. To determine the effects of ingested histamine on parasite infection success, we quantified midgut oocysts and salivary gland sporozoites in mosquitoes infected with Plasmodium yoelii and Plasmodium falciparum. Our data show that provisioning An. stephensi with histamine at levels consistent with severe malaria can enhance mosquito behaviors and parasite infection success in a manner that would be expected to amplify parasite transmission to and from human hosts. Such knowledge could be used to connect clinical interventions by reducing elevated histamine to mitigate human disease pathology with the delivery of novel lures for improved malaria control.
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Affiliation(s)
- Anna M. Rodriguez
- Department of Entomology, Plant Pathology and Nematology, University of Idaho, Moscow, ID 83843-3051, USA; (A.M.R.); (M.G.H.); (R.S.-G.); (C.L.); (E.E.L.)
| | - Malayna G. Hambly
- Department of Entomology, Plant Pathology and Nematology, University of Idaho, Moscow, ID 83843-3051, USA; (A.M.R.); (M.G.H.); (R.S.-G.); (C.L.); (E.E.L.)
| | - Sandeep Jandu
- Department of Biology, University of Washington, Seattle, WA 98195-1800, USA; (S.J.); (J.A.R.)
| | - Raquel Simão-Gurge
- Department of Entomology, Plant Pathology and Nematology, University of Idaho, Moscow, ID 83843-3051, USA; (A.M.R.); (M.G.H.); (R.S.-G.); (C.L.); (E.E.L.)
| | - Casey Lowder
- Department of Entomology, Plant Pathology and Nematology, University of Idaho, Moscow, ID 83843-3051, USA; (A.M.R.); (M.G.H.); (R.S.-G.); (C.L.); (E.E.L.)
| | - Edwin E. Lewis
- Department of Entomology, Plant Pathology and Nematology, University of Idaho, Moscow, ID 83843-3051, USA; (A.M.R.); (M.G.H.); (R.S.-G.); (C.L.); (E.E.L.)
| | - Jeffrey A. Riffell
- Department of Biology, University of Washington, Seattle, WA 98195-1800, USA; (S.J.); (J.A.R.)
| | - Shirley Luckhart
- Department of Entomology, Plant Pathology and Nematology, University of Idaho, Moscow, ID 83843-3051, USA; (A.M.R.); (M.G.H.); (R.S.-G.); (C.L.); (E.E.L.)
- Department of Biological Sciences, University of Idaho, Moscow, ID 83843-3051, USA
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Marin AC, Schaefer AT, Ackels T. Spatial information from the odour environment in mammalian olfaction. Cell Tissue Res 2021; 383:473-483. [PMID: 33515294 PMCID: PMC7872987 DOI: 10.1007/s00441-020-03395-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Accepted: 12/10/2020] [Indexed: 11/24/2022]
Abstract
The sense of smell is an essential modality for many species, in particular nocturnal and crepuscular mammals, to gather information about their environment. Olfactory cues provide information over a large range of distances, allowing behaviours ranging from simple detection and recognition of objects, to tracking trails and navigating using odour plumes from afar. In this review, we discuss the features of the natural olfactory environment and provide a brief overview of how odour information can be sampled and might be represented and processed by the mammalian olfactory system. Finally, we discuss recent behavioural approaches that address how mammals extract spatial information from the environment in three different contexts: odour trail tracking, odour plume tracking and, more general, olfactory-guided navigation. Recent technological developments have seen the spatiotemporal aspect of mammalian olfaction gain significant attention, and we discuss both the promising aspects of rapidly developing paradigms and stimulus control technologies as well as their limitations. We conclude that, while still in its beginnings, research on the odour environment offers an entry point into understanding the mechanisms how mammals extract information about space.
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Affiliation(s)
- Alina Cristina Marin
- Sensory Circuits and Neurotechnology Laboratory, The Francis Crick Institute, London, UK
- Department of Neuroscience, Physiology & Pharmacology, University College London, London, UK
| | - Andreas T Schaefer
- Sensory Circuits and Neurotechnology Laboratory, The Francis Crick Institute, London, UK.
- Department of Neuroscience, Physiology & Pharmacology, University College London, London, UK.
| | - Tobias Ackels
- Sensory Circuits and Neurotechnology Laboratory, The Francis Crick Institute, London, UK.
- Department of Neuroscience, Physiology & Pharmacology, University College London, London, UK.
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10
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Stöckl AL, Kelber A. Fuelling on the wing: sensory ecology of hawkmoth foraging. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2019; 205:399-413. [PMID: 30880349 PMCID: PMC6579779 DOI: 10.1007/s00359-019-01328-2] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2018] [Revised: 02/25/2019] [Accepted: 03/05/2019] [Indexed: 11/28/2022]
Abstract
Hawkmoths (Lepidoptera, Sphingidae) comprise around 1500 species, most of which forage on nectar from flowers in their adult stage, usually while hovering in front of the flower. The majority of species have a nocturnal lifestyle and are important nocturnal pollinators, but some species have turned to a diurnal lifestyle. Hawkmoths use visual and olfactory cues including CO2 and humidity to detect and recognise rewarding flowers; they find the nectary in the flowers by means of mechanoreceptors on the proboscis and vision, evaluate it with gustatory receptors on the proboscis, and control their hovering flight position using antennal mechanoreception and vision. Here, we review what is presently known about the sensory organs and sensory-guided behaviour that control feeding behaviour of this fascinating pollinator taxon. We also suggest that more experiments on hawkmoth behaviour in natural settings are needed to fully appreciate their sensory capabilities.
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Affiliation(s)
- Anna Lisa Stöckl
- Biozentrum, University of Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Almut Kelber
- Department of Biology, Lund University, Sölvegatan 35, 22362, Lund, Sweden.
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