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Boyan G, Ehrhardt E. From bristle to brain: embryonic development of topographic projections from basiconic sensilla in the antennal nervous system of the locust Schistocerca gregaria. Dev Genes Evol 2024; 234:33-44. [PMID: 38691194 PMCID: PMC11226553 DOI: 10.1007/s00427-024-00716-2] [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: 02/07/2024] [Accepted: 04/26/2024] [Indexed: 05/03/2024]
Abstract
The antennal flagellum of the locust S. gregaria is an articulated structure bearing a spectrum of sensilla that responds to sensory stimuli. In this study, we focus on the basiconic-type bristles as a model for sensory system development in the antenna. At the end of embryogenesis, these bristles are found at fixed locations and then on only the most distal six articulations of the antenna. They are innervated by a dendrite from a sensory cell cluster in the underlying epithelium, with each cluster directing fused axons topographically to an antennal tract running to the brain. We employ confocal imaging and immunolabeling to (a) identify mitotically active sense organ precursors for sensory cell clusters in the most distal annuli of the early embryonic antenna; (b) observe the subsequent spatial appearance of their neuronal progeny; and (c) map the spatial and temporal organization of axon projections from such clusters into the antennal tracts. We show that early in embryogenesis, proliferative precursors are localized circumferentially within discrete epithelial domains of the flagellum. Progeny first appear distally at the antennal tip and then sequentially in a proximal direction so that sensory neuron populations are distributed in an age-dependent manner along the antenna. Autotracing reveals that axon fasciculation with a tract is also sequential and reflects the location and age of the cell cluster along the most distal annuli. Cell cluster location and bristle location are therefore represented topographically and temporally within the axon profile of the tract and its projection to the brain.
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Affiliation(s)
- George Boyan
- Graduate School of Systemic Neuroscience, Biocenter, Ludwig-Maximilians-Universität München, Grosshadernerstrasse 2, Martinsried, 82152, Planegg, Germany.
| | - Erica Ehrhardt
- Graduate School of Systemic Neuroscience, Biocenter, Ludwig-Maximilians-Universität München, Grosshadernerstrasse 2, Martinsried, 82152, Planegg, Germany
- Institute of Zoology, AG Ito, Universität Zu Köln, Zülpicher Str. 47B, 50674, Cologne, Germany
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2
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Althaus V, Exner G, von Hadeln J, Homberg U, Rosner R. Anatomical organization of the cerebrum of the praying mantis Hierodula membranacea. J Comp Neurol 2024; 532:e25607. [PMID: 38501930 DOI: 10.1002/cne.25607] [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: 10/06/2023] [Revised: 02/22/2024] [Accepted: 03/07/2024] [Indexed: 03/20/2024]
Abstract
Many predatory animals, such as the praying mantis, use vision for prey detection and capture. Mantises are known in particular for their capability to estimate distances to prey by stereoscopic vision. While the initial visual processing centers have been extensively documented, we lack knowledge on the architecture of central brain regions, pivotal for sensory motor transformation and higher brain functions. To close this gap, we provide a three-dimensional (3D) reconstruction of the central brain of the Asian mantis, Hierodula membranacea. The atlas facilitates in-depth analysis of neuron ramification regions and aides in elucidating potential neuronal pathways. We integrated seven 3D-reconstructed visual interneurons into the atlas. In total, 42 distinct neuropils of the cerebrum were reconstructed based on synapsin-immunolabeled whole-mount brains. Backfills from the antenna and maxillary palps, as well as immunolabeling of γ-aminobutyric acid (GABA) and tyrosine hydroxylase (TH), further substantiate the identification and boundaries of brain areas. The composition and internal organization of the neuropils were compared to the anatomical organization of the brain of the fruit fly (Drosophila melanogaster) and the two available brain atlases of Polyneoptera-the desert locust (Schistocerca gregaria) and the Madeira cockroach (Rhyparobia maderae). This study paves the way for detailed analyses of neuronal circuitry and promotes cross-species brain comparisons. We discuss differences in brain organization between holometabolous and polyneopteran insects. Identification of ramification sites of the visual neurons integrated into the atlas supports previous claims about homologous structures in the optic lobes of flies and mantises.
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Affiliation(s)
- Vanessa Althaus
- Department of Biology, Animal Physiology, Philipps-University of Marburg, Marburg, Germany
| | - Gesa Exner
- Department of Biology, Animal Physiology, Philipps-University of Marburg, Marburg, Germany
- Center for Mind Brain and Behavior (CMBB), University of Marburg and Justus Liebig University of Giessen, Marburg, Germany
| | - Joss von Hadeln
- Department of Biology, Animal Physiology, Philipps-University of Marburg, Marburg, Germany
| | - Uwe Homberg
- Department of Biology, Animal Physiology, Philipps-University of Marburg, Marburg, Germany
- Center for Mind Brain and Behavior (CMBB), University of Marburg and Justus Liebig University of Giessen, Marburg, Germany
| | - Ronny Rosner
- Department of Biology, Animal Physiology, Philipps-University of Marburg, Marburg, Germany
- Department of Biology, Institute of Developmental Biology and Neurobiology, Johannes Gutenberg University of Mainz, Mainz, Germany
- Biosciences Institute, Henry Wellcome Building for Neuroecology, Newcastle University, Framlington Place, Newcastle upon Tyne, UK
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3
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Grob R, Müller VL, Grübel K, Rössler W, Fleischmann PN. Importance of magnetic information for neuronal plasticity in desert ants. Proc Natl Acad Sci U S A 2024; 121:e2320764121. [PMID: 38346192 PMCID: PMC10895258 DOI: 10.1073/pnas.2320764121] [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: 11/29/2023] [Accepted: 12/28/2023] [Indexed: 02/15/2024] Open
Abstract
Many animal species rely on the Earth's magnetic field during navigation, but where in the brain magnetic information is processed is still unknown. To unravel this, we manipulated the natural magnetic field at the nest entrance of Cataglyphis desert ants and investigated how this affects relevant brain regions during early compass calibration. We found that manipulating the Earth's magnetic field has profound effects on neuronal plasticity in two sensory integration centers. Magnetic field manipulations interfere with a typical look-back behavior during learning walks of naive ants. Most importantly, structural analyses in the ants' neuronal compass (central complex) and memory centers (mushroom bodies) demonstrate that magnetic information affects neuronal plasticity during early visual learning. This suggests that magnetic information does not only serve as a compass cue for navigation but also as a global reference system crucial for spatial memory formation. We propose a neural circuit for integration of magnetic information into visual guidance networks in the ant brain. Taken together, our results provide an insight into the neural substrate for magnetic navigation in insects.
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Affiliation(s)
- Robin Grob
- Department of Biology, Faculty of Natural Sciences, Norwegian University of Science and Technology, 7034Trondheim, Norway
- Division of Behavioral Physiology and Sociobiology (Zoology II), Biocenter, University of Würzburg, 97074Würzburg, Germany
| | - Valentin L. Müller
- Division of Behavioral Physiology and Sociobiology (Zoology II), Biocenter, University of Würzburg, 97074Würzburg, Germany
| | - Kornelia Grübel
- Division of Behavioral Physiology and Sociobiology (Zoology II), Biocenter, University of Würzburg, 97074Würzburg, Germany
| | - Wolfgang Rössler
- Division of Behavioral Physiology and Sociobiology (Zoology II), Biocenter, University of Würzburg, 97074Würzburg, Germany
| | - Pauline N. Fleischmann
- Division of Behavioral Physiology and Sociobiology (Zoology II), Biocenter, University of Würzburg, 97074Würzburg, Germany
- Department V - School of Mathematics and Science, Institute of Biology and Environmental Sciences, Carl von Ossietzky Universität Oldenburg, 26129Oldenburg, Germany
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4
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Boyan G, Williams L, Ehrhardt E. Central projections from Johnston's organ in the locust: Axogenesis and brain neuroarchitecture. Dev Genes Evol 2023; 233:147-159. [PMID: 37695323 PMCID: PMC10746777 DOI: 10.1007/s00427-023-00710-0] [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: 06/18/2023] [Accepted: 08/25/2023] [Indexed: 09/12/2023]
Abstract
Johnston's organ (Jo) acts as an antennal wind-sensitive and/or auditory organ across a spectrum of insect species and its axons universally project to the brain. In the locust, this pathway is already present at mid-embryogenesis but the process of fasciculation involved in its construction has not been investigated. Terminal projections into the fine neuropilar organization of the brain also remain unresolved, information essential not only for understanding the neural circuitry mediating Jo-mediated behavior but also for providing comparative data offering insights into its evolution. In our study here, we employ neuron-specific, axon-specific, and epithelial domain labels to show that the pathway to the brain of the locust is built in a stepwise manner during early embryogenesis as processes from Jo cell clusters in the pedicel fasciculate first with one another, and then with the two tracts constituting the pioneer axon scaffold of the antenna. A comparison of fasciculation patterns confirms that projections from cell clusters of Jo stereotypically associate with only one axon tract according to their location in the pedicellar epithelium, consistent with a topographic plan. At the molecular level, all neuronal elements of the Jo pathway to the brain express the lipocalin Lazarillo, a cell surface epitope that regulates axogenesis in the primary axon scaffold itself, and putatively during fasciculation of the Jo projections to the brain. Central projections from Jo first contact the primary axon scaffold of the deutocerebral brain at mid-embryogenesis, and in the adult traverse mechanosensory/motor neuropils similar to those in Drosophila. These axons then terminate among protocerebral commissures containing premotor interneurons known to regulate flight behavior.
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Affiliation(s)
- George Boyan
- Graduate School of Systemic Neuroscience, Biocenter, Ludwig-Maximilians-Universität München, Grosshadernerstrasse 2, 82152, Munich, Planegg-Martinsried, Germany.
| | - Leslie Williams
- Graduate School of Systemic Neuroscience, Biocenter, Ludwig-Maximilians-Universität München, Grosshadernerstrasse 2, 82152, Munich, Planegg-Martinsried, Germany
| | - Erica Ehrhardt
- Graduate School of Systemic Neuroscience, Biocenter, Ludwig-Maximilians-Universität München, Grosshadernerstrasse 2, 82152, Munich, Planegg-Martinsried, Germany
- Institute of Zoology, AG Ito, Universität Zu Köln, Zülpicher Str. 47B, 50674, Cologne, Germany
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Goulard R, Heinze S, Webb B. Emergent spatial goals in an integrative model of the insect central complex. PLoS Comput Biol 2023; 19:e1011480. [PMID: 38109465 PMCID: PMC10760860 DOI: 10.1371/journal.pcbi.1011480] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Revised: 01/02/2024] [Accepted: 12/01/2023] [Indexed: 12/20/2023] Open
Abstract
The insect central complex appears to encode and process spatial information through vector manipulation. Here, we draw on recent insights into circuit structure to fuse previous models of sensory-guided navigation, path integration and vector memory. Specifically, we propose that the allocentric encoding of location provided by path integration creates a spatially stable anchor for converging sensory signals that is relevant in multiple behavioural contexts. The allocentric reference frame given by path integration transforms a goal direction into a goal location and we demonstrate through modelling that it can enhance approach of a sensory target in noisy, cluttered environments or with temporally sparse stimuli. We further show the same circuit can improve performance in the more complex navigational task of route following. The model suggests specific functional roles for circuit elements of the central complex that helps explain their high preservation across insect species.
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Affiliation(s)
- Roman Goulard
- Lund Vision Group, Department of Biology, Lund University, Lund, Sweden
| | - Stanley Heinze
- Lund Vision Group, Department of Biology, Lund University, Lund, Sweden
| | - Barbara Webb
- Institute for Perception, Action, and Behaviour, School of Informatics, University of Edinburgh, Edinburgh, Scotland, United Kingdom
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Rössler W, Grob R, Fleischmann PN. The role of learning-walk related multisensory experience in rewiring visual circuits in the desert ant brain. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2022:10.1007/s00359-022-01600-y. [DOI: 10.1007/s00359-022-01600-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2022] [Revised: 11/21/2022] [Accepted: 12/02/2022] [Indexed: 12/13/2022]
Abstract
AbstractEfficient spatial orientation in the natural environment is crucial for the survival of most animal species. Cataglyphis desert ants possess excellent navigational skills. After far-ranging foraging excursions, the ants return to their inconspicuous nest entrance using celestial and panoramic cues. This review focuses on the question about how naïve ants acquire the necessary spatial information and adjust their visual compass systems. Naïve ants perform structured learning walks during their transition from the dark nest interior to foraging under bright sunlight. During initial learning walks, the ants perform rotational movements with nest-directed views using the earth’s magnetic field as an earthbound compass reference. Experimental manipulations demonstrate that specific sky compass cues trigger structural neuronal plasticity in visual circuits to integration centers in the central complex and mushroom bodies. During learning walks, rotation of the sky-polarization pattern is required for an increase in volume and synaptic complexes in both integration centers. In contrast, passive light exposure triggers light-spectrum (especially UV light) dependent changes in synaptic complexes upstream of the central complex. We discuss a multisensory circuit model in the ant brain for pathways mediating structural neuroplasticity at different levels following passive light exposure and multisensory experience during the performance of learning walks.
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Boyan G, Ehrhardt E. Early embryonic development of Johnston's organ in the antenna of the desert locust Schistocerca gregaria. Dev Genes Evol 2022; 232:103-113. [PMID: 36138225 PMCID: PMC9691482 DOI: 10.1007/s00427-022-00695-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2022] [Accepted: 09/13/2022] [Indexed: 01/30/2023]
Abstract
Johnston's organ has been shown to act as an antennal auditory organ across a spectrum of insect species. In the hemimetabolous desert locust Schistocerca gregaria, Johnston's organ must be functional on hatching and so develops in the pedicellar segment of the antenna during embryogenesis. Here, we employ the epithelial cell marker Lachesin to identify the pedicellar domain of the early embryonic antenna and then triple-label against Lachesin, the mitosis marker phosphohistone-3, and neuron-specific horseradish peroxidase to reveal the sense-organ precursors for Johnston's organ and their lineages. Beginning with a single progenitor at approximately a third of embryogenesis, additional precursors subsequently appear in both the ventral and dorsal pedicellar domains, each generating a lineage or clone. Lineage locations are remarkably conserved across preparations and ages, consistent with the epithelium possessing an underlying topographic coordinate system that determines the cellular organization of Johnston's organ. By mid-embryogenesis, twelve lineages are arranged circumferentially in the pedicel as in the adult structure. Each sense-organ precursor is associated with a smaller mitotically active cell from which the neuronal complement of each clone may derive. Neuron numbers within a clone increase in discrete steps with age and are invariant between clones and across preparations of a given age. At mid-embryogenesis, each clone comprises five cells consolidated into a tightly bound cartridge. A long scolopale extends apically from each cartridge to an insertion point in the epithelium, and bundled axons project basally toward the brain. Comparative data suggest mechanisms that might also regulate the developmental program of Johnston's organ in the locust.
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Affiliation(s)
- George Boyan
- Graduate School of Systemic Neuroscience, Biocenter, Ludwig-Maximilians-Universität München, Grosshadernerstrasse 2, 82152, Munich, Planegg-Martinsried, Germany.
| | - Erica Ehrhardt
- Graduate School of Systemic Neuroscience, Biocenter, Ludwig-Maximilians-Universität München, Grosshadernerstrasse 2, 82152, Munich, Planegg-Martinsried, Germany
- Institute of Zoology, Universität Zu Köln, Zülpicher Str. 47b, 50674, Cologne, Germany
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8
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Sansom TM, Oberst S, Richter A, Lai JCS, Saadatfar M, Nowotny M, Evans TA. Low radiodensity μCT scans to reveal detailed morphology of the termite leg and its subgenual organ. ARTHROPOD STRUCTURE & DEVELOPMENT 2022; 70:101191. [PMID: 35816830 DOI: 10.1016/j.asd.2022.101191] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2021] [Revised: 05/27/2022] [Accepted: 06/09/2022] [Indexed: 06/15/2023]
Abstract
Termites sense tiny substrate-borne vibrations through subgenual organs (SGOs) located within their legs' tibiae. Little is known about the SGOs' structure and physical properties. We applied high-resolution (voxel size 0.45 μm) micro-computed tomography (μCT) to Australian termites, Coptotermes lacteus and Nasutitermes exitiosus (Hill) to test two staining techniques. We compared the effectiveness of a single stain of Lugol's iodine solution (LS) to LS followed by Phosphotungstic acid (PTA) solutions (1% and 2%). We then present results of a soldier of Nasutitermes exitiosus combining μCT with LS + 2%PTS stains and scanning electron microscopy to exemplify the visualisation of their SGOs. The termite's SGO due to its approximately oval shape was shown to have a maximum diameter of 60 μm and a minimum of 48 μm, covering 60 ± 4% of the leg's cross-section and 90.4 ± 5% of the residual haemolymph channel. Additionally, the leg and residual haemolymph channel cross-sectional area decreased around the SGO by 33% and 73%, respectively. We hypothesise that this change in cross-sectional area amplifies the vibrations for the SGO. Since SGOs are directly connected to the cuticle, their mechanical properties and the geometric details identified here may enable new approaches to determine how termites sense micro-vibrations.
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Affiliation(s)
- Travers M Sansom
- University of Technology Sydney, Centre for Audio, Acoustics and Vibration, Sydney, NSW, 2007, Australia.
| | - Sebastian Oberst
- University of Technology Sydney, Centre for Audio, Acoustics and Vibration, Sydney, NSW, 2007, Australia; School of Engineering and IT, University of New South Wales Canberra, Northcott Dr, Campbell ACT, 2612, Australia.
| | - Adrian Richter
- Institute of Zoology and Evolutionary Research, Friedrich-Schiller-University, Jena, Germany
| | - Joseph C S Lai
- School of Engineering and IT, University of New South Wales Canberra, Northcott Dr, Campbell ACT, 2612, Australia
| | - Mohammad Saadatfar
- School of Civil Engineering, The University of Sydney, 2006, Sydney, Australia
| | - Manuela Nowotny
- Institute of Zoology and Evolutionary Research, Friedrich-Schiller-University, Jena, Germany
| | - Theodore A Evans
- School of Biological Sciences, The University of Western Australia, 35 Stirling Hwy, Crawley, WA, 6009, Australia
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Grob R, Holland Cunz O, Grübel K, Pfeiffer K, Rössler W, Fleischmann PN. Rotation of skylight polarization during learning walks is necessary to trigger neuronal plasticity in Cataglyphis ants. Proc Biol Sci 2022; 289:20212499. [PMID: 35078368 PMCID: PMC8790360 DOI: 10.1098/rspb.2021.2499] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Accepted: 01/05/2022] [Indexed: 01/11/2023] Open
Abstract
Many animals use celestial cues for impressive navigational performances in challenging habitats. Since the position of the sun and associated skylight cues change throughout the day and season, it is crucial to correct for these changes. Cataglyphis desert ants possess a time-compensated skylight compass allowing them to navigate back to their nest using the shortest way possible. The ants have to learn the sun's daily course (solar ephemeris) during initial learning walks (LW) before foraging. This learning phase is associated with substantial structural changes in visual neuronal circuits of the ant's brain. Here, we test whether the rotation of skylight polarization during LWs is the necessary cue to induce learning-dependent rewiring in synaptic circuits in high-order integration centres of the ant brain. Our results show that structural neuronal changes in the central complex and mushroom bodies are triggered only when LWs were performed under a rotating skylight polarization pattern. By contrast, when naive ants did not perform LWs, but were exposed to skylight cues, plasticity was restricted to light spectrum-dependent changes in synaptic complexes of the lateral complex. The results identify sky-compass cues triggering learning-dependent versus -independent neuronal plasticity during the behavioural transition from interior workers to outdoor foragers.
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Affiliation(s)
- Robin Grob
- Behavioural Physiology and Sociobiology (Zoology II), Biocentre, University of Würzburg, 97074 Würzburg, Germany
| | - Oliver Holland Cunz
- Behavioural Physiology and Sociobiology (Zoology II), Biocentre, University of Würzburg, 97074 Würzburg, Germany
| | - Kornelia Grübel
- Behavioural Physiology and Sociobiology (Zoology II), Biocentre, University of Würzburg, 97074 Würzburg, Germany
| | - Keram Pfeiffer
- Behavioural Physiology and Sociobiology (Zoology II), Biocentre, University of Würzburg, 97074 Würzburg, Germany
| | - Wolfgang Rössler
- Behavioural Physiology and Sociobiology (Zoology II), Biocentre, University of Würzburg, 97074 Würzburg, Germany
| | - Pauline N. Fleischmann
- Behavioural Physiology and Sociobiology (Zoology II), Biocentre, University of Würzburg, 97074 Würzburg, Germany
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Grob R, Heinig N, Grübel K, Rössler W, Fleischmann PN. Sex-specific and caste-specific brain adaptations related to spatial orientation in Cataglyphis ants. J Comp Neurol 2021; 529:3882-3892. [PMID: 34313343 DOI: 10.1002/cne.25221] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2021] [Revised: 07/19/2021] [Accepted: 07/20/2021] [Indexed: 11/10/2022]
Abstract
Cataglyphis desert ants are charismatic central place foragers. After long-ranging foraging trips, individual workers navigate back to their nest relying mostly on visual cues. The reproductive caste faces other orientation challenges, i.e. mate finding and colony foundation. Here we compare brain structures involved in spatial orientation of Cataglyphis nodus males, gynes, and foragers by quantifying relative neuropil volumes associated with two visual pathways, and numbers and volumes of antennal lobe (AL) olfactory glomeruli. Furthermore, we determined absolute numbers of synaptic complexes in visual and olfactory regions of the mushroom bodies (MB) and a major relay station of the sky-compass pathway to the central complex (CX). Both female castes possess enlarged brain centers for sensory integration, learning, and memory, reflected in voluminous MBs containing about twice the numbers of synaptic complexes compared with males. Overall, male brains are smaller compared with both female castes, but the relative volumes of the optic lobes and CX are enlarged indicating the importance of visual guidance during innate behaviors. Male ALs contain greatly enlarged glomeruli, presumably involved in sex-pheromone detection. Adaptations at both the neuropil and synaptic levels clearly reflect differences in sex-specific and caste-specific demands for sensory processing and behavioral plasticity underlying spatial orientation.
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Affiliation(s)
- Robin Grob
- Behavioral Physiology and Sociobiology (Zoology II), Biocentre, University of Würzburg, Würzburg, Germany
| | - Niklas Heinig
- Behavioral Physiology and Sociobiology (Zoology II), Biocentre, University of Würzburg, Würzburg, Germany
| | - Kornelia Grübel
- Behavioral Physiology and Sociobiology (Zoology II), Biocentre, University of Würzburg, Würzburg, Germany
| | - Wolfgang Rössler
- Behavioral Physiology and Sociobiology (Zoology II), Biocentre, University of Würzburg, Würzburg, Germany
| | - Pauline N Fleischmann
- Behavioral Physiology and Sociobiology (Zoology II), Biocentre, University of Würzburg, Würzburg, Germany
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11
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Habenstein J, Thamm M, Rössler W. Neuropeptides as potential modulators of behavioral transitions in the ant Cataglyphis nodus. J Comp Neurol 2021; 529:3155-3170. [PMID: 33950523 DOI: 10.1002/cne.25166] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Revised: 04/26/2021] [Accepted: 04/29/2021] [Indexed: 12/12/2022]
Abstract
Age-related behavioral plasticity is a major prerequisite for the ecological success of insect societies. Although ecological aspects of behavioral flexibility have been targeted in many studies, the underlying intrinsic mechanisms controlling the diverse changes in behavior along the individual life history of social insects are not completely understood. Recently, the neuropeptides allatostatin-A, corazonin, and tachykinin have been associated with the regulation of behavioral transitions in social insects. Here, we investigated changes in brain localization and expression of these neuropeptides following major behavioral transitions in Cataglyphis nodus ants. Our immunohistochemical analyses in the brain revealed that the overall branching pattern of neurons immunoreactive (ir) for the three neuropeptides is largely independent of the behavioral stages. Numerous allatostatin-A- and tachykinin-ir neurons innervate primary sensory neuropils and high-order integration centers of the brain. In contrast, the number of corazonergic neurons is restricted to only four neurons per brain hemisphere with cell bodies located in the pars lateralis and axons extending to the medial protocerebrum and the retrocerebral complex. Most interestingly, the cell-body volumes of these neurons are significantly increased in foragers compared to freshly eclosed ants and interior workers. Quantification of mRNA expression levels revealed a stage-related change in the expression of allatostatin-A and corazonin mRNA in the brain. Given the presence of the neuropeptides in major control centers of the brain and the neurohemal organs, these mRNA-changes strongly suggest an important modulatory role of both neuropeptides in the behavioral maturation of Cataglyphis ants.
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Affiliation(s)
- Jens Habenstein
- Behavioral Physiology and Sociobiology (Zoology II), Biocenter, University of Würzburg, Würzburg, Germany
| | - Markus Thamm
- Behavioral Physiology and Sociobiology (Zoology II), Biocenter, University of Würzburg, Würzburg, Germany
| | - Wolfgang Rössler
- Behavioral Physiology and Sociobiology (Zoology II), Biocenter, University of Würzburg, Würzburg, Germany
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