1
|
Vilimelis Aceituno P, Dall'Osto D, Pisokas I. Theoretical principles explain the structure of the insect head direction circuit. eLife 2024; 13:e91533. [PMID: 38814703 PMCID: PMC11139481 DOI: 10.7554/elife.91533] [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: 08/02/2023] [Accepted: 03/28/2024] [Indexed: 05/31/2024] Open
Abstract
To navigate their environment, insects need to keep track of their orientation. Previous work has shown that insects encode their head direction as a sinusoidal activity pattern around a ring of neurons arranged in an eight-column structure. However, it is unclear whether this sinusoidal encoding of head direction is just an evolutionary coincidence or if it offers a particular functional advantage. To address this question, we establish the basic mathematical requirements for direction encoding and show that it can be performed by many circuits, all with different activity patterns. Among these activity patterns, we prove that the sinusoidal one is the most noise-resilient, but only when coupled with a sinusoidal connectivity pattern between the encoding neurons. We compare this predicted optimal connectivity pattern with anatomical data from the head direction circuits of the locust and the fruit fly, finding that our theory agrees with experimental evidence. Furthermore, we demonstrate that our predicted circuit can emerge using Hebbian plasticity, implying that the neural connectivity does not need to be explicitly encoded in the genetic program of the insect but rather can emerge during development. Finally, we illustrate that in our theory, the consistent presence of the eight-column organisation of head direction circuits across multiple insect species is not a chance artefact but instead can be explained by basic evolutionary principles.
Collapse
Affiliation(s)
| | - Dominic Dall'Osto
- Institute of Neuroinformatics, University of Zürich and ETH ZürichZurichSwitzerland
| | - Ioannis Pisokas
- School of Informatics, University of EdinburghEdinburghUnited Kingdom
| |
Collapse
|
2
|
Green DA, Polidori S, Stratton SM. Modular switches shift monarch butterfly migratory flight behavior at their Mexican overwintering sites. iScience 2024; 27:109063. [PMID: 38420583 PMCID: PMC10901092 DOI: 10.1016/j.isci.2024.109063] [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: 10/18/2023] [Revised: 01/05/2024] [Accepted: 01/25/2024] [Indexed: 03/02/2024] Open
Abstract
Eastern North American migratory monarch butterflies exhibit migratory behavioral states in fall and spring characterized by sun-dependent oriented flight. However, it is unclear how monarchs transition between these behavioral states at their overwintering site. Using a modified Mouritsen-Frost flight simulator, we confirm individual directionality and compass-based orientation (leading to group orientation) in fall migrants, and also uncover sustained flight propensity and direction-based flight reinforcement as distinctly migratory behavioral traits. By testing monarchs at their Mexican overwintering sites, we show that overwintering monarchs show reduced propensity for sustained flight and lose individual directionality, leading to the loss of group-level orientation. Overwintering fliers orient axially in a time-of-day dependent manner, which may indicate local versus long-distance directional heading. These results support a model of migratory flight behavior in which modular, state-dependent switches for flight propensity and orientation control are highly dynamic and are controlled in season- and location-dependent manners.
Collapse
Affiliation(s)
- Delbert A. Green
- Department of Ecology and Evolutionary Biology, University of Michigan—Ann Arbor, 1105 N. University Avenue, Ann Arbor, MI 48109, USA
| | - Sean Polidori
- Department of Ecology and Evolutionary Biology, University of Michigan—Ann Arbor, 1105 N. University Avenue, Ann Arbor, MI 48109, USA
| | - Samuel M. Stratton
- Department of Ecology and Evolutionary Biology, University of Michigan—Ann Arbor, 1105 N. University Avenue, Ann Arbor, MI 48109, USA
| |
Collapse
|
3
|
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.
Collapse
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
| |
Collapse
|
4
|
Wainwright JB, Schofield C, Conway M, Phillips D, Martin-Silverstone E, Brodrick EA, Cicconardi F, How MJ, Roberts NW, Montgomery SH. Multiple axes of visual system diversity in Ithomiini, an ecologically diverse tribe of mimetic butterflies. J Exp Biol 2023; 226:jeb246423. [PMID: 37921078 PMCID: PMC10714147 DOI: 10.1242/jeb.246423] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2023] [Accepted: 10/31/2023] [Indexed: 11/04/2023]
Abstract
The striking structural variation seen in arthropod visual systems can be explained by the overall quantity and spatio-temporal structure of light within habitats coupled with developmental and physiological constraints. However, little is currently known about how fine-scale variation in visual structures arises across shorter evolutionary and ecological scales. In this study, we characterise patterns of interspecific (between species), intraspecific (between sexes) and intraindividual (between eye regions) variation in the visual system of four ithomiine butterfly species. These species are part of a diverse 26-million-year-old Neotropical radiation where changes in mimetic colouration are associated with fine-scale shifts in ecology, such as microhabitat preference. Using a combination of selection analyses on visual opsin sequences, in vivo ophthalmoscopy, micro-computed tomography (micro-CT), immunohistochemistry, confocal microscopy and neural tracing, we quantify and describe physiological, anatomical and molecular traits involved in visual processing. Using these data, we provide evidence of substantial variation within the visual systems of Ithomiini, including: (i) relaxed selection on visual opsins, perhaps mediated by habitat preference, (ii) interspecific shifts in visual system physiology and anatomy, and (iii) extensive sexual dimorphism, including the complete absence of a butterfly-specific optic neuropil in the males of some species. We conclude that considerable visual system variation can exist within diverse insect radiations, hinting at the evolutionary lability of these systems to rapidly develop specialisations to distinct visual ecologies, with selection acting at the perceptual, processing and molecular level.
Collapse
Affiliation(s)
- J. Benito Wainwright
- School of Biological Sciences, University of Bristol, 24 Tyndall Avenue, Bristol BS8 1TQ, UK
| | - Corin Schofield
- School of Biological Sciences, University of Bristol, 24 Tyndall Avenue, Bristol BS8 1TQ, UK
| | - Max Conway
- School of Biological Sciences, University of Bristol, 24 Tyndall Avenue, Bristol BS8 1TQ, UK
| | - Daniel Phillips
- School of Biological Sciences, University of Bristol, 24 Tyndall Avenue, Bristol BS8 1TQ, UK
| | - Elizabeth Martin-Silverstone
- Bristol Palaeobiology Group, School of Earth Sciences, University of Bristol, 24 Tyndall Avenue, Bristol BS8 1TQ, UK
| | - Emelie A. Brodrick
- Living Systems Institute, University of Exeter, Stocker Road, Exeter EX4 4QD, UK
| | - Francesco Cicconardi
- School of Biological Sciences, University of Bristol, 24 Tyndall Avenue, Bristol BS8 1TQ, UK
| | - Martin J. How
- School of Biological Sciences, University of Bristol, 24 Tyndall Avenue, Bristol BS8 1TQ, UK
| | - Nicholas W. Roberts
- School of Biological Sciences, University of Bristol, 24 Tyndall Avenue, Bristol BS8 1TQ, UK
| | - Stephen H. Montgomery
- School of Biological Sciences, University of Bristol, 24 Tyndall Avenue, Bristol BS8 1TQ, UK
| |
Collapse
|
5
|
Beetz MJ, El Jundi B. The neurobiology of the Monarch butterfly compass. CURRENT OPINION IN INSECT SCIENCE 2023; 60:101109. [PMID: 37660836 DOI: 10.1016/j.cois.2023.101109] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Revised: 08/17/2023] [Accepted: 08/28/2023] [Indexed: 09/05/2023]
Abstract
Monarch butterflies (Danaus plexippus) have become a superb model system to unravel how the tiny insect brain controls an impressive navigation behavior, such as long-distance migration. Moreover, the ability to compare the neural substrate between migratory and nonmigratory Monarch butterflies provides us with an attractive model to specifically study how the insect brain is adapted for migration. We here review our current progress on the neural substrate of spatial orientation in Monarch butterflies and how their spectacular annual migration might be controlled by their brain. We also discuss open research questions, the answers to which will provide important missing pieces to obtain a full picture of insect migration - from the perception of orientation cues to the neural control of migration.
Collapse
Affiliation(s)
- M Jerome Beetz
- Zoology II, Biocenter, University of Würzburg, Würzburg, Germany
| | - Basil El Jundi
- Animal Physiology, Department of Biology, Norwegian University of Science and Technology, Trondheim, Norway.
| |
Collapse
|
6
|
Green Ii DA. Tracking technologies: advances driving new insights into monarch migration. CURRENT OPINION IN INSECT SCIENCE 2023; 60:101111. [PMID: 37678709 DOI: 10.1016/j.cois.2023.101111] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2023] [Revised: 09/01/2023] [Accepted: 09/02/2023] [Indexed: 09/09/2023]
Abstract
Understanding the rules of how monarch butterflies complete their annual North American migration will be clarified by studying them within a movement ecology framework. Insect movement ecology is growing at a rapid pace due to the development of novel monitoring systems that allow ever-smaller animals to be tracked at higher spatiotemporal resolution for longer periods of time. New innovations in tracking hardware and associated software, including miniaturization, energy autonomy, data management, and wireless communication, are reducing the size and increasing the capability of next-generation tracking technologies, bringing the goal of tracking monarchs over their entire migration closer within reach. These tools are beginning to be leveraged to provide insight into different aspects of monarch biology and ecology, and to contribute to a growing capacity to understand insect movement ecology more broadly and its impact on human life.
Collapse
Affiliation(s)
- Delbert A Green Ii
- Department of Ecology and Evolutionary Biology, University of Michigan, 1105 N University Ave, Ann Arbor, MI 48109, USA.
| |
Collapse
|
7
|
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.
Collapse
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
| |
Collapse
|
8
|
Garner D, Kind E, Nern A, Houghton L, Zhao A, Sancer G, Rubin GM, Wernet MF, Kim SS. Connectomic reconstruction predicts the functional organization of visual inputs to the navigation center of the Drosophila brain. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.29.569241. [PMID: 38076786 PMCID: PMC10705420 DOI: 10.1101/2023.11.29.569241] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/22/2023]
Abstract
Many animals, including humans, navigate their surroundings by visual input, yet we understand little about how visual information is transformed and integrated by the navigation system. In Drosophila melanogaster, compass neurons in the donut-shaped ellipsoid body of the central complex generate a sense of direction by integrating visual input from ring neurons, a part of the anterior visual pathway (AVP). Here, we densely reconstruct all neurons in the AVP using FlyWire, an AI-assisted tool for analyzing electron-microscopy data. The AVP comprises four neuropils, sequentially linked by three major classes of neurons: MeTu neurons, which connect the medulla in the optic lobe to the small unit of anterior optic tubercle (AOTUsu) in the central brain; TuBu neurons, which connect the anterior optic tubercle to the bulb neuropil; and ring neurons, which connect the bulb to the ellipsoid body. Based on neuronal morphologies, connectivity between different neural classes, and the locations of synapses, we identified non-overlapping channels originating from four types of MeTu neurons, which we further divided into ten subtypes based on the presynaptic connections in medulla and postsynaptic connections in AOTUsu. To gain an objective measure of the natural variation within the pathway, we quantified the differences between anterior visual pathways from both hemispheres and between two electron-microscopy datasets. Furthermore, we infer potential visual features and the visual area from which any given ring neuron receives input by combining the connectivity of the entire AVP, the MeTu neurons' dendritic fields, and presynaptic connectivity in the optic lobes. These results provide a strong foundation for understanding how distinct visual features are extracted and transformed across multiple processing stages to provide critical information for computing the fly's sense of direction.
Collapse
Affiliation(s)
- Dustin Garner
- Molecular, Cellular, and Developmental Biology, University of California Santa Barbara, Santa Barbara, CA, USA
| | - Emil Kind
- Department of Biology, Freie Universität Berlin, Berlin, Germany
| | - Aljoscha Nern
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
| | - Lucy Houghton
- Molecular, Cellular, and Developmental Biology, University of California Santa Barbara, Santa Barbara, CA, USA
| | - Arthur Zhao
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
| | - Gizem Sancer
- Department of Biology, Freie Universität Berlin, Berlin, Germany
| | - Gerald M. Rubin
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
| | | | - Sung Soo Kim
- Molecular, Cellular, and Developmental Biology, University of California Santa Barbara, Santa Barbara, CA, USA
| |
Collapse
|
9
|
Kendzel MJ, Parlin AF, Guerra PA. Gravisensation and modulation of gravitactic responses by other sensory cues in the monarch butterfly (Danaus plexippus). J Exp Biol 2023; 226:jeb245451. [PMID: 37818736 PMCID: PMC10651108 DOI: 10.1242/jeb.245451] [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: 12/21/2022] [Accepted: 10/03/2023] [Indexed: 10/13/2023]
Abstract
Using the monarch butterfly (Danaus plexippus), we studied how animals can use cues from multiple sensory modalities for deriving directional information from their environment to display oriented movement. Our work focused on determining how monarchs use gravity as a cue for oriented movement and determined how cues from other sensory modalities, cues that by themselves also produce oriented movement (visual and magnetic directional cues), might modulate gravisensation. In two tests of gravisensation (movement in a vertical tube; righting behavior), we found that monarchs display negative gravitaxis only (movement opposite to the direction of gravity). Negative gravitaxis can be modulated by either visual (light) or magnetic field cues (inclination angle) that provide directional information. The modulation of gravity-mediated responses, however, depends on the relationship between cues when presented during trials, such as when cues are in accord or in conflict. For example, when light cues that elicit positive phototaxis conflicted with negative gravitaxis (light from below the monarch), monarch gravisensation was unaffected by directional light cues. We also found that the antennae play a role in gravity-mediated movement (righting), as, with antennae removed, monarch movement behavior was no longer the same as when the antennae were intact. Our results demonstrate that monarchs can use and integrate multiple, multimodal cues for oriented movement, but that the use of such cues can be hierarchical (that is, one cue dominant for movement), and the hierarchy of cues, and the responses towards them when found together, depends on the physical relationships between cues during movement.
Collapse
Affiliation(s)
- Mitchell J. Kendzel
- Department of Biological Sciences, University of Cincinnati, Cincinnati, OH 45221, USA
| | - Adam F. Parlin
- Department of Biological Sciences, University of Cincinnati, Cincinnati, OH 45221, USA
| | - Patrick A. Guerra
- Department of Biological Sciences, University of Cincinnati, Cincinnati, OH 45221, USA
| |
Collapse
|
10
|
Jahn S, Althaus V, Heckmann J, Janning M, Seip AK, Takahashi N, Grigoriev C, Kolano J, Homberg U. Neuroarchitecture of the central complex in the Madeira cockroach Rhyparobia maderae: Pontine and columnar neuronal cell types. J Comp Neurol 2023; 531:1689-1714. [PMID: 37608556 DOI: 10.1002/cne.25535] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2023] [Revised: 07/27/2023] [Accepted: 08/03/2023] [Indexed: 08/24/2023]
Abstract
Insects have evolved remarkable abilities to navigate over short distances and during long-range seasonal migrations. The central complex (CX) is a navigation center in the insect brain that controls spatial orientation and directed locomotion. It is composed of the protocerebral bridge (PB), the upper (CBU) and lower (CBL) division of the central body, and a pair of noduli. While most of its functional organization and involvement in head-direction coding has been obtained from work on flies, bees, and locusts that largely rely on vision for navigation, little contribution has been provided by work on nocturnal species. To close this gap, we have investigated the columnar organization of the CX in the cockroach Rhyparobia maderae. Rhyparobia maderae is a highly agile nocturnal insect that relies largely but not exclusively on antennal information for navigation. A particular feature of the cockroach CX is an organization of the CBU and CBL into interleaved series of eight and nine columns. Single-cell tracer injections combined with imaging and 3D analysis revealed five systems of pontine neurons connecting columns along the vertical and horizontal axis and 18 systems of columnar neurons with topographically organized projection patterns. Among these are six types of neurons with no correspondence in other species. Many neurons send processes into the anterior lip, a brain area highly reduced in bees and unknown in flies. While sharing many features with the CX in other species, the cockroach CX shows some unique attributes that may be related to the ecological niche of this insect.
Collapse
Affiliation(s)
- Stefanie Jahn
- Animal Physiology, Department of Biology, Philipps University of Marburg, Marburg, Germany
| | - Vanessa Althaus
- Animal Physiology, Department of Biology, Philipps University of Marburg, Marburg, Germany
| | - Jannik Heckmann
- Animal Physiology, Department of Biology, Philipps University of Marburg, Marburg, Germany
| | - Mona Janning
- Animal Physiology, Department of Biology, Philipps University of Marburg, Marburg, Germany
| | - Ann-Katrin Seip
- Animal Physiology, Department of Biology, Philipps University of Marburg, Marburg, Germany
| | - Naomi Takahashi
- Animal Physiology, Department of Biology, Philipps University of Marburg, Marburg, Germany
| | - Clara Grigoriev
- Animal Physiology, Department of Biology, Philipps University of Marburg, Marburg, Germany
| | - Juliana Kolano
- Animal Physiology, Department of Biology, Philipps University of Marburg, Marburg, Germany
| | - Uwe Homberg
- Animal Physiology, Department of Biology, Philipps University of Marburg, Marburg, Germany
- Center for Mind Brain and Behavior (CMBB), University of Marburg and Justus Liebig University Giessen, Marburg, Germany
| |
Collapse
|
11
|
Wernet MF, Roberts NW, Belušič G. Non-celestial polarization vision in arthropods. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2023; 209:855-857. [PMID: 37874372 DOI: 10.1007/s00359-023-01679-x] [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: 09/24/2023] [Revised: 10/05/2023] [Accepted: 10/09/2023] [Indexed: 10/25/2023]
Abstract
Most insects can detect the pattern of polarized light in the sky with the dorsal rim area in their compound eyes and use this visual information to navigate in their environment by means of 'celestial' polarization vision. 'Non-celestial polarization vision', in contrast, refers to the ability of arthropods to analyze polarized light by means of the 'main' retina, excluding the dorsal rim area. The ability of using the main retina for polarization vision has been attracting sporadic, but steady attention during the last decade. This special issue of the Journal of Comparative Physiology A presents recent developments with a collection of seven original research articles, addressing different aspects of non-celestial polarization vision in crustaceans and insects. The contributions cover different sources of linearly polarized light in nature, the underlying retinal and neural mechanisms of object detection using polarization vision and the behavioral responses of arthropods to polarized reflections from water.
Collapse
Affiliation(s)
- Mathias F Wernet
- Division of Neurobiology, Institute of Biology, Fachbereich Biologie, Freie Universität Berlin, Chemie and PharmazieKönigin-Luise Strasse 1-3, 14195, Berlin, Germany
| | - Nicholas W Roberts
- Ecology of Vision Group, School of Biological Sciences, University of Bristol, Bristol, BS8 1TQ, UK
| | - Gregor Belušič
- Biotechnical Faculty, Department of Biology, University of Ljubljana, Večna Pot 111, 1000, Ljubljana, Slovenia.
| |
Collapse
|
12
|
Beetz MJ, Kraus C, El Jundi B. Neural representation of goal direction in the monarch butterfly brain. Nat Commun 2023; 14:5859. [PMID: 37730704 PMCID: PMC10511513 DOI: 10.1038/s41467-023-41526-w] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2022] [Accepted: 09/04/2023] [Indexed: 09/22/2023] Open
Abstract
Neural processing of a desired moving direction requires the continuous comparison between the current heading and the goal direction. While the neural basis underlying the current heading is well-studied, the coding of the goal direction remains unclear in insects. Here, we used tetrode recordings in tethered flying monarch butterflies to unravel how a goal direction is represented in the insect brain. While recording, the butterflies maintained robust goal directions relative to a virtual sun. By resetting their goal directions, we found neurons whose spatial tuning was tightly linked to the goal directions. Importantly, their tuning was unaffected when the butterflies changed their heading after compass perturbations, showing that these neurons specifically encode the goal direction. Overall, we here discovered invertebrate goal-direction neurons that share functional similarities to goal-direction cells reported in mammals. Our results give insights into the evolutionarily conserved principles of goal-directed spatial orientation in animals.
Collapse
Affiliation(s)
- M Jerome Beetz
- Zoology II, Biocenter, University of Würzburg, Würzburg, Germany.
| | - Christian Kraus
- Zoology II, Biocenter, University of Würzburg, Würzburg, Germany
- Animal Physiology, Department of Biology, Norwegian University of Science and Technology, Trondheim, Norway
| | - Basil El Jundi
- Zoology II, Biocenter, University of Würzburg, Würzburg, Germany
- Animal Physiology, Department of Biology, Norwegian University of Science and Technology, Trondheim, Norway
| |
Collapse
|
13
|
Sehadová H, Podlahová Š, Reppert SM, Sauman I. 3D reconstruction of larval and adult brain neuropils of two giant silk moth species: Hyalophora cecropia and Antheraea pernyi. JOURNAL OF INSECT PHYSIOLOGY 2023; 149:104546. [PMID: 37451537 DOI: 10.1016/j.jinsphys.2023.104546] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Revised: 06/21/2023] [Accepted: 07/07/2023] [Indexed: 07/18/2023]
Abstract
We present a detailed analysis of the brain anatomy of two saturniid species, the cecropia silk moth, Hyalophora cecropia, and the Chinese oak silk moth, Antheraea pernyi, including 3D reconstructions of the major brain neuropils in the larva and in male and female adults. The 3D reconstructions, prepared from high-resolution optical sections, showed that the corresponding neuropils of these saturniid species are virtually identical. Similarities between the two species include a pronounced sexual dimorphism in the adults in the form of a male-specific assembly of markedly enlarged glomeruli forming the so-called macroglomerular complex. From the reports published to date, it can be concluded that the neuropil architecture of saturniids resembles that of other nocturnal moths, including the sibling family Sphingidae. In addition, compared with previous anatomical data on diurnal lepidopteran species, significant differences were observed in the two saturniid species, which include the thickness of the Y-tract of the mushroom body, the size of the main neuropils of the optic lobes, and the sexual dimorphisms of the antennal lobes.
Collapse
Affiliation(s)
- Hana Sehadová
- Biology Centre CAS, Institute of Entomology, Branisovska 31, 370 05 Ceske Budejovice, Czech Republic; University of South Bohemia in Ceske Budejovice, Faculty of Science, Branisovska 31, 370 05 Ceske Budejovice, Czech Republic.
| | - Šárka Podlahová
- Biology Centre CAS, Institute of Entomology, Branisovska 31, 370 05 Ceske Budejovice, Czech Republic; University of South Bohemia in Ceske Budejovice, Faculty of Science, Branisovska 31, 370 05 Ceske Budejovice, Czech Republic.
| | - Steven M Reppert
- Department of Neurobiology, University of Massachusetts Medical School, 364 Plantation Street, Worcester, MA 01605, USA.
| | - Ivo Sauman
- Biology Centre CAS, Institute of Entomology, Branisovska 31, 370 05 Ceske Budejovice, Czech Republic; University of South Bohemia in Ceske Budejovice, Faculty of Science, Branisovska 31, 370 05 Ceske Budejovice, Czech Republic.
| |
Collapse
|
14
|
Hebberecht L, Wainwright JB, Thompson C, Kershenbaum S, McMillan WO, Montgomery SH. Plasticity and genetic effects contribute to different axes of neural divergence in a community of mimetic Heliconius butterflies. J Evol Biol 2023; 36:1116-1132. [PMID: 37341138 DOI: 10.1111/jeb.14188] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Revised: 03/12/2023] [Accepted: 04/16/2023] [Indexed: 06/22/2023]
Abstract
Changes in ecological preference, often driven by spatial and temporal variation in resource distribution, can expose populations to environments with divergent information content. This can lead to adaptive changes in the degree to which individuals invest in sensory systems and downstream processes, to optimize behavioural performance in different contexts. At the same time, environmental conditions can produce plastic responses in nervous system development and maturation, providing an alternative route to integrating neural and ecological variation. Here, we explore how these two processes play out across a community of Heliconius butterflies. Heliconius communities exhibit multiple Mullerian mimicry rings, associated with habitat partitioning across environmental gradients. These environmental differences have previously been linked to heritable divergence in brain morphology in parapatric species pairs. They also exhibit a unique dietary adaptation, known as pollen feeding, that relies heavily on learning foraging routes, or trap-lines, between resources, which implies an important environmental influence on behavioural development. By comparing brain morphology across 133 wild-caught and insectary-reared individuals from seven Heliconius species, we find strong evidence for interspecific variation in patterns of neural investment. These largely fall into two distinct patterns of variation; first, we find consistent patterns of divergence in the size of visual brain components across both wild and insectary-reared individuals, suggesting genetically encoded divergence in the visual pathway. Second, we find interspecific differences in mushroom body size, a central component of learning and memory systems, but only among wild caught individuals. The lack of this effect in common-garden individuals suggests an extensive role for developmental plasticity in interspecific variation in the wild. Finally, we illustrate the impact of relatively small-scale spatial effects on mushroom body plasticity by performing experiments altering the cage size and structure experienced by individual H. hecale. Our data provide a comprehensive survey of community level variation in brain structure, and demonstrate that genetic effects and developmental plasticity contribute to different axes of interspecific neural variation.
Collapse
Affiliation(s)
- Laura Hebberecht
- School of Biological Sciences, University of Bristol, Bristol, UK
- Department of Zoology, University of Cambridge, Cambridge, UK
- Smithsonian Tropical Research Institute, Gamboa, Panama
| | | | | | | | | | - Stephen H Montgomery
- School of Biological Sciences, University of Bristol, Bristol, UK
- Smithsonian Tropical Research Institute, Gamboa, Panama
| |
Collapse
|
15
|
Homberg U, Kirchner M, Kowalewski K, Pitz V, Kinoshita M, Kern M, Seyfarth J. Comparative morphology of serotonin-immunoreactive neurons innervating the central complex in the brain of dicondylian insects. J Comp Neurol 2023. [PMID: 37478205 DOI: 10.1002/cne.25529] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Revised: 06/28/2023] [Accepted: 07/08/2023] [Indexed: 07/23/2023]
Abstract
Serotonin (5-hydroxytryptamine) acts as a widespread neuromodulator in the nervous system of vertebrates and invertebrates. In insects, it promotes feeding, enhances olfactory sensitivity, modulates aggressive behavior, and, in the central complex of Drosophila, serves a role in sleep homeostasis. In addition to a role in sleep-wake regulation, the central complex has a prominent role in spatial orientation, goal-directed locomotion, and navigation vector memory. To further understand the role of serotonergic signaling in this brain area, we analyzed the distribution and identity of serotonin-immunoreactive neurons across a wide range of insect species. While one bilateral pair of tangential neurons innervating the central body was present in all species studied, a second type was labeled in all neopterans but not in dragonflies and firebrats. Both cell types show conserved major fiber trajectories but taxon-specific differences in dendritic targets outside the central body and axonal terminals in the central body, noduli, and lateral accessory lobes. In addition, numerous tangential neurons of the protocerebral bridge were labeled in all studied polyneopteran species except for Phasmatodea, but not in Holometabola. Lepidoptera and Diptera showed additional labeling of two bilateral pairs of neurons of a third type. The presence of serotonin in systems of columnar neurons apparently evolved independently in dragonflies and desert locusts. The data suggest distinct evolutionary changes in the composition of serotonin-immunolabeled neurons of the central complex and provides a promising basis for a phylogenetic study in a wider range of arthropod species.
Collapse
Affiliation(s)
- Uwe Homberg
- Department of Biology, Animal Physiology, Philipps-Universität Marburg, Marburg, Germany
- Center for Mind, Brain and Behavior (CMBB), University of Marburg and Justus Liebig University Giessen, Marburg, Germany
| | - Michelle Kirchner
- Department of Biology, Animal Physiology, Philipps-Universität Marburg, Marburg, Germany
| | - Kevin Kowalewski
- Department of Biology, Animal Physiology, Philipps-Universität Marburg, Marburg, Germany
| | - Vanessa Pitz
- Department of Biology, Animal Physiology, Philipps-Universität Marburg, Marburg, Germany
| | - Michiyo Kinoshita
- Laboratory of Neuroethology, SOKENDAI, The Graduate University for Advanced Studies, Hayama, Japan
| | - Martina Kern
- Department of Biology, Animal Physiology, Philipps-Universität Marburg, Marburg, Germany
| | - Jutta Seyfarth
- Department of Biology, Animal Physiology, Philipps-Universität Marburg, Marburg, Germany
| |
Collapse
|
16
|
Helmbrecht H, Lin TJ, Janakiraman S, Decker K, Nance E. Prevalence and practices of immunofluorescent cell image processing: a systematic review. Front Cell Neurosci 2023; 17:1188858. [PMID: 37545881 PMCID: PMC10400723 DOI: 10.3389/fncel.2023.1188858] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2023] [Accepted: 07/06/2023] [Indexed: 08/08/2023] Open
Abstract
Background We performed a systematic review that identified at least 9,000 scientific papers on PubMed that include immunofluorescent images of cells from the central nervous system (CNS). These CNS papers contain tens of thousands of immunofluorescent neural images supporting the findings of over 50,000 associated researchers. While many existing reviews discuss different aspects of immunofluorescent microscopy, such as image acquisition and staining protocols, few papers discuss immunofluorescent imaging from an image-processing perspective. We analyzed the literature to determine the image processing methods that were commonly published alongside the associated CNS cell, microscopy technique, and animal model, and highlight gaps in image processing documentation and reporting in the CNS research field. Methods We completed a comprehensive search of PubMed publications using Medical Subject Headings (MeSH) terms and other general search terms for CNS cells and common fluorescent microscopy techniques. Publications were found on PubMed using a combination of column description terms and row description terms. We manually tagged the comma-separated values file (CSV) metadata of each publication with the following categories: animal or cell model, quantified features, threshold techniques, segmentation techniques, and image processing software. Results Of the almost 9,000 immunofluorescent imaging papers identified in our search, only 856 explicitly include image processing information. Moreover, hundreds of the 856 papers are missing thresholding, segmentation, and morphological feature details necessary for explainable, unbiased, and reproducible results. In our assessment of the literature, we visualized current image processing practices, compiled the image processing options from the top twelve software programs, and designed a road map to enhance image processing. We determined that thresholding and segmentation methods were often left out of publications and underreported or underutilized for quantifying CNS cell research. Discussion Less than 10% of papers with immunofluorescent images include image processing in their methods. A few authors are implementing advanced methods in image analysis to quantify over 40 different CNS cell features, which can provide quantitative insights in CNS cell features that will advance CNS research. However, our review puts forward that image analysis methods will remain limited in rigor and reproducibility without more rigorous and detailed reporting of image processing methods. Conclusion Image processing is a critical part of CNS research that must be improved to increase scientific insight, explainability, reproducibility, and rigor.
Collapse
Affiliation(s)
- Hawley Helmbrecht
- Department of Chemical Engineering, University of Washington, Seattle, WA, United States
| | - Teng-Jui Lin
- Department of Chemical Engineering, University of Washington, Seattle, WA, United States
| | - Sanjana Janakiraman
- Paul G. Allen School of Computer Science & Engineering, Seattle, WA, United States
| | - Kaleb Decker
- Department of Chemical Engineering, University of Washington, Seattle, WA, United States
| | - Elizabeth Nance
- Department of Chemical Engineering, University of Washington, Seattle, WA, United States
- Department of Bioengineering, University of Washington, Seattle, WA, United States
| |
Collapse
|
17
|
Beetz MJ, El Jundi B. The influence of stimulus history on directional coding in the monarch butterfly brain. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2023:10.1007/s00359-023-01633-x. [PMID: 37095358 DOI: 10.1007/s00359-023-01633-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2022] [Revised: 04/05/2023] [Accepted: 04/12/2023] [Indexed: 04/26/2023]
Abstract
The central complex is a brain region in the insect brain that houses a neural network specialized to encode directional information. Directional coding has traditionally been investigated with compass cues that revolve in full rotations and at constant angular velocities around the insect's head. However, these stimulus conditions do not fully simulate an insect's sensory perception of compass cues during navigation. In nature, an insect flight is characterized by abrupt changes in moving direction as well as constant changes in velocity. The influence of such varying cue dynamics on compass coding remains unclear. We performed long-term tetrode recordings from the brain of monarch butterflies to study how central complex neurons respond to different stimulus velocities and directions. As these butterflies derive directional information from the sun during migration, we measured the neural response to a virtual sun. The virtual sun was either presented as a spot that appeared at random angular positions or was rotated around the butterfly at different angular velocities and directions. By specifically manipulating the stimulus velocity and trajectory, we dissociated the influence of angular velocity and direction on compass coding. While the angular velocity substantially affected the tuning directedness, the stimulus trajectory influenced the shape of the angular tuning curve. Taken together, our results suggest that the central complex flexibly adjusts its directional coding to the current stimulus dynamics ensuring a precise compass even under highly demanding conditions such as during rapid flight maneuvers.
Collapse
Affiliation(s)
- M Jerome Beetz
- Zoology II, Biocenter, University of Würzburg, Würzburg, Germany.
| | - Basil El Jundi
- Zoology II, Biocenter, University of Würzburg, Würzburg, Germany
- Animal Physiology, Department of Biology, Norwegian University of Science and Technology, Trondheim, Norway
| |
Collapse
|
18
|
Honkanen A, Hensgen R, Kannan K, Adden A, Warrant E, Wcislo W, Heinze S. Parallel motion vision pathways in the brain of a tropical bee. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2023:10.1007/s00359-023-01625-x. [PMID: 37017717 DOI: 10.1007/s00359-023-01625-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2022] [Revised: 03/01/2023] [Accepted: 03/09/2023] [Indexed: 04/06/2023]
Abstract
Spatial orientation is a prerequisite for most behaviors. In insects, the underlying neural computations take place in the central complex (CX), the brain's navigational center. In this region different streams of sensory information converge to enable context-dependent navigational decisions. Accordingly, a variety of CX input neurons deliver information about different navigation-relevant cues. In bees, direction encoding polarized light signals converge with translational optic flow signals that are suited to encode the flight speed of the animals. The continuous integration of speed and directions in the CX can be used to generate a vector memory of the bee's current position in space in relation to its nest, i.e., perform path integration. This process depends on specific, complex features of the optic flow encoding CX input neurons, but it is unknown how this information is derived from the visual periphery. Here, we thus aimed at gaining insight into how simple motion signals are reshaped upstream of the speed encoding CX input neurons to generate their complex features. Using electrophysiology and anatomical analyses of the halictic bees Megalopta genalis and Megalopta centralis, we identified a wide range of motion-sensitive neurons connecting the optic lobes with the central brain. While most neurons formed pathways with characteristics incompatible with CX speed neurons, we showed that one group of lobula projection neurons possess some physiological and anatomical features required to generate the visual responses of CX optic-flow encoding neurons. However, as these neurons cannot explain all features of CX speed cells, local interneurons of the central brain or alternative input cells from the optic lobe are additionally required to construct inputs with sufficient complexity to deliver speed signals suited for path integration in bees.
Collapse
Affiliation(s)
- Anna Honkanen
- Lund Vision Group, Department of Biology, Lund University, Lund, Sweden
| | - Ronja Hensgen
- Lund Vision Group, Department of Biology, Lund University, Lund, Sweden
| | - Kavitha Kannan
- Lund Vision Group, Department of Biology, Lund University, Lund, Sweden
| | - Andrea Adden
- Lund Vision Group, Department of Biology, Lund University, Lund, Sweden
- Neural Circuits and Evolution Lab, The Francis Crick Institute, London, UK
| | - Eric Warrant
- Lund Vision Group, Department of Biology, Lund University, Lund, Sweden
| | - William Wcislo
- Smithsonian Tropical Research Institute, Panama City, República de Panamá
| | - Stanley Heinze
- Lund Vision Group, Department of Biology, Lund University, Lund, Sweden.
- NanoLund, Lund University, Lund, Sweden.
| |
Collapse
|
19
|
Mangan M, Floreano D, Yasui K, Trimmer BA, Gravish N, Hauert S, Webb B, Manoonpong P, Szczecinski N. A virtuous cycle between invertebrate and robotics research: perspective on a decade of Living Machines research. BIOINSPIRATION & BIOMIMETICS 2023; 18:035005. [PMID: 36881919 DOI: 10.1088/1748-3190/acc223] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Accepted: 03/07/2023] [Indexed: 06/18/2023]
Abstract
Many invertebrates are ideal model systems on which to base robot design principles due to their success in solving seemingly complex tasks across domains while possessing smaller nervous systems than vertebrates. Three areas are particularly relevant for robot designers: Research on flying and crawling invertebrates has inspired new materials and geometries from which robot bodies (their morphologies) can be constructed, enabling a new generation of softer, smaller, and lighter robots. Research on walking insects has informed the design of new systems for controlling robot bodies (their motion control) and adapting their motion to their environment without costly computational methods. And research combining wet and computational neuroscience with robotic validation methods has revealed the structure and function of core circuits in the insect brain responsible for the navigation and swarming capabilities (their mental faculties) displayed by foraging insects. The last decade has seen significant progress in the application of principles extracted from invertebrates, as well as the application of biomimetic robots to model and better understand how animals function. This Perspectives paper on the past 10 years of the Living Machines conference outlines some of the most exciting recent advances in each of these fields before outlining lessons gleaned and the outlook for the next decade of invertebrate robotic research.
Collapse
Affiliation(s)
- Michael Mangan
- The University of Sheffield, Mappin St, Sheffield S10 2TN, United Kingdom
| | - Dario Floreano
- Ecole Polytechnique Federale de Lausanne, Laboratory of Intelligent Systems, Station 9, Lausanne CH-1015, Switzerland
| | - Kotaro Yasui
- Tohoku University, Frontier Research Institute for Interdisciplinary Sciences, 6-3 Aramaki aza Aoba, Aoba-ku, Sendai 980-8578, Japan
| | - Barry A Trimmer
- Tufts University, Biology, 200 Boston Av, Boston, MA 02111, United States of America
| | - Nick Gravish
- University of California San Diego, Mechanical and Aerospace Engineering, Building EBU II, La Jolla, CA 92093, United States of America
| | - Sabine Hauert
- University of Bristol, Engineering Mathematics, Bristol BS8 1QU, United Kingdom
| | - Barbara Webb
- University of Edinburgh, School of Informatics, 10 Crichton St, Edinburgh EH8 9AB, United Kingdom
| | - Poramate Manoonpong
- College of Mechanical and Electrical Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, People's Republic of China
- Bio-Inspired Robotics and Neural Engineering Laboratory, School of Information Science and Technology, Vidyasirimedhi Institute of Science and Technology, Wangchan Valley, Rayong 21210, Thailand
| | - Nicholas Szczecinski
- West Virginia University, Mechanical and Aerospace Engineering, Morgantown, WV 26506-6201, United States of America
| |
Collapse
|
20
|
Kandimalla P, Omoto JJ, Hong EJ, Hartenstein V. Lineages to circuits: the developmental and evolutionary architecture of information channels into the central complex. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2023:10.1007/s00359-023-01616-y. [PMID: 36932234 DOI: 10.1007/s00359-023-01616-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Revised: 01/27/2023] [Accepted: 01/28/2023] [Indexed: 03/19/2023]
Abstract
The representation and integration of internal and external cues is crucial for any organism to execute appropriate behaviors. In insects, a highly conserved region of the brain, the central complex (CX), functions in the representation of spatial information and behavioral states, as well as the transformation of this information into desired navigational commands. How does this relatively invariant structure enable the incorporation of information from the diversity of anatomical, behavioral, and ecological niches occupied by insects? Here, we examine the input channels to the CX in the context of their development and evolution. Insect brains develop from ~ 100 neuroblasts per hemisphere that divide systematically to form "lineages" of sister neurons, that project to their target neuropils along anatomically characteristic tracts. Overlaying this developmental tract information onto the recently generated Drosophila "hemibrain" connectome and integrating this information with the anatomical and physiological recording of neurons in other species, we observe neuropil and lineage-specific innervation, connectivity, and activity profiles in CX input channels. We posit that the proliferative potential of neuroblasts and the lineage-based architecture of information channels enable the modification of neural networks across existing, novel, and deprecated modalities in a species-specific manner, thus forming the substrate for the evolution and diversification of insect navigational circuits.
Collapse
Affiliation(s)
- Pratyush Kandimalla
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA. .,Department of Molecular, Cell and Developmental Biology, University of California, Los Angeles, CA, USA.
| | - Jaison Jiro Omoto
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA.,Department of Molecular, Cell and Developmental Biology, University of California, Los Angeles, CA, USA
| | - Elizabeth J Hong
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA
| | - Volker Hartenstein
- Department of Molecular, Cell and Developmental Biology, University of California, Los Angeles, CA, USA
| |
Collapse
|
21
|
Buehlmann C, Dell-Cronin S, Diyalagoda Pathirannahelage A, Goulard R, Webb B, Niven JE, Graham P. Impact of central complex lesions on innate and learnt visual navigation in ants. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2023:10.1007/s00359-023-01613-1. [PMID: 36790487 DOI: 10.1007/s00359-023-01613-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Revised: 12/31/2022] [Accepted: 01/10/2023] [Indexed: 02/16/2023]
Abstract
Wood ants are excellent navigators, using a combination of innate and learnt navigational strategies to travel between their nest and feeding sites. Visual navigation in ants has been studied extensively, however, we have little direct evidence for the underlying neural mechanisms. Here, we perform lateralized mechanical lesions in the central complex (CX) of wood ants, a midline structure known to allow an insect to keep track of the direction of sensory cues relative to its own orientation and to control movement. We lesioned two groups of ants and observed their behaviour in an arena with a large visual landmark present. The first group of ants were naïve and when intact such ants show a clear innate attraction to the conspicuous landmark. The second group of ants were trained to aim to a food location to the side of the landmark. The general heading of naïve ants towards a visual cue was not altered by the lesions, but the heading of ants trained to a landmark adjacent food position was affected. Thus, CX lesions had a specific impact on learnt visual guidance. We also observed that lateralised lesions altered the fine details of turning with lesioned ants spending less time turning to the side ipsilateral of the lesion. The results confirm the role of the CX in turn control and highlight its important role in the implementation of learnt behaviours that rely on information from other brain regions.
Collapse
Affiliation(s)
| | | | | | - Roman Goulard
- School of Informatics, University of Edinburgh, Edinburgh, EH8 9AB, UK.,Lund Vision Group, Department of Biology, Lund University, 223 62, Lund, Sweden
| | - Barbara Webb
- School of Informatics, University of Edinburgh, Edinburgh, EH8 9AB, UK
| | - Jeremy E Niven
- School of Life Sciences, University of Sussex, Brighton, BN1 9QG, UK
| | - Paul Graham
- School of Life Sciences, University of Sussex, Brighton, BN1 9QG, UK
| |
Collapse
|
22
|
Clement L, Schwarz S, Wystrach A. An intrinsic oscillator underlies visual navigation in ants. Curr Biol 2023; 33:411-422.e5. [PMID: 36538930 DOI: 10.1016/j.cub.2022.11.059] [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: 09/07/2022] [Revised: 11/06/2022] [Accepted: 11/24/2022] [Indexed: 12/23/2022]
Abstract
Many insects display lateral oscillations while moving, but how these oscillations are produced and participate in visual navigation remains unclear. Here, we show that visually navigating ants continuously display regular lateral oscillations coupled with variations of forward speed that strongly optimize the distance covered while simultaneously enabling them to scan left and right directions. This pattern of movement is produced endogenously and conserved across navigational contexts in two phylogenetically distant ant species. Moreover, the oscillations' amplitude can be modulated by both innate or learnt visual cues to adjust the exploration/exploitation balance to the current need. This lower-level motor pattern thus drastically reduces the degree of freedom needed for higher-level strategies to control behavior. The observed dynamical signature readily emerges from a simple neural circuit model of the insect's conserved pre-motor area known as the lateral accessory lobe, offering a surprisingly simple but effective neural control and endorsing oscillation as a core, ancestral way of moving in insects.
Collapse
Affiliation(s)
- Leo Clement
- Centre de Recherches sur la Cognition Animale, CBI, CNRS, Université Paul Sabatier, 31062 Toulouse Cedex 09, France.
| | - Sebastian Schwarz
- Centre de Recherches sur la Cognition Animale, CBI, CNRS, Université Paul Sabatier, 31062 Toulouse Cedex 09, France
| | - Antoine Wystrach
- Centre de Recherches sur la Cognition Animale, CBI, CNRS, Université Paul Sabatier, 31062 Toulouse Cedex 09, France
| |
Collapse
|
23
|
Tenger-Trolander A, Julick CR, Lu W, Green DA, Montooth KL, Kronforst MR. Seasonal plasticity in morphology and metabolism differs between migratory North American and resident Costa Rican monarch butterflies. Ecol Evol 2023; 13:e9796. [PMID: 36844673 PMCID: PMC9943933 DOI: 10.1002/ece3.9796] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Revised: 01/16/2023] [Accepted: 01/18/2023] [Indexed: 02/24/2023] Open
Abstract
Environmental heterogeneity in temperate latitudes is expected to maintain seasonally plastic life-history strategies that include the tuning of morphologies and metabolism that support overwintering. For species that have expanded their ranges into tropical latitudes, it is unclear the extent to which the capacity for plasticity will be maintained or will erode with disuse. The migratory generations of the North American (NA) monarch butterfly Danaus plexippus lead distinctly different lives from their summer generation NA parents and their tropical descendants living in Costa Rica (CR). NA migratory monarchs postpone reproduction, travel thousands of kilometers south to overwinter in Mexico, and subsist on little food for months. Whether recently dispersed populations of monarchs such as those in Costa Rica, which are no longer subject to selection imposed by migration, retain ancestral seasonal plasticity is unclear. To investigate the differences in seasonal plasticity, we reared the NA and CR monarchs in summer and autumn in Illinois, USA, and measured the seasonal reaction norms for aspects of morphology and metabolism related to flight. NA monarchs were seasonally plastic in forewing and thorax size, increasing wing area and thorax to body mass ratio in autumn. While CR monarchs increased thorax mass in autumn, they did not increase the area of the forewing. NA monarchs maintained similar resting and maximal flight metabolic rates across seasons. However, CR monarchs had elevated metabolic rates in autumn. Our findings suggest that the recent expansion of monarchs into habitats that support year-round breeding may be accompanied by (1) the loss of some aspects of morphological plasticity as well as (2) the underlying physiological mechanisms that maintain metabolic homeostasis in the face of temperature heterogeneity.
Collapse
Affiliation(s)
- Ayşe Tenger-Trolander
- Department of Ecology and Evolution University of Chicago Chicago Illinois USA.,Ecology and Evolutionary Biology University of Michigan Ann Arbor Michigan USA
| | - Cole R Julick
- School of Biological Sciences University of Nebraska-Lincoln Lincoln Nebraska USA
| | - Wei Lu
- Department of Ecology and Evolution University of Chicago Chicago Illinois USA
| | - Delbert André Green
- Ecology and Evolutionary Biology University of Michigan Ann Arbor Michigan USA
| | - Kristi L Montooth
- School of Biological Sciences University of Nebraska-Lincoln Lincoln Nebraska USA
| | - Marcus R Kronforst
- Department of Ecology and Evolution University of Chicago Chicago Illinois USA
| |
Collapse
|
24
|
Althaus V, Jahn S, Massah A, Stengl M, Homberg U. 3D-atlas of the brain of the cockroach Rhyparobia maderae. J Comp Neurol 2022; 530:3126-3156. [PMID: 36036660 DOI: 10.1002/cne.25396] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Revised: 07/21/2022] [Accepted: 07/24/2022] [Indexed: 11/07/2022]
Abstract
The Madeira cockroach Rhyparobia maderae is a nocturnal insect and a prominent model organism for the study of circadian rhythms. Its master circadian clock, controlling circadian locomotor activity and sleep-wake cycles, is located in the accessory medulla of the optic lobe. For a better understanding of brain regions controlled by the circadian clock and brain organization of this insect in general, we created a three-dimensional (3D) reconstruction of all neuropils of the cerebral ganglia based on anti-synapsin and anti-γ-aminobutyric acid immunolabeling of whole mount brains. Forty-nine major neuropils were identified and three-dimensionally reconstructed. Single-cell dye fills complement the data and provide evidence for distinct subdivisions of certain brain areas. Most neuropils defined in the fruit fly Drosophila melanogaster could be distinguished in the cockroach as well. However, some neuropils identified in the fruit fly do not exist as distinct entities in the cockroach while others are lacking in the fruit fly. In addition to neuropils, major fiber systems, tracts, and commissures were reconstructed and served as important landmarks separating brain areas. Being a nocturnal insect, R. maderae is an important new species to the growing collection of 3D insect brain atlases and only the second hemimetabolous insect, for which a detailed 3D brain atlas is available. This atlas will be highly valuable for an evolutionary comparison of insect brain organization and will greatly facilitate addressing brain areas that are supervised by the circadian clock.
Collapse
Affiliation(s)
- Vanessa Althaus
- Department of Biology, Animal Physiology, Philipps-University of Marburg, Marburg, Germany
| | - Stefanie Jahn
- Department of Biology, Animal Physiology, Philipps-University of Marburg, Marburg, Germany
| | - Azar Massah
- Faculty of Mathematics and Natural Sciences, Institute of Biology, Animal Physiology, University of Kassel, Kassel, Germany
| | - Monika Stengl
- Faculty of Mathematics and Natural Sciences, Institute of Biology, Animal Physiology, University of Kassel, Kassel, 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
| |
Collapse
|
25
|
Wainwright JB, Montgomery SH. Neuroanatomical shifts mirror patterns of ecological divergence in three diverse clades of mimetic butterflies. Evolution 2022; 76:1806-1820. [PMID: 35767896 PMCID: PMC9540801 DOI: 10.1111/evo.14547] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Revised: 05/30/2022] [Accepted: 06/06/2022] [Indexed: 01/22/2023]
Abstract
Microhabitat partitioning in heterogenous environments can support more diverse communities but may expose partitioned species to distinct perceptual challenges. Divergence across microhabitats could therefore lead to local adaptation to contrasting sensory conditions across small spatial scales, but this aspect of community structuring is rarely explored. Diverse communities of ithomiine butterflies provide an example where closely related species partition tropical forests, where shifts in mimetic coloration are tightly associated with shifts in habitat preference. We test the hypothesis that these mimetic and ecological shifts are associated with distinct patterns of sensory neural investment by comparing brain structure across 164 individuals of 16 species from three ithomiine clades. We find distinct brain morphologies between Oleriina and Hypothyris, which are mimetically homogenous and occupy a single microhabitat. Oleriina, which occurs in low-light microhabitats, invests less in visual brain regions than Hypothyris, with one notable exception, Hyposcada anchiala, the only Oleriina sampled to have converged on mimicry rings found in Hypothyris. We also find that Napeogenes, which has diversified into a range of mimicry rings, shows intermediate patterns of sensory investment. We identify flight height as a critical factor shaping neuroanatomical diversity, with species that fly higher in the canopy investing more in visual structures. Our work suggests that the sensory ecology of species may be impacted by, and interact with, the ways in which communities of closely related organisms are adaptively assembled.
Collapse
|
26
|
Nguyen TAT, Beetz MJ, Merlin C, Pfeiffer K, el Jundi B. Weighting of Celestial and Terrestrial Cues in the Monarch Butterfly Central Complex. Front Neural Circuits 2022; 16:862279. [PMID: 35847485 PMCID: PMC9285895 DOI: 10.3389/fncir.2022.862279] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Accepted: 06/10/2022] [Indexed: 12/02/2022] Open
Abstract
Monarch butterflies rely on external cues for orientation during their annual long-distance migration from Northern US and Canada to Central Mexico. These external cues can be celestial cues, such as the sun or polarized light, which are processed in a brain region termed the central complex (CX). Previous research typically focused on how individual simulated celestial cues are encoded in the butterfly's CX. However, in nature, the butterflies perceive several celestial cues at the same time and need to integrate them to effectively use the compound of all cues for orientation. In addition, a recent behavioral study revealed that monarch butterflies can rely on terrestrial cues, such as the panoramic skyline, for orientation and use them in combination with the sun to maintain a directed flight course. How the CX encodes a combination of celestial and terrestrial cues and how they are weighted in the butterfly's CX is still unknown. Here, we examined how input neurons of the CX, termed TL neurons, combine celestial and terrestrial information. While recording intracellularly from the neurons, we presented a sun stimulus and polarized light to the butterflies as well as a simulated sun and a panoramic scene simultaneously. Our results show that celestial cues are integrated linearly in these cells, while the combination of the sun and a panoramic skyline did not always follow a linear integration of action potential rates. Interestingly, while the sun and polarized light were invariantly weighted between individual neurons, the sun stimulus and panoramic skyline were dynamically weighted when both stimuli were simultaneously presented. Taken together, this dynamic weighting between celestial and terrestrial cues may allow the butterflies to flexibly set their cue preference during navigation.
Collapse
Affiliation(s)
| | - M. Jerome Beetz
- Biocenter, Zoology II, University of Wuerzburg, Würzburg, Germany
| | - Christine Merlin
- Department of Biology and Center for Biological Clocks Research, Texas A&M University, College Station, TX, United States
| | - Keram Pfeiffer
- Biocenter, Zoology II, University of Wuerzburg, Würzburg, Germany
| | - Basil el Jundi
- Biocenter, Zoology II, University of Wuerzburg, Würzburg, Germany
- Department of Biology, Animal Physiology, Norwegian University of Science and Technology, Trondheim, Norway
- *Correspondence: Basil el Jundi
| |
Collapse
|
27
|
Kaiser A, Hensgen R, Tschirner K, Beetz E, Wüstenberg H, Pfaff M, Mota T, Pfeiffer K. A three-dimensional atlas of the honeybee central complex, associated neuropils and peptidergic layers of the central body. J Comp Neurol 2022; 530:2416-2438. [PMID: 35593178 DOI: 10.1002/cne.25339] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2022] [Revised: 04/15/2022] [Accepted: 04/26/2022] [Indexed: 11/11/2022]
Abstract
The central complex (CX) in the brain of insects is a highly conserved group of midline-spanning neuropils consisting of the upper and lower division of the central body, the protocerebral bridge, and the paired noduli. These neuropils are the substrate for a number of behaviors, most prominently goal-oriented locomotion. Honeybees have been a model organism for sky-compass orientation for more than 70 years, but there is still very limited knowledge about the structure and function of their CX. To advance and facilitate research on this brain area, we created a high-resolution three-dimensional atlas of the honeybee's CX and associated neuropils, including the posterior optic tubercles, the bulbs, and the anterior optic tubercles. To this end, we developed a modified version of the iterative shape averaging technique, which allowed us to achieve high volumetric accuracy of the neuropil models. For a finer definition of spatial locations within the central body, we defined layers based on immunostaining against the neuropeptides locustatachykinin, FMRFamide, gastrin/cholecystokinin, and allatostatin and included them into the atlas by elastic registration. Our honeybee CX atlas provides a platform for future neuroanatomical work.
Collapse
Affiliation(s)
- Andreas Kaiser
- Department of Biology/Animal Physiology, Philipps-University Marburg, Marburg, Germany
| | - Ronja Hensgen
- Department of Biology/Animal Physiology, Philipps-University Marburg, Marburg, Germany
| | - Katja Tschirner
- Behavioural Physiology and Sociobiology (Zoology II), Biocenter, University of Würzburg, Würzburg, Germany
| | - Evelyn Beetz
- Behavioural Physiology and Sociobiology (Zoology II), Biocenter, University of Würzburg, Würzburg, Germany
| | - Hauke Wüstenberg
- Department of Biology/Animal Physiology, Philipps-University Marburg, Marburg, Germany
| | - Marcel Pfaff
- Behavioural Physiology and Sociobiology (Zoology II), Biocenter, University of Würzburg, Würzburg, Germany
| | - Theo Mota
- Department of Physiology and Biophysics, Federal University of Minas Gerais, Belo Horizonte, Brazil
| | - Keram Pfeiffer
- Department of Biology/Animal Physiology, Philipps-University Marburg, Marburg, Germany.,Behavioural Physiology and Sociobiology (Zoology II), Biocenter, University of Würzburg, Würzburg, Germany
| |
Collapse
|
28
|
Schmalz F, El Jundi B, Rössler W, Strube-Bloss M. Categorizing Visual Information in Subpopulations of Honeybee Mushroom Body Output Neurons. Front Physiol 2022; 13:866807. [PMID: 35574496 PMCID: PMC9092450 DOI: 10.3389/fphys.2022.866807] [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: 01/31/2022] [Accepted: 04/08/2022] [Indexed: 11/17/2022] Open
Abstract
Multisensory integration plays a central role in perception, as all behaviors usually require the input of different sensory signals. For instance, for a foraging honeybee the association of a food source includes the combination of olfactory and visual cues to be categorized as a flower. Moreover, homing after successful foraging using celestial cues and the panoramic scenery may be dominated by visual cues. Hence, dependent on the context, one modality might be leading and influence the processing of other modalities. To unravel the complex neural mechanisms behind this process we studied honeybee mushroom body output neurons (MBON). MBONs represent the first processing level after olfactory-visual convergence in the honeybee brain. This was physiologically confirmed in our previous study by characterizing a subpopulation of multisensory MBONs. These neurons categorize incoming sensory inputs into olfactory, visual, and olfactory-visual information. However, in addition to multisensory units a prominent population of MBONs was sensitive to visual cues only. Therefore, we asked which visual features might be represented at this high-order integration level. Using extracellular, multi-unit recordings in combination with visual and olfactory stimulation, we separated MBONs with multisensory responses from purely visually driven MBONs. Further analysis revealed, for the first time, that visually driven MBONs of both groups encode detailed aspects within this individual modality, such as light intensity and light identity. Moreover, we show that these features are separated by different MBON subpopulations, for example by extracting information about brightness and wavelength. Most interestingly, the latter MBON population was tuned to separate UV-light from other light stimuli, which were only poorly differentiated from each other. A third MBON subpopulation was neither tuned to brightness nor to wavelength and encoded the general presence of light. Taken together, our results support the view that the mushroom body, a high-order sensory integration, learning and memory center in the insect brain, categorizes sensory information by separating different behaviorally relevant aspects of the multisensory scenery and that these categories are channeled into distinct MBON subpopulations.
Collapse
Affiliation(s)
- Fabian Schmalz
- Behavioral Physiology and Sociobiology (Zoology II), Biozentrum, University of Würzburg, Würzburg, Germany
| | - Basil El Jundi
- Behavioral Physiology and Sociobiology (Zoology II), Biozentrum, University of Würzburg, Würzburg, Germany
| | - Wolfgang Rössler
- Behavioral Physiology and Sociobiology (Zoology II), Biozentrum, University of Würzburg, Würzburg, Germany
| | - Martin Strube-Bloss
- Department of Biological Cybernetics and Theoretical Biology, University of Bielefeld, Bielefeld, Germany
| |
Collapse
|
29
|
Arganda S, Arganda-Carreras I, Gordon DG, Hoadley AP, Pérez-Escudero A, Giurfa M, Traniello JFA. Statistical Atlases and Automatic Labeling Strategies to Accelerate the Analysis of Social Insect Brain Evolution. Front Ecol Evol 2022. [DOI: 10.3389/fevo.2021.745707] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Current methods used to quantify brain size and compartmental scaling relationships in studies of social insect brain evolution involve manual annotations of images from histological samples, confocal microscopy or other sources. This process is susceptible to human bias and error and requires time-consuming effort by expert annotators. Standardized brain atlases, constructed through 3D registration and automatic segmentation, surmount these issues while increasing throughput to robustly sample diverse morphological and behavioral phenotypes. Here we design and evaluate three strategies to construct statistical brain atlases, or templates, using ants as a model taxon. The first technique creates a template by registering multiple brains of the same species. Brain regions are manually annotated on the template, and the labels are transformed back to each individual brain to obtain an automatic annotation, or to any other brain aligned with the template. The second strategy also creates a template from multiple brain images but obtains labels as a consensus from multiple manual annotations of individual brains comprising the template. The third technique is based on a template comprising brains from multiple species and the consensus of their labels. We used volume similarity as a metric to evaluate the automatic segmentation produced by each method against the inter- and intra-individual variability of human expert annotators. We found that automatic and manual methods are equivalent in volume accuracy, making the template technique an extraordinary tool to accelerate data collection and reduce human bias in the study of the evolutionary neurobiology of ants and other insects.
Collapse
|
30
|
Performance of polarization-sensitive neurons of the locust central complex at different degrees of polarization. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2022; 208:387-403. [PMID: 35157117 PMCID: PMC9123078 DOI: 10.1007/s00359-022-01545-2] [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: 09/08/2021] [Revised: 01/18/2022] [Accepted: 01/25/2022] [Indexed: 10/29/2022]
Abstract
The polarization pattern of the sky is exploited by many insects for spatial orientation and navigation. It derives from Rayleigh scattering in the atmosphere and depends directly on the position of the sun. In the insect brain, the central complex (CX) houses neurons tuned to the angle of polarization (AoP), that together constitute an internal compass for celestial navigation. Polarized light is not only characterized by the AoP, but also by the degree of polarization (DoP), which can be highly variable, depending on sky conditions. Under a clear sky, the DoP of polarized sky light may reach up to 0.75 but is usually much lower especially when light is scattered by clouds or haze. To investigate how the polarization-processing network of the CX copes with low DoPs, we recorded intracellularly from neurons of the locust CX at different stages of processing, while stimulating with light of different DoPs. Significant responses to polarized light occurred down to DoPs of 0.05 indicating reliable coding of the AoP even at unfavorable sky conditions. Moreover, we found that the activity of neurons at the CX input stage may be strongly influenced by nearly unpolarized light, while the activity of downstream neurons appears less affected.
Collapse
|
31
|
Franzke M, Kraus C, Gayler M, Dreyer D, Pfeiffer K, el Jundi B. Stimulus-dependent orientation strategies in monarch butterflies. J Exp Biol 2022; 225:274064. [PMID: 35048981 PMCID: PMC8918799 DOI: 10.1242/jeb.243687] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Accepted: 01/12/2022] [Indexed: 11/20/2022]
Abstract
Insects are well-known for their ability to keep track of their heading direction based on a combination of skylight cues and visual landmarks. This allows them to navigate back to their nest, disperse throughout unfamiliar environments, as well as migrate over large distances between their breeding and non-breeding habitats. The monarch butterfly (Danaus plexippus) for instance is known for its annual southward migration from North America to certain trees in Central Mexico. To maintain a constant flight route, these butterflies use a time-compensated sun compass for orientation which is processed in a region in the brain, termed the central complex. However, to successfully complete their journey, the butterflies’ brain must generate a multitude of orientation strategies, allowing them to dynamically switch from sun-compass orientation to a tactic behavior toward a certain target. To study if monarch butterflies exhibit different orientation modes and if they can switch between them, we observed the orientation behavior of tethered flying butterflies in a flight simulator while presenting different visual cues to them. We found that the butterflies’ behavior depended on the presented visual stimulus. Thus, while a dark stripe was used for flight stabilization, a bright stripe was fixated by the butterflies in their frontal visual field. If we replaced a bright stripe by a simulated sun stimulus, the butterflies switched their behavior and exhibited compass orientation. Taken together, our data show that monarch butterflies rely on and switch between different orientation modes, allowing the animal to adjust orientation to its actual behavioral demands.
Collapse
Affiliation(s)
- Myriam Franzke
- University of Wuerzburg, Biocenter, Zoology II, Würzburg, Germany
| | - Christian Kraus
- University of Wuerzburg, Biocenter, Zoology II, Würzburg, Germany
| | - Maria Gayler
- University of Wuerzburg, Biocenter, Zoology II, Würzburg, Germany
| | - David Dreyer
- Lund University, Department of Biology, Lund Vision Group, Lund, Sweden
| | - Keram Pfeiffer
- University of Wuerzburg, Biocenter, Zoology II, Würzburg, Germany
| | - Basil el Jundi
- University of Wuerzburg, Biocenter, Zoology II, Würzburg, Germany
| |
Collapse
|
32
|
Pocius VM, Majewska AA, Freedman MG. The Role of Experiments in Monarch Butterfly Conservation: A Review of Recent Studies and Approaches. ANNALS OF THE ENTOMOLOGICAL SOCIETY OF AMERICA 2022; 115:10-24. [PMID: 35069967 PMCID: PMC8764570 DOI: 10.1093/aesa/saab036] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2021] [Indexed: 06/14/2023]
Abstract
Monarch butterflies (Danaus plexippus) (Lepidoptera Danaidae Danaus plexippus (Linnaeus)) are an iconic species of conservation concern due to declines in the overwintering colonies over the past twenty years. Because of this downward trend in overwintering numbers in both California and Mexico, monarchs are currently considered 'warranted-but-precluded' for listing under the Endangered Species Act. Monarchs have a fascinating life history and have become a model system in chemical ecology, migration biology, and host-parasite interactions, but many aspects of monarch biology important for informing conservation practices remain unresolved. In this review, we focus on recent advances using experimental and genetic approaches that inform monarch conservation. In particular, we emphasize three areas of broad importance, which could have an immediate impact on monarch conservation efforts: 1) breeding habitat and host plant use, 2) natural enemies and exotic caterpillar food plants, and 3) the utility of genetic and genomic approaches for understanding monarch biology and informing ongoing conservation efforts. We also suggest future studies in these areas that could improve our understanding of monarch behavior and conservation.
Collapse
Affiliation(s)
- Victoria M Pocius
- Department of Biological Sciences, University of Alabama, Tuscaloosa, AL, USA
| | | | - Micah G Freedman
- Department of Ecology and Evolution, University of Chicago, Chicago, IL, USA
| |
Collapse
|
33
|
Moura PA, Corso G, Montgomery SH, Cardoso MZ. True site fidelity in pollen‐feeding butterflies. Funct Ecol 2021. [DOI: 10.1111/1365-2435.13976] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- Priscila A. Moura
- Departamento de Ecologia Universidade Federal do Rio Grande do Norte Natal Brazil
| | - Giberto Corso
- Departamento de Biofísica e Farmacologia Universidade Federal do Rio Grande do Norte Natal Brazil
| | | | - Marcio Z. Cardoso
- Departamento de Ecologia Universidade Federal do Rio Grande do Norte Natal Brazil
- Departamento de Ecologia Instituto de Biologia Universidade Federal do Rio de Janeiro Rio de Janeiro Brazil
| |
Collapse
|
34
|
Beetz MJ, Kraus C, Franzke M, Dreyer D, Strube-Bloss MF, Rössler W, Warrant EJ, Merlin C, El Jundi B. Flight-induced compass representation in the monarch butterfly heading network. Curr Biol 2021; 32:338-349.e5. [PMID: 34822766 DOI: 10.1016/j.cub.2021.11.009] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Revised: 09/27/2021] [Accepted: 11/03/2021] [Indexed: 10/19/2022]
Abstract
For navigation, animals use a robust internal compass. Compass navigation is crucial for long-distance migrating animals like monarch butterflies, which use the sun to navigate over 4,000 km to their overwintering sites every fall. Sun-compass neurons of the central complex have only been recorded in immobile butterflies, and experimental evidence for encoding the animal's heading in these neurons is still missing. Although the activity of central-complex neurons exhibits a locomotor-dependent modulation in many insects, the function of such modulations remains unexplored. Here, we developed tetrode recordings from tethered flying monarch butterflies to reveal how flight modulates heading representation. We found that, during flight, heading-direction neurons change their tuning, transforming the central-complex network to function as a global compass. This compass is characterized by the dominance of processing steering feedback and allows for robust heading representation even under unreliable visual scenarios, an ideal strategy for maintaining a migratory heading over enormous distances.
Collapse
Affiliation(s)
- M Jerome Beetz
- Zoology II, Biocenter, University of Würzburg, Am Hubland 1, 97074 Würzburg, Germany.
| | - Christian Kraus
- Zoology II, Biocenter, University of Würzburg, Am Hubland 1, 97074 Würzburg, Germany
| | - Myriam Franzke
- Zoology II, Biocenter, University of Würzburg, Am Hubland 1, 97074 Würzburg, Germany
| | - David Dreyer
- Lund Vision Group, Department of Biology, Lund University, Sölvegatan 35, 22362 Lund, Sweden
| | - Martin F Strube-Bloss
- Department of Biological Cybernetics, University of Bielefeld, Universitätsstraße 25, 33615 Bielefeld, Germany
| | - Wolfgang Rössler
- Zoology II, Biocenter, University of Würzburg, Am Hubland 1, 97074 Würzburg, Germany
| | - Eric J Warrant
- Lund Vision Group, Department of Biology, Lund University, Sölvegatan 35, 22362 Lund, Sweden
| | - Christine Merlin
- Department of Biology and Center for Biological Clocks Research, Texas A&M University, College Station, TX 77843, USA
| | - Basil El Jundi
- Zoology II, Biocenter, University of Würzburg, Am Hubland 1, 97074 Würzburg, Germany.
| |
Collapse
|
35
|
Hulse BK, Haberkern H, Franconville R, Turner-Evans DB, Takemura SY, Wolff T, Noorman M, Dreher M, Dan C, Parekh R, Hermundstad AM, Rubin GM, Jayaraman V. A connectome of the Drosophila central complex reveals network motifs suitable for flexible navigation and context-dependent action selection. eLife 2021; 10:66039. [PMID: 34696823 PMCID: PMC9477501 DOI: 10.7554/elife.66039] [Citation(s) in RCA: 118] [Impact Index Per Article: 39.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Accepted: 09/07/2021] [Indexed: 11/13/2022] Open
Abstract
Flexible behaviors over long timescales are thought to engage recurrent neural networks in deep brain regions, which are experimentally challenging to study. In insects, recurrent circuit dynamics in a brain region called the central complex (CX) enable directed locomotion, sleep, and context- and experience-dependent spatial navigation. We describe the first complete electron-microscopy-based connectome of the Drosophila CX, including all its neurons and circuits at synaptic resolution. We identified new CX neuron types, novel sensory and motor pathways, and network motifs that likely enable the CX to extract the fly's head-direction, maintain it with attractor dynamics, and combine it with other sensorimotor information to perform vector-based navigational computations. We also identified numerous pathways that may facilitate the selection of CX-driven behavioral patterns by context and internal state. The CX connectome provides a comprehensive blueprint necessary for a detailed understanding of network dynamics underlying sleep, flexible navigation, and state-dependent action selection.
Collapse
Affiliation(s)
- Brad K Hulse
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | - Hannah Haberkern
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | - Romain Franconville
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | | | | | - Tanya Wolff
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | - Marcella Noorman
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | - Marisa Dreher
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | - Chuntao Dan
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | - Ruchi Parekh
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | | | - Gerald M Rubin
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| | - Vivek Jayaraman
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
| |
Collapse
|
36
|
Garcia-Perez NC, Bucher G, Buescher M. Shaking hands is a homeodomain transcription factor that controls axon outgrowth of central complex neurons in the insect model Tribolium. Development 2021; 148:272435. [PMID: 34415334 PMCID: PMC8543150 DOI: 10.1242/dev.199368] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Accepted: 08/09/2021] [Indexed: 01/22/2023]
Abstract
Gene regulatory mechanisms that specify subtype identity of central complex (CX) neurons are the subject of intense investigation. The CX is a compartment within the brain common to all insect species and functions as a ‘command center’ that directs motor actions. It is made up of several thousand neurons, with more than 60 morphologically distinct identities. Accordingly, transcriptional programs must effect the specification of at least as many neuronal subtypes. We demonstrate a role for the transcription factor Shaking hands (Skh) in the specification of embryonic CX neurons in Tribolium. The developmental dynamics of skh expression are characteristic of terminal selectors of subtype identity. In the embryonic brain, skh expression is restricted to a subset of neurons, many of which survive to adulthood and contribute to the mature CX. skh expression is maintained throughout the lifetime in at least some CX neurons. skh knockdown results in axon outgrowth defects, thus preventing the formation of an embryonic CX primordium. The previously unstudied Drosophila skh shows a similar embryonic expression pattern, suggesting that subtype specification of CX neurons may be conserved. Summary: A detailed examination of the developmental expression of the homeodomain transcription factor Shaking hands in Tribolium reveals a role in the formation of the central complex primordium.
Collapse
Affiliation(s)
- Natalia Carolina Garcia-Perez
- Johann Friedrich Blumenbach Institute of Zoology, GZMB, Department of Evolutionary Developmental Genetics, University of Goettingen, Justus-von-Liebig Weg 11, 37077 Goettingen, Germany
| | - Gregor Bucher
- Johann Friedrich Blumenbach Institute of Zoology, GZMB, Department of Evolutionary Developmental Genetics, University of Goettingen, Justus-von-Liebig Weg 11, 37077 Goettingen, Germany
| | - Marita Buescher
- Johann Friedrich Blumenbach Institute of Zoology, GZMB, Department of Evolutionary Developmental Genetics, University of Goettingen, Justus-von-Liebig Weg 11, 37077 Goettingen, Germany
| |
Collapse
|
37
|
Massy R, Hawkes WLS, Doyle T, Troscianko J, Menz MHM, Roberts NW, Chapman JW, Wotton KR. Hoverflies use a time-compensated sun compass to orientate during autumn migration. Proc Biol Sci 2021; 288:20211805. [PMID: 34547904 PMCID: PMC8456149 DOI: 10.1098/rspb.2021.1805] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Accepted: 08/31/2021] [Indexed: 12/11/2022] Open
Abstract
The sun is the most reliable celestial cue for orientation available to daytime migrants. It is widely assumed that diurnal migratory insects use a 'time-compensated sun compass' to adjust for the changing position of the sun throughout the day, as demonstrated in some butterfly species. The mechanisms used by other groups of diurnal insect migrants remain to be elucidated. Migratory species of hoverflies (Diptera: Syrphidae) are one of the most abundant and beneficial groups of diurnal migrants, providing multiple ecosystem services and undergoing directed seasonal movements throughout much of the temperate zone. To identify the hoverfly navigational strategy, a flight simulator was used to measure orientation responses of the hoverflies Scaeva pyrastri and Scaeva selenitica to celestial cues during their autumn migration. Hoverflies oriented southwards when they could see the sun and shifted this orientation westward following a 6 h advance of their circadian clocks. Our results demonstrate the use of a time-compensated sun compass as the primary navigational mechanism, consistent with field observations that hoverfly migration occurs predominately under clear and sunny conditions.
Collapse
Affiliation(s)
- Richard Massy
- Centre for Ecology and Conservation, University of Exeter, Cornwall Campus, Penryn, UK
| | - Will L. S. Hawkes
- Centre for Ecology and Conservation, University of Exeter, Cornwall Campus, Penryn, UK
| | - Toby Doyle
- Centre for Ecology and Conservation, University of Exeter, Cornwall Campus, Penryn, UK
| | - Jolyon Troscianko
- Centre for Ecology and Conservation, University of Exeter, Cornwall Campus, Penryn, UK
| | - Myles H. M. Menz
- Department of Migration, Max Planck Institute of Animal Behaviour, Radolfzell, Germany
- Department of Biology, University of Konstanz, Konstanz, Germany
- School of Biological Sciences, The University of Western Australia, Crawley, WA, Australia
| | | | - Jason W. Chapman
- Centre for Ecology and Conservation, University of Exeter, Cornwall Campus, Penryn, UK
- Environment and Sustainability Institute, University of Exeter, Cornwall Campus, Penryn, UK
- Department of Entomology, Nanjing Agricultural University, Nanjing, People's Republic of China
| | - Karl R. Wotton
- Centre for Ecology and Conservation, University of Exeter, Cornwall Campus, Penryn, UK
| |
Collapse
|
38
|
Sayre ME, Templin R, Chavez J, Kempenaers J, Heinze S. A projectome of the bumblebee central complex. eLife 2021; 10:e68911. [PMID: 34523418 PMCID: PMC8504972 DOI: 10.7554/elife.68911] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Accepted: 09/14/2021] [Indexed: 12/29/2022] Open
Abstract
Insects have evolved diverse and remarkable strategies for navigating in various ecologies all over the world. Regardless of species, insects share the presence of a group of morphologically conserved neuropils known collectively as the central complex (CX). The CX is a navigational center, involved in sensory integration and coordinated motor activity. Despite the fact that our understanding of navigational behavior comes predominantly from ants and bees, most of what we know about the underlying neural circuitry of such behavior comes from work in fruit flies. Here, we aim to close this gap, by providing the first comprehensive map of all major columnar neurons and their projection patterns in the CX of a bee. We find numerous components of the circuit that appear to be highly conserved between the fly and the bee, but also highlight several key differences which are likely to have important functional ramifications.
Collapse
Affiliation(s)
- Marcel Ethan Sayre
- Lund University, Lund Vision Group, Department of BiologyLundSweden
- Macquarie University, Department of Biological SciencesSydneyAustralia
| | - Rachel Templin
- Queensland Brain Institute, University of QueenslandBrisbaneSweden
| | - Johanna Chavez
- Lund University, Lund Vision Group, Department of BiologyLundSweden
| | | | - Stanley Heinze
- Lund University, Lund Vision Group, Department of BiologyLundSweden
- Lund University, NanoLundLundSweden
| |
Collapse
|
39
|
Rozanski AN, Cini A, Lopreto TE, Gandia KM, Hauber ME, Cervo R, Uy FMK. Differential investment in visual and olfactory brain regions is linked to the sensory needs of a wasp social parasite and its host. J Comp Neurol 2021; 530:756-767. [PMID: 34473851 DOI: 10.1002/cne.25242] [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: 01/17/2021] [Revised: 08/03/2021] [Accepted: 08/31/2021] [Indexed: 01/30/2023]
Abstract
Obligate insect social parasites evolve traits to effectively locate and then exploit their hosts, whereas hosts have complex social behavioral repertoires, which include sensory recognition to reject potential conspecific intruders and heterospecific parasites. While social parasites and host behaviors have been studied extensively, less is known about how their sensory systems function to meet their specific selective pressures. Here, we compare investment in visual and olfactory brain regions in the paper wasp Polistes dominula, and its obligate social parasite P. sulcifer, to explore the links among sensory systems,brain and behavior. Our results show significant relative volumetric differences between these two closely related species, consistent with their very different life histories. Social parasites show proportionally larger optic lobes and central complex to likely navigate long-distance migrations and unfamiliar landscapes to locate the specific species of hosts they usurp. Contrastingly, hosts have larger antennal lobes and calyces of the mushroom bodies compared with social parasites, as predicted by their sensory means to maintain social cohesion via olfactory signals, allocate colony tasks, forage, and recognize conspecific and heterospecific intruders. Our work suggests how this tradeoff between visual and olfactory brain regions may facilitate different sensory adaptations needed to perform social and foraging tasks by the host, including recognition of parasites, or to fly long distances and successful host localizing by the social parasite.
Collapse
Affiliation(s)
| | - Alessandro Cini
- Department of Biology, University of Florence, Sesto Fiorentino, Firenze, Italy.,Centre for Biodiversity and Environment Research, University College London, London, UK
| | - Taylor E Lopreto
- Department of Biology, University of Miami, Coral Gables, Florida, USA
| | - Kristine M Gandia
- Department of Biology, University of Miami, Coral Gables, Florida, USA
| | - Mark E Hauber
- Department of Evolution, Ecology and Behavior, School of Integrative Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - Rita Cervo
- Department of Biology, University of Florence, Sesto Fiorentino, Firenze, Italy
| | - Floria M K Uy
- Department of Biology, University of Miami, Coral Gables, Florida, USA.,Department of Biology, University of Rochester, Rochester, New York, USA
| |
Collapse
|
40
|
Goulard R, Buehlmann C, Niven JE, Graham P, Webb B. A unified mechanism for innate and learned visual landmark guidance in the insect central complex. PLoS Comput Biol 2021; 17:e1009383. [PMID: 34555013 PMCID: PMC8491911 DOI: 10.1371/journal.pcbi.1009383] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Revised: 10/05/2021] [Accepted: 08/26/2021] [Indexed: 11/24/2022] Open
Abstract
Insects can navigate efficiently in both novel and familiar environments, and this requires flexiblity in how they are guided by sensory cues. A prominent landmark, for example, can elicit strong innate behaviours (attraction or menotaxis) but can also be used, after learning, as a specific directional cue as part of a navigation memory. However, the mechanisms that allow both pathways to co-exist, interact or override each other are largely unknown. Here we propose a model for the behavioural integration of innate and learned guidance based on the neuroanatomy of the central complex (CX), adapted to control landmark guided behaviours. We consider a reward signal provided either by an innate attraction to landmarks or a long-term visual memory in the mushroom bodies (MB) that modulates the formation of a local vector memory in the CX. Using an operant strategy for a simulated agent exploring a simple world containing a single visual cue, we show how the generated short-term memory can support both innate and learned steering behaviour. In addition, we show how this architecture is consistent with the observed effects of unilateral MB lesions in ants that cause a reversion to innate behaviour. We suggest the formation of a directional memory in the CX can be interpreted as transforming rewarding (positive or negative) sensory signals into a mapping of the environment that describes the geometrical attractiveness (or repulsion). We discuss how this scheme might represent an ideal way to combine multisensory information gathered during the exploration of an environment and support optimal cue integration.
Collapse
Affiliation(s)
- Roman Goulard
- Institute for Perception, Action, and Behaviour, School of Informatics, University of Edinburgh, Edinburgh, Scotland, United Kingdom
| | - Cornelia Buehlmann
- School of Life Sciences, University of Sussex, John Maynard Smith Building, Falmer, Brighton, United Kingdom
| | - Jeremy E. Niven
- School of Life Sciences, University of Sussex, John Maynard Smith Building, Falmer, Brighton, United Kingdom
| | - Paul Graham
- School of Life Sciences, University of Sussex, John Maynard Smith Building, Falmer, Brighton, United Kingdom
| | - Barbara Webb
- Institute for Perception, Action, and Behaviour, School of Informatics, University of Edinburgh, Edinburgh, Scotland, United Kingdom
| |
Collapse
|
41
|
Heinze S, El Jundi B, Berg BG, Homberg U, Menzel R, Pfeiffer K, Hensgen R, Zittrell F, Dacke M, Warrant E, Pfuhl G, Rybak J, Tedore K. A unified platform to manage, share, and archive morphological and functional data in insect neuroscience. eLife 2021; 10:65376. [PMID: 34427185 PMCID: PMC8457822 DOI: 10.7554/elife.65376] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2020] [Accepted: 08/21/2021] [Indexed: 01/08/2023] Open
Abstract
Insect neuroscience generates vast amounts of highly diverse data, of which only a small fraction are findable, accessible and reusable. To promote an open data culture, we have therefore developed the InsectBrainDatabase (IBdb), a free online platform for insect neuroanatomical and functional data. The IBdb facilitates biological insight by enabling effective cross-species comparisons, by linking neural structure with function, and by serving as general information hub for insect neuroscience. The IBdb allows users to not only effectively locate and visualize data, but to make them widely available for easy, automated reuse via an application programming interface. A unique private mode of the database expands the IBdb functionality beyond public data deposition, additionally providing the means for managing, visualizing, and sharing of unpublished data. This dual function creates an incentive for data contribution early in data management workflows and eliminates the additional effort normally associated with publicly depositing research data. Insect neuroscience, like any field in the natural sciences, generates vast amounts of data. Currently, only a fraction are publicly available, and even less are reusable. This is because insect neuroscience data come in many formats and from many species. Some experiments focus on what insect brains look like (morphology), while others focus on how insect brains work (function). Some data come in the form of high-speed video, while other data contain voltage traces from individual neurons. Sharing is not as simple as uploading the raw files to the internet. To get a clear picture of how insect brains work, researchers need a way to cross-reference and connect different experiments. But, as it stands, there is no dedicated place for insect neuroscientists to share and explore such a diverse body of work. The community needs an open data repository that can link different types of data across many species, and can evolve as more data become available. Above all, this repository needs to be easy for researchers to use. To meet these specifications, Heinze et al. developed the Insect Brain Database. The database organizes data into three categories: species, brain structures, and neuron types. Within these categories, each entry has its own profile page. These pages bring different experiments together under one heading, allowing researchers to combine and compare data of different types. As researchers add more experiments, the profile pages will grow and evolve. To make the data easy to navigate, Heinze et al. developed a visual search tool. A combination of 2D and 3D images allow users to explore the data by anatomical location, without the need for expert knowledge. Researchers also have the option to upload their work in private mode, allowing them to securely share unpublished data. The Insect Brain Database brings data together in a way that is accessible not only to researchers, but also to students, and non-scientists. It will help researchers to find related work, to reuse existing data, and to build an open data culture. This has the potential to drive new discoveries combining research across the whole of the insect neuroscience field.
Collapse
Affiliation(s)
- Stanley Heinze
- Department of Biology, Lund University, Lund, Sweden.,NanoLund, Lund University, Lund, Sweden
| | - Basil El Jundi
- Biocenter, Behavioral Physiology and Sociobiology, University of Würzburg, Würzburg, Germany
| | - Bente G Berg
- Department of Psychology, Chemosensory lab, Norwegian University of Science and Technology, Trondheim, Norway
| | - Uwe Homberg
- Fachbereich Biologie, Tierphysiologie, and Center for Mind Brain and Behavior (CMBB), University of Marburg and Justus Liebig University Giessen, Marburg, Germany
| | - Randolf Menzel
- Institut für Biologie - Neurobiologie, Free University, Berlin, Germany
| | - Keram Pfeiffer
- Biocenter, Behavioral Physiology and Sociobiology, University of Würzburg, Würzburg, Germany
| | - Ronja Hensgen
- Fachbereich Biologie, Tierphysiologie, and Center for Mind Brain and Behavior (CMBB), University of Marburg and Justus Liebig University Giessen, Marburg, Germany
| | - Frederick Zittrell
- Fachbereich Biologie, Tierphysiologie, and Center for Mind Brain and Behavior (CMBB), University of Marburg and Justus Liebig University Giessen, Marburg, Germany
| | - Marie Dacke
- Department of Biology, Lund University, Lund, Sweden
| | - Eric Warrant
- Research School of Biology, Australian National University, Canberra, Australia
| | - Gerit Pfuhl
- Department of Psychology, Chemosensory lab, Norwegian University of Science and Technology, Trondheim, Norway.,Department of Psychology, UiT The Arctic University of Norway, Tromso, Norway
| | - Jürgen Rybak
- Department of Evolutionary Neuroethology, Max Planck Institute for Chemical Ecology, Jena, Germany
| | - Kevin Tedore
- Department of Biology, Lund University, Lund, Sweden
| |
Collapse
|
42
|
Hensgen R, Göthe J, Jahn S, Hümmert S, Schneider KL, Takahashi N, Pegel U, Gotthardt S, Homberg U. Organization and neural connections of the lateral complex in the brain of the desert locust. J Comp Neurol 2021; 529:3533-3560. [PMID: 34216020 DOI: 10.1002/cne.25209] [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: 03/19/2021] [Revised: 06/24/2021] [Accepted: 06/28/2021] [Indexed: 11/08/2022]
Abstract
The lateral complexes (LXs) are bilaterally paired neuropils in the insect brain that mediate communication between the central complex (CX), a brain center controlling spatial orientation, various sensory processing areas, and thoracic motor centers that execute locomotion. The LX of the desert locust consists of the lateral accessory lobe (LAL), and the medial and lateral bulb. We have analyzed the anatomical organization and the neuronal connections of the LX in the locust, to provide a basis for future functional studies. Reanalyzing the morphology of neurons connecting the CX and the LX revealed likely feedback loops in the sky compass network of the CX via connections in the gall of the LAL and a newly identified neuropil termed ovoid body. In addition, we characterized 16 different types of neuron that connect the LAL with other areas in the brain. Eight types of neuron provide information flow between both LALs, five types are LAL input neurons, and three types are LAL output neurons. Among these are neurons providing input from sensory brain areas such as the lobula and antennal neuropils. Brain regions most often targeted by LAL neurons are the posterior slope, the wedge, and the crepine. Two descending neurons with dendrites in the LAL were identified. Our data support and complement existing knowledge about how the LAL is embedded in the neuronal network involved in processing of sensory information and generation of appropriate behavioral output for goal-directed locomotion.
Collapse
Affiliation(s)
- Ronja Hensgen
- Department of Biology, Animal Physiology, Philipps-Universität Marburg, Marburg, Germany
| | - Jonas Göthe
- Department of Biology, Animal Physiology, Philipps-Universität Marburg, Marburg, Germany
| | - Stefanie Jahn
- Department of Biology, Animal Physiology, Philipps-Universität Marburg, Marburg, Germany
| | - Sophie Hümmert
- Department of Biology, Animal Physiology, Philipps-Universität Marburg, Marburg, Germany
| | - Kim Lucia Schneider
- Department of Biology, Animal Physiology, Philipps-Universität Marburg, Marburg, Germany
| | - Naomi Takahashi
- Department of Biology, Animal Physiology, Philipps-Universität Marburg, Marburg, Germany
| | - Uta Pegel
- Department of Biology, Animal Physiology, Philipps-Universität Marburg, Marburg, Germany
| | - Sascha Gotthardt
- Department of Biology, Animal Physiology, Philipps-Universität Marburg, Marburg, Germany
| | - Uwe Homberg
- Department of Biology, Animal Physiology, Philipps-Universität Marburg, Marburg, Germany.,Center for Mind, Brain and Behavior (CMBB), University of Marburg and Justus Liebig University Giessen, Marburg, Germany
| |
Collapse
|
43
|
Rother L, Kraft N, Smith DB, El Jundi B, Gill RJ, Pfeiffer K. A micro-CT-based standard brain atlas of the bumblebee. Cell Tissue Res 2021; 386:29-45. [PMID: 34181089 PMCID: PMC8526489 DOI: 10.1007/s00441-021-03482-z] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2020] [Accepted: 06/03/2021] [Indexed: 02/07/2023]
Abstract
In recent years, bumblebees have become a prominent insect model organism for a variety of biological disciplines, particularly to investigate learning behaviors as well as visual performance. Understanding these behaviors and their underlying neurobiological principles requires a clear understanding of brain anatomy. Furthermore, to be able to compare neuronal branching patterns across individuals, a common framework is required, which has led to the development of 3D standard brain atlases in most of the neurobiological insect model species. Yet, no bumblebee 3D standard brain atlas has been generated. Here we present a brain atlas for the buff-tailed bumblebee Bombus terrestris using micro-computed tomography (micro-CT) scans as a source for the raw data sets, rather than traditional confocal microscopy, to produce the first ever micro-CT-based insect brain atlas. We illustrate the advantages of the micro-CT technique, namely, identical native resolution in the three cardinal planes and 3D structure being better preserved. Our Bombus terrestris brain atlas consists of 30 neuropils reconstructed from ten individual worker bees, with micro-CT allowing us to segment neuropils completely intact, including the lamina, which is a tissue structure often damaged when dissecting for immunolabeling. Our brain atlas can serve as a platform to facilitate future neuroscience studies in bumblebees and illustrates the advantages of micro-CT for specific applications in insect neuroanatomy.
Collapse
Affiliation(s)
- Lisa Rother
- Department of Behavioral Physiology and Sociobiology, Biocenter, University of Würzburg, 97074, Würzburg, Germany
| | - Nadine Kraft
- Department of Behavioral Physiology and Sociobiology, Biocenter, University of Würzburg, 97074, Würzburg, Germany
| | - Dylan B Smith
- Department of Life Sciences, Imperial College London, Silwood Park, Buckhurst Road, Ascot, Berkshire, SL5 7PY, UK
| | - Basil El Jundi
- Department of Behavioral Physiology and Sociobiology, Biocenter, University of Würzburg, 97074, Würzburg, Germany
| | - Richard J Gill
- Department of Life Sciences, Imperial College London, Silwood Park, Buckhurst Road, Ascot, Berkshire, SL5 7PY, UK
| | - Keram Pfeiffer
- Department of Behavioral Physiology and Sociobiology, Biocenter, University of Würzburg, 97074, Würzburg, Germany.
| |
Collapse
|
44
|
Hardcastle BJ, Omoto JJ, Kandimalla P, Nguyen BCM, Keleş MF, Boyd NK, Hartenstein V, Frye MA. A visual pathway for skylight polarization processing in Drosophila. eLife 2021; 10:e63225. [PMID: 33755020 PMCID: PMC8051946 DOI: 10.7554/elife.63225] [Citation(s) in RCA: 50] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Accepted: 03/08/2021] [Indexed: 11/13/2022] Open
Abstract
Many insects use patterns of polarized light in the sky to orient and navigate. Here, we functionally characterize neural circuitry in the fruit fly, Drosophila melanogaster, that conveys polarized light signals from the eye to the central complex, a brain region essential for the fly's sense of direction. Neurons tuned to the angle of polarization of ultraviolet light are found throughout the anterior visual pathway, connecting the optic lobes with the central complex via the anterior optic tubercle and bulb, in a homologous organization to the 'sky compass' pathways described in other insects. We detail how a consistent, map-like organization of neural tunings in the peripheral visual system is transformed into a reduced representation suited to flexible processing in the central brain. This study identifies computational motifs of the transformation, enabling mechanistic comparisons of multisensory integration and central processing for navigation in the brains of insects.
Collapse
Affiliation(s)
- Ben J Hardcastle
- Department of Integrative Biology and Physiology, University of California, Los AngelesLos AngelesUnited States
| | - Jaison J Omoto
- Department of Molecular, Cell and Developmental Biology, University of California, Los AngelesLos AngelesUnited States
| | - Pratyush Kandimalla
- Department of Molecular, Cell and Developmental Biology, University of California, Los AngelesLos AngelesUnited States
| | - Bao-Chau M Nguyen
- Department of Molecular, Cell and Developmental Biology, University of California, Los AngelesLos AngelesUnited States
| | - Mehmet F Keleş
- Department of Integrative Biology and Physiology, University of California, Los AngelesLos AngelesUnited States
| | - Natalie K Boyd
- Department of Molecular, Cell and Developmental Biology, University of California, Los AngelesLos AngelesUnited States
| | - Volker Hartenstein
- Department of Molecular, Cell and Developmental Biology, University of California, Los AngelesLos AngelesUnited States
| | - Mark A Frye
- Department of Integrative Biology and Physiology, University of California, Los AngelesLos AngelesUnited States
| |
Collapse
|
45
|
Nguyen TAT, Beetz MJ, Merlin C, el Jundi B. Sun compass neurons are tuned to migratory orientation in monarch butterflies. Proc Biol Sci 2021; 288:20202988. [PMID: 33622121 PMCID: PMC7935079 DOI: 10.1098/rspb.2020.2988] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Accepted: 01/27/2021] [Indexed: 12/19/2022] Open
Abstract
Every autumn, monarch butterflies migrate from North America to their overwintering sites in Central Mexico. To maintain their southward direction, these butterflies rely on celestial cues as orientation references. The position of the sun combined with additional skylight cues are integrated in the central complex, a region in the butterfly's brain that acts as an internal compass. However, the central complex does not solely guide the butterflies on their migration but also helps monarchs in their non-migratory form manoeuvre on foraging trips through their habitat. By comparing the activity of input neurons of the central complex between migratory and non-migratory butterflies, we investigated how a different lifestyle affects the coding of orientation information in the brain. During recording, we presented the animals with different simulated celestial cues and found that the encoding of the sun was narrower in migratory compared to non-migratory butterflies. This feature might reflect the need of the migratory monarchs to rely on a precise sun compass to keep their direction during their journey. Taken together, our study sheds light on the neural coding of celestial cues and provides insights into how a compass is adapted in migratory animals to successfully steer them to their destination.
Collapse
Affiliation(s)
| | - M. Jerome Beetz
- University of Wuerzburg, Biocenter, Zoology II, Würzburg, Germany
| | - Christine Merlin
- Department of Biology and Center for Biological Clocks Research, Texas A&M University, College Station, TX, USA
| | - Basil el Jundi
- University of Wuerzburg, Biocenter, Zoology II, Würzburg, Germany
| |
Collapse
|
46
|
Buhl E, Kottler B, Hodge JJL, Hirth F. Thermoresponsive motor behavior is mediated by ring neuron circuits in the central complex of Drosophila. Sci Rep 2021; 11:155. [PMID: 33420240 PMCID: PMC7794218 DOI: 10.1038/s41598-020-80103-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Accepted: 12/11/2020] [Indexed: 02/05/2023] Open
Abstract
Insects are ectothermal animals that are constrained in their survival and reproduction by external temperature fluctuations which require either active avoidance of or movement towards a given heat source. In Drosophila, different thermoreceptors and neurons have been identified that mediate temperature sensation to maintain the animal’s thermal preference. However, less is known how thermosensory information is integrated to gate thermoresponsive motor behavior. Here we use transsynaptic tracing together with calcium imaging, electrophysiology and thermogenetic manipulations in freely moving Drosophila exposed to elevated temperature and identify different functions of ellipsoid body ring neurons, R1-R4, in thermoresponsive motor behavior. Our results show that warming of the external surroundings elicits calcium influx specifically in R2-R4 but not in R1, which evokes threshold-dependent neural activity in the outer layer ring neurons. In contrast to R2, R3 and R4d neurons, thermogenetic inactivation of R4m and R1 neurons expressing the temperature-sensitive mutant allele of dynamin, shibireTS, results in impaired thermoresponsive motor behavior at elevated 31 °C. trans-Tango mediated transsynaptic tracing together with physiological and behavioral analyses indicate that integrated sensory information of warming is registered by neural activity of R4m as input layer of the ellipsoid body ring neuropil and relayed on to R1 output neurons that gate an adaptive motor response. Together these findings imply that segregated activities of central complex ring neurons mediate sensory-motor transformation of external temperature changes and gate thermoresponsive motor behavior in Drosophila.
Collapse
Affiliation(s)
- Edgar Buhl
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, University Walk, Bristol, UK.
| | - Benjamin Kottler
- Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK
| | - James J L Hodge
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, University Walk, Bristol, UK
| | - Frank Hirth
- Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK.
| |
Collapse
|
47
|
Dacke M, Baird E, El Jundi B, Warrant EJ, Byrne M. How Dung Beetles Steer Straight. ANNUAL REVIEW OF ENTOMOLOGY 2021; 66:243-256. [PMID: 32822556 DOI: 10.1146/annurev-ento-042020-102149] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Distant and predictable features in the environment make ideal compass cues to allow movement along a straight path. Ball-rolling dung beetles use a wide range of different signals in the day or night sky to steer themselves along a fixed bearing. These include the sun, the Milky Way, and the polarization pattern generated by the moon. Almost two decades of research into these remarkable creatures have shown that the dung beetle's compass is flexible and readily adapts to the cues available in its current surroundings. In the morning and afternoon, dung beetles use the sun to orient, but at midday, they prefer to use the wind, and at night or in a forest, they rely primarily on polarized skylight to maintain straight paths. We are just starting to understand the neuronal substrate underlying the dung beetle's compass and the mystery of why these beetles start each journey with a dance.
Collapse
Affiliation(s)
- Marie Dacke
- Department of Biology, Lund University, 223 62 Lund, Sweden; ,
- School of Animal, Plant and Environmental Sciences, University of the Witwatersrand, Johannesburg, South Africa;
| | - Emily Baird
- Department of Zoology, Stockholm University, 106 91 Stockholm, Sweden;
| | - Basil El Jundi
- Biocenter, University of Wuerzburg, 97074 Wuerzburg, Germany;
| | - Eric J Warrant
- Department of Biology, Lund University, 223 62 Lund, Sweden; ,
| | - Marcus Byrne
- School of Animal, Plant and Environmental Sciences, University of the Witwatersrand, Johannesburg, South Africa;
| |
Collapse
|
48
|
Polilov AA, Makarova AA. Constant neuropilar ratio in the insect brain. Sci Rep 2020; 10:21426. [PMID: 33293636 PMCID: PMC7722839 DOI: 10.1038/s41598-020-78599-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Accepted: 11/27/2020] [Indexed: 01/10/2023] Open
Abstract
Revealing scaling rules is necessary for understanding the morphology, physiology and evolution of living systems. Studies of animal brains have revealed both general patterns, such as Haller's rule, and patterns specific for certain animal taxa. However, large-scale studies aimed at studying the ratio of the entire neuropil and the cell body rind in the insect brain have never been performed. Here we performed morphometric study of the adult brain in 37 insect species of 26 families and ten orders, ranging in volume from the smallest to the largest by a factor of more than 4,000,000, and show that all studied insects display a similar ratio of the volume of the neuropil to the cell body rind, 3:2. Allometric analysis for all insects shows that the ratio of the volume of the neuropil to the volume of the brain changes strictly isometrically. Analyses within particular taxa, size groups, and metamorphosis types also reveal no significant differences in the relative volume of the neuropil; isometry is observed in all cases. Thus, we establish a new scaling rule, according to which the relative volume of the entire neuropil in insect brain averages 60% and remains constant.
Collapse
Affiliation(s)
- Alexey A Polilov
- Department of Entomology, Biological Faculty, Lomonosov Moscow State University, 119234, Moscow, Russia.
| | - Anastasia A Makarova
- Department of Entomology, Biological Faculty, Lomonosov Moscow State University, 119234, Moscow, Russia
| |
Collapse
|
49
|
Tai CY, Chin AL, Chiang AS. Comprehensive map of visual projection neurons for processing ultraviolet information in the Drosophila brain. J Comp Neurol 2020; 529:1988-2013. [PMID: 33174208 PMCID: PMC8049075 DOI: 10.1002/cne.25068] [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: 07/22/2020] [Revised: 11/01/2020] [Accepted: 11/02/2020] [Indexed: 11/11/2022]
Abstract
The brain perceives visual information and controls behavior depending on its underlying neural circuits. How UV information is represented and processed in the brain remains poorly understood. In Drosophila melanogaster, UV light is detected by the R7 photoreceptor that projects exclusively into the medulla layer 6 (M6 ). Herein, we imaged 28,768 single neurons and identified 238 visual projection neurons linking M6 to the central brain. Based on morphology and connectivity, these visual projection neurons were systematically classified into 94 cell types belonging to 12 families. Three tracts connected M6 in each optic lobe to the central brain: One dorsal tract linking to the ipsilateral lateral anterior optic tubercle (L-AOTU) and two medial tracts linking to the ipsilateral ventral medial protocerebrum (VMP) and the contralateral VMP. The M6 information was primarily represented in the L-AOTU. Each L-AOTU consisted of four columns that each contained three glomeruli. Each L-AOTU glomerulus received inputs from M6 subdomains and gave outputs to a glomerulus within the ellipsoid body dendritic region, suggesting specific processing of spatial information through the dorsal pathway. Furthermore, the middle columns of the L-AOTUs of both hemispheres were connected via the intertubercle tract, suggesting information integration between the two eyes. In contrast, an ascending neuron linked each VMP to all glomeruli in the bulb and the L-AOTU, bilaterally, suggesting general processing of information through the ventral pathway. Altogether, these diverse morphologies of the visual projection neurons suggested multi-dimensional processing of UV information through parallel and bilateral circuits in the Drosophila brain.
Collapse
Affiliation(s)
- Chu-Yi Tai
- Institute of Biotechnology, National Tsing Hua University, Hsinchu, Taiwan
| | - An-Lun Chin
- Brain Research Center, National Tsing Hua University, Hsinchu, Taiwan
| | - Ann-Shyn Chiang
- Institute of Biotechnology, National Tsing Hua University, Hsinchu, Taiwan.,Brain Research Center, National Tsing Hua University, Hsinchu, Taiwan.,Institute of Systems Neuroscience, National Tsing Hua University, Hsinchu, Taiwan.,Graduate Institute of Clinical Medical Science, China Medical University, Taichung, Taiwan.,Institute of Molecular and Genomic Medicine, National Health Research Institutes, Miaoli County, Taiwan.,Department of Biomedical Science and Environmental Biology, Kaohsiung Medical University, Kaohsiung, Taiwan.,Kavli Institute for Brain and Mind, University of California at San Diego, La Jolla, California, USA
| |
Collapse
|
50
|
Guerra PA. The Monarch Butterfly as a Model for Understanding the Role of Environmental Sensory Cues in Long-Distance Migratory Phenomena. Front Behav Neurosci 2020; 14:600737. [PMID: 33343312 PMCID: PMC7744611 DOI: 10.3389/fnbeh.2020.600737] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Accepted: 11/12/2020] [Indexed: 11/13/2022] Open
Abstract
The awe-inspiring annual migration of monarch butterflies (Danaus plexippus) is an iconic example of long-distance migratory phenomena in which environmental sensory cues help drive successful migration. In this mini-review article, I begin by describing how studies on monarch migration can provide us with generalizable information on how sensory cues can mediate key aspects of animal movement. I describe how environmental sensory cues can trigger the development and progression of the monarch migration, as well as inform sensory-based movement mechanisms in order to travel to and reach their goal destination, despite monarchs being on their maiden voyage. I also describe how sensory cues can trigger season-appropriate changes in migratory direction during the annual cycle. I conclude this mini-review article by discussing how contemporary environmental challenges threaten the persistence of the monarch migration. Environmental challenges such as climate change and shifting land use can significantly alter the sensory environments that monarchs migrate through, as well as degrade or eliminate the sources of sensory cues that are necessary for successful migration.
Collapse
Affiliation(s)
- Patrick A. Guerra
- Department of Biological Sciences, College of Arts and Sciences, University of Cincinnati, Cincinnati, OH, United States
| |
Collapse
|