1
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AnimalTraits - a curated animal trait database for body mass, metabolic rate and brain size. Sci Data 2022; 9:265. [PMID: 35654905 PMCID: PMC9163144 DOI: 10.1038/s41597-022-01364-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2021] [Accepted: 04/26/2022] [Indexed: 11/23/2022] Open
Abstract
Trait databases have become important resources for large-scale comparative studies in ecology and evolution. Here we introduce the AnimalTraits database, a curated database of body mass, metabolic rate and brain size, in standardised units, for terrestrial animals. The database has broad taxonomic breadth, including tetrapods, arthropods, molluscs and annelids from almost 2000 species and 1000 genera. All data recorded in the database are sourced from their original empirical publication, and the original metrics and measurements are included with each record. This allows for subsequent data transformations as required. We have included rich metadata to allow users to filter the dataset. The additional R scripts we provide will assist researchers with aggregating standardised observations into species-level trait values. Our goals are to provide this resource without restrictions, to keep the AnimalTraits database current, and to grow the number of relevant traits in the future. Measurement(s) | metabolic rate quantification • body mass • brain size | Technology Type(s) | metabolic rate measurement • body mass quantification • brain mass brain volume |
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2
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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.
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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
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3
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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.
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4
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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.
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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
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5
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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.
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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
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6
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Morris BJ, Couto A, Aydin A, Montgomery SH. Re-emergence and diversification of a specialized antennal lobe morphology in ithomiine butterflies. Evolution 2021; 75:3191-3202. [PMID: 34383301 DOI: 10.1111/evo.14324] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Revised: 07/15/2021] [Accepted: 08/02/2021] [Indexed: 11/29/2022]
Abstract
How an organism's sensory system functions is central to how it navigates its environment. The insect olfactory system is a prominent model for investigating how ecological factors impact sensory reception and processing. Notably, work in Lepidoptera led to the discovery of vastly expanded structures, termed macroglomerular complexes (MGCs), within the primary olfactory processing centre. MGCs typically process pheromonal cues, are usually larger in males, and provide classic examples of how variation in the size of neural structures reflects the importance of sensory cues. Though prevalent across moths, MGCs were lost during the origin of butterflies, consistent with evidence that courtship initiation in butterflies is primarily reliant on visual cues, rather than long distance chemical signals. However, an MGC was recently described in a species of ithomiine butterfly, suggesting that this once lost neural adaptation has re-emerged in this tribe. Here, we show that MGC-like morphologies are widely distributed across ithomiines, but vary in both their structure and prevalence of sexual dimorphism. Based on this interspecific variation we suggest that the ithomiine MGC is involved in processing both plant and pheromonal cues, which have similarities in their chemical constitution, and co-evolved with an increased importance of plant derived chemical compounds.
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Affiliation(s)
- Billy J Morris
- Department of Zoology, University of Cambridge, Cambridge, UK
| | - Antoine Couto
- Department of Zoology, University of Cambridge, Cambridge, UK.,School of Biological Sciences, University of Bristol, Bristol, UK
| | - Asli Aydin
- School of Medicine, Koc University, Rumelifeneri Yolu, Istanbul, Turkey
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7
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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.
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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.
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8
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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.
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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
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9
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Eriksson M, Janz N, Nylin S, Carlsson MA. Structural plasticity of olfactory neuropils in relation to insect diapause. Ecol Evol 2020; 10:14423-14434. [PMID: 33391725 PMCID: PMC7771155 DOI: 10.1002/ece3.7046] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2020] [Revised: 10/19/2020] [Accepted: 10/23/2020] [Indexed: 12/14/2022] Open
Abstract
Many insects that live in temperate zones spend the cold season in a state of dormancy, referred to as diapause. As the insect must rely on resources that were gathered before entering diapause, keeping a low metabolic rate is of utmost importance. Organs that are metabolically expensive to maintain, such as the brain, can therefore become a liability to survival if they are too large.Insects that go through diapause as adults generally do so before entering the season of reproduction. This order of events introduces a conflict between maintaining low metabolism during dormancy and emerging afterward with highly developed sensory systems that improve fitness during the mating season.We investigated the timing of when investments into the olfactory system are made by measuring the volumes of primary and secondary olfactory neuropils in the brain as they fluctuate in size throughout the extended diapause life-period of adult Polygonia c-album butterflies.Relative volumes of both olfactory neuropils increase significantly during early adult development, indicating the importance of olfaction to this species, but still remain considerably smaller than those of nondiapausing conspecifics. However, despite butterflies being kept under the same conditions as before the dormancy, their olfactory neuropil volumes decreased significantly during the postdormancy period.The opposing directions of change in relative neuropil volumes before and after diapause dormancy indicate that the investment strategies governing structural plasticity during the two life stages could be functionally distinct. As butterflies were kept in stimulus-poor conditions, we find it likely that investments into these brain regions rely on experience-expectant processes before diapause and experience-dependent processes after diapause conditions are broken.As the shift in investment strategies coincides with a hard shift from premating season to mating season, we argue that these developmental characteristics could be adaptations that mitigate the trade-off between dormancy survival and reproductive fitness.
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Affiliation(s)
| | - Niklas Janz
- Department of ZoologyStockholm UniversityStockholmSweden
| | - Sören Nylin
- Department of ZoologyStockholm UniversityStockholmSweden
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10
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Chu X, Heinze S, Ian E, Berg BG. A Novel Major Output Target for Pheromone-Sensitive Projection Neurons in Male Moths. Front Cell Neurosci 2020; 14:147. [PMID: 32581719 PMCID: PMC7294775 DOI: 10.3389/fncel.2020.00147] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Accepted: 05/04/2020] [Indexed: 01/13/2023] Open
Abstract
Even though insects have comparably small brains, they achieve astoundingly complex behaviors. One example is flying moths tracking minute amounts of pheromones using olfactory circuits. The tracking distance can be up to 1 km, which makes it essential that male moths respond efficiently and reliably to very few pheromone molecules. The male-specific macroglomerular complex (MGC) in the moth antennal lobe contains circuitry dedicated to pheromone processing. Output neurons from this region project along three parallel pathways, the medial, mediolateral, and lateral tracts. The MGC-neurons of the lateral tract are least described and their functional significance is mainly unknown. We used mass staining, calcium imaging, and intracellular recording/staining to characterize the morphological and physiological properties of these neurons in the noctuid moth, Helicoverpa armigera. All lateral-tract MGC neurons targeted the column, a small region within the superior intermediate neuropil. We identified this region as a unique converging site for MGC lateral-tract neurons responsive to pheromones, as well as a dense congregating site for plant odor information since a substantial number of lateral-tract neurons from ordinary glomeruli (OG) also terminates in this region. The lateral-tract MGC-neurons responded with a shorter peak latency than the well-described neurons in the medial tract. Different from the medial-tract MGC neurons encoding odor quality important for species-specific signal identification, those in the lateral tract convey a more robust and rapid signal-potentially important for fast control of hard-wired behavior.
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Affiliation(s)
- Xi Chu
- Chemosensory Laboratory, Department of Psychology, Norwegian University of Science and Technology, Trondheim, Norway
| | - Stanley Heinze
- Lund Vision Group, Department of Biology, Lund University, Lund, Sweden
| | - Elena Ian
- Chemosensory Laboratory, Department of Psychology, Norwegian University of Science and Technology, Trondheim, Norway
| | - Bente G. Berg
- Chemosensory Laboratory, Department of Psychology, Norwegian University of Science and Technology, Trondheim, Norway
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11
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Habenstein J, Amini E, Grübel K, el Jundi B, Rössler W. The brain of
Cataglyphis
ants: Neuronal organization and visual projections. J Comp Neurol 2020; 528:3479-3506. [DOI: 10.1002/cne.24934] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2020] [Revised: 04/15/2020] [Accepted: 04/20/2020] [Indexed: 12/25/2022]
Affiliation(s)
- Jens Habenstein
- Biocenter, Behavioral Physiology and Sociobiology (Zoology II) University of Würzburg Würzburg Germany
| | - Emad Amini
- Biocenter, Neurobiology and Genetics University of Würzburg Würzburg Germany
| | - Kornelia Grübel
- Biocenter, Behavioral Physiology and Sociobiology (Zoology II) University of Würzburg Würzburg Germany
| | - Basil el Jundi
- Biocenter, Behavioral Physiology and Sociobiology (Zoology II) University of Würzburg Würzburg Germany
| | - Wolfgang Rössler
- Biocenter, Behavioral Physiology and Sociobiology (Zoology II) University of Würzburg Würzburg Germany
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12
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Adden A, Wibrand S, Pfeiffer K, Warrant E, Heinze S. The brain of a nocturnal migratory insect, the Australian Bogong moth. J Comp Neurol 2020; 528:1942-1963. [PMID: 31994724 DOI: 10.1002/cne.24866] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2019] [Revised: 01/16/2020] [Accepted: 01/18/2020] [Indexed: 12/12/2022]
Abstract
Every year, millions of Australian Bogong moths (Agrotis infusa) complete an astonishing journey: In Spring, they migrate over 1,000 km from their breeding grounds to the alpine regions of the Snowy Mountains, where they endure the hot summer in the cool climate of alpine caves. In autumn, the moths return to their breeding grounds, where they mate, lay eggs and die. These moths can use visual cues in combination with the geomagnetic field to guide their flight, but how these cues are processed and integrated into the brain to drive migratory behavior is unknown. To generate an access point for functional studies, we provide a detailed description of the Bogong moth's brain. Based on immunohistochemical stainings against synapsin and serotonin (5HT), we describe the overall layout as well as the fine structure of all major neuropils, including the regions that have previously been implicated in compass-based navigation. The resulting average brain atlas consists of 3D reconstructions of 25 separate neuropils, comprising the most detailed account of a moth brain to date. Our results show that the Bogong moth brain follows the typical lepidopteran ground pattern, with no major specializations that can be attributed to their spectacular migratory lifestyle. These findings suggest that migratory behavior does not require widespread modifications of brain structure, but might be achievable via small adjustments of neural circuitry in key brain areas. Locating these subtle changes will be a challenging task for the future, for which our study provides an essential anatomical framework.
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Affiliation(s)
- Andrea Adden
- Lund Vision Group, Department of Biology, Lund University, Lund, Sweden
| | - Sara Wibrand
- Lund Vision Group, Department of Biology, Lund University, Lund, Sweden
| | | | - Eric Warrant
- Lund Vision Group, Department of Biology, Lund University, Lund, Sweden
| | - Stanley Heinze
- Lund Vision Group, Department of Biology, Lund University, Lund, Sweden.,NanoLund, Department of Biology, Lund University, Lund, Sweden
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13
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Watanabe T. Evolution of the neural sex-determination system in insects: does fruitless homologue regulate neural sexual dimorphism in basal insects? INSECT MOLECULAR BIOLOGY 2019; 28:807-827. [PMID: 31066110 DOI: 10.1111/imb.12590] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
In the brain of holometabolous insects such as the fruit fly Drosophila melanogaster, the fruitless gene produces sex-specific gene products under the control of the sex-specific splicing cascade and contributes to the formation of the sexually dimorphic circuits. Similar sex-specific gene products of fruitless homologues have been identified in other holometabolous insects such as mosquitoes and a parasitic wasp, suggesting the fruitless-dependent neural sex-determination system is widely conserved amongst holometabolous insects. However, it remains obscure whether the fruitless-dependent neural sex-determination system is present in basal hemimetabolous insects. To address this issue, identification, characterization, and expression analyses of the fruitless homologue were conducted in the two-spotted cricket, Gryllus bimaculatus, as a model hemimetabolous insect. The Gryllus fruitless gene encodes multiple isoforms with a unique zinc finger domain, and does not encode a sex-specific gene product. The Gryllus Fruitless protein is broadly expressed in the neurones and glial cells in the brain, and there was no prominent sex-related difference in the expression levels of Gryllus fruitless isoforms. The results suggest that the Gryllus fruitless gene is not involved in the neural sex-determination in the cricket brain.
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Affiliation(s)
- T Watanabe
- Department of Biological Sciences, Faculty of Science, Hokkaido University, Sapporo, Japan
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14
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Xie GY, Ma BW, Liu XL, Chang YJ, Chen WB, Li GP, Feng HQ, Zhang YJ, Berg BG, Zhao XC. Brain Organization of Apolygus lucorum: A Hemipteran Species With Prominent Antennal Lobes. Front Neuroanat 2019; 13:70. [PMID: 31379518 PMCID: PMC6654032 DOI: 10.3389/fnana.2019.00070] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Accepted: 06/24/2019] [Indexed: 11/13/2022] Open
Abstract
The anatomical organization of distinct regions in the insect brain often reflects their functions. In the present study, the brain structure of Apolygus lucorum was examined by using immunolabeling and three-dimensional reconstruction. The results revealed the location and volume of prominent neuropils, such as the antennal lobes (AL), optic lobes (OL), anterior optic tubercles (AOTU), central body (CB), lateral accessory lobes (LAL), mushroom lobes, and distinct tritocerebral neuropils. As expected, this brain is similar to that of other insects. One exception, however, is that the antennal lobes were found to be the most prominent neuropils. Their size relative to the entire brain is the largest among all insect species studied so far. In contrast, the calyx, a region getting direct input from the antennal lobe, has a smaller size relative to the brain than that of other species. These findings may suggest that olfaction plays an essential role for A. lucorum.
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Affiliation(s)
- Gui-Ying Xie
- Department of Entomology, College of Plant Protection, Henan Agricultural University, Zhengzhou, China
| | - Bai-Wei Ma
- Department of Entomology, College of Plant Protection, Henan Agricultural University, Zhengzhou, China
| | - Xiao-Lan Liu
- Department of Entomology, College of Plant Protection, Henan Agricultural University, Zhengzhou, China
| | - Ya-Jun Chang
- Department of Entomology, College of Plant Protection, Henan Agricultural University, Zhengzhou, China
| | - Wen-Bo Chen
- Department of Entomology, College of Plant Protection, Henan Agricultural University, Zhengzhou, China
| | - Guo-Ping Li
- Institute of Plant Protection, Henan Academy of Agricultural Sciences (HAAS), Zhengzhou, China
| | - Hong-Qiang Feng
- Institute of Plant Protection, Henan Academy of Agricultural Sciences (HAAS), Zhengzhou, China
| | - Yong-Jun Zhang
- State Key Laboratory for Biology of Plant Disease and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Bente G Berg
- Department of Psychology, Norwegian University of Science and Technology, Trondheim, Norway
| | - Xin-Cheng Zhao
- Department of Entomology, College of Plant Protection, Henan Agricultural University, Zhengzhou, China
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15
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Groothuis J, Pfeiffer K, El Jundi B, Smid HM. The Jewel Wasp Standard Brain: Average shape atlas and morphology of the female Nasonia vitripennis brain. ARTHROPOD STRUCTURE & DEVELOPMENT 2019; 51:41-51. [PMID: 31357033 DOI: 10.1016/j.asd.2019.100878] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2019] [Revised: 07/25/2019] [Accepted: 07/25/2019] [Indexed: 06/10/2023]
Abstract
Nasonia, a genus of parasitoid wasps, is a promising model system in the study of developmental and evolutionary genetics, as well as complex traits such as learning. Of these "jewel wasps", the species Nasonia vitripennis is widely spread and widely studied. To accelerate neuroscientific research in this model species, fundamental knowledge of its nervous system is needed. To this end, we present an average standard brain of recently eclosed naïve female N. vitripennis wasps obtained by the iterative shape averaging method. This "Jewel Wasp Standard Brain" includes the optic lobe (excluding the lamina), the anterior optic tubercle, the antennal lobe, the lateral horn, the mushroom body, the central complex, and the remaining unclassified neuropils in the central brain. Furthermore, we briefly describe these well-defined neuropils and their subregions in the N. vitripennis brain. A volumetric analysis of these neuropils is discussed in the context of brains of other insect species. The Jewel Wasp Standard Brain will provide a framework to integrate and consolidate the results of future neurobiological studies in N. vitripennis. In addition, the volumetric analysis provides a baseline for future work on age- and experience-dependent brain plasticity.
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Affiliation(s)
- Jitte Groothuis
- Laboratory of Entomology, Wageningen University, Droevendaalsesteeg 1, 6708 PB, Wageningen, the Netherlands
| | - Keram Pfeiffer
- Behavioral Physiology and Sociobiology (Zoology II), University of Würzburg, Biocenter, Am Hubland, 97074, Würzburg, Germany
| | - Basil El Jundi
- Behavioral Physiology and Sociobiology (Zoology II), University of Würzburg, Biocenter, Am Hubland, 97074, Würzburg, Germany
| | - Hans M Smid
- Laboratory of Entomology, Wageningen University, Droevendaalsesteeg 1, 6708 PB, Wageningen, the Netherlands.
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16
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Stöckl AL, Kelber A. Fuelling on the wing: sensory ecology of hawkmoth foraging. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2019; 205:399-413. [PMID: 30880349 PMCID: PMC6579779 DOI: 10.1007/s00359-019-01328-2] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2018] [Revised: 02/25/2019] [Accepted: 03/05/2019] [Indexed: 11/28/2022]
Abstract
Hawkmoths (Lepidoptera, Sphingidae) comprise around 1500 species, most of which forage on nectar from flowers in their adult stage, usually while hovering in front of the flower. The majority of species have a nocturnal lifestyle and are important nocturnal pollinators, but some species have turned to a diurnal lifestyle. Hawkmoths use visual and olfactory cues including CO2 and humidity to detect and recognise rewarding flowers; they find the nectary in the flowers by means of mechanoreceptors on the proboscis and vision, evaluate it with gustatory receptors on the proboscis, and control their hovering flight position using antennal mechanoreception and vision. Here, we review what is presently known about the sensory organs and sensory-guided behaviour that control feeding behaviour of this fascinating pollinator taxon. We also suggest that more experiments on hawkmoth behaviour in natural settings are needed to fully appreciate their sensory capabilities.
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Affiliation(s)
- Anna Lisa Stöckl
- Biozentrum, University of Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Almut Kelber
- Department of Biology, Lund University, Sölvegatan 35, 22362, Lund, Sweden.
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17
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Sheehan ZBV, Kamhi JF, Seid MA, Narendra A. Differential investment in brain regions for a diurnal and nocturnal lifestyle in Australian Myrmecia ants. J Comp Neurol 2019; 527:1261-1277. [PMID: 30592041 DOI: 10.1002/cne.24617] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2018] [Revised: 12/07/2018] [Accepted: 12/22/2018] [Indexed: 12/29/2022]
Abstract
Animals are active at different times of the day. Each temporal niche offers a unique light environment, which affects the quality of the available visual information. To access reliable visual signals in dim-light environments, insects have evolved several visual adaptations to enhance their optical sensitivity. The extent to which these adaptations reflect on the sensory processing and integration capabilities within the brain of a nocturnal insect is unknown. To address this, we analyzed brain organization in congeneric species of the Australian bull ant, Myrmecia, that rely predominantly on visual information and range from being strictly diurnal to strictly nocturnal. Weighing brains and optic lobes of seven Myrmecia species, showed that after controlling for body mass, the brain mass was not significantly different between diurnal and nocturnal ants. However, the optic lobe mass, after controlling for central brain mass, differed between day- and night-active ants. Detailed volumetric analyses showed that the nocturnal ants invested relatively less in the primary visual processing regions but relatively more in both the primary olfactory processing regions and in the integration centers of visual and olfactory sensory information. We discuss how the temporal niche occupied by each species may affect cognitive demands, thus shaping brain organization among insects active in dim-light conditions.
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Affiliation(s)
- Zachary B V Sheehan
- Department of Biological Sciences, Macquarie University, Sydney, New South Wales, Australia
| | - J Frances Kamhi
- Department of Biological Sciences, Macquarie University, Sydney, New South Wales, Australia
| | - Marc A Seid
- Department of Biological Sciences, Macquarie University, Sydney, New South Wales, Australia.,Biology Department, Neuroscience Program, The University of Scranton, Scranton, Pennsylvania
| | - Ajay Narendra
- Department of Biological Sciences, Macquarie University, Sydney, New South Wales, Australia
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18
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Brain evolution in social insects: advocating for the comparative approach. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2019; 205:13-32. [DOI: 10.1007/s00359-019-01315-7] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Revised: 01/09/2019] [Accepted: 01/11/2019] [Indexed: 10/27/2022]
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19
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El Jundi B, Warrant EJ, Pfeiffer K, Dacke M. Neuroarchitecture of the dung beetle central complex. J Comp Neurol 2018; 526:2612-2630. [PMID: 30136721 DOI: 10.1002/cne.24520] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Revised: 08/12/2018] [Accepted: 08/15/2018] [Indexed: 01/09/2023]
Abstract
Despite their tiny brains, insects show impressive abilities when navigating over short distances during path integration or during migration over thousands of kilometers across entire continents. Celestial compass cues often play an important role as references during navigation. In contrast to many other insects, South African dung beetles rely exclusively on celestial cues for visual reference during orientation. After finding a dung pile, these animals cut off a piece of dung from the pat, shape it into a ball and roll it away along a straight path until a suitable place for underground consumption is found. To maintain a constant bearing, a brain region in the beetle's brain, called the central complex, is crucially involved in the processing of skylight cues, similar to what has already been shown for path-integrating and migrating insects. In this study, we characterized the neuroanatomy of the sky-compass network and the central complex in the dung beetle brain in detail. Using tracer injections, combined with imaging and 3D modeling, we describe the anatomy of the possible sky-compass network in the central brain. We used a quantitative approach to study the central-complex network and found that several types of neuron exhibit a highly organized connectivity pattern. The architecture of the sky-compass network and central complex is similar to that described in insects that perform path integration or are migratory. This suggests that, despite their different orientation behaviors, this neural circuitry for compass orientation is highly conserved among the insects.
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Affiliation(s)
- Basil El Jundi
- Biocenter, Zoology II, Emmy Noether Animal Navigation Group, University of Würzburg, Germany
| | - Eric J Warrant
- Vision Group, Department of Biology, Lund University, Lund, Sweden
| | | | - Marie Dacke
- Vision Group, Department of Biology, Lund University, Lund, Sweden
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20
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Stöckl A, Smolka J, O'Carroll D, Warrant E. Resolving the Trade-off Between Visual Sensitivity and Spatial Acuity-Lessons from Hawkmoths. Integr Comp Biol 2017; 57:1093-1103. [PMID: 28992251 DOI: 10.1093/icb/icx058] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The visual systems of many animals, particularly those active during the day, are optimized for high spatial acuity. However, at night, when photons are sparse and the visual signal competes with increased noise levels, fine spatial resolution cannot be sustained and is traded-off for the greater sensitivity required to see in dim light. High spatial acuity demands detectors and successive visual processing units whose receptive fields each cover only a small area of visual space, in order to reassemble a finely sampled and well resolved image. However, the smaller the sampled area, the fewer the photons that can be collected, and thus the worse the visual sensitivity becomes-leading to the classical trade-off between sensitivity and resolution. Nocturnal animals usually resolve this trade-off in favour of sensitivity, and thus have lower spatial acuity than their diurnal counterparts. Here we review results highlighting how hawkmoths, a highly visual group of insects with species active at different light intensities, resolve the trade-off between sensitivity and spatial resolution. We compare adaptations both in the optics and retina, as well as at higher levels of neural processing in a nocturnal and a diurnal hawkmoth species, and also give a perspective on the behavioral consequences. We broaden the scope of our review by drawing comparisons with the adaptive strategies used by other nocturnal and diurnal insects.
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Affiliation(s)
- Anna Stöckl
- Department of Biology, Lund University, Lund 22362, Sweden
| | - Jochen Smolka
- Department of Biology, Lund University, Lund 22362, Sweden
| | | | - Eric Warrant
- Department of Biology, Lund University, Lund 22362, Sweden
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21
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de Vries L, Pfeiffer K, Trebels B, Adden AK, Green K, Warrant E, Heinze S. Comparison of Navigation-Related Brain Regions in Migratory versus Non-Migratory Noctuid Moths. Front Behav Neurosci 2017; 11:158. [PMID: 28928641 PMCID: PMC5591330 DOI: 10.3389/fnbeh.2017.00158] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2017] [Accepted: 08/15/2017] [Indexed: 11/13/2022] Open
Abstract
Brain structure and function are tightly correlated across all animals. While these relations are ultimately manifestations of differently wired neurons, many changes in neural circuit architecture lead to larger-scale alterations visible already at the level of brain regions. Locating such differences has served as a beacon for identifying brain areas that are strongly associated with the ecological needs of a species-thus guiding the way towards more detailed investigations of how brains underlie species-specific behaviors. Particularly in relation to sensory requirements, volume-differences in neural tissue between closely related species reflect evolutionary investments that correspond to sensory abilities. Likewise, memory-demands imposed by lifestyle have revealed similar adaptations in regions associated with learning. Whether this is also the case for species that differ in their navigational strategy is currently unknown. While the brain regions associated with navigational control in insects have been identified (central complex (CX), lateral complex (LX) and anterior optic tubercles (AOTU)), it remains unknown in what way evolutionary investments have been made to accommodate particularly demanding navigational strategies. We have thus generated average-shape atlases of navigation-related brain regions of a migratory and a non-migratory noctuid moth and used volumetric analysis to identify differences. We further compared the results to identical data from Monarch butterflies. Whereas we found differences in the size of the nodular unit of the AOTU, the LX and the protocerebral bridge (PB) between the two moths, these did not unambiguously reflect migratory behavior across all three species. We conclude that navigational strategy, at least in the case of long-distance migration in lepidopteran insects, is not easily deductible from overall neuropil anatomy. This suggests that the adaptations needed to ensure successful migratory behavior are found in the detailed wiring characteristics of the neural circuits underlying navigation-differences that are only accessible through detailed physiological and ultrastructural investigations. The presented results aid this task in two ways. First, the identified differences in neuropil volumes serve as promising initial targets for electrophysiology. Second, the new standard atlases provide an anatomical reference frame for embedding all functional data obtained from the brains of the Bogong and the Turnip moth.
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Affiliation(s)
- Liv de Vries
- Lund Vision Group, Department of Biology, Lund UniversityLund, Sweden
| | - Keram Pfeiffer
- Department of Biology, Marburg UniversityMarburg, Germany
| | - Björn Trebels
- Department of Biology, Marburg UniversityMarburg, Germany
| | - Andrea K Adden
- Lund Vision Group, Department of Biology, Lund UniversityLund, Sweden
| | - Ken Green
- New South Wales National Parks and Wildlife ServiceJindabyne, NSW, Australia
| | - Eric Warrant
- Lund Vision Group, Department of Biology, Lund UniversityLund, Sweden
| | - Stanley Heinze
- Lund Vision Group, Department of Biology, Lund UniversityLund, Sweden
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22
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Immonen EV, Dacke M, Heinze S, El Jundi B. Anatomical organization of the brain of a diurnal and a nocturnal dung beetle. J Comp Neurol 2017; 525:1879-1908. [PMID: 28074466 DOI: 10.1002/cne.24169] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2016] [Revised: 12/14/2016] [Accepted: 12/21/2016] [Indexed: 12/25/2022]
Abstract
To avoid the fierce competition for food, South African ball-rolling dung beetles carve a piece of dung off a dung-pile, shape it into a ball and roll it away along a straight line path. For this unidirectional exit from the busy dung pile, at night and day, the beetles use a wide repertoire of celestial compass cues. This robust and relatively easily measurable orientation behavior has made ball-rolling dung beetles an attractive model organism for the study of the neuroethology behind insect orientation and sensory ecology. Although there is already some knowledge emerging concerning how celestial cues are processed in the dung beetle brain, little is known about its general neural layout. Mapping the neuropils of the dung beetle brain is thus a prerequisite to understand the neuronal network that underlies celestial compass orientation. Here, we describe and compare the brains of a day-active and a night-active dung beetle species based on immunostainings against synapsin and serotonin. We also provide 3D reconstructions for all brain areas and many of the fiber bundles in the brain of the day-active dung beetle. Comparison of neuropil structures between the two dung beetle species revealed differences that reflect adaptations to different light conditions. Altogether, our results provide a reference framework for future studies on the neuroethology of insects in general and dung beetles in particular.
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Affiliation(s)
- Esa-Ville Immonen
- Nano and Molecular Systems Research Unit, Faculty of Science, University of Oulu, Oulu, Finland.,Lund Vision Group, Department of Biology, Lund University, Lund, Sweden
| | - Marie Dacke
- Nano and Molecular Systems Research Unit, Faculty of Science, University of Oulu, Oulu, Finland
| | - Stanley Heinze
- Nano and Molecular Systems Research Unit, Faculty of Science, University of Oulu, Oulu, Finland
| | - Basil El Jundi
- Nano and Molecular Systems Research Unit, Faculty of Science, University of Oulu, Oulu, Finland
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23
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Kinoshita M, Homberg U. Insect Brains: Minute Structures Controlling Complex Behaviors. ACTA ACUST UNITED AC 2017. [DOI: 10.1007/978-4-431-56469-0_6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Xi J, Toyoda I, Shiga S. Afferent neural pathways from the photoperiodic receptor in the bean bug, Riptortus pedestris. Cell Tissue Res 2017; 368:469-485. [PMID: 28144785 DOI: 10.1007/s00441-016-2565-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2016] [Accepted: 12/20/2016] [Indexed: 11/24/2022]
Abstract
Adult diapause in the bean bug, Riptortus pedestris, is controlled by the photoperiod, which is received by retinal cells in the central region of the compound eyes. To resolve the afferent neural pathways involved in the photoperiodic response, we examine fibre projections from the photoperiodic receptors to the brain and investigate the roles of the posterior optic tract (POT) in the photoperiodic response. Reduced-silver impregnation and synapsin immunolabelling revealed that the medulla was divided into nine strata: the outer layer comprises 4 strata, the inner layer comprises 4 strata and a serpentine layer separates the inner and outer layers. Biotin injection revealed that retinal fibres from the central region of the compound eye terminated in either the central part of the lamina or the central part of the medulla 3rd or 4th layer. Biotin injection into the central part of the medulla labelled 5 distinct afferent pathways: two terminated in a region of ipsilateral anterior protocerebrum, while the other three had contralateral projections. One pathway ran through the POT and connected to the bilateral medulla serpentine layers. When the POT was surgically severed, diapause incidence under short-day conditions was significantly reduced compared to that observed following a sham operation. However, an incision at a posterior part of the medulla and lobula boundary, as a control experiment, did not affect the photoperiodic response. These results suggest that photoperiodic signals from the central region of the compound eye are transferred to neurons with fibres running in the POT for photoperiodic response in R. pedestris.
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Affiliation(s)
- Jili Xi
- Department of Biology and Geosciences, Graduate School of Science, Osaka City University, Osaka, 558-8585, Japan
| | - Ikuyo Toyoda
- Department of Biology and Geosciences, Graduate School of Science, Osaka City University, Osaka, 558-8585, Japan
| | - Sakiko Shiga
- Department of Biology and Geosciences, Graduate School of Science, Osaka City University, Osaka, 558-8585, Japan. .,Department of Biological Science, Graduate School of Science, Osaka University, Osaka, 560-0043, Japan.
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25
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Namiki S, Kanzaki R. Comparative Neuroanatomy of the Lateral Accessory Lobe in the Insect Brain. Front Physiol 2016; 7:244. [PMID: 27445837 PMCID: PMC4917559 DOI: 10.3389/fphys.2016.00244] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2016] [Accepted: 06/03/2016] [Indexed: 11/13/2022] Open
Abstract
The lateral accessory lobe (LAL) mediates signals from the central complex to the thoracic motor centers. The results obtained from different insects suggest that the LAL is highly relevant to the locomotion. Perhaps due to its deep location and lack of clear anatomical boundaries, few studies have focused on this brain region. Systematic data of LAL interneurons are available in the silkmoth. We here review individual neurons constituting the LAL by comparing the silkmoth and other insects. The survey through the connectivity and intrinsic organization suggests potential homology in the organization of the LAL among insects.
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Affiliation(s)
- Shigehiro Namiki
- Research Center for Advanced Science and Technology, The University of Tokyo Tokyo, Japan
| | - Ryohei Kanzaki
- Research Center for Advanced Science and Technology, The University of Tokyo Tokyo, Japan
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26
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Rybak J, Talarico G, Ruiz S, Arnold C, Cantera R, Hansson BS. Synaptic circuitry of identified neurons in the antennal lobe of Drosophila melanogaster. J Comp Neurol 2016; 524:1920-56. [PMID: 26780543 PMCID: PMC6680330 DOI: 10.1002/cne.23966] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2015] [Revised: 01/05/2016] [Accepted: 01/13/2016] [Indexed: 11/09/2022]
Abstract
In Drosophila melanogaster olfactory sensory neurons (OSNs) establish synapses with projection neurons (PNs) and local interneurons within antennal lobe (AL) glomeruli. Substantial knowledge regarding this circuitry has been obtained by functional studies, whereas ultrastructural evidence of synaptic contacts is scarce. To fill this gap, we studied serial sections of three glomeruli using electron microscopy. Ectopic expression of a membrane-bound peroxidase allowed us to map synaptic sites along PN dendrites. Our data prove for the first time that each of the three major types of AL neurons is both pre- and postsynaptic to the other two types, as previously indicated by functional studies. PN dendrites carry a large proportion of output synapses, with approximately one output per every three input synapses. Detailed reconstructions of PN dendrites showed that these synapses are distributed unevenly, with input and output sites partially segregated along a proximal-distal gradient and the thinnest branches carrying solely input synapses. Moreover, our data indicate synapse clustering, as we found evidence of dendritic tiling of PN dendrites. PN output synapses exhibited T-shaped presynaptic densities, mostly arranged as tetrads. In contrast, output synapses from putative OSNs showed elongated presynaptic densities in which the T-bar platform was supported by several pedestals and contacted as many as 20 postsynaptic profiles. We also discovered synaptic contacts between the putative OSNs. The average synaptic density in the glomerular neuropil was about two synapses/µm(3) . These results are discussed with regard to current models of olfactory glomerular microcircuits across species.
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Affiliation(s)
- Jürgen Rybak
- Department of Evolutionary NeuroethologyMax Planck Institute for Chemical Ecology07745JenaGermany
| | - Giovanni Talarico
- Department of Evolutionary NeuroethologyMax Planck Institute for Chemical Ecology07745JenaGermany
| | - Santiago Ruiz
- Clemente Estable Institute of Biological Research11600 MontevideoUruguay
| | - Christopher Arnold
- Department of Evolutionary NeuroethologyMax Planck Institute for Chemical Ecology07745JenaGermany
| | - Rafael Cantera
- Clemente Estable Institute of Biological Research11600 MontevideoUruguay
- Zoology DepartmentStockholm University10691StockholmSweden
| | - Bill S. Hansson
- Department of Evolutionary NeuroethologyMax Planck Institute for Chemical Ecology07745JenaGermany
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27
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Differential investment in visual and olfactory brain areas reflects behavioural choices in hawk moths. Sci Rep 2016; 6:26041. [PMID: 27185464 PMCID: PMC4869021 DOI: 10.1038/srep26041] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2016] [Accepted: 04/26/2016] [Indexed: 11/08/2022] Open
Abstract
Nervous tissue is one of the most metabolically expensive animal tissues, thus evolutionary investments that result in enlarged brain regions should also result in improved behavioural performance. Indeed, large-scale comparative studies in vertebrates and invertebrates have successfully linked differences in brain anatomy to differences in ecology and behaviour, but their precision can be limited by the detail of the anatomical measurements, or by only measuring behaviour indirectly. Therefore, detailed case studies are valuable complements to these investigations, and have provided important evidence linking brain structure to function in a range of higher-order behavioural traits, such as foraging experience or aggressive behaviour. Here, we show that differences in the size of both lower and higher-order sensory brain areas reflect differences in the relative importance of these senses in the foraging choices of hawk moths, as suggested by previous anatomical work in Lepidopterans. To this end we combined anatomical and behavioural quantifications of the relative importance of vision and olfaction in two closely related hawk moth species. We conclude that differences in sensory brain volume in these hawk moths can indeed be interpreted as differences in the importance of these senses for the animal’s behaviour.
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Koniszewski NDB, Kollmann M, Bigham M, Farnworth M, He B, Büscher M, Hütteroth W, Binzer M, Schachtner J, Bucher G. The insect central complex as model for heterochronic brain development-background, concepts, and tools. Dev Genes Evol 2016; 226:209-19. [PMID: 27056385 PMCID: PMC4896989 DOI: 10.1007/s00427-016-0542-7] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2016] [Accepted: 03/17/2016] [Indexed: 11/28/2022]
Abstract
The adult insect brain is composed of neuropils present in most taxa. However, the relative size, shape, and developmental timing differ between species. This diversity of adult insect brain morphology has been extensively described while the genetic mechanisms of brain development are studied predominantly in Drosophila melanogaster. However, it has remained enigmatic what cellular and genetic mechanisms underlie the evolution of neuropil diversity or heterochronic development. In this perspective paper, we propose a novel approach to study these questions. We suggest using genome editing to mark homologous neural cells in the fly D. melanogaster, the beetle Tribolium castaneum, and the Mediterranean field cricket Gryllus bimaculatus to investigate developmental differences leading to brain diversification. One interesting aspect is the heterochrony observed in central complex development. Ancestrally, the central complex is formed during embryogenesis (as in Gryllus) but in Drosophila, it arises during late larval and metamorphic stages. In Tribolium, it forms partially during embryogenesis. Finally, we present tools for brain research in Tribolium including 3D reconstruction and immunohistochemistry data of first instar brains and the generation of transgenic brain imaging lines. Further, we characterize reporter lines labeling the mushroom bodies and reflecting the expression of the neuroblast marker gene Tc-asense, respectively.
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Affiliation(s)
- Nikolaus Dieter Bernhard Koniszewski
- Department of Evolutionary Developmental Genetics, Johann-Friedrich-Blumenbach Institute, GZMB, CNMPB, Georg-August-University Göttingen, Göttingen Campus, Göttingen, Germany.,Institute of Medical Microbiology, Otto-von-Guericke-University, Magdeburg, Germany
| | - Martin Kollmann
- Department of Biology, Animal Physiology, Philipps-University, Marburg, Germany
| | - Mahdiyeh Bigham
- Department of Evolutionary Developmental Genetics, Johann-Friedrich-Blumenbach Institute, GZMB, CNMPB, Georg-August-University Göttingen, Göttingen Campus, Göttingen, Germany
| | - Max Farnworth
- Department of Evolutionary Developmental Genetics, Johann-Friedrich-Blumenbach Institute, GZMB, CNMPB, Georg-August-University Göttingen, Göttingen Campus, Göttingen, Germany
| | - Bicheng He
- Department of Evolutionary Developmental Genetics, Johann-Friedrich-Blumenbach Institute, GZMB, CNMPB, Georg-August-University Göttingen, Göttingen Campus, Göttingen, Germany
| | - Marita Büscher
- Department of Evolutionary Developmental Genetics, Johann-Friedrich-Blumenbach Institute, GZMB, CNMPB, Georg-August-University Göttingen, Göttingen Campus, Göttingen, Germany
| | - Wolf Hütteroth
- Department of Biology, Animal Physiology, Philipps-University, Marburg, Germany.,Department of Biology, Neurobiology, University of Konstanz, Constance, Germany
| | - Marlene Binzer
- Department of Biology, Animal Physiology, Philipps-University, Marburg, Germany
| | - Joachim Schachtner
- Department of Biology, Animal Physiology, Philipps-University, Marburg, Germany
| | - Gregor Bucher
- Department of Evolutionary Developmental Genetics, Johann-Friedrich-Blumenbach Institute, GZMB, CNMPB, Georg-August-University Göttingen, Göttingen Campus, Göttingen, Germany.
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Montgomery SH, Merrill RM, Ott SR. Brain composition inHeliconiusbutterflies, posteclosion growth and experience-dependent neuropil plasticity. J Comp Neurol 2016; 524:1747-69. [DOI: 10.1002/cne.23993] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2015] [Revised: 02/12/2016] [Accepted: 02/15/2016] [Indexed: 12/21/2022]
Affiliation(s)
- Stephen H. Montgomery
- Department of Genetics, Evolution & Environment; University College London; London UK
- Smithsonian Tropical Research Institute; Panama
| | - Richard M. Merrill
- Smithsonian Tropical Research Institute; Panama
- Department of Zoology; University of Cambridge; Cambridge UK
| | - Swidbert R. Ott
- Department of Neuroscience, Psychology and Behaviour; University of Leicester; Leicester UK
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30
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Seada MA, Ghaninia M. Deep-tissue confocal imaging of the central projections of ovipositor sensory afferents in the Egyptian cotton leafworm, Spodoptera littoralis. Micron 2016; 82:52-62. [PMID: 26774745 DOI: 10.1016/j.micron.2015.12.009] [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: 11/09/2015] [Revised: 12/22/2015] [Accepted: 12/22/2015] [Indexed: 11/29/2022]
Abstract
The pre-ovipositon behavior of moths is largely dependent upon the cues that a gravid female perceives while assessing potential oviposition sites. Assessment of such sites is accomplished, at least in part, by mechanosensory and gustatory sensilla located on the ovipositor whose sensory neurons project into the terminal abdominal ganglion (TAG). Using anterograde backfill staining, confocal laser scanning microscopy, and three dimensional reconstruction, we traced and analyzed the central projections of the sensory neurons housed in the sensilla located on the ovipositor papillae and explored the neuropilar composition of the TAG in the Egyptian cotton leafworm, Spodoptera littoralis. The TAG consists of three fused neuromeres (6-8th Ner) associated with the 6-8th abdominal segments. Within the TAG, and specifically in the 8th neuromere, four unstructured neuropilar compartments are present; the dorso-ipsilateral motor neuropil (MN), the medio-ipsilateral mechanosensory neuropil (MchN), the medio-ipsilateral small gustatory neuropil (GN), and the medio-contralateral posterior ovipositor glomerulus (Og). The Og appears quite compact, with a hollow core free of terminal arborizations. The MchN is further subdivided into 4 unstructured glomeruli in the 8th neuromere, whose afferents are subsequently extended into 3 glomeruli in the 7th and 6th neuromeres. Few neurites of the Og are populated with large dense varicosities reminiscent of neurosecretory vesicles. Given that all ovipositor nerves converge into a common ganglionic center, the TAG, we assume that this ganglion may be a center for coordination of oviposition behaviors, including movements of the ovipositor during assessment of oviposition substrates and egg laying in S. littoralis.
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Affiliation(s)
- Mervat A Seada
- Division of Entomology, Department of Zoology, Tanta University, 31527 Tanta, El-Gharbiya, Egypt.
| | - Majid Ghaninia
- Division of Entomology, Department of Plant Protection, College of Plant Production, Gorgan University of Agricultural Sciences and Natural Resources, Gorgan, Iran
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31
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Daly KC, Bradley S, Chapman PD, Staudacher EM, Tiede R, Schachtner J. Space Takes Time: Concentration Dependent Output Codes from Primary Olfactory Networks Rapidly Provide Additional Information at Defined Discrimination Thresholds. Front Cell Neurosci 2016; 9:515. [PMID: 26834563 PMCID: PMC4712294 DOI: 10.3389/fncel.2015.00515] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2015] [Accepted: 12/22/2015] [Indexed: 11/13/2022] Open
Abstract
As odor concentration increases, primary olfactory network representations expand in spatial distribution, temporal complexity and duration. However, the direct relationship between concentration dependent odor representations and the psychophysical thresholds of detection and discrimination is poorly understood. This relationship is absolutely critical as thresholds signify transition points whereby representations become meaningful to the organism. Here, we matched stimulus protocols for psychophysical assays and intracellular recordings of antennal lobe (AL) projection neurons (PNs) in the moth Manduca sexta to directly compare psychophysical thresholds and the output representations they elicit. We first behaviorally identified odor detection and discrimination thresholds across an odor dilution series for a panel of structurally similar odors. We then characterized spatiotemporal spiking patterns across a population of individually filled and identified AL PNs in response to those odors at concentrations below, at, and above identified thresholds. Using spatial and spatiotemporal based analyses we observed that each stimulus produced unique representations, even at sub-threshold concentrations. Mean response latency did not decrease and the percent glomerular activation did not increase with concentration until undiluted odor. Furthermore, correlations between spatial patterns for odor decreased, but only significantly with undiluted odor. Using time-integrated Euclidean distance (ED) measures, we determined that added spatiotemporal information was present at the discrimination but not detection threshold. This added information was evidenced by an increase in integrated distance between the sub-detection and discrimination threshold concentrations (of the same odor) that was not present in comparison of the sub-detection and detection threshold. After consideration of delays for information to reach the AL we find that it takes ~120-140 ms for the AL to output identity information. Overall, these results demonstrate that as odor concentration increases, added information about odor identity is embedded in the spatiotemporal representation at the discrimination threshold.
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Affiliation(s)
- Kevin C Daly
- Department of Biology, West Virginia University Morgantown, WV, USA
| | - Samual Bradley
- Department of Biology, West Virginia University Morgantown, WV, USA
| | | | | | - Regina Tiede
- Fachbereich Biologie, Philipps-Universität Marburg, Germany
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Krieger J, Braun P, Rivera NT, Schubart CD, Müller CH, Harzsch S. Comparative analyses of olfactory systems in terrestrial crabs (Brachyura): evidence for aerial olfaction? PeerJ 2015; 3:e1433. [PMID: 26713228 PMCID: PMC4690415 DOI: 10.7717/peerj.1433] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2015] [Accepted: 11/03/2015] [Indexed: 11/30/2022] Open
Abstract
Adaptations to a terrestrial lifestyle occurred convergently multiple times during the evolution of the arthropods. This holds also true for the "true crabs" (Brachyura), a taxon that includes several lineages that invaded land independently. During an evolutionary transition from sea to land, animals have to develop a variety of physiological and anatomical adaptations to a terrestrial life style related to respiration, reproduction, development, circulation, ion and water balance. In addition, sensory systems that function in air instead of in water are essential for an animal's life on land. Besides vision and mechanosensory systems, on land, the chemical senses have to be modified substantially in comparison to their function in water. Among arthropods, insects are the most successful ones to evolve aerial olfaction. Various aspects of terrestrial adaptation have also been analyzed in those crustacean lineages that evolved terrestrial representatives including the taxa Anomala, Brachyura, Amphipoda, and Isopoda. We are interested in how the chemical senses of terrestrial crustaceans are modified to function in air. Therefore, in this study, we analyzed the brains and more specifically the structure of the olfactory system of representatives of brachyuran crabs that display different degrees of terrestriality, from exclusively marine to mainly terrestrial. The methods we used included immunohistochemistry, detection of autofluorescence- and confocal microscopy, as well as three-dimensional reconstruction and morphometry. Our comparative approach shows that both the peripheral and central olfactory pathways are reduced in terrestrial members in comparison to their marine relatives, suggesting a limited function of their olfactory system on land. We conclude that for arthropod lineages that invaded land, evolving aerial olfaction is no trivial task.
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Affiliation(s)
- Jakob Krieger
- Zoological Institute and Museum, Department of Cytology and Evolutionary Biology, Ernst-Moritz-Arndt Universität Greifswald, Greifswald, Germany
| | - Philipp Braun
- Zoological Institute and Museum, Department of Cytology and Evolutionary Biology, Ernst-Moritz-Arndt Universität Greifswald, Greifswald, Germany
| | - Nicole T. Rivera
- Institute for Zoology, Department of Zoology & Evolution, Universität Regensburg, Regensburg, Germany
| | - Christoph D. Schubart
- Institute for Zoology, Department of Zoology & Evolution, Universität Regensburg, Regensburg, Germany
| | - Carsten H.G. Müller
- Zoological Institute and Museum, Department of General and Systematic Zoology, Ernst-Moritz-Arndt Universität Greifswald, Greifswald, Germany
| | - Steffen Harzsch
- Zoological Institute and Museum, Department of Cytology and Evolutionary Biology, Ernst-Moritz-Arndt Universität Greifswald, Greifswald, Germany
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33
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Zeller M, Held M, Bender J, Berz A, Heinloth T, Hellfritz T, Pfeiffer K. Transmedulla Neurons in the Sky Compass Network of the Honeybee (Apis mellifera) Are a Possible Site of Circadian Input. PLoS One 2015; 10:e0143244. [PMID: 26630286 PMCID: PMC4667876 DOI: 10.1371/journal.pone.0143244] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2015] [Accepted: 11/02/2015] [Indexed: 01/27/2023] Open
Abstract
Honeybees are known for their ability to use the sun's azimuth and the sky's polarization pattern for spatial orientation. Sky compass orientation in bees has been extensively studied at the behavioral level but our knowledge about the underlying neuronal systems and mechanisms is very limited. Electrophysiological studies in other insect species suggest that neurons of the sky compass system integrate information about the polarization pattern of the sky, its chromatic gradient, and the azimuth of the sun. In order to obtain a stable directional signal throughout the day, circadian changes between the sky polarization pattern and the solar azimuth must be compensated. Likewise, the system must be modulated in a context specific way to compensate for changes in intensity, polarization and chromatic properties of light caused by clouds, vegetation and landscape. The goal of this study was to identify neurons of the sky compass pathway in the honeybee brain and to find potential sites of circadian and neuromodulatory input into this pathway. To this end we first traced the sky compass pathway from the polarization-sensitive dorsal rim area of the compound eye via the medulla and the anterior optic tubercle to the lateral complex using dye injections. Neurons forming this pathway strongly resembled neurons of the sky compass pathway in other insect species. Next we combined tracer injections with immunocytochemistry against the circadian neuropeptide pigment dispersing factor and the neuromodulators serotonin, and γ-aminobutyric acid. We identified neurons, connecting the dorsal rim area of the medulla to the anterior optic tubercle, as a possible site of neuromodulation and interaction with the circadian system. These neurons have conspicuous spines in close proximity to pigment dispersing factor-, serotonin-, and GABA-immunoreactive neurons. Our data therefore show for the first time a potential interaction site between the sky compass pathway and the circadian clock.
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Affiliation(s)
- Maximilian Zeller
- Department of Biology - Animal Physiology, Philipps-University Marburg, Marburg, Germany
| | - Martina Held
- Department of Biology - Animal Physiology, Philipps-University Marburg, Marburg, Germany
| | - Julia Bender
- Department of Biology - Animal Physiology, Philipps-University Marburg, Marburg, Germany
| | - Annuska Berz
- Department of Biology - Animal Physiology, Philipps-University Marburg, Marburg, Germany
| | - Tanja Heinloth
- Department of Biology - Animal Physiology, Philipps-University Marburg, Marburg, Germany
| | - Timm Hellfritz
- Department of Biology - Animal Physiology, Philipps-University Marburg, Marburg, Germany
| | - Keram Pfeiffer
- Department of Biology - Animal Physiology, Philipps-University Marburg, Marburg, Germany
- * E-mail:
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34
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Kollmann M, Rupenthal AL, Neumann P, Huetteroth W, Schachtner J. Novel antennal lobe substructures revealed in the small hive beetle Aethina tumida. Cell Tissue Res 2015; 363:679-92. [PMID: 26496732 DOI: 10.1007/s00441-015-2282-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2015] [Accepted: 08/17/2015] [Indexed: 12/28/2022]
Abstract
The small hive beetle, Aethina tumida, is an emerging pest of social bee colonies. A. tumida shows a specialized life style for which olfaction seems to play a crucial role. To better understand the olfactory system of the beetle, we used immunohistochemistry and 3-D reconstruction to analyze brain structures, especially the paired antennal lobes (AL), which represent the first integration centers for odor information in the insect brain. The basic neuroarchitecture of the A. tumida brain compares well to the typical beetle and insect brain. In comparison to other insects, the AL are relatively large in relationship to other brain areas, suggesting that olfaction is of major importance for the beetle. The AL of both sexes contain about 70 olfactory glomeruli with no obvious size differences of the glomeruli between sexes. Similar to all other insects including beetles, immunostaining with an antiserum against serotonin revealed a large cell that projects from one AL to the contralateral AL to densely innervate all glomeruli. Immunostaining with an antiserum against tachykinin-related peptides (TKRP) revealed hitherto unknown structures in the AL. Small TKRP-immunoreactive spherical substructures are in both sexes evenly distributed within all glomeruli. The source for these immunoreactive islets is very likely a group of about 80 local AL interneurons. We offer two hypotheses on the function of such structures.
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Affiliation(s)
- Martin Kollmann
- Department of Biology, Animal Physiology, Philipps-University Marburg, Karl-von-Frisch-Str. 8, 35032, Marburg, Germany
| | - Anna Lena Rupenthal
- Department of Biology, Animal Physiology, Philipps-University Marburg, Karl-von-Frisch-Str. 8, 35032, Marburg, Germany
| | - Peter Neumann
- Institute of Bee Health, Vetsuisse Faculty, University of Bern, Bern, Switzerland
| | - Wolf Huetteroth
- Department of Biology, Animal Physiology, Philipps-University Marburg, Karl-von-Frisch-Str. 8, 35032, Marburg, Germany.,Department of Biology, Neurobiology, University of Konstanz, 78457, Konstanz, Germany
| | - Joachim Schachtner
- Department of Biology, Animal Physiology, Philipps-University Marburg, Karl-von-Frisch-Str. 8, 35032, Marburg, Germany.
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35
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Stöckl AL, Heinze S. A clearer view of the insect brain-combining bleaching with standard whole-mount immunocytochemistry allows confocal imaging of pigment-covered brain areas for 3D reconstruction. Front Neuroanat 2015; 9:121. [PMID: 26441552 PMCID: PMC4561338 DOI: 10.3389/fnana.2015.00121] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2015] [Accepted: 08/21/2015] [Indexed: 11/26/2022] Open
Abstract
In the study of insect neuroanatomy, three-dimensional (3D) reconstructions of neurons and neuropils have become a standard technique. As images have to be obtained from whole-mount brain preparations, pigmentation on the brain surface poses a serious challenge to imaging. In insects, this is a major problematic in the first visual neuropil of the optic lobe, the lamina, which is obstructed by the pigment of the retina as well as by the pigmented fenestration layer. This has prevented inclusion of this major processing center of the insect visual system into most neuroanatomical brain atlases and hinders imaging of neurons within the lamina by confocal microscopy. It has recently been shown that hydrogen peroxide bleaching is compatible with immunohistochemical labeling in insect brains, and we therefore developed a simple technique for removal of pigments on the surface of insect brains by chemical bleaching. We show that our technique enables imaging of the pigment-obstructed regions of insect brains when combined with standard protocols for both anti-synapsin-labeled as well as neurobiotin-injected samples. This method can be combined with different fixation procedures, as well as different fluorophore excitation wavelengths without negative effects on staining quality. It can therefore serve as an effective addition to most standard histology protocols used in insect neuroanatomy.
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36
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Stöckl AL, Ribi WA, Warrant EJ. Adaptations for nocturnal and diurnal vision in the hawkmoth lamina. J Comp Neurol 2015; 524:160-75. [DOI: 10.1002/cne.23832] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2015] [Revised: 06/06/2015] [Accepted: 06/09/2015] [Indexed: 11/09/2022]
Affiliation(s)
- Anna L. Stöckl
- Department of Biology; Lund University; 22362 Lund Sweden
| | - Willi A. Ribi
- Department of Biology; Lund University; 22362 Lund Sweden
- Research School of Biology, Australian National University; Canberra ACT 02200 Australia
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37
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Montgomery SH, Ott SR. Brain composition in Godyris zavaleta, a diurnal butterfly, Reflects an increased reliance on olfactory information. J Comp Neurol 2015; 523:869-91. [PMID: 25400217 PMCID: PMC4354442 DOI: 10.1002/cne.23711] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2014] [Revised: 10/17/2014] [Accepted: 11/04/2014] [Indexed: 11/15/2022]
Abstract
Interspecific comparisons of brain structure can inform our functional understanding of brain regions, identify adaptations to species-specific ecologies, and explore what constrains adaptive changes in brain structure, and coevolution between functionally related structures. The value of such comparisons is enhanced when the species considered have known ecological differences. The Lepidoptera have long been a favored model in evolutionary biology, but to date descriptions of brain anatomy have largely focused on a few commonly used neurobiological model species. We describe the brain of Godyris zavaleta (Ithomiinae), a member of a subfamily of Neotropical butterflies with enhanced reliance on olfactory information. We demonstrate for the first time the presence of sexually dimorphic glomeruli within a distinct macroglomerular complex (MGC) in the antennal lobe of a diurnal butterfly. This presents a striking convergence with the well-known moth MGC, prompting a discussion of the potential mechanisms behind the independent evolution of specialized glomeruli. Interspecific analyses across four Lepidoptera further show that the relative size of sensory neuropils closely mirror interspecific variation in sensory ecology, with G. zavaleta displaying levels of sensory investment intermediate between the diurnal monarch butterfly (Danaus plexippus), which invests heavily in visual neuropil, and night-flying moths, which invest more in olfactory neuropil. We identify several traits that distinguish butterflies from moths, and several that distinguish D. plexippus and G. zavaleta. Our results illustrate that ecological selection pressures mold the structure of invertebrate brains, and exemplify how comparative analyses across ecologically divergent species can illuminate the functional significance of variation in brain structure.
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Affiliation(s)
- Stephen H Montgomery
- Department of Genetics, Evolution & Environment, University College LondonLondon, UK, WC1E 6BT
| | - Swidbert R Ott
- Department of Biology, University of LeicesterLeicester, UK, LE1 7RH
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38
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Sombke A, Lipke E, Michalik P, Uhl G, Harzsch S. Potential and limitations of X-Ray micro-computed tomography in arthropod neuroanatomy: a methodological and comparative survey. J Comp Neurol 2015; 523:1281-95. [PMID: 25728683 PMCID: PMC4409823 DOI: 10.1002/cne.23741] [Citation(s) in RCA: 86] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2014] [Accepted: 01/02/2015] [Indexed: 01/15/2023]
Abstract
Classical histology or immunohistochemistry combined with fluorescence or confocal laser scanning microscopy are common techniques in arthropod neuroanatomy, and these methods often require time-consuming and difficult dissections and sample preparations. Moreover, these methods are prone to artifacts due to compression and distortion of tissues, which often result in information loss and especially affect the spatial relationships of the examined parts of the nervous system in their natural anatomical context. Noninvasive approaches such as X-ray micro-computed tomography (micro-CT) can overcome such limitations and have been shown to be a valuable tool for understanding and visualizing internal anatomy and structural complexity. Nevertheless, knowledge about the potential of this method for analyzing the anatomy and organization of nervous systems, especially of taxa with smaller body size (e.g., many arthropods), is limited. This study set out to analyze the brains of selected arthropods with micro-CT, and to compare these results with available histological and immunohistochemical data. Specifically, we explored the influence of different sample preparation procedures. Our study shows that micro-CT is highly suitable for analyzing arthropod neuroarchitecture in situ and allows specific neuropils to be distinguished within the brain to extract quantitative data such as neuropil volumes. Moreover, data acquisition is considerably faster compared with many classical histological techniques. Thus, we conclude that micro-CT is highly suitable for targeting neuroanatomy, as it reduces the risk of artifacts and is faster than classical techniques.
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Affiliation(s)
- Andy Sombke
- Zoological Institute and Museum, Ernst-Moritz-Arndt-University of Greifswald, 17487, Greifswald, Germany
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39
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Beetz MJ, El Jundi B, Heinze S, Homberg U. Topographic organization and possible function of the posterior optic tubercles in the brain of the desert locust Schistocerca gregaria. J Comp Neurol 2015; 523:1589-607. [PMID: 25557150 DOI: 10.1002/cne.23736] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2014] [Revised: 12/23/2014] [Accepted: 12/23/2014] [Indexed: 01/01/2023]
Abstract
Migrating desert locusts, Schistocerca gregaria, are able to use the skylight polarization pattern for navigation. They detect polarized light with a specialized dorsal rim area in their compound eye. After multistage processing, polarization signals are transferred to the central complex, a midline-spanning brain area involved in locomotor control. Polarization-sensitive tangential neurons (TB-neurons) of the protocerebral bridge, a part of the central complex, give rise to a topographic arrangement of preferred polarization angles in the bridge, suggesting that the central complex acts as an internal sky compass. TB-neurons connect the protocerebral bridge with two adjacent brain areas, the posterior optic tubercles. To analyze the polarotopic organization of the central complex further, we investigated the number and morphologies of TB-neurons and the presence and colocalization of three neuroactive substances in these neurons. Triple immunostaining with antisera against Diploptera punctata allatostatin (Dip-AST), Manduca sexta allatotropin (Mas-AT), and serotonin (5HT) raised in the same host species revealed three spatially distinct TB-neuron clusters, each consisting of 10 neurons per hemisphere: cluster 1 and 3 showed Dip-AST/5HT immunostaining, whereas cluster 2 showed Dip-AST/Mas-AT immunostaining. Five subtypes of TB-neuron could be distinguished based on ramification patterns. Corresponding to ramification domains in the protocerebral bridge, the neurons invaded distinct but overlapping layers within the posterior optic tubercle. Similarly, neurons interconnecting the tubercles of the two hemispheres also targeted distinct layers of these neuropils. From these data we propose a neuronal circuit that may be suited to stabilize the internal sky compass in the central complex of the locust.
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Affiliation(s)
- M Jerome Beetz
- Fachbereich Biologie, Tierphysiologie, Philipps-Universität Marburg, D-35032, Marburg, Germany
| | - Basil El Jundi
- Fachbereich Biologie, Tierphysiologie, Philipps-Universität Marburg, D-35032, Marburg, Germany
| | - Stanley Heinze
- Fachbereich Biologie, Tierphysiologie, Philipps-Universität Marburg, D-35032, Marburg, Germany
| | - Uwe Homberg
- Fachbereich Biologie, Tierphysiologie, Philipps-Universität Marburg, D-35032, Marburg, Germany
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40
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Bressan JMA, Benz M, Oettler J, Heinze J, Hartenstein V, Sprecher SG. A map of brain neuropils and fiber systems in the ant Cardiocondyla obscurior. Front Neuroanat 2015; 8:166. [PMID: 25698935 PMCID: PMC4316776 DOI: 10.3389/fnana.2014.00166] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2014] [Accepted: 12/24/2014] [Indexed: 11/28/2022] Open
Abstract
A wide spectrum of occupied ecological niches and spectacular morphological adaptations make social insects a prime object for comparative neuroanatomical studies. Eusocial insects have evolved complex societies based on caste polyphenism. A diverse behavioral repertoire of morphologically distinct castes of the same species requires a high degree of plasticity in the central nervous system. We have analyzed the central brain neuropils and fiber tract systems of the worker of the ant Cardiocondylaobscurior, a model for the study of social traits. Our analysis is based on whole mount preparations of adult brains labeled with an antibody against Drosophila-Synapsin, which cross-reacts strongly with synapses in Cardiocondyla. Neuropil compartments stand out as domains with a certain texture and intensity of the anti-Synapsin signal. By contrast, fiber tracts, which are composed of bundles of axons accompanied by glia and are devoid of synapses, appear as channels or sheaths with low anti-Synapsin signal. We have generated a digital 3D atlas of the Cardiocondyla brain neuropil. The atlas provides a reference for future studies of brain polymorphisms in distinct castes, brain development or localization of neurotransmitter systems.
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Affiliation(s)
- Joris M A Bressan
- Department of Biology, Institute of Developmental and Cell Biology, University of Fribourg Fribourg, Switzerland
| | - Martin Benz
- Department of Biology, Institute of Developmental and Cell Biology, University of Fribourg Fribourg, Switzerland
| | - Jan Oettler
- Biologie I, Universität Regensburg Regensburg, Germany
| | - Jürgen Heinze
- Biologie I, Universität Regensburg Regensburg, Germany
| | - Volker Hartenstein
- Department of Molecular, Cell and Developmental Biology, University of California Los Angeles, CA, USA
| | - Simon G Sprecher
- Department of Biology, Institute of Developmental and Cell Biology, University of Fribourg Fribourg, Switzerland
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Hao-Chiang Shao, Cheng-Chi Wu, Guan-Yu Chen, Hsiu-Ming Chang, Ann-Shyn Chiang, Yung-Chang Chen. Developing a Stereotypical Drosophila Brain Atlas. IEEE Trans Biomed Eng 2014; 61:2848-58. [DOI: 10.1109/tbme.2014.2332175] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Zhao XC, Kvello P, Løfaldli BB, Lillevoll SC, Mustaparta H, Berg BG. Representation of pheromones, interspecific signals, and plant odors in higher olfactory centers; mapping physiologically identified antennal-lobe projection neurons in the male heliothine moth. Front Syst Neurosci 2014; 8:186. [PMID: 25346663 PMCID: PMC4191081 DOI: 10.3389/fnsys.2014.00186] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2014] [Accepted: 09/14/2014] [Indexed: 11/28/2022] Open
Abstract
The arrangement of anatomically separated systems for information about general and pheromone odorants is well documented at the initial levels of the olfactory pathway both in vertebrates and insects. In the primary olfactory center of the moth brain, for example, a few enlarged glomeruli situated dorsally, at the entrance of the antennal nerve, are devoted to information about female-produced substances whereas a set of more numerous ordinary glomeruli (OG) receives input about general odorants. Heliothine moths are particularly suitable for studying central chemosensory mechanisms not only because of their anatomically separated systems for plant odors and pheromones but also due to their use of female-produced substances in communication across the species. Thus, the male-specific system of heliothine moths includes two sub-arrangements, one ensuring attraction and mating behavior by carrying information about pheromones released by conspecifics, and the other inhibition of attraction via signal information emitted from heterospecifics. Based on previous tracing experiments, a general chemotopic organization of the male-specific glomeruli has been demonstrated in a number of heliothine species. As compared to the well explored organization of the moth antennal lobe (AL), demonstrating a non-overlapping representation of the biologically relevant stimuli, less is known about the neural arrangement residing at the following synaptic level, i.e., the mushroom body calyces and the lateral horn. In the study presented here, we have labeled physiologically characterized antennal-lobe projection neurons in males of the two heliothine species, Heliothis virescens and Helicoverpa assulta, for the purpose of mapping their target regions in the protocerebrum. In order to compare the representation of plant odors, pheromones, and interspecific signals in the higher brain regions of each species, we have created standard brain atlases and registered three-dimensional models of distinct uniglomerular projection neuron types into the relevant atlas.
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Affiliation(s)
- Xin-Cheng Zhao
- Department of Psychology, Norwegian University of Science and Technology (NTNU) Trondheim, Norway
| | - Pål Kvello
- Department of Biology/Neuroscience Unit, MTFS, Norwegian University of Science and Technology (NTNU) Trondheim, Norway
| | - Bjarte B Løfaldli
- Department of Biology/Neuroscience Unit, MTFS, Norwegian University of Science and Technology (NTNU) Trondheim, Norway
| | - Siri C Lillevoll
- Department of Psychology, Norwegian University of Science and Technology (NTNU) Trondheim, Norway
| | - Hanna Mustaparta
- Department of Psychology, Norwegian University of Science and Technology (NTNU) Trondheim, Norway
| | - Bente G Berg
- Department of Psychology, Norwegian University of Science and Technology (NTNU) Trondheim, Norway
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Smolla M, Ruchty M, Nagel M, Kleineidam CJ. Clearing pigmented insect cuticle to investigate small insects' organs in situ using confocal laser-scanning microscopy (CLSM). ARTHROPOD STRUCTURE & DEVELOPMENT 2014; 43:175-181. [PMID: 24412654 DOI: 10.1016/j.asd.2013.12.006] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2013] [Revised: 12/20/2013] [Accepted: 12/20/2013] [Indexed: 06/03/2023]
Abstract
Various microscopic techniques allow investigating structures from submicron to millimeter range, however, this is only possible if the structures of interest are not covered by pigmented cuticle. Here, we present a protocol that combines clearing of pigmented cuticle while preserving both, hard and soft tissues. The resulting transparent cuticle allows confocal laser-scanning microscopy (CLSM), which yields high-resolution images of e.g. the brain, glands, muscles and fine cuticular structures. Using a fluorescent dye, even single labeled neurons can be visualized and resolved up to an imaging depth of 150 μm through the cleared cuticle. Hydrogen-peroxide, which was used to clear the cuticle, does not preclude immunocytochemical techniques, shown by successful labeling of serotonin-immunoreactive neurons (5HT-ir) in the ants' brain. The 'transparent insect protocol' presented here is especially suited for small arthropods where dissection of organs is very demanding and difficult to achieve. Furthermore, the insect organs are preserved in situ thus allowing a more precise three-dimensional reconstruction of the structures of interest compared to, e.g., dissected or sectioned tissue.
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Affiliation(s)
- Marco Smolla
- Department of Biology, Universitätsstraße 10, University of Konstanz, Konstanz 78457, Germany; Department of Behavioral Physiology and Sociobiology, Biozentrum, Am Hubland, University of Würzburg, Würzburg, Germany; Computational and Evolutionary Biology, Faculty of Life Science, University of Manchester, Manchester, United Kingdom.
| | - Markus Ruchty
- Life Science Division, Max Schmidheiny-Strasse 201, Leica Microsystems (Schweiz) AG, Heerbrugg, Switzerland.
| | - Manuel Nagel
- Department of Biology, Universitätsstraße 10, University of Konstanz, Konstanz 78457, Germany; Department of Behavioral Physiology and Sociobiology, Biozentrum, Am Hubland, University of Würzburg, Würzburg, Germany.
| | - Christoph J Kleineidam
- Department of Biology, Universitätsstraße 10, University of Konstanz, Konstanz 78457, Germany.
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Streinzer M, Kelber C, Pfabigan S, Kleineidam CJ, Spaethe J. Sexual dimorphism in the olfactory system of a solitary and a eusocial bee species. J Comp Neurol 2014; 521:2742-55. [PMID: 23359124 DOI: 10.1002/cne.23312] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2011] [Revised: 08/31/2012] [Accepted: 01/18/2013] [Indexed: 12/20/2022]
Abstract
Sexually dimorphic sensory systems are common in Hymenoptera and are considered to result from sex-specific selection pressures. An extreme example of sensory dimorphism is found in the solitary bee tribe Eucerini. Males of long-horned bees bear antennae that exceed body length. This study investigated the pronounced sexual dimorphism of the peripheral olfactory system and its representation in higher brain centers of the species Eucera berlandi. Eucera males have elongated antennae, with 10 times more pore plates and three times more olfactory receptor neurons than females. The male antennal lobe (AL) comprises fewer glomeruli than the female AL (∼100 vs. ∼130), of which four are male-specific macroglomeruli. No sex differences were found in the relative volume of the mushroom bodies, a higher order neuropil essential for learning and memory in Hymenoptera. Compared with the Western honeybee, the degree of sexual dimorphism in Eucera is more pronounced at the periphery. In contrast, sex differences in glomerular numbers are higher in the eusocial honeybee and a sexual dimorphism of the relative investment in mushroom body tissue is observed only in Apis. The observed differences between the eusocial and the solitary bee species may reflect differences in male-specific behavioral traits and associated selection pressures, which are discussed in brief.
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Affiliation(s)
- Martin Streinzer
- Department of Evolutionary Biology, Faculty of Life Sciences, University of Vienna, A-1090 Vienna, Austria
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Heinze S, Florman J, Asokaraj S, El Jundi B, Reppert SM. Anatomical basis of sun compass navigation II: the neuronal composition of the central complex of the monarch butterfly. J Comp Neurol 2013; 521:267-98. [PMID: 22886450 DOI: 10.1002/cne.23214] [Citation(s) in RCA: 114] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2012] [Revised: 08/01/2012] [Accepted: 08/03/2012] [Indexed: 12/25/2022]
Abstract
Each fall, eastern North American monarch butterflies in their northern range undergo a long-distance migration south to their overwintering grounds in Mexico. Migrants use a time-compensated sun compass to determine directionality during the migration. This compass system uses information extracted from sun-derived skylight cues that is compensated for time of day and ultimately transformed into the appropriate motor commands. The central complex (CX) is likely the site of the actual sun compass, because neurons in this brain region are tuned to specific skylight cues. To help illuminate the neural basis of sun compass navigation, we examined the neuronal composition of the CX and its associated brain regions. We generated a standardized version of the sun compass neuropils, providing reference volumes, as well as a common frame of reference for the registration of neuron morphologies. Volumetric comparisons between migratory and nonmigratory monarchs substantiated the proposed involvement of the CX and related brain areas in migratory behavior. Through registration of more than 55 neurons of 34 cell types, we were able to delineate the major input pathways to the CX, output pathways, and intrinsic neurons. Comparison of these neural elements with those of other species, especially the desert locust, revealed a surprising degree of conservation. From these interspecies data, we have established key components of a conserved core network of the CX, likely complemented by species-specific neurons, which together may comprise the neural substrates underlying the computations performed by the CX.
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Affiliation(s)
- Stanley Heinze
- Department of Neurobiology, University of Massachusetts Medical School, Worcester, Massachusetts 01605, USA.
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Asadulina A, Panzera A, Verasztó C, Liebig C, Jékely G. Whole-body gene expression pattern registration in Platynereis larvae. EvoDevo 2012. [PMID: 23199348 PMCID: PMC3586958 DOI: 10.1186/2041-9139-3-27] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
Background Digital anatomical atlases are increasingly used in order to depict different gene expression patterns and neuronal morphologies within a standardized reference template. In evo-devo, a discipline in which the comparison of gene expression patterns is a widely used approach, such standardized anatomical atlases would allow a more rigorous assessment of the conservation of and changes in gene expression patterns during micro- and macroevolutionary time scales. Due to its small size and invariant early development, the annelid Platynereis dumerilii is particularly well suited for such studies. Recently a reference template with registered gene expression patterns has been generated for the anterior part (episphere) of the Platynereis trochophore larva and used for the detailed study of neuronal development. Results Here we introduce and evaluate a method for whole-body gene expression pattern registration for Platynereis trochophore and nectochaete larvae based on whole-mount in situ hybridization, confocal microscopy, and image registration. We achieved high-resolution whole-body scanning using the mounting medium 2,2’-thiodiethanol (TDE), which allows the matching of the refractive index of the sample to that of glass and immersion oil thereby reducing spherical aberration and improving depth penetration. This approach allowed us to scan entire whole-mount larvae stained with nitroblue tetrazolium/5-bromo-4-chloro-3-indolyl phosphate (NBT/BCIP) in situ hybridization and counterstained fluorescently with an acetylated-tubulin antibody and the nuclear stain 4’6-diamidino-2-phenylindole (DAPI). Due to the submicron isotropic voxel size whole-mount larvae could be scanned in any orientation. Based on the whole-body scans, we generated four different reference templates by the iterative registration and averaging of 40 individual image stacks using either the acetylated-tubulin or the nuclear-stain signal for each developmental stage. We then registered to these templates the expression patterns of cell-type specific genes. In order to evaluate the gene expression pattern registration, we analyzed the absolute deviation of cell-center positions. Both the acetylated-tubulin- and the nuclear-stain-based templates allowed near-cellular-resolution gene expression registration. Nuclear-stain-based templates often performed significantly better than acetylated-tubulin-based templates. We provide detailed guidelines and scripts for the use and further expansion of the Platynereis gene expression atlas. Conclusions We established whole-body reference templates for the generation of gene expression atlases for Platynereis trochophore and nectochaete larvae. We anticipate that nuclear-staining-based image registration will be applicable for whole-body alignment of the embryonic and larval stages of other organisms in a similar size range.
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Affiliation(s)
- Albina Asadulina
- Max Planck Institute for Developmental Biology, Spemannstrasse 35, Tübingen, 72076, Germany.
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Weissteiner S, Huetteroth W, Kollmann M, Weißbecker B, Romani R, Schachtner J, Schütz S. Cockchafer larvae smell host root scents in soil. PLoS One 2012; 7:e45827. [PMID: 23049688 PMCID: PMC3462172 DOI: 10.1371/journal.pone.0045827] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2012] [Accepted: 08/22/2012] [Indexed: 11/18/2022] Open
Abstract
In many insect species olfaction is a key sensory modality. However, examination of the chemical ecology of insects has focussed up to now on insects living above ground. Evidence for behavioral responses to chemical cues in the soil other than CO(2) is scarce and the role played by olfaction in the process of finding host roots below ground is not yet understood. The question of whether soil-dwelling beetle larvae can smell their host plant roots has been under debate, but proof is as yet lacking that olfactory perception of volatile compounds released by damaged host plants, as is known for insects living above ground, occurs. Here we show that soil-dwelling larvae of Melolontha hippocastani are well equipped for olfactory perception and respond electrophysiologically and behaviorally to volatiles released by damaged host-plant roots. An olfactory apparatus consisting of pore plates at the antennae and about 70 glomeruli as primary olfactory processing units indicates a highly developed olfactory system. Damage induced host plant volatiles released by oak roots such as eucalyptol and anisol are detected by larval antennae down to 5 ppbv in soil air and elicit directed movement of the larvae in natural soil towards the odor source. Our results demonstrate that plant-root volatiles are likely to be perceived by the larval olfactory system and to guide soil-dwelling white grubs through the dark below ground to their host plants. Thus, to find below-ground host plants cockchafer larvae employ mechanisms that are similar to those employed by the adult beetles flying above ground, despite strikingly different physicochemical conditions in the soil.
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Affiliation(s)
- Sonja Weissteiner
- Forest Zoology and Forest Protection, Georg-August-Universität, Göttingen, Germany
| | - Wolf Huetteroth
- Neurobiology/Ethology, Philipps-University, Marburg, Germany
| | - Martin Kollmann
- Neurobiology/Ethology, Philipps-University, Marburg, Germany
| | - Bernhard Weißbecker
- Forest Zoology and Forest Protection, Georg-August-Universität, Göttingen, Germany
| | - Roberto Romani
- Dipartimento di Scienze Agrarie e Ambientali, University of Perugia, Perugia, Italy
| | | | - Stefan Schütz
- Forest Zoology and Forest Protection, Georg-August-Universität, Göttingen, Germany
- * E-mail:
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Gonzalez-Bellido PT, Wardill TJ. Labeling and confocal imaging of neurons in thick invertebrate tissue samples. Cold Spring Harb Protoc 2012; 2012:969-983. [PMID: 22949711 DOI: 10.1101/pdb.prot069625] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Neuroscience researchers have long sought methods to describe the neural connectivity of the circuits responsible for specific behaviors. One major obstacle is scale: Neural spines can be <1 µm in diameter, but axons can range from millimeters to centimeters (or larger) in length, making tissue imaging and neuron reconstruction a challenging task. New tissue-clearing agents and long-working-distance objectives offer improved imaging conditions, and here we present a complete protocol for invertebrate tissue that uses these advances. In this protocol, tissue-processing steps previously published in separate articles are combined with recent advances in confocal imaging to visualize invertebrate tissue samples that are >500 µm thick and contain dye-filled neurons. The steps describe dye filling, fixing, antibody labeling, clearing, whole tissue mounting, and confocal imaging with matched refractive indexes. Thus, manual sectioning or "flipping" the tissue to image the whole volume is not required. With matched refractive indexes, loss of resolution and signal is avoided. Tissue volumes are imaged in one stack and nonlinear deformations caused by tissue flipping are prevented. We apply the protocol to whole dragonfly thoracic ganglia (2 × 1 × 0.6 mm) and cephalopod skin samples (20 × 2 × 0.6 mm) with minimal tissue deformation. The resulting images will be used to develop a three-dimensional connectivity atlas of dragonfly ganglia and cephalopod skin innervation. This protocol can be applied to other invertebrate species, and has the advantage that it avoids problems with antigen specificity.
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Van Truong T, Byun D, Lavine LC, Emlen DJ, Park HC, Kim MJ. Flight behavior of the rhinoceros beetle Trypoxylus dichotomus during electrical nerve stimulation. BIOINSPIRATION & BIOMIMETICS 2012; 7:036021. [PMID: 22711210 DOI: 10.1088/1748-3182/7/3/036021] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Neuronal stimulation is an intricate part of understanding insect flight behavior and control insect itself. In this study, we investigated the effects of electrical pulses applied to the brain and basalar muscle of the rhinoceros beetle (Trypoxylus dichotomus). To understand specific neuronal stimulation mechanisms, responses and flight behavior of the beetle, four electrodes were implanted into the two optic lobes, the brain's central complex and the ventral nerve cord in the posterior pronotum. We demonstrated flight initiation, turning and cessation by stimulating the brain. The change undergone by the wing flapping in response to the electrical signal was analyzed from a sequence of images captured by a high-speed camera. Here, we provide evidence to distinguish the important differences between neuronal and muscular flight stimulations in beetles. We found that in the neural potential stimulation, both the hind wing and the elytron were suppressed. Interestingly, the beetle stopped flying whenever a stimulus potential was applied between the pronotum and one side of the optic lobe, or between the ventral nerve cord in the posterior pronotum and the central complex. In-depth experimentation demonstrated the effective of neural stimulation over muscle stimulation for flight control. During electrical stimulation of the optic lobes, the beetle performed unstable flight, resulting in alternating left and right turns. By applying the electrical signal into both the optic lobes and the central complex of the brain, we could precisely control the direction of the beetle flight. This work provides an insight into insect flight behavior for future development of insect-micro air vehicle.
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Affiliation(s)
- Tien Van Truong
- Department of Aerospace Information Engineering, Konkuk University, Seoul 143-701, Korea
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50
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Chen GY, Wu CC, Shao HC, Chang HM, Chiang AS, Chen YC. Retention of features on a mapped Drosophila brain surface using a Bézier-tube-based surface model averaging technique. IEEE Trans Biomed Eng 2012; 59:3314-26. [PMID: 22922691 DOI: 10.1109/tbme.2012.2214774] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Model averaging is a widely used technique in biomedical applications. Two established model averaging methods, iterative shape averaging (ISA) method and virtual insect brain (VIB) method, have been applied to several organisms to generate average representations of their brain surfaces. However, without sufficient samples, some features of the average Drosophila brain surface obtained using the above methods may disappear or become distorted. To overcome this problem, we propose a Bézier-tube-based surface model averaging strategy. The proposed method first compensates for disparities in position, orientation, and dimension of input surfaces, and then evaluates the average surface by performing shape-based interpolation. Structural features with larger individual disparities are simplified with half-ellipse-shaped Bézier tubes, and are unified according to these tubes to avoid distortion during the averaging process. Experimental results show that the average model yielded by our method could preserve fine features and avoid structural distortions even if only a limit amount of input samples are used. Finally, we qualitatively compare our results with those obtained by ISA and VIB methods by measuring the surface-to-surface distances between input surfaces and the averaged ones. The comparisons show that the proposed method could generate a more representative average surface than both ISA and VIB methods.
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Affiliation(s)
- Guan-Yu Chen
- Department of Electrical Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan
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