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Steffen Harzsch - One of the best experts on this subject based on the ideXlab platform.
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the synganglion of the jumping spider marpissa muscosa arachnida salticidae insights from histology immunohistochemistry and microct analysis
Arthropod Structure & Development, 2017Co-Authors: Philip O M Steinhoff, Andy Sombke, Steffen Harzsch, Jannis Liedtke, Jutta M Schneider, Gabriele UhlAbstract:Jumping spiders are known for their extraordinary cognitive abilities. The underlying nervous system structures, however, are largely unknown. Here, we explore and describe the anatomy of the brain in the jumping spider Marpissa muscosa (Clerck, 1757) by means of paraffin histology, X-ray microCT analysis and immunohistochemistry as well as three-dimensional reconstruction. In the prosoma, the CNS is a clearly demarcated mass that surrounds the esophagus. The anteriormost neuromere, the protocerebrum, comprises nine bilaterally paired Neuropils, including the mushroom bodies and one unpaired midline Neuropil, the arcuate body. Further ventrally, the synganglion comprises the cheliceral (deutocerebrum) and pedipalpal Neuropils (tritocerebrum). Synapsin-immunoreactivity in all Neuropils is generally strong, while allatostatin-immunoreactivity is mostly present in association with the arcuate body and the stomodeal bridge. The most prominent Neuropils in the spider brain, the mushroom bodies and the arcuate body, were suggested to be higher integrating centers of the arthropod brain. The mushroom body in M. muscosa is connected to first and second order visual Neuropils of the lateral eyes, and the arcuate body to the second order Neuropils of the anterior median eyes (primary eyes) through a visual tract. The connection of both, visual Neuropils and eyes and arcuate body, as well as their large size corroborates the hypothesis that these Neuropils play an important role in cognition and locomotion control of jumping spiders. In addition, we show that the architecture of the brain of M. muscosa and some previously investigated salticids differs significantly from that of the wandering spider Cupiennius salei, especially with regard to structure and arrangement of visual Neuropils and mushroom body. Thus, we need to explore the anatomical conformities and specificities of the brains of different spider taxa in order to understand evolutionary transformations of the arthropod brain.
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immunolocalization of histamine in the optic Neuropils of scutigera coleoptrata myriapoda chilopoda reveals the basal organization of visual systems in mandibulata
Neuroscience Letters, 2015Co-Authors: Andy Sombke, Steffen HarzschAbstract:Myriapods play a crucial role in considerations of evolutionary transformations of arthropod nervous systems. The existing descriptions of the identity and connectivity of myriapod optic Neuropils are contradictory. This study asks if the first and second optic Neuropil of the scutigeromorph centipede Scutigera coleoptrata correspond to the optic Neuropils of Hexapoda and malacostracan Crustacea, the lamina and medulla which are linked by neurites that are arranged in a characteristic optic chiasm. To identify photoreceptor axons, we used immunohistochemistry against histamine which is the universal transmitter of arthropod photoreceptors. Our results provide evidence that the two optic Neuropils of S. coleoptrata correspond to the lamina and medulla of Hexapoda and Malacostraca and strongly argue against a correspondence of the optic Neuropils in branchiopod crustaceans and scutigeromorphs, as was previously suggested. We conclude that these two retinotopic optic Neuropils and an outer optic chiasm are part of the ground pattern of Mandibulata and that the visual systems of branchiopod crustaceans were simplified from this ground pattern.
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brain architecture of the largest living land arthropod the giant robber crab birgus latro crustacea anomura coenobitidae evidence for a prominent central olfactory pathway
Frontiers in Zoology, 2010Co-Authors: Jakob Krieger, Steffen Harzsch, Bill S Hansson, Renate E Sandeman, David C SandemanAbstract:Several lineages within the Crustacea conquered land independently during evolution, thereby requiring physiological adaptations for a semi-terrestrial or even a fully terrestrial lifestyle. Birgus latro Linnaeus, 1767, the giant robber crab or coconut crab (Anomura, Coenobitidae), is the largest land-living arthropod and inhabits Indo-Pacific islands such as Christmas Island. B. latro has served as a model in numerous studies of physiological aspects related to the conquest of land by crustaceans. From an olfactory point of view, a transition from sea to land means that molecules need to be detected in gas phase instead of in water solution. Previous studies have provided physiological evidence that terrestrial hermit crabs (Coenobitidae) such as B. latro have a sensitive and well differentiated sense of smell. Here we analyze the brain, in particular the olfactory processing areas of B. latro, by morphological analysis followed by 3 D reconstruction and immunocytochemical studies of synaptic proteins and a neuropeptide. The primary and secondary olfactory centers dominate the brain of B. latro and together account for ca. 40% of the Neuropil volume in its brain. The paired olfactory Neuropils are tripartite and composed of more than 1,000 columnar olfactory glomeruli, which are radially arranged around the periphery of the olfactory Neuropils. The glomeruli are innervated ca. 90,000 local interneurons and ca. 160,000 projection neurons per side. The secondary olfactory centers, the paired hemiellipsoid Neuropils, are targeted by the axons of these olfactory projection neurons. The projection neuron axonal branches make contact to ca. 250.000 interneurons (per side) associated with the hemiellipsoid Neuropils. The hemiellipsoid body Neuropil is organized into parallel Neuropil lamellae, a design that is quite unusual for decapod crustaceans. The architecture of the optic Neuropils and areas associated with antenna two suggest that B. latro has visual and mechanosensory skills that are comparable to those of marine Crustacea. In parallel to previous behavioral findings that B. latro has aerial olfaction, our results indicate that their central olfactory pathway is indeed most prominent. Similar findings from the closely related terrestrial hermit crab Coenobita clypeatus suggest that in Coenobitidae, olfaction is a major sensory modality processed by the brain, and that for these animals, exploring the olfactory landscape is vital for survival in their terrestrial habitat. Future studies on terrestrial members of other crustacean taxa such as Isopoda, Amphipoda, Astacida, and Brachyura will shed light on how frequently the establishment of an aerial sense of olfaction evolved in Crustacea during the transition from sea to land. Amounting to ca. 1,000,000, the numbers of interneurons that analyse the olfactory input in B. latro brains surpasses that in other terrestrial arthropods, as e.g. the honeybee Apis mellifera or the moth Manduca sexta, by two orders of magnitude suggesting that B. latro in fact is a land-living arthropod that has devoted a substantial amount of nervous tissue to the sense of smell.
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Brain architecture of the largest living land arthropod, the Giant Robber Crab Birgus latro (Crustacea, Anomura, Coenobitidae): evidence for a prominent central olfactory pathway?
Frontiers in Zoology, 2010Co-Authors: Jakob Krieger, Bill S Hansson, Renate E Sandeman, David C Sandeman, Steffen HarzschAbstract:Background Several lineages within the Crustacea conquered land independently during evolution, thereby requiring physiological adaptations for a semi-terrestrial or even a fully terrestrial lifestyle. Birgus latro Linnaeus, 1767, the giant robber crab or coconut crab (Anomura, Coenobitidae), is the largest land-living arthropod and inhabits Indo-Pacific islands such as Christmas Island. B. latro has served as a model in numerous studies of physiological aspects related to the conquest of land by crustaceans. From an olfactory point of view, a transition from sea to land means that molecules need to be detected in gas phase instead of in water solution. Previous studies have provided physiological evidence that terrestrial hermit crabs (Coenobitidae) such as B. latro have a sensitive and well differentiated sense of smell. Here we analyze the brain, in particular the olfactory processing areas of B. latro , by morphological analysis followed by 3 D reconstruction and immunocytochemical studies of synaptic proteins and a neuropeptide. Results The primary and secondary olfactory centers dominate the brain of B. latro and together account for ca. 40% of the Neuropil volume in its brain. The paired olfactory Neuropils are tripartite and composed of more than 1,000 columnar olfactory glomeruli, which are radially arranged around the periphery of the olfactory Neuropils. The glomeruli are innervated ca. 90,000 local interneurons and ca. 160,000 projection neurons per side. The secondary olfactory centers, the paired hemiellipsoid Neuropils, are targeted by the axons of these olfactory projection neurons. The projection neuron axonal branches make contact to ca. 250.000 interneurons (per side) associated with the hemiellipsoid Neuropils. The hemiellipsoid body Neuropil is organized into parallel Neuropil lamellae, a design that is quite unusual for decapod crustaceans. The architecture of the optic Neuropils and areas associated with antenna two suggest that B. latro has visual and mechanosensory skills that are comparable to those of marine Crustacea. Conclusions In parallel to previous behavioral findings that B. latro has aerial olfaction, our results indicate that their central olfactory pathway is indeed most prominent. Similar findings from the closely related terrestrial hermit crab Coenobita clypeatus suggest that in Coenobitidae, olfaction is a major sensory modality processed by the brain, and that for these animals, exploring the olfactory landscape is vital for survival in their terrestrial habitat. Future studies on terrestrial members of other crustacean taxa such as Isopoda, Amphipoda, Astacida, and Brachyura will shed light on how frequently the establishment of an aerial sense of olfaction evolved in Crustacea during the transition from sea to land. Amounting to ca. 1,000,000, the numbers of interneurons that analyse the olfactory input in B. latro brains surpasses that in other terrestrial arthropods, as e.g. the honeybee Apis mellifera or the moth Manduca sexta , by two orders of magnitude suggesting that B. latro in fact is a land-living arthropod that has devoted a substantial amount of nervous tissue to the sense of smell.
Tobias Lehmann - One of the best experts on this subject based on the ideXlab platform.
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outsourcing a visual Neuropil the central visual system of the median eyes of galeodes granti pocock 1903 arachnida solifugae
Arthropod Structure & Development, 2021Co-Authors: Tobias Lehmann, Roland R MelzerAbstract:Abstract Only a few studies have examined the central visual system of Solifugae until now. To get new insights suitable for phylogenetic analysis we studied the R-cell (or retinula cell) projections and visual Neuropils of Galeodes granti using various methods. G. granti possesses large median eyes and rudimentary lateral eyes. In this study, only the R-cells and Neuropils of the median eyes were successfully stained. The R-cells terminate in two distinct visual Neuropils. The first Neuropil is located externally to the protocerebrum directly below the retina, the second Neuropil lies in the cell body rind of the protocerebrum, and immediately adjacent is the arcuate body. This layout of the median eye visual system differs from Arachnopulmonata (Scorpiones + Tetrapulmonata). However, there are several similarities with Opiliones. In both, (1) the R-cells are connected to a first and second visual Neuropil and not to any other region of the brain, (2) the first Neuropil is not embedded in the cell body rind of the protocerebrum, it is rather external to the protocerebrum, (3) the second visual Neuropil is embedded in the cell body rind, and (4) the second Neuropil abuts the arcuate body. These findings may provide important new characters for the discussion on arachnid phylogeny.
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Also looking like Limulus? – retinula axons and visual Neuropils of Amblypygi (whip spiders)
BMC, 2018Co-Authors: Tobias Lehmann, Roland R MelzerAbstract:Abstract Background Only a few studies have examined the visual systems of Amblypygi (whip spiders) until now. To get new insights suitable for phylogenetic analysis we studied the axonal trajectories and Neuropil architecture of the visual systems of several whip spider species (Heterophrynus elaphus, Damon medius, Phrynus pseudoparvulus, and P. marginemaculatus) with different neuroanatomical techniques. The R-cell axon terminals were identified with Cobalt fills. To describe the morphology of the visual Neuropils and of the protocerebrum generally we used Wigglesworth stains and μCT. Results The visual system of whip spiders comprises one pair of median and three pairs of lateral eyes. The R-cells of both eye types terminate each in a first and a second visual Neuropil. Furthermore, a few R-cell fibres from the median eyes leave the second median eye visual Neuropil and terminate in the second lateral eye Neuropil. This means R-cell terminals from the lateral eyes and the median eyes overlap. Additionally, the arcuate body and the mushroom bodies are described. Conclusions A detailed comparison of our findings with previously studied chelicerate visual systems (i.e., Xiphosura, Scorpiones, Pseudoscorpiones, Opiliones, and Araneae) seem to support the idea of close evolutionary relationships between Xiphosura, Scorpiones, and Amblypygi
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also looking like limulus retinula axons and visual Neuropils of amblypygi whip spiders
Frontiers in Zoology, 2018Co-Authors: Tobias Lehmann, Roland R MelzerAbstract:Only a few studies have examined the visual systems of Amblypygi (whip spiders) until now. To get new insights suitable for phylogenetic analysis we studied the axonal trajectories and Neuropil architecture of the visual systems of several whip spider species (Heterophrynus elaphus, Damon medius, Phrynus pseudoparvulus, and P. marginemaculatus) with different neuroanatomical techniques. The R-cell axon terminals were identified with Cobalt fills. To describe the morphology of the visual Neuropils and of the protocerebrum generally we used Wigglesworth stains and μCT. The visual system of whip spiders comprises one pair of median and three pairs of lateral eyes. The R-cells of both eye types terminate each in a first and a second visual Neuropil. Furthermore, a few R-cell fibres from the median eyes leave the second median eye visual Neuropil and terminate in the second lateral eye Neuropil. This means R-cell terminals from the lateral eyes and the median eyes overlap. Additionally, the arcuate body and the mushroom bodies are described. A detailed comparison of our findings with previously studied chelicerate visual systems (i.e., Xiphosura, Scorpiones, Pseudoscorpiones, Opiliones, and Araneae) seem to support the idea of close evolutionary relationships between Xiphosura, Scorpiones, and Amblypygi.
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a tiny visual system retinula axons and visual Neuropils of neobisium carcinoides hermann 1804 chelicerata arachnida pseudoscorpiones
Zoologischer Anzeiger, 2017Co-Authors: Tobias Lehmann, Roland R MelzerAbstract:Abstract Only a few studies have examined the visual system of Pseudoscorpiones until now. To fill this knowledge gap we analysed the axonal trajectories and Neuropil architecture of the visual system of the pseudoscorpion Neobisium carcinoides (Hermann, 1804) with different neuroanatomical techniques. The R-cell axon terminals were identified with Cobalt fills and the morphology of the visual Neuropils and the protocerebrum generally is described by means of the osmium-ethyl gallate procedure and TEM. N. carcinoides has two lateral eyes on each side of the prosoma. The R-cells of the eyes per hemisphere are linked to a first and a second visual Neuropil, located in the dorsolateral protocerebrum. The first visual Neuropil is subdivided into two hemiNeuropils, one for each lateral eye, while the second Neuropil is not. Furthermore, the two-layered arcuate body is found − isolated from the visual Neuropils − in the midline of the protocerebrum at a dorsoposterior position. These findings allow a detailed comparison of the pseudoscorpion visual system with that of other previously studied taxa and shed new light on lateral eye evolution in Chelicerata.
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the visual system of harvestmen opiliones arachnida chelicerata a re examination
Frontiers in Zoology, 2016Co-Authors: Tobias Lehmann, Eva Loddebensch, Martina MetzAbstract:Background The visual systems in chelicerates are poorly understood, even though they show strong variation in eye and visual Neuropil architecture, thus may provide valuable insights for the understanding of chelicerate phylogeny and eye evolution. Comparable morphological characters are desperately sought for reconstructions of the phylogeny of Chelicerata, especially with respect to Arachnida. So far, reliable data exist only for Pycnogonida, Xiphosura, Scorpiones, and Araneae. The few earlier studies of the organisation of the visual system in harvestmen are contradictory concerning the number, morphology, and position of the visual Neuropils.
Roland R Melzer - One of the best experts on this subject based on the ideXlab platform.
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outsourcing a visual Neuropil the central visual system of the median eyes of galeodes granti pocock 1903 arachnida solifugae
Arthropod Structure & Development, 2021Co-Authors: Tobias Lehmann, Roland R MelzerAbstract:Abstract Only a few studies have examined the central visual system of Solifugae until now. To get new insights suitable for phylogenetic analysis we studied the R-cell (or retinula cell) projections and visual Neuropils of Galeodes granti using various methods. G. granti possesses large median eyes and rudimentary lateral eyes. In this study, only the R-cells and Neuropils of the median eyes were successfully stained. The R-cells terminate in two distinct visual Neuropils. The first Neuropil is located externally to the protocerebrum directly below the retina, the second Neuropil lies in the cell body rind of the protocerebrum, and immediately adjacent is the arcuate body. This layout of the median eye visual system differs from Arachnopulmonata (Scorpiones + Tetrapulmonata). However, there are several similarities with Opiliones. In both, (1) the R-cells are connected to a first and second visual Neuropil and not to any other region of the brain, (2) the first Neuropil is not embedded in the cell body rind of the protocerebrum, it is rather external to the protocerebrum, (3) the second visual Neuropil is embedded in the cell body rind, and (4) the second Neuropil abuts the arcuate body. These findings may provide important new characters for the discussion on arachnid phylogeny.
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also looking like limulus retinula axons and visual Neuropils of amblypygi whip spiders
Frontiers in Zoology, 2018Co-Authors: Tobias Lehmann, Roland R MelzerAbstract:Only a few studies have examined the visual systems of Amblypygi (whip spiders) until now. To get new insights suitable for phylogenetic analysis we studied the axonal trajectories and Neuropil architecture of the visual systems of several whip spider species (Heterophrynus elaphus, Damon medius, Phrynus pseudoparvulus, and P. marginemaculatus) with different neuroanatomical techniques. The R-cell axon terminals were identified with Cobalt fills. To describe the morphology of the visual Neuropils and of the protocerebrum generally we used Wigglesworth stains and μCT. The visual system of whip spiders comprises one pair of median and three pairs of lateral eyes. The R-cells of both eye types terminate each in a first and a second visual Neuropil. Furthermore, a few R-cell fibres from the median eyes leave the second median eye visual Neuropil and terminate in the second lateral eye Neuropil. This means R-cell terminals from the lateral eyes and the median eyes overlap. Additionally, the arcuate body and the mushroom bodies are described. A detailed comparison of our findings with previously studied chelicerate visual systems (i.e., Xiphosura, Scorpiones, Pseudoscorpiones, Opiliones, and Araneae) seem to support the idea of close evolutionary relationships between Xiphosura, Scorpiones, and Amblypygi.
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Also looking like Limulus? – retinula axons and visual Neuropils of Amblypygi (whip spiders)
BMC, 2018Co-Authors: Tobias Lehmann, Roland R MelzerAbstract:Abstract Background Only a few studies have examined the visual systems of Amblypygi (whip spiders) until now. To get new insights suitable for phylogenetic analysis we studied the axonal trajectories and Neuropil architecture of the visual systems of several whip spider species (Heterophrynus elaphus, Damon medius, Phrynus pseudoparvulus, and P. marginemaculatus) with different neuroanatomical techniques. The R-cell axon terminals were identified with Cobalt fills. To describe the morphology of the visual Neuropils and of the protocerebrum generally we used Wigglesworth stains and μCT. Results The visual system of whip spiders comprises one pair of median and three pairs of lateral eyes. The R-cells of both eye types terminate each in a first and a second visual Neuropil. Furthermore, a few R-cell fibres from the median eyes leave the second median eye visual Neuropil and terminate in the second lateral eye Neuropil. This means R-cell terminals from the lateral eyes and the median eyes overlap. Additionally, the arcuate body and the mushroom bodies are described. Conclusions A detailed comparison of our findings with previously studied chelicerate visual systems (i.e., Xiphosura, Scorpiones, Pseudoscorpiones, Opiliones, and Araneae) seem to support the idea of close evolutionary relationships between Xiphosura, Scorpiones, and Amblypygi
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a tiny visual system retinula axons and visual Neuropils of neobisium carcinoides hermann 1804 chelicerata arachnida pseudoscorpiones
Zoologischer Anzeiger, 2017Co-Authors: Tobias Lehmann, Roland R MelzerAbstract:Abstract Only a few studies have examined the visual system of Pseudoscorpiones until now. To fill this knowledge gap we analysed the axonal trajectories and Neuropil architecture of the visual system of the pseudoscorpion Neobisium carcinoides (Hermann, 1804) with different neuroanatomical techniques. The R-cell axon terminals were identified with Cobalt fills and the morphology of the visual Neuropils and the protocerebrum generally is described by means of the osmium-ethyl gallate procedure and TEM. N. carcinoides has two lateral eyes on each side of the prosoma. The R-cells of the eyes per hemisphere are linked to a first and a second visual Neuropil, located in the dorsolateral protocerebrum. The first visual Neuropil is subdivided into two hemiNeuropils, one for each lateral eye, while the second Neuropil is not. Furthermore, the two-layered arcuate body is found − isolated from the visual Neuropils − in the midline of the protocerebrum at a dorsoposterior position. These findings allow a detailed comparison of the pseudoscorpion visual system with that of other previously studied taxa and shed new light on lateral eye evolution in Chelicerata.
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Dissecting a neuron network: FIB-SEM-based 3D-reconstruction of the visual Neuropils in the sea spider Achelia langi (Dohrn, 1881) (Pycnogonida).
BMC Biology, 2014Co-Authors: Tobias Lehmann, Martin Heß, Gerhard Wanner, Roland R MelzerAbstract:The research field of connectomics arose just recently with the development of new three-dimensional-electron microscopy (EM) techniques and increasing computing power. So far, only a few model species (for example, mouse, the nematode Caenorhabditis elegans, and the fruit fly Drosophila melanogaster) have been studied using this approach. Here, we present a first attempt to expand this circle to include pycnogonids, which hold a key position for the understanding of arthropod evolution. The visual Neuropils in Achelia langi are studied using a focused ion beam-scanning electron microscope (FIB-SEM) crossbeam-workstation, and a three-dimensional serial reconstruction of the connectome is presented. The two eyes of each hemisphere of the sea spider’s eye tubercle are connected to a first and a second visual Neuropil. The first visual Neuropil is subdivided in two hemiNeuropils, each responsible for one eye and stratified into three layers. Six different neuron types postsynaptic to the retinula (R-cells) axons are characterized by their morphology: five types of descending unipolar neurons and one type of ascending neurons. These cell types are also identified by Golgi impregnations. Mapping of all identifiable chemical synapses indicates that the descending unipolar neurons are postsynaptic to the R-cells and, hence, are second-order neurons. The ascending neurons are predominantly presynaptic and sometimes postsynaptic to the R-cells and may play a feedback role. Comparing these results with the compound eye visual system of crustaceans and insects – the only arthropod visual system studied so far in such detail – we found striking similarities in the morphology and synaptic organization of the different neuron types. Hence, the visual system of pycnogonids shows features of both chelicerate median and mandibulate lateral eyes.
Bill S Hansson - One of the best experts on this subject based on the ideXlab platform.
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central projections of antennular chemosensory and mechanosensory afferents in the brain of the terrestrial hermit crab coenobita clypeatus coenobitidae anomura
Frontiers in Neuroanatomy, 2015Co-Authors: Oksana Tuchina, Nicholas J. Strausfeld, Jurgen Rybak, Stefan Koczan, Gabriella H Wolff, Bill S HanssonAbstract:The Coenobitidae (Decapoda, Anomura, Paguroidea) is a taxon of hermit crabs that includes two genera with a fully terrestrial life style as adults. Previous studies have shown that Coenobitidae have evolved a sense of spatial odor localization that is behaviorally highly relevant. Here, we examined the central olfactory pathway of these animals by analyzing central projections of the antennular nerve of Coenobita clypeatus, combining backfilling of the nerve with dextran-coupled dye, Golgi impregnations and three-dimensional reconstruction of the primary olfactory center, the antennular lobe. The principal pattern of putative olfactory sensory afferents in C. clypeatus is in many aspects similar to what have been established for aquatic decapod crustaceans, such as the spiny lobster Panulirus argus. However, there are also obvious differences that may, or may not represent adaptations related to a terrestrial lifestyle. In C. clypeatus, the antennular lobe dominates the deutocerebrum, having more than one thousand allantoid-shaped subunits. We observed two distinct patterns of sensory neuron innervation: putative olfactory afferents from the aesthetascs either supply the cap/subcap region of the subunits or they extend through its full depth. Our data also demonstrate that any one sensory axon can supply input to several subunits. Putative chemosensory (non-aesthetasc) and mechanosensory axons represent a different pathway and innervate the lateral and median antennular Neuropils. Hence, we suggest that the chemosensory input in C. clypeatus might be represented via a dual pathway: aesthetascs target the antennular lobe, and bimodal sensilla target the lateral antennular Neuropil and median antennular Neuropil. The present data is compared to related findings in other decapod crustaceans.
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brain architecture of the largest living land arthropod the giant robber crab birgus latro crustacea anomura coenobitidae evidence for a prominent central olfactory pathway
Frontiers in Zoology, 2010Co-Authors: Jakob Krieger, Steffen Harzsch, Bill S Hansson, Renate E Sandeman, David C SandemanAbstract:Several lineages within the Crustacea conquered land independently during evolution, thereby requiring physiological adaptations for a semi-terrestrial or even a fully terrestrial lifestyle. Birgus latro Linnaeus, 1767, the giant robber crab or coconut crab (Anomura, Coenobitidae), is the largest land-living arthropod and inhabits Indo-Pacific islands such as Christmas Island. B. latro has served as a model in numerous studies of physiological aspects related to the conquest of land by crustaceans. From an olfactory point of view, a transition from sea to land means that molecules need to be detected in gas phase instead of in water solution. Previous studies have provided physiological evidence that terrestrial hermit crabs (Coenobitidae) such as B. latro have a sensitive and well differentiated sense of smell. Here we analyze the brain, in particular the olfactory processing areas of B. latro, by morphological analysis followed by 3 D reconstruction and immunocytochemical studies of synaptic proteins and a neuropeptide. The primary and secondary olfactory centers dominate the brain of B. latro and together account for ca. 40% of the Neuropil volume in its brain. The paired olfactory Neuropils are tripartite and composed of more than 1,000 columnar olfactory glomeruli, which are radially arranged around the periphery of the olfactory Neuropils. The glomeruli are innervated ca. 90,000 local interneurons and ca. 160,000 projection neurons per side. The secondary olfactory centers, the paired hemiellipsoid Neuropils, are targeted by the axons of these olfactory projection neurons. The projection neuron axonal branches make contact to ca. 250.000 interneurons (per side) associated with the hemiellipsoid Neuropils. The hemiellipsoid body Neuropil is organized into parallel Neuropil lamellae, a design that is quite unusual for decapod crustaceans. The architecture of the optic Neuropils and areas associated with antenna two suggest that B. latro has visual and mechanosensory skills that are comparable to those of marine Crustacea. In parallel to previous behavioral findings that B. latro has aerial olfaction, our results indicate that their central olfactory pathway is indeed most prominent. Similar findings from the closely related terrestrial hermit crab Coenobita clypeatus suggest that in Coenobitidae, olfaction is a major sensory modality processed by the brain, and that for these animals, exploring the olfactory landscape is vital for survival in their terrestrial habitat. Future studies on terrestrial members of other crustacean taxa such as Isopoda, Amphipoda, Astacida, and Brachyura will shed light on how frequently the establishment of an aerial sense of olfaction evolved in Crustacea during the transition from sea to land. Amounting to ca. 1,000,000, the numbers of interneurons that analyse the olfactory input in B. latro brains surpasses that in other terrestrial arthropods, as e.g. the honeybee Apis mellifera or the moth Manduca sexta, by two orders of magnitude suggesting that B. latro in fact is a land-living arthropod that has devoted a substantial amount of nervous tissue to the sense of smell.
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Brain architecture of the largest living land arthropod, the Giant Robber Crab Birgus latro (Crustacea, Anomura, Coenobitidae): evidence for a prominent central olfactory pathway?
Frontiers in Zoology, 2010Co-Authors: Jakob Krieger, Bill S Hansson, Renate E Sandeman, David C Sandeman, Steffen HarzschAbstract:Background Several lineages within the Crustacea conquered land independently during evolution, thereby requiring physiological adaptations for a semi-terrestrial or even a fully terrestrial lifestyle. Birgus latro Linnaeus, 1767, the giant robber crab or coconut crab (Anomura, Coenobitidae), is the largest land-living arthropod and inhabits Indo-Pacific islands such as Christmas Island. B. latro has served as a model in numerous studies of physiological aspects related to the conquest of land by crustaceans. From an olfactory point of view, a transition from sea to land means that molecules need to be detected in gas phase instead of in water solution. Previous studies have provided physiological evidence that terrestrial hermit crabs (Coenobitidae) such as B. latro have a sensitive and well differentiated sense of smell. Here we analyze the brain, in particular the olfactory processing areas of B. latro , by morphological analysis followed by 3 D reconstruction and immunocytochemical studies of synaptic proteins and a neuropeptide. Results The primary and secondary olfactory centers dominate the brain of B. latro and together account for ca. 40% of the Neuropil volume in its brain. The paired olfactory Neuropils are tripartite and composed of more than 1,000 columnar olfactory glomeruli, which are radially arranged around the periphery of the olfactory Neuropils. The glomeruli are innervated ca. 90,000 local interneurons and ca. 160,000 projection neurons per side. The secondary olfactory centers, the paired hemiellipsoid Neuropils, are targeted by the axons of these olfactory projection neurons. The projection neuron axonal branches make contact to ca. 250.000 interneurons (per side) associated with the hemiellipsoid Neuropils. The hemiellipsoid body Neuropil is organized into parallel Neuropil lamellae, a design that is quite unusual for decapod crustaceans. The architecture of the optic Neuropils and areas associated with antenna two suggest that B. latro has visual and mechanosensory skills that are comparable to those of marine Crustacea. Conclusions In parallel to previous behavioral findings that B. latro has aerial olfaction, our results indicate that their central olfactory pathway is indeed most prominent. Similar findings from the closely related terrestrial hermit crab Coenobita clypeatus suggest that in Coenobitidae, olfaction is a major sensory modality processed by the brain, and that for these animals, exploring the olfactory landscape is vital for survival in their terrestrial habitat. Future studies on terrestrial members of other crustacean taxa such as Isopoda, Amphipoda, Astacida, and Brachyura will shed light on how frequently the establishment of an aerial sense of olfaction evolved in Crustacea during the transition from sea to land. Amounting to ca. 1,000,000, the numbers of interneurons that analyse the olfactory input in B. latro brains surpasses that in other terrestrial arthropods, as e.g. the honeybee Apis mellifera or the moth Manduca sexta , by two orders of magnitude suggesting that B. latro in fact is a land-living arthropod that has devoted a substantial amount of nervous tissue to the sense of smell.
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the antennal lobe of orthoptera anatomy and evolution
Brain Behavior and Evolution, 2001Co-Authors: Rickard Ignell, Sylvia Anton, Bill S HanssonAbstract:The first odor-processing Neuropils of insects comprise glomeruli, islets of Neuropil, that are supplied by olfactory receptor neurons and give rise to efferent axons to higher brain centers. Glomeruli size and organization varies in a taxon-specific manner across the Insecta, suggesting possible correlates between their organization and chemosensory behaviors in different insect groups. Comparative studies of antennal lobe glomeruli within the Orthoptera have been used to infer how the various taxon-specific arrangements of odorant-processing structures (glomeruli) might have evolved. The cellular arrangements in glomeruli have been surveyed using anterograde filling and Golgi impregnation of antennal receptor neurons projecting to the antennal lobe in Stenopelmatidae, Tettigoniidae, Gryllidae, Tetrigidae and Acrididae. These taxa, which represent the two sub-orders of Orthoptera, reveal a high correlation between the neural architecture of the glomeruli and structures within the glomeruli. Using a recent molecular phylogeny of the Orthoptera we have mapped the occurrence of glomerular characteristics to infer the evolution of antennal lobe structures in orthopterans. The functional implications of these results are discussed.
Jakob Krieger - One of the best experts on this subject based on the ideXlab platform.
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Neuroanatomical correlates of mobility: Sensory brain centres are bigger in winged than in wingless parthenogenetic pea aphid females
Arthropod Structure and Development, 2019Co-Authors: Christophe Gadenne, Jakob Krieger, Claudia Groh, Kornelia Grübel, Jens Joschinski, Jochen Krauss, Wolfgang Rössler, Sylvia AntonAbstract:Many aphid species reproduce parthenogenetically throughout most of the year, with individuals having identical genomes. Nevertheless, aphid clones display a marked polyphenism with associated behavioural differences. Pea aphids (Acyrthosiphon pisum), when crowded, produce winged individuals, which have a larger dispersal range than wingless individuals. We examined here if brain structures linked to primary sensory processing and high-order motor control change in size as a function of wing polyphenism. Using micro-computing tomography (micro-CT) scans and immunocytochemical staining with anti-synapsin antibody, we reconstructed primary visual (optic lobes) and olfactory (antennal lobes) Neuropils, together with the central body of winged and wingless parthenogenetic females of A. pisum for volume measurements. Absolute Neuropil volumes were generally bigger in anti-synapsin labelled brains compared to micro-CT scans. This is potentially due to differences in rearing conditions of the used aphids. Independent of the method used, however, winged females consistently had larger antennal lobes and optic lobes than wingless females in spite of a larger overall body size of wingless compared to winged females. The volume of the central body, on the other hand was not significantly different between the two morphs. The larger primary sensory centres in winged aphids might thus provide the neuronal substrate for processing different environmental information due to the increased mobility during flight.
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brain architecture of the largest living land arthropod the giant robber crab birgus latro crustacea anomura coenobitidae evidence for a prominent central olfactory pathway
Frontiers in Zoology, 2010Co-Authors: Jakob Krieger, Steffen Harzsch, Bill S Hansson, Renate E Sandeman, David C SandemanAbstract:Several lineages within the Crustacea conquered land independently during evolution, thereby requiring physiological adaptations for a semi-terrestrial or even a fully terrestrial lifestyle. Birgus latro Linnaeus, 1767, the giant robber crab or coconut crab (Anomura, Coenobitidae), is the largest land-living arthropod and inhabits Indo-Pacific islands such as Christmas Island. B. latro has served as a model in numerous studies of physiological aspects related to the conquest of land by crustaceans. From an olfactory point of view, a transition from sea to land means that molecules need to be detected in gas phase instead of in water solution. Previous studies have provided physiological evidence that terrestrial hermit crabs (Coenobitidae) such as B. latro have a sensitive and well differentiated sense of smell. Here we analyze the brain, in particular the olfactory processing areas of B. latro, by morphological analysis followed by 3 D reconstruction and immunocytochemical studies of synaptic proteins and a neuropeptide. The primary and secondary olfactory centers dominate the brain of B. latro and together account for ca. 40% of the Neuropil volume in its brain. The paired olfactory Neuropils are tripartite and composed of more than 1,000 columnar olfactory glomeruli, which are radially arranged around the periphery of the olfactory Neuropils. The glomeruli are innervated ca. 90,000 local interneurons and ca. 160,000 projection neurons per side. The secondary olfactory centers, the paired hemiellipsoid Neuropils, are targeted by the axons of these olfactory projection neurons. The projection neuron axonal branches make contact to ca. 250.000 interneurons (per side) associated with the hemiellipsoid Neuropils. The hemiellipsoid body Neuropil is organized into parallel Neuropil lamellae, a design that is quite unusual for decapod crustaceans. The architecture of the optic Neuropils and areas associated with antenna two suggest that B. latro has visual and mechanosensory skills that are comparable to those of marine Crustacea. In parallel to previous behavioral findings that B. latro has aerial olfaction, our results indicate that their central olfactory pathway is indeed most prominent. Similar findings from the closely related terrestrial hermit crab Coenobita clypeatus suggest that in Coenobitidae, olfaction is a major sensory modality processed by the brain, and that for these animals, exploring the olfactory landscape is vital for survival in their terrestrial habitat. Future studies on terrestrial members of other crustacean taxa such as Isopoda, Amphipoda, Astacida, and Brachyura will shed light on how frequently the establishment of an aerial sense of olfaction evolved in Crustacea during the transition from sea to land. Amounting to ca. 1,000,000, the numbers of interneurons that analyse the olfactory input in B. latro brains surpasses that in other terrestrial arthropods, as e.g. the honeybee Apis mellifera or the moth Manduca sexta, by two orders of magnitude suggesting that B. latro in fact is a land-living arthropod that has devoted a substantial amount of nervous tissue to the sense of smell.
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Brain architecture of the largest living land arthropod, the Giant Robber Crab Birgus latro (Crustacea, Anomura, Coenobitidae): evidence for a prominent central olfactory pathway?
Frontiers in Zoology, 2010Co-Authors: Jakob Krieger, Bill S Hansson, Renate E Sandeman, David C Sandeman, Steffen HarzschAbstract:Background Several lineages within the Crustacea conquered land independently during evolution, thereby requiring physiological adaptations for a semi-terrestrial or even a fully terrestrial lifestyle. Birgus latro Linnaeus, 1767, the giant robber crab or coconut crab (Anomura, Coenobitidae), is the largest land-living arthropod and inhabits Indo-Pacific islands such as Christmas Island. B. latro has served as a model in numerous studies of physiological aspects related to the conquest of land by crustaceans. From an olfactory point of view, a transition from sea to land means that molecules need to be detected in gas phase instead of in water solution. Previous studies have provided physiological evidence that terrestrial hermit crabs (Coenobitidae) such as B. latro have a sensitive and well differentiated sense of smell. Here we analyze the brain, in particular the olfactory processing areas of B. latro , by morphological analysis followed by 3 D reconstruction and immunocytochemical studies of synaptic proteins and a neuropeptide. Results The primary and secondary olfactory centers dominate the brain of B. latro and together account for ca. 40% of the Neuropil volume in its brain. The paired olfactory Neuropils are tripartite and composed of more than 1,000 columnar olfactory glomeruli, which are radially arranged around the periphery of the olfactory Neuropils. The glomeruli are innervated ca. 90,000 local interneurons and ca. 160,000 projection neurons per side. The secondary olfactory centers, the paired hemiellipsoid Neuropils, are targeted by the axons of these olfactory projection neurons. The projection neuron axonal branches make contact to ca. 250.000 interneurons (per side) associated with the hemiellipsoid Neuropils. The hemiellipsoid body Neuropil is organized into parallel Neuropil lamellae, a design that is quite unusual for decapod crustaceans. The architecture of the optic Neuropils and areas associated with antenna two suggest that B. latro has visual and mechanosensory skills that are comparable to those of marine Crustacea. Conclusions In parallel to previous behavioral findings that B. latro has aerial olfaction, our results indicate that their central olfactory pathway is indeed most prominent. Similar findings from the closely related terrestrial hermit crab Coenobita clypeatus suggest that in Coenobitidae, olfaction is a major sensory modality processed by the brain, and that for these animals, exploring the olfactory landscape is vital for survival in their terrestrial habitat. Future studies on terrestrial members of other crustacean taxa such as Isopoda, Amphipoda, Astacida, and Brachyura will shed light on how frequently the establishment of an aerial sense of olfaction evolved in Crustacea during the transition from sea to land. Amounting to ca. 1,000,000, the numbers of interneurons that analyse the olfactory input in B. latro brains surpasses that in other terrestrial arthropods, as e.g. the honeybee Apis mellifera or the moth Manduca sexta , by two orders of magnitude suggesting that B. latro in fact is a land-living arthropod that has devoted a substantial amount of nervous tissue to the sense of smell.