1
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Roggenbuck EC, Hall EA, Hanson IB, Roby AA, Zhang KK, Alkatib KA, Carter JA, Clewner JE, Gelfius AL, Gong S, Gordon FR, Iseler JN, Kotapati S, Li M, Maysun A, McCormick EO, Rastogi G, Sengupta S, Uzoma CU, Wolkov MA, Clowney EJ. Let's talk about sex: Mechanisms of neural sexual differentiation in Bilateria. WIREs Mech Dis 2024; 16:e1636. [PMID: 38185860 DOI: 10.1002/wsbm.1636] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2023] [Revised: 11/20/2023] [Accepted: 11/21/2023] [Indexed: 01/09/2024]
Abstract
In multicellular organisms, sexed gonads have evolved that facilitate release of sperm versus eggs, and bilaterian animals purposefully combine their gametes via mating behaviors. Distinct neural circuits have evolved that control these physically different mating events for animals producing eggs from ovaries versus sperm from testis. In this review, we will describe the developmental mechanisms that sexually differentiate neural circuits across three major clades of bilaterian animals-Ecdysozoa, Deuterosomia, and Lophotrochozoa. While many of the mechanisms inducing somatic and neuronal sex differentiation across these diverse organisms are clade-specific rather than evolutionarily conserved, we develop a common framework for considering the developmental logic of these events and the types of neuronal differences that produce sex-differentiated behaviors. This article is categorized under: Congenital Diseases > Stem Cells and Development Neurological Diseases > Stem Cells and Development.
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Affiliation(s)
- Emma C Roggenbuck
- MCDB 464 - Cellular Diversity: Sex Differentiation of the Brain, University of Michigan, Ann Arbor, Michigan, USA
| | - Elijah A Hall
- MCDB 464 - Cellular Diversity: Sex Differentiation of the Brain, University of Michigan, Ann Arbor, Michigan, USA
| | - Isabel B Hanson
- MCDB 464 - Cellular Diversity: Sex Differentiation of the Brain, University of Michigan, Ann Arbor, Michigan, USA
| | - Alyssa A Roby
- MCDB 464 - Cellular Diversity: Sex Differentiation of the Brain, University of Michigan, Ann Arbor, Michigan, USA
| | - Katherine K Zhang
- MCDB 464 - Cellular Diversity: Sex Differentiation of the Brain, University of Michigan, Ann Arbor, Michigan, USA
| | - Kyle A Alkatib
- MCDB 464 - Cellular Diversity: Sex Differentiation of the Brain, University of Michigan, Ann Arbor, Michigan, USA
| | - Joseph A Carter
- MCDB 464 - Cellular Diversity: Sex Differentiation of the Brain, University of Michigan, Ann Arbor, Michigan, USA
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, Michigan, USA
| | - Jarred E Clewner
- MCDB 464 - Cellular Diversity: Sex Differentiation of the Brain, University of Michigan, Ann Arbor, Michigan, USA
| | - Anna L Gelfius
- MCDB 464 - Cellular Diversity: Sex Differentiation of the Brain, University of Michigan, Ann Arbor, Michigan, USA
| | - Shiyuan Gong
- MCDB 464 - Cellular Diversity: Sex Differentiation of the Brain, University of Michigan, Ann Arbor, Michigan, USA
| | - Finley R Gordon
- MCDB 464 - Cellular Diversity: Sex Differentiation of the Brain, University of Michigan, Ann Arbor, Michigan, USA
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, Michigan, USA
| | - Jolene N Iseler
- MCDB 464 - Cellular Diversity: Sex Differentiation of the Brain, University of Michigan, Ann Arbor, Michigan, USA
| | - Samhita Kotapati
- MCDB 464 - Cellular Diversity: Sex Differentiation of the Brain, University of Michigan, Ann Arbor, Michigan, USA
| | - Marilyn Li
- MCDB 464 - Cellular Diversity: Sex Differentiation of the Brain, University of Michigan, Ann Arbor, Michigan, USA
| | - Areeba Maysun
- MCDB 464 - Cellular Diversity: Sex Differentiation of the Brain, University of Michigan, Ann Arbor, Michigan, USA
| | - Elise O McCormick
- MCDB 464 - Cellular Diversity: Sex Differentiation of the Brain, University of Michigan, Ann Arbor, Michigan, USA
| | - Geetanjali Rastogi
- MCDB 464 - Cellular Diversity: Sex Differentiation of the Brain, University of Michigan, Ann Arbor, Michigan, USA
| | - Srijani Sengupta
- MCDB 464 - Cellular Diversity: Sex Differentiation of the Brain, University of Michigan, Ann Arbor, Michigan, USA
| | - Chantal U Uzoma
- MCDB 464 - Cellular Diversity: Sex Differentiation of the Brain, University of Michigan, Ann Arbor, Michigan, USA
| | - Madison A Wolkov
- MCDB 464 - Cellular Diversity: Sex Differentiation of the Brain, University of Michigan, Ann Arbor, Michigan, USA
| | - E Josephine Clowney
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, Michigan, USA
- Michigan Neuroscience Institute Affiliate, University of Michigan, Ann Arbor, Michigan, USA
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2
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Couto A, Marty S, Dawson EH, d'Ettorre P, Sandoz JC, Montgomery SH. Evolution of the neuronal substrate for kin recognition in social Hymenoptera. Biol Rev Camb Philos Soc 2023; 98:2226-2242. [PMID: 37528574 DOI: 10.1111/brv.13003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Revised: 07/18/2023] [Accepted: 07/20/2023] [Indexed: 08/03/2023]
Abstract
In evolutionary terms, life is about reproduction. Yet, in some species, individuals forgo their own reproduction to support the reproductive efforts of others. Social insect colonies for example, can contain up to a million workers that actively cooperate in tasks such as foraging, brood care and nest defence, but do not produce offspring. In such societies the division of labour is pronounced, and reproduction is restricted to just one or a few individuals, most notably the queen(s). This extreme eusocial organisation exists in only a few mammals, crustaceans and insects, but strikingly, it evolved independently up to nine times in the order Hymenoptera (including ants, bees and wasps). Transitions from a solitary lifestyle to an organised society can occur through natural selection when helpers obtain a fitness benefit from cooperating with kin, owing to the indirect transmission of genes through siblings. However, this process, called kin selection, is vulnerable to parasitism and opportunistic behaviours from unrelated individuals. An ability to distinguish kin from non-kin, and to respond accordingly, could therefore critically facilitate the evolution of eusociality and the maintenance of non-reproductive workers. The question of how the hymenopteran brain has adapted to support this function is therefore a fundamental issue in evolutionary neuroethology. Early neuroanatomical investigations proposed that social Hymenoptera have expanded integrative brain areas due to selection for increased cognitive capabilities in the context of processing social information. Later studies challenged this assumption and instead pointed to an intimate link between higher social organisation and the existence of developed sensory structures involved in recognition and communication. In particular, chemical signalling of social identity, known to be mediated through cuticular hydrocarbons (CHCs), may have evolved hand in hand with a specialised chemosensory system in Hymenoptera. Here, we compile the current knowledge on this recognition system, from emitted identity signals, to the molecular and neuronal basis of chemical detection, with particular emphasis on its evolutionary history. Finally, we ask whether the evolution of social behaviour in Hymenoptera could have driven the expansion of their complex olfactory system, or whether the early origin and conservation of an olfactory subsystem dedicated to social recognition could explain the abundance of eusocial species in this insect order. Answering this question will require further comparative studies to provide a comprehensive view on lineage-specific adaptations in the olfactory pathway of Hymenoptera.
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Affiliation(s)
- Antoine Couto
- School of Biological Sciences, University of Bristol, 24 Tyndall Avenue, Bristol, BS8 1TQ, UK
- Evolution, Genomes, Behaviour and Ecology (UMR 9191), IDEEV, Université Paris-Saclay, CNRS, IRD, 12 route 128, Gif-sur-Yvette, 91190, France
| | - Simon Marty
- Evolution, Genomes, Behaviour and Ecology (UMR 9191), IDEEV, Université Paris-Saclay, CNRS, IRD, 12 route 128, Gif-sur-Yvette, 91190, France
| | - Erika H Dawson
- Laboratory of Experimental and Comparative Ethology, UR 4443 (LEEC), Université Sorbonne Paris Nord, 99 avenue J.-B. Clément, Villetaneuse, 93430, France
| | - Patrizia d'Ettorre
- Laboratory of Experimental and Comparative Ethology, UR 4443 (LEEC), Université Sorbonne Paris Nord, 99 avenue J.-B. Clément, Villetaneuse, 93430, France
- Institut Universitaire de France (IUF), 103 Boulevard Saint-Michel, Paris, 75005, France
| | - Jean-Christophe Sandoz
- Evolution, Genomes, Behaviour and Ecology (UMR 9191), IDEEV, Université Paris-Saclay, CNRS, IRD, 12 route 128, Gif-sur-Yvette, 91190, France
| | - Stephen H Montgomery
- School of Biological Sciences, University of Bristol, 24 Tyndall Avenue, Bristol, BS8 1TQ, UK
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3
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King BH, Gunathunga PB. Gustation in insects: taste qualities and types of evidence used to show taste function of specific body parts. JOURNAL OF INSECT SCIENCE (ONLINE) 2023; 23:11. [PMID: 37014302 PMCID: PMC10072106 DOI: 10.1093/jisesa/iead018] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Revised: 02/03/2023] [Accepted: 03/10/2023] [Indexed: 06/19/2023]
Abstract
The insect equivalent of taste buds are gustatory sensilla, which have been found on mouthparts, pharynxes, antennae, legs, wings, and ovipositors. Most gustatory sensilla are uniporous, but not all apparently uniporous sensilla are gustatory. Among sensilla containing more than one neuron, a tubular body on one dendrite is also indicative of a taste sensillum, with the tubular body adding tactile function. But not all taste sensilla are also tactile. Additional morphological criteria are often used to recognize if a sensillum is gustatory. Further confirmation of such criteria by electrophysiological or behavioral evidence is needed. The five canonical taste qualities to which insects respond are sweet, bitter, sour, salty, and umami. But not all tastants that insects respond to easily fit in these taste qualities. Categories of insect tastants can be based not only on human taste perception, but also on whether the response is deterrent or appetitive and on chemical structure. Other compounds that at least some insects taste include, but are not limited to: water, fatty acids, metals, carbonation, RNA, ATP, pungent tastes as in horseradish, bacterial lipopolysaccharides, and contact pheromones. We propose that, for insects, taste be defined not only as a response to nonvolatiles but also be restricted to responses that are, or are thought to be, mediated by a sensillum. This restriction is useful because some of the receptor proteins in gustatory sensilla are also found elsewhere.
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Watanabe H, Ogata S, Nodomi N, Tateishi K, Nishino H, Matsubara R, Ozaki M, Yokohari F. Cuticular hydrocarbon reception by sensory neurons in basiconic sensilla of the Japanese carpenter ant. Front Cell Neurosci 2023; 17:1084803. [PMID: 36814868 PMCID: PMC9940637 DOI: 10.3389/fncel.2023.1084803] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Accepted: 01/17/2023] [Indexed: 02/09/2023] Open
Abstract
To maintain the eusociality of a colony, ants recognize subtle differences in colony-specific sets of cuticular hydrocarbons (CHCs). The CHCs are received by female-specific antennal basiconic sensilla and processed in specific brain regions. However, it is controversial whether a peripheral or central neural mechanism is mainly responsible for discrimination of CHC blends. In the Japanese carpenter ant, Camponotus japonicus, about 140 sensory neurons (SNs) are co-housed in a single basiconic sensillum and receive colony-specific blends of 18 CHCs. The complexity of this CHC sensory process makes the neural basis of peripheral nestmate recognition difficult to understand. Here, we electrophysiologically recorded responses of single basiconic sensilla to each of 18 synthesized CHCs, and identified CHC responses of each SN co-housed in a single sensillum. Each CHC activated different sets of SNs and each SN was broadly tuned to CHCs. Multiple SNs in a given sensillum fired in synchrony, and the synchronicity of spikes was impaired by treatment with a gap junction inhibitor. These results indicated that SNs in single basiconic sensilla were electrically coupled. Quantitative analysis indicated that the Japanese carpenter ants have the potential to discriminate chemical structures of CHCs based on the combinational patterns of activated SNs. SNs of ants from different colonies exhibited different CHC response spectra. In addition, ants collected from the same colony but bred in separate groups also exhibited different CHC response spectra. These results support the hypothesis that the peripheral sensory mechanism is important for discrimination between nestmate and non-nestmate ants.
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Affiliation(s)
- Hidehiro Watanabe
- Department of Earth System Science, Fukuoka University, Fukuoka, Japan,*Correspondence: Hidehiro Watanabe,
| | - Shoji Ogata
- Department of Earth System Science, Fukuoka University, Fukuoka, Japan
| | - Nonoka Nodomi
- Department of Earth System Science, Fukuoka University, Fukuoka, Japan
| | - Kosuke Tateishi
- Department of Earth System Science, Fukuoka University, Fukuoka, Japan
| | - Hiroshi Nishino
- Research Institute for Electronic Science, Hokkaido University, Sapporo, Japan
| | - Ryosuke Matsubara
- Department of Chemistry, Graduate School of Science, Kobe University, Kobe, Japan
| | - Mamiko Ozaki
- Department of Biology, Graduate School of Science, Kobe University, Kobe, Japan,KYOUSEI Science Center for Life and Nature, Nara Women’s University, Nara, Japan
| | - Fumio Yokohari
- Department of Earth System Science, Fukuoka University, Fukuoka, Japan
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5
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Uebi T, Sakita T, Ikeda R, Sakanishi K, Tsutsumi T, Zhang Z, Ma H, Matsubara R, Matsuyama S, Nakajima S, Huang RN, Habe S, Hefetz A, Ozaki M. Chemical identification of an active component and putative neural mechanism for repellent effect of a native ant’s odor on invasive species. Front Physiol 2022; 13:844084. [PMID: 36111148 PMCID: PMC9468892 DOI: 10.3389/fphys.2022.844084] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2021] [Accepted: 07/25/2022] [Indexed: 11/18/2022] Open
Abstract
The invasive Argentine ants (Linepithema humile) and the red imported fire ants (Solenopsis invicta) constitute a worldwide threat, causing severe disruption to ecological systems and harming human welfare. In view of the limited success of current pest control measures, we propose here to employ repellents as means to mitigate the effect of these species. We demonstrate that cuticular hydrocarbons (CHCs) used as nestmate-recognition pheromone in the Japanese carpenter ant (Camponotus japonicus), and particularly its (Z)-9-tricosene component, induced vigorous olfactory response and intense aversion in these invasive species. (Z)-9-Tricosene, when given to their antennae, caused indiscriminate glomerular activation of antennal lobe (AL) regions, creating neural disarray and leading to aversive behavior. Considering the putative massive central neural effect, we suggest that the appropriate use of certain CHCs of native ants can facilitate aversive withdrawal of invasive ants.
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Affiliation(s)
- Tatsuya Uebi
- Department of Biology, Graduate School of Science, Kobe University, Kobe, Japan
- KYOUSEI Science Center for Life and Nature, Nara Women’s University, Nara, Japan
| | - Tomoya Sakita
- Department of Biology, Graduate School of Science, Kobe University, Kobe, Japan
| | - Ryo Ikeda
- Department of Biology, Graduate School of Science, Kobe University, Kobe, Japan
| | - Keita Sakanishi
- Department of Biology, Graduate School of Science, Kobe University, Kobe, Japan
| | - Tomoaki Tsutsumi
- Department of Chemistry, Graduate School of Science, Kobe University, Kobe, Japan
| | - Zijian Zhang
- Department of Chemistry, Graduate School of Science, Kobe University, Kobe, Japan
| | - Huiying Ma
- Department of Chemistry, Graduate School of Science, Kobe University, Kobe, Japan
| | - Ryosuke Matsubara
- Department of Chemistry, Graduate School of Science, Kobe University, Kobe, Japan
| | - Shigeru Matsuyama
- Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Japan
| | - Satoko Nakajima
- Graduate School of Life and Environmental Sciences, Kyoto Prefectural University, Kyoto, Japan
| | - Rong-Nan Huang
- Department of Entomology, National Taiwan University, Taipei, Taiwan
| | - Shunya Habe
- Department of Biology, Graduate School of Science, Kobe University, Kobe, Japan
| | - Abraham Hefetz
- School of Zoology, Tel Aviv University, Tel Aviv, Israel
| | - Mamiko Ozaki
- Department of Biology, Graduate School of Science, Kobe University, Kobe, Japan
- KYOUSEI Science Center for Life and Nature, Nara Women’s University, Nara, Japan
- Department of Chemical Science and Engineering, Graduate School of Engineering, Kobe University, Kobe, Japan
- Morphogenetic Signaling Team, RIKEN Center for Biosystems Dynamics Research, Kobe, Japan
- *Correspondence: Mamiko Ozaki,
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6
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Godfrey RK, Oberski JT, Allmark T, Givens C, Hernandez-Rivera J, Gronenberg W. Olfactory System Morphology Suggests Colony Size Drives Trait Evolution in Odorous Ants (Formicidae: Dolichoderinae). Front Ecol Evol 2021. [DOI: 10.3389/fevo.2021.733023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
In social insects colony fitness is determined in part by individual worker phenotypes. Across ant species, colony size varies greatly and is thought to affect worker trait variation in both proximate and ultimate ways. Little is known about the relationship between colony size and worker trait evolution, but hypotheses addressing the role of social structure in brain evolution suggest workers of small-colony species may have larger brains or larger brain regions necessary for complex behaviors. In previous work on odorous ants (Formicidae: Dolichoderinae) we found no correlation between colony size and these brain properties, but found that relative antennal lobe size scaled negatively with colony size. Therefore, we now test whether sensory systems scale with colony size, with particular attention to olfactory components thought to be involved in nestmate recognition. Across three species of odorous ants, Forelius mccooki, Dorymyrmex insanus, and D. bicolor, which overlap in habitat and foraging ecology but vary in colony size, we compare olfactory sensory structures, comparing those thought to be involved in nestmate recognition. We use the visual system, a sensory modality not as important in social communication in ants, as a control comparison. We find that body size scaling largely explains differences in eye size, antennal length, antennal sensilla density, and total number of olfactory glomeruli across these species. However, sensilla basiconica and olfactory glomeruli in the T6 cluster of the antennal lobe, structures known to be involved in nestmate recognition, do not follow body size scaling observed for other structures. Instead, we find evidence from the closely related Dorymyrmex species that the larger colony species, D. bicolor, invests more in structures implicated in nestmate recognition. To test for functional consequences, we compare nestmate and non-nestmate interactions between these two species and find D. bicolor pairs of either type engage in more interactions than D. insaus pairs. Thus, we do not find evidence supporting a universal pattern of sensory system scaling associated with changes in colony size, but hypothesize that observed differences in the olfactory components in two closely related Dorymyrmex species are evidence of a link between colony size and sensory trait evolution.
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Couto A, Arnold G, Ai H, Sandoz JC. Interspecific variation of antennal lobe composition among four hornet species. Sci Rep 2021; 11:20883. [PMID: 34686710 PMCID: PMC8536693 DOI: 10.1038/s41598-021-00280-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Accepted: 09/27/2021] [Indexed: 11/09/2022] Open
Abstract
Olfaction is a crucial sensory modality underlying foraging, social and mating behaviors in many insects. Since the olfactory system is at the interface between the animal and its environment, it receives strong evolutionary pressures that promote neuronal adaptations and phenotypic variations across species. Hornets are large eusocial predatory wasps with a highly developed olfactory system, critical for foraging and intra-specific communication. In their natural range, hornet species display contrasting ecologies and olfactory-based behaviors, which might match to adaptive shifts in their olfactory system. The first olfactory processing center of the insect brain, the antennal lobe, is made of morphological and functional units called glomeruli. Using fluorescent staining, confocal microscopy and 3D reconstructions, we compared antennal lobe structure, glomerular numbers and volumes in four hornet species (Vespa crabro, Vespa velutina, Vespa mandarinia and Vespa orientalis) with marked differences in nesting site preferences and predatory behaviors. Despite a conserved organization of their antennal lobe compartments, glomeruli numbers varied strongly between species, including in a subsystem thought to process intraspecific cuticular signals. Moreover, specific adaptations involving enlarged glomeruli appeared in two species, V. crabro and V. mandarinia, but not in the others. We discuss the possible function of these adaptations based on species-specific behavioral differences.
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Affiliation(s)
- Antoine Couto
- Laboratory Evolution Genomes Behavior and Ecology, CNRS, University Paris-Sud, IRD, Université Paris Saclay, 1 avenue de la Terrasse, 91198, Gif-sur-Yvette, France.,School of Biological Sciences, University of Bristol, 24 Tyndall Avenue, Bristol, BS8 1TQ, UK
| | - Gérard Arnold
- Laboratory Evolution Genomes Behavior and Ecology, CNRS, University Paris-Sud, IRD, Université Paris Saclay, 1 avenue de la Terrasse, 91198, Gif-sur-Yvette, France
| | - Hiroyuki Ai
- Department of Earth System Science, Fukuoka University, Fukuoka, 814-0180, Japan
| | - Jean-Christophe Sandoz
- Laboratory Evolution Genomes Behavior and Ecology, CNRS, University Paris-Sud, IRD, Université Paris Saclay, 1 avenue de la Terrasse, 91198, Gif-sur-Yvette, France.
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8
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McKenzie SK, Winston ME, Grewe F, Vargas Asensio G, Rodríguez-Hernández N, Rubin BER, Murillo-Cruz C, von Beeren C, Moreau CS, Suen G, Pinto-Tomás AA, Kronauer DJC. The genomic basis of army ant chemosensory adaptations. Mol Ecol 2021; 30:6627-6641. [PMID: 34582590 PMCID: PMC9292994 DOI: 10.1111/mec.16198] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Revised: 09/06/2021] [Accepted: 09/15/2021] [Indexed: 12/23/2022]
Abstract
The evolution of mass raiding has allowed army ants to become dominant arthropod predators in the tropics. Although a century of research has led to many discoveries about behavioural, morphological and physiological adaptations in army ants, almost nothing is known about the molecular basis of army ant biology. Here we report the genome of the iconic New World army ant Eciton burchellii, and show that it is unusually compact, with a reduced gene complement relative to other ants. In contrast to this overall reduction, a particular gene subfamily (9‐exon ORs) expressed predominantly in female antennae is expanded. This subfamily has previously been linked to the recognition of hydrocarbons, key olfactory cues used in insect communication and prey discrimination. Confocal microscopy of the brain showed a corresponding expansion in a putative hydrocarbon response centre within the antennal lobe, while scanning electron microscopy of the antenna revealed a particularly high density of hydrocarbon‐sensitive sensory hairs. E. burchellii shares these features with its predatory and more cryptic relative, the clonal raider ant. By integrating genomic, transcriptomic and anatomical analyses in a comparative context, our work thus provides evidence that army ants and their relatives possess a suite of modifications in the chemosensory system that may be involved in behavioural coordination and prey selection during social predation. It also lays the groundwork for future studies of army ant biology at the molecular level.
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Affiliation(s)
- Sean K McKenzie
- Laboratory of Social Evolution and Behavior, The Rockefeller University, New York, New York, USA.,Department of Ecology and Evolution, University of Lausanne, Lausanne, Switzerland
| | | | - Felix Grewe
- Grainger Bioinformatics Center, Science and Education, Field Museum of Natural History, Chicago, Illinois, USA
| | - Gabriel Vargas Asensio
- Centro de Investigación en Biología Molecular y Celular (CIBCM), Universidad de Costa Rica, San José, Costa Rica.,Department of Bacteriology, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Natalia Rodríguez-Hernández
- Centro de Investigación en Estructuras Microscópicas (CIEMIC), Universidad de Costa Rica, San José, Costa Rica
| | - Benjamin E R Rubin
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, New Jersey, USA
| | - Catalina Murillo-Cruz
- Centro de Investigación en Estructuras Microscópicas (CIEMIC), Universidad de Costa Rica, San José, Costa Rica
| | - Christoph von Beeren
- Laboratory of Social Evolution and Behavior, The Rockefeller University, New York, New York, USA.,Ecological Networks, Department of Biology, Technical University of Darmstadt, Darmstadt, Germany
| | - Corrie S Moreau
- Departments of Entomology and Ecology & Evolutionary Biology, Cornell University, Ithaca, New York, USA
| | - Garret Suen
- Department of Bacteriology, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Adrian A Pinto-Tomás
- Centro de Investigación en Biología Molecular y Celular (CIBCM), Universidad de Costa Rica, San José, Costa Rica.,Centro de Investigación en Estructuras Microscópicas (CIEMIC), Universidad de Costa Rica, San José, Costa Rica.,Escuela de Medicina, Departamento de Bioquímica, Universidad de Costa Rica, San José, Costa Rica
| | - Daniel J C Kronauer
- Laboratory of Social Evolution and Behavior, The Rockefeller University, New York, New York, USA
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9
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Sung JY, Harris OK, Hensley NM, Chemero AP, Morehouse NI. Beyond cognitive templates: re-examining template metaphors used for animal recognition and navigation. Integr Comp Biol 2021; 61:825-841. [PMID: 33970266 DOI: 10.1093/icb/icab040] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
The term 'cognitive template' originated from work in human-based cognitive science to describe a literal, stored, neural representation used in recognition tasks. As the study of cognition has expanded to non-human animals, the term has diffused to describe a wider range of animal cognitive tools and strategies that guide action through the recognition of and discrimination between external states. One potential reason for this non-standardized meaning and variable employment is that researchers interested in the broad range of animal recognition tasks enjoy the simplicity of the cognitive template concept and have allowed it to become shorthand for many dissimilar or unknown neural processes without deep scrutiny of how this metaphor might comport with underlying neurophysiology. We review the functional evidence for cognitive templates in fields such as perception, navigation, communication, and learning, highlighting any neural correlates identified by these studies. We find that the concept of cognitive templates has facilitated valuable exploration at the interface between animal behavior and cognition, but the quest for a literal template has failed to attain mechanistic support at the level of neurophysiology. This may be the result of a misled search for a single physical locus for the 'template' itself. We argue that recognition and discrimination processes are best treated as emergent and, as such, may not be physically localized within single structures of the brain. Rather, current evidence suggests that such tasks are accomplished through synergies between multiple distributed processes in animal nervous systems. We thus advocate for researchers to move towards a more ecological, process-oriented conception, especially when discussing the neural underpinnings of recognition-based cognitive tasks.
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Affiliation(s)
- Jenny Y Sung
- Department of Biological Sciences, University of Cincinnati
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10
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Ferguson ST, Bakis I, Zwiebel LJ. Advances in the Study of Olfaction in Eusocial Ants. INSECTS 2021; 12:252. [PMID: 33802783 PMCID: PMC8002415 DOI: 10.3390/insects12030252] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Revised: 03/09/2021] [Accepted: 03/13/2021] [Indexed: 11/16/2022]
Abstract
Over the past decade, spurred in part by the sequencing of the first ant genomes, there have been major advances in the field of olfactory myrmecology. With the discovery of a significant expansion of the odorant receptor gene family, considerable efforts have been directed toward understanding the olfactory basis of complex social behaviors in ant colonies. Here, we review recent pivotal studies that have begun to reveal insights into the development of the olfactory system as well as how olfactory stimuli are peripherally and centrally encoded. Despite significant biological and technical impediments, substantial progress has been achieved in the application of gene editing and other molecular techniques that notably distinguish the complex olfactory system of ants from other well-studied insect model systems, such as the fruit fly. In doing so, we hope to draw attention not only to these studies but also to critical knowledge gaps that will serve as a compass for future research endeavors.
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Affiliation(s)
| | | | - Laurence J. Zwiebel
- Department of Biological Sciences, Vanderbilt University, Nashville, TN 37235, USA; (S.T.F.); (I.B.)
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11
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Shah JS, Renthal R. Antennal Proteome of the Solenopsis invicta (Hymenoptera: Formicidae): Caste Differences in Olfactory Receptors and Chemosensory Support Proteins. JOURNAL OF INSECT SCIENCE (ONLINE) 2020; 20:5937575. [PMID: 33098433 PMCID: PMC7585320 DOI: 10.1093/jisesa/ieaa118] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Indexed: 06/11/2023]
Abstract
Little is known about the expression pattern of odorant and pheromone transporters, receptors, and deactivation enzymes in the antennae of ants carrying out different tasks. In order to begin filling in this information gap, we compared the proteomes of the antennae of workers and males of the red fire ant, Solenopsis invicta Buren (Hymenoptera: Formicidae). Male ants do not perform any colony work, and their only activity is to leave the nest on a mating flight. Previous studies showed that male ants express fewer types of odorant receptors than workers. Thus, we expected to find large differences between male and worker antennae for expression of receptors, transporters, and deactivators of signaling chemicals. We found that the abundance of receptors was consistent with the expected caste-specific signaling complexity, but the numbers of different antenna-specific transporters and deactivating enzymes in males and workers were similar. It is possible that some of these proteins have antenna-specific functions that are unrelated to chemosensory reception. Alternatively, the similar complexity could be a vestige of ant progenitors that had more behaviorally active males. As the reduced behavior of male ants evolved, the selection process may have favored a complex repertoire of transporters and deactivating enzymes alongside a limited repertoire of odorant receptors.
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Affiliation(s)
- Jaee Shailesh Shah
- Department of Biology, University of Texas at San Antonio, San Antonio, TX
| | - Robert Renthal
- Department of Biology, University of Texas at San Antonio, San Antonio, TX
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12
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Ge J, Ge Z, Zhu D, Wang X. Pheromonal Regulation of the Reproductive Division of Labor in Social Insects. Front Cell Dev Biol 2020; 8:837. [PMID: 32974354 PMCID: PMC7468439 DOI: 10.3389/fcell.2020.00837] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Accepted: 08/05/2020] [Indexed: 11/13/2022] Open
Abstract
The reproductive altruism in social insects is an evolutionary enigma that has been puzzling scientists starting from Darwin. Unraveling how reproductive skew emerges and maintains is crucial to understand the reproductive altruism involved in the consequent division of labor. The regulation of adult worker reproduction involves conspecific inhibitory signals, which are thought to be chemical signals by numerous studies. Despite the primary identification of few chemical ligands, the action modes of primer pheromones that regulate reproduction and their molecular causes and effects remain challenging. Here, these questions were elucidated by comprehensively reviewing recent advances. The coordination with other modalities of queen pheromones (QPs) and its context-dependent manner to suppress worker reproduction were discussed under the vast variation and plasticity of reproduction during colony development and across taxa. In addition to the effect of QPs, special attention was paid to recent studies revealing the regulatory effect of brood pheromones. Considering the correlation between pheromone and hormone, this study focused on the production and perception of pheromones under the endocrine control and highlighted the pivotal roles of nutrition-related pathways. The novel chemicals and gene pathways discovered by recent works provide new insights into the understanding of social regulation of reproductive division of labor in insects.
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Affiliation(s)
- Jin Ge
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
- CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing, China
| | - Zhuxi Ge
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
- CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing, China
| | - Dan Zhu
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
- CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing, China
| | - Xianhui Wang
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
- CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing, China
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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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Takeichi Y, Uebi T, Miyazaki N, Murata K, Yasuyama K, Inoue K, Suzaki T, Kubo H, Kajimura N, Takano J, Omori T, Yoshimura R, Endo Y, Hojo MK, Takaya E, Kurihara S, Tatsuta K, Ozaki K, Ozaki M. Putative Neural Network Within an Olfactory Sensory Unit for Nestmate and Non-nestmate Discrimination in the Japanese Carpenter Ant: The Ultra-structures and Mathematical Simulation. Front Cell Neurosci 2018; 12:310. [PMID: 30283303 PMCID: PMC6157317 DOI: 10.3389/fncel.2018.00310] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2018] [Accepted: 08/27/2018] [Indexed: 11/13/2022] Open
Abstract
Ants are known to use a colony-specific blend of cuticular hydrocarbons (CHCs) as a pheromone to discriminate between nestmates and non-nestmates and the CHCs were sensed in the basiconic type of antennal sensilla (S. basiconica). To investigate the functional design of this type of antennal sensilla, we observed the ultra-structures at 2D and 3D in the Japanese carpenter ant, Camponotus japonicus, using a serial block-face scanning electron microscope (SBF-SEM), and conventional and high-voltage transmission electron microscopes. Based on the serial images of 352 cross sections of SBF-SEM, we reconstructed a 3D model of the sensillum revealing that each S. basiconica houses > 100 unbranched dendritic processes, which extend from the same number of olfactory receptor neurons (ORNs). The dendritic processes had characteristic beaded-structures and formed a twisted bundle within the sensillum. At the "beads," the cell membranes of the processes were closely adjacent in the interdigitated profiles, suggesting functional interactions via gap junctions (GJs). Immunohistochemistry with anti-innexin (invertebrate GJ protein) antisera revealed positive labeling in the antennae of C. japonicus. Innexin 3, one of the five antennal innexin subtypes, was detected as a dotted signal within the S. basiconica as a sensory organ for nestmate recognition. These morphological results suggest that ORNs form an electrical network via GJs between dendritic processes. We were unable to functionally certify the electric connections in an olfactory sensory unit comprising such multiple ORNs; however, with the aid of simulation of a mathematical model, we examined the putative function of this novel chemosensory information network, which possibly contributes to the distinct discrimination of colony-specific blends of CHCs or other odor detection.
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Affiliation(s)
- Yusuke Takeichi
- Department of Biology, Graduate School of Science, Kobe University, Kobe, Japan
| | - Tatsuya Uebi
- Department of Biology, Graduate School of Science, Kobe University, Kobe, Japan
| | | | | | - Kouji Yasuyama
- Division of Biology, Department of Natural Sciences, Kawasaki Medical School, Kurashiki, Japan
| | - Kanako Inoue
- Research Center for Ultra-High Voltage Electron Microscopy, Osaka University, Ibaraki, Japan
| | - Toshinobu Suzaki
- Department of Biology, Graduate School of Science, Kobe University, Kobe, Japan
| | - Hideo Kubo
- Department of Mathematics, Faculty of Sciences, Hokkaido University, Sapporo, Japan
| | - Naoko Kajimura
- Graduate School of Frontier Biosciences, Osaka University, Suita, Japan
| | - Jo Takano
- Department of Electrical and Electronic Engineering, Graduate School of Engineering, Kobe University, Kobe, Japan
| | - Toshiaki Omori
- Department of Electrical and Electronic Engineering, Graduate School of Engineering, Kobe University, Kobe, Japan
| | - Ryoichi Yoshimura
- Department of Applied Biology, Kyoto Institute of Technology, Kyoto, Japan
| | - Yasuhisa Endo
- Department of Applied Biology, Kyoto Institute of Technology, Kyoto, Japan
| | - Masaru K Hojo
- Department of Biology, Graduate School of Science, Kobe University, Kobe, Japan
| | - Eichi Takaya
- Graduate School of Information Systems, The University of Electro-Communications, Chofu, Japan
| | - Satoshi Kurihara
- Graduate School of Information Systems, The University of Electro-Communications, Chofu, Japan
| | - Kenta Tatsuta
- Department of Biological Science, Faculty of Life and Environmental Science, Shimane University, Matsue, Japan
| | - Koichi Ozaki
- Department of Biological Science, Faculty of Life and Environmental Science, Shimane University, Matsue, Japan
| | - Mamiko Ozaki
- Department of Biology, Graduate School of Science, Kobe University, Kobe, Japan
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15
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Ghaninia M, Berger SL, Reinberg D, Zwiebel LJ, Ray A, Liebig J. Antennal Olfactory Physiology and Behavior of Males of the Ponerine Ant Harpegnathos saltator. J Chem Ecol 2018; 44:999-1007. [PMID: 30191433 DOI: 10.1007/s10886-018-1013-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2018] [Revised: 07/27/2018] [Accepted: 08/27/2018] [Indexed: 11/26/2022]
Abstract
In comparison to the large amount of study on the communication abilities of females in ant societies and their associated chemical ecology and sensory physiology, such study of male ants has been largely ignored; accordingly, little is known about their olfactory sensory capabilities. To address this, we explored peripheral odor sensitivities in male Harpegnathos saltator by measuring the electrophysiological activity of olfactory sensory neurons within antennal trichoid and coeloconic sensilla using an extracellular recording technique. In an initial trial of 46 compounds, sensilla trichodea responded strongly to two alarm pheromone components, while a limited number of non-hydrocarbon odorants elicited strong responses in sensilla coeloconica. Both sensillar types responded indifferently to 31 cuticular hydrocarbons (CHCs) and synthetic long-chain hydrocarbons (HCs) typically found on insect cuticle. In a search for sensilla responding to CHCs and other compounds, we found some sensilla that responded to synthetic HCs and CHCs from virgin queen postpharyngeal glands that are potentially used in close range mate recognition. Olfactometer bioassays of male ants to 15 non-HCs correlated sensory responsiveness to the respective behavioral responses. Comparing olfactory responses between H. saltator males and females, we found that sensilla coeloconica and basiconica of workers showed greater responses and broader selectivity to all compounds. The rarity of CHC-responding trichoid sensilla in Harpegnathos males suggests a more specific role in sexual communication compared to that in females, which use CHCs in a broader communication context.
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Affiliation(s)
- Majid Ghaninia
- School of Life Sciences, Arizona State University, 427 East Tyler Mall, Tempe, AZ, 85283, USA.
- Division of Entomology, Department of Plant Protection, Gorgan University of Agricultural Sciences and Natural Resources, Grogan, Iran.
| | - Shelley L Berger
- Departments of Cell and Developmental Biology, Genetics and Biology, University of Pennsylvania, Philadelphia, PA, USA
| | - Danny Reinberg
- Howard Hughes, Medical Institute and Department of Molecular Pharmacology and Biochemistry, New York University School of Medicine, New York, NY, 10016, USA
| | - Laurence J Zwiebel
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, USA
| | - Anandasankar Ray
- Department of Molecular Cell and Systems Biology, University of California, Riverside, CA, 92521, USA
| | - Jürgen Liebig
- School of Life Sciences, Arizona State University, 427 East Tyler Mall, Tempe, AZ, 85283, USA
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16
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Lin T, Li C, Liu J, Smith BH, Lei H, Zeng X. Glomerular Organization in the Antennal Lobe of the Oriental Fruit Fly Bactrocera dorsalis. Front Neuroanat 2018; 12:71. [PMID: 30233333 PMCID: PMC6127620 DOI: 10.3389/fnana.2018.00071] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Accepted: 08/06/2018] [Indexed: 11/30/2022] Open
Abstract
The oriental fruit fly, Bactrocera dorsalis is one of the most destructive pests of horticultural crops in tropical and subtropical Asia. The insect relies heavily on its olfactory system to select suitable hosts for development and reproduction. To understand the neural basis of its odor-driven behaviors, it is fundamental to characterize the anatomy of its olfactory system. In this study, we investigated the anatomical organization of the antennal lobe (AL), the primary olfactory center, in B. dorsalis, and constructed a 3D glomerular atlas of the AL based on synaptic antibody staining combined with computerized 3D reconstruction. To facilitate identification of individual glomeruli, we also applied mass staining of olfactory sensory neurons (OSNs) and projection neurons (PNs). In total, 64 or 65 glomeruli are identifiable in both sexes based on their shape, size, and relative spatial relationship. The overall glomerular volume of two sexes is not statistically different. However, eight glomeruli are sexually dimorphic: four (named AM2, C1, L2, and L3) are larger in males, and four are larger in females (A3, AD1, DM3, and M1). The results from anterograde staining, obtained by applying dye in the antennal lobe, show that three typical medial, media lateral, and lateral antennal-lobe tracts form parallel connections between the antennal lobe and protocerebrum. In addition to these three tracts, we also found a transverse antennal-lobe tract. Based on the retrograde staining of the calyx in the mushroom body, we also characterize the arrangement of roots and cell body clusters linked to the medial antennal-lobe tracts. These data provide a foundation for future studies on the olfactory processing of host odors in B. dorsalis.
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Affiliation(s)
- Tao Lin
- Guangdong Engineering Research Center for Insect Behavior Regulation, South China Agricultural University, Guangzhou, China
| | - Chaofeng Li
- Guangdong Engineering Research Center for Insect Behavior Regulation, South China Agricultural University, Guangzhou, China
| | - Jiali Liu
- Guangdong Engineering Research Center for Insect Behavior Regulation, South China Agricultural University, Guangzhou, China
| | - Brian H. Smith
- School of Life Sciences, Arizona State University, Tempe, AZ, United States
| | - Hong Lei
- School of Life Sciences, Arizona State University, Tempe, AZ, United States
| | - Xinnian Zeng
- Guangdong Engineering Research Center for Insect Behavior Regulation, South China Agricultural University, Guangzhou, China
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17
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Queen Control or Queen Signal in Ants: What Remains of the Controversy 25 Years After Keller and Nonacs' Seminal Paper? J Chem Ecol 2018; 44:805-817. [PMID: 29858748 DOI: 10.1007/s10886-018-0974-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Revised: 04/05/2018] [Accepted: 05/25/2018] [Indexed: 10/14/2022]
Abstract
Ant queen pheromones (QPs) have long been known to affect colony functioning. In many species, QPs affect important reproductive functions such as diploid larvae sexualization and egg-laying by workers, unmated queens (gynes), or other queens. Until the 1990s, these effects were generally viewed to be the result of queen manipulation through the use of coercive or dishonest signals. However, in their seminal 1993 paper, Keller and Nonacs challenged this idea, suggesting that QPs had evolved as honest signals that informed workers and other colony members of the queen's presence and reproductive state. This paper has greatly influenced the study of ant QPs and inspired numerous attempts to identify fertility-related compounds and test their physiological and behavioral effects. In the present article, we review the literature on ant QPs in various contexts and pay special attention to the role of cuticular hydrocarbons (CHCs). Although the controversy generated by Keller and Nonacs' (Anim Behav 45:787-794, 1993) paper is currently less intensively debated, there is still no clear evidence which allows the rejection of the queen control hypothesis in favor of the queen signal hypothesis. We argue that important questions remain regarding the mode of action of QPs, and their targets which may help understanding their evolution.
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18
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Trible W, Olivos-Cisneros L, McKenzie SK, Saragosti J, Chang NC, Matthews BJ, Oxley PR, Kronauer DJC. orco Mutagenesis Causes Loss of Antennal Lobe Glomeruli and Impaired Social Behavior in Ants. Cell 2017; 170:727-735.e10. [PMID: 28802042 DOI: 10.1016/j.cell.2017.07.001] [Citation(s) in RCA: 167] [Impact Index Per Article: 23.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2017] [Revised: 05/24/2017] [Accepted: 06/29/2017] [Indexed: 11/25/2022]
Abstract
Life inside ant colonies is orchestrated with diverse pheromones, but it is not clear how ants perceive these social signals. It has been proposed that pheromone perception in ants evolved via expansions in the numbers of odorant receptors (ORs) and antennal lobe glomeruli. Here, we generate the first mutant lines in the clonal raider ant, Ooceraea biroi, by disrupting orco, a gene required for the function of all ORs. We find that orco mutants exhibit severe deficiencies in social behavior and fitness, suggesting they are unable to perceive pheromones. Surprisingly, unlike in Drosophila melanogaster, orco mutant ants also lack most of the ∼500 antennal lobe glomeruli found in wild-type ants. These results illustrate that ORs are essential for ant social organization and raise the possibility that, similar to mammals, receptor function is required for the development and/or maintenance of the highly complex olfactory processing areas in the ant brain. VIDEO ABSTRACT.
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Affiliation(s)
- Waring Trible
- Laboratory of Social Evolution and Behavior, The Rockefeller University, New York, NY 10065, USA.
| | - Leonora Olivos-Cisneros
- Laboratory of Social Evolution and Behavior, The Rockefeller University, New York, NY 10065, USA
| | - Sean K McKenzie
- Laboratory of Social Evolution and Behavior, The Rockefeller University, New York, NY 10065, USA
| | - Jonathan Saragosti
- Laboratory of Social Evolution and Behavior, The Rockefeller University, New York, NY 10065, USA
| | - Ni-Chen Chang
- Laboratory of Social Evolution and Behavior, The Rockefeller University, New York, NY 10065, USA
| | - Benjamin J Matthews
- Laboratory of Neurogenetics and Behavior, The Rockefeller University, New York, NY 10065, USA; Howard Hughes Medical Institute, Chevy Chase, MD 23930, USA
| | - Peter R Oxley
- Laboratory of Social Evolution and Behavior, The Rockefeller University, New York, NY 10065, USA
| | - Daniel J C Kronauer
- Laboratory of Social Evolution and Behavior, The Rockefeller University, New York, NY 10065, USA.
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19
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Decoding ants' olfactory system sheds light on the evolution of social communication. Proc Natl Acad Sci U S A 2017; 114:8911-8913. [PMID: 28811370 DOI: 10.1073/pnas.1711075114] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
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20
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Couto A, Mitra A, Thiéry D, Marion-Poll F, Sandoz JC. Hornets Have It: A Conserved Olfactory Subsystem for Social Recognition in Hymenoptera? Front Neuroanat 2017; 11:48. [PMID: 28659767 PMCID: PMC5469875 DOI: 10.3389/fnana.2017.00048] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2016] [Accepted: 05/26/2017] [Indexed: 01/06/2023] Open
Abstract
Eusocial Hymenoptera colonies are characterized by the presence of altruistic individuals, which rear their siblings instead of their own offspring. In the course of evolution, such sterile castes are thought to have emerged through the process of kin selection, altruistic traits being transmitted to following generation if they benefit relatives. By allowing kinship recognition, the detection of cuticular hydrocarbons (CHCs) might be instrumental for kin selection. In carpenter ants, a female-specific olfactory subsystem processes CHC information through antennal detection by basiconic sensilla. It is still unclear if other families of eusocial Hymenoptera use the same subsystem for sensing CHCs. Here, we examined the existence of such a subsystem in Vespidae (using the hornet Vespa velutina), a family in which eusociality emerged independently of ants. The antennae of both males and female hornets contain large basiconic sensilla. Sensory neurons from the large basiconic sensilla exclusively project to a conspicuous cluster of small glomeruli in the antennal lobe, with anatomical and immunoreactive features that are strikingly similar to those of the ant CHC-sensitive subsystem. Extracellular electrophysiological recordings further show that sensory neurons within hornet basiconic sensilla preferentially respond to CHCs. Although this subsystem is not female-specific in hornets, the observed similarities with the olfactory system of ants are striking. They suggest that the basiconic sensilla subsystem could be an ancestral trait, which may have played a key role in the advent of eusociality in these hymenopteran families by allowing kin recognition and the production of altruistic behaviors toward relatives.
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Affiliation(s)
- Antoine Couto
- Evolution Genomes Behavior and Ecology, Centre National de la Recherche Scientifique, Univ Paris-Sud, IRD, Université Paris SaclayGif-sur-Yvette, France
| | - Aniruddha Mitra
- Evolution Genomes Behavior and Ecology, Centre National de la Recherche Scientifique, Univ Paris-Sud, IRD, Université Paris SaclayGif-sur-Yvette, France
| | - Denis Thiéry
- UMR 1065 Santé et Agroécologie du Vignoble, INRA, Université de Bordeaux, ISVVVillenave d'Ornon, France
| | - Frédéric Marion-Poll
- Evolution Genomes Behavior and Ecology, Centre National de la Recherche Scientifique, Univ Paris-Sud, IRD, Université Paris SaclayGif-sur-Yvette, France
| | - Jean-Christophe Sandoz
- Evolution Genomes Behavior and Ecology, Centre National de la Recherche Scientifique, Univ Paris-Sud, IRD, Université Paris SaclayGif-sur-Yvette, France
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21
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Carle T, Watanabe H, Yamawaki Y, Yokohari F. Organization of the antennal lobes in the praying mantis (Tenodera aridifolia). J Comp Neurol 2017; 525:1685-1706. [PMID: 28001299 DOI: 10.1002/cne.24159] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2016] [Revised: 11/09/2016] [Accepted: 11/17/2016] [Indexed: 11/08/2022]
Abstract
Olfaction in insects plays pivotal roles in searching for food and/or for sexual partners. Although many studies have focused on the olfactory processes of nonpredatory insect species, little is known about those in predatory insects. Here, we investigated the anatomical features of the primary olfactory center (antennal lobes) in an insect predator whose visual system is well developed, the praying mantis Tenodera aridifolia. Both sexes of T. aridifolia were found to possess 54 glomeruli, and each glomerulus was identified based on its location and size. Moreover, we found a sexual dimorphism in three glomeruli (macroglomeruli) located at the entrance of the antennal nerves, which are 15 times bigger in males than their homologs in females. We additionally deduced the target glomeruli of olfactory sensory neurons housed in cognate types of sensilla by degenerating the sensory afferents. The macroglomeruli received sensory inputs from grooved peg sensilla, which are present in a large number at the proximal part of the males' antennae. Furthermore, our findings suggest that glomeruli at the posteriodorsal part of the antennal lobes receive sensory information from putative hygro- and thermosensitive sensilla. The origins of projections connected to the protocerebrum are also discussed. J. Comp. Neurol. 525:1685-1706, 2017. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Thomas Carle
- Department of Biology, Faculty of Science, Kyushu University, Fukuoka, Japan
| | - Hidehiro Watanabe
- Division of Biology, Department of Earth System Science, Faculty of Science, Fukuoka University, Fukuoka, Japan
| | - Yoshifumi Yamawaki
- Department of Biology, Faculty of Science, Kyushu University, Fukuoka, Japan
| | - Fumio Yokohari
- Division of Biology, Department of Earth System Science, Faculty of Science, Fukuoka University, Fukuoka, Japan
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22
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Kollmann M, Schmidt R, Heuer CM, Schachtner J. Variations on a Theme: Antennal Lobe Architecture across Coleoptera. PLoS One 2016; 11:e0166253. [PMID: 27973569 PMCID: PMC5156346 DOI: 10.1371/journal.pone.0166253] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2016] [Accepted: 10/25/2016] [Indexed: 12/02/2022] Open
Abstract
Beetles comprise about 400,000 described species, nearly one third of all known animal species. The enormous success of the order Coleoptera is reflected by a rich diversity of lifestyles, behaviors, morphological, and physiological adaptions. All these evolutionary adaptions that have been driven by a variety of parameters over the last about 300 million years, make the Coleoptera an ideal field to study the evolution of the brain on the interface between the basic bauplan of the insect brain and the adaptions that occurred. In the current study we concentrated on the paired antennal lobes (AL), the part of the brain that is typically responsible for the first processing of olfactory information collected from olfactory sensilla on antenna and mouthparts. We analyzed 63 beetle species from 22 different families and thus provide an extensive comparison of principal neuroarchitecture of the AL. On the examined anatomical level, we found a broad diversity including AL containing a wide range of glomeruli numbers reaching from 50 to 150 glomeruli and several species with numerous small glomeruli, resembling the microglomerular design described in acridid grasshoppers and diving beetles, and substructures within the glomeruli that have to date only been described for the small hive beetle, Aethina tumida. A first comparison of the various anatomical features of the AL with available descriptions of lifestyle and behaviors did so far not reveal useful correlations. In summary, the current study provides a solid basis for further studies to unravel mechanisms that are basic to evolutionary adaptions of the insect olfactory system.
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Affiliation(s)
- Martin Kollmann
- Department of Biology—Animal Physiology, Philipps-University Marburg, Marburg, Germany
| | - Rovenna Schmidt
- Department of Biology—Animal Physiology, Philipps-University Marburg, Marburg, Germany
- Institute of Veterinary Anatomy, Histology and Embryology, Justus-Liebig University Gießen, Gießen, Germany
| | - Carsten M. Heuer
- Department of Biology—Animal Physiology, Philipps-University Marburg, Marburg, Germany
- Fraunhofer-Institut für Naturwissenschaftlich-Technische Trendanalysen INT, Euskirchen, Germany
| | - Joachim Schachtner
- Department of Biology—Animal Physiology, Philipps-University Marburg, Marburg, Germany
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McKenzie SK, Fetter-Pruneda I, Ruta V, Kronauer DJC. Transcriptomics and neuroanatomy of the clonal raider ant implicate an expanded clade of odorant receptors in chemical communication. Proc Natl Acad Sci U S A 2016; 113:14091-14096. [PMID: 27911792 PMCID: PMC5150400 DOI: 10.1073/pnas.1610800113] [Citation(s) in RCA: 82] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
A major aim of sociogenomic research is to uncover common principles in the molecular evolution of sociality. This endeavor has been hampered by the small number of specific genes currently known to function in social behavior. Here we provide several lines of evidence suggesting that ants have evolved a large and novel clade of odorant receptor (OR) genes to perceive hydrocarbon-based pheromones, arguably the most important signals in ant communication. This genomic expansion is also mirrored in the ant brain via a corresponding expansion of a specific cluster of glomeruli in the antennal lobe. We show that in the clonal raider ant, hydrocarbon-sensitive basiconic sensilla are found only on the ventral surface of the female antennal club. Correspondingly, nearly all genes in a clade of 180 ORs within the 9-exon subfamily of ORs are expressed exclusively in females and are highly enriched in expression in the ventral half of the antennal club. Furthermore, we found that across species and sexes, the number of 9-exon ORs expressed in antennae is tightly correlated with the number of glomeruli in the antennal lobe region innervated by odorant receptor neurons from basiconic sensilla. Evolutionary analyses show that this clade underwent a striking gene expansion in the ancestors of all ants and slower but continued expansion in extant ant lineages. This evidence suggests that ants have evolved a large clade of genes to support pheromone perception and that gene duplications have played an important role in the molecular evolution of ant communication.
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Affiliation(s)
- Sean K McKenzie
- Laboratory of Social Evolution and Behavior, The Rockefeller University, New York, NY 10065;
| | - Ingrid Fetter-Pruneda
- Laboratory of Social Evolution and Behavior, The Rockefeller University, New York, NY 10065
| | - Vanessa Ruta
- Laboratory of Neurophysiology and Behavior, The Rockefeller University, New York, NY 10065
| | - Daniel J C Kronauer
- Laboratory of Social Evolution and Behavior, The Rockefeller University, New York, NY 10065
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Zhao XC, Chen QY, Guo P, Xie GY, Tang QB, Guo XR, Berg BG. Glomerular identification in the antennal lobe of the male mothHelicoverpa armigera. J Comp Neurol 2016; 524:2993-3013. [DOI: 10.1002/cne.24003] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2016] [Revised: 03/16/2016] [Accepted: 03/24/2016] [Indexed: 01/02/2023]
Affiliation(s)
- Xin-Cheng Zhao
- Department of Entomology, College of Plant Protection; Henan Agricultural University; Zhengzhou 450002 China
| | - Qiu-Yan Chen
- Department of Entomology, College of Plant Protection; Henan Agricultural University; Zhengzhou 450002 China
| | - Pei Guo
- Department of Entomology, College of Plant Protection; Henan Agricultural University; Zhengzhou 450002 China
| | - Gui-Ying Xie
- Department of Entomology, College of Plant Protection; Henan Agricultural University; Zhengzhou 450002 China
| | - Qing-Bo Tang
- Department of Entomology, College of Plant Protection; Henan Agricultural University; Zhengzhou 450002 China
| | - Xian-Ru Guo
- Department of Entomology, College of Plant Protection; Henan Agricultural University; Zhengzhou 450002 China
- Collaborative Innovation Center of Henan Grain Crops; Zhengzhou 450002 China
| | - Bente G. Berg
- Department of Psychology; Norwegian University of Science and Technology; Trondheim 7489 Norway
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25
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Couto A, Lapeyre B, Thiéry D, Sandoz JC. Olfactory pathway of the hornet Vespa velutina
: New insights into the evolution of the hymenopteran antennal lobe. J Comp Neurol 2016; 524:2335-59. [DOI: 10.1002/cne.23975] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2015] [Revised: 01/20/2016] [Accepted: 01/29/2016] [Indexed: 01/16/2023]
Affiliation(s)
- Antoine Couto
- Laboratory Evolution Genome Behavior and Ecology, CNRS, Université Paris-Sud, IRD, Université Paris Saclay; F-91198 Gif-sur-Yvette France
| | - Benoit Lapeyre
- Laboratory Evolution Genome Behavior and Ecology, CNRS, Université Paris-Sud, IRD, Université Paris Saclay; F-91198 Gif-sur-Yvette France
| | - Denis Thiéry
- UMR 1065 Santé et Agroécologie du Vignoble, INRA; F-33883 Villenave d'Ornon France
- Université de Bordeaux, ISVV, UMR 1065 Santé et Agroécologie du Vignoble, Bordeaux Sciences Agro; F-33883 Villenave d'Ornon France
| | - Jean-Christophe Sandoz
- Laboratory Evolution Genome Behavior and Ecology, CNRS, Université Paris-Sud, IRD, Université Paris Saclay; F-91198 Gif-sur-Yvette France
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Sharma KR, Enzmann BL, Schmidt Y, Moore D, Jones GR, Parker J, Berger SL, Reinberg D, Zwiebel LJ, Breit B, Liebig J, Ray A. Cuticular Hydrocarbon Pheromones for Social Behavior and Their Coding in the Ant Antenna. Cell Rep 2015; 12:1261-71. [PMID: 26279569 DOI: 10.1016/j.celrep.2015.07.031] [Citation(s) in RCA: 90] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2015] [Revised: 07/10/2015] [Accepted: 07/15/2015] [Indexed: 01/08/2023] Open
Abstract
The sophisticated organization of eusocial insect societies is largely based on the regulation of complex behaviors by hydrocarbon pheromones present on the cuticle. We used electrophysiology to investigate the detection of cuticular hydrocarbons (CHCs) by female-specific olfactory sensilla basiconica on the antenna of Camponotus floridanus ants through the utilization of one of the largest family of odorant receptors characterized so far in insects. These sensilla, each of which contains multiple olfactory receptor neurons, are differentially sensitive to CHCs and allow them to be classified into three broad groups that collectively detect every hydrocarbon tested, including queen and worker-enriched CHCs. This broad-spectrum sensitivity is conserved in a related species, Camponotus laevigatus, allowing these ants to detect CHCs from both nestmates and non-nestmates. Behavioral assays demonstrate that these ants are excellent at discriminating CHCs detected by the antenna, including enantiomers of a candidate queen pheromone that regulates the reproductive division of labor.
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Affiliation(s)
- Kavita R Sharma
- Department of Entomology, University of California, Riverside, CA 92521, USA
| | | | - Yvonne Schmidt
- Institut für Organische Chemie, Albert-Ludwigs-Universität Freiburg, Albertstrasse 21, 79104 Freiburg im Breisgau, Germany
| | - Dani Moore
- School of Life Sciences, Arizona State University, Tempe, AZ 85287, USA
| | - Graeme R Jones
- Chemical Ecology Group, School of Physical and Geographical Sciences, Lennard-Jones Laboratory, Keele University, Staffordshire ST5 5GB, UK
| | - Jane Parker
- Chemical Ecology Group, School of Physical and Geographical Sciences, Lennard-Jones Laboratory, Keele University, Staffordshire ST5 5GB, UK
| | - Shelley L Berger
- Departments of Cell and Developmental Biology, Genetics, and Biology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Danny Reinberg
- Department of Molecular Pharmacology and Biochemistry, New York University School of Medicine, New York, NY 10016, USA
| | - Laurence J Zwiebel
- Department of Biological Sciences, Vanderbilt University, Nashville, TN 37235, USA
| | - Bernhard Breit
- Institut für Organische Chemie, Albert-Ludwigs-Universität Freiburg, Albertstrasse 21, 79104 Freiburg im Breisgau, Germany
| | - Jürgen Liebig
- School of Life Sciences, Arizona State University, Tempe, AZ 85287, USA
| | - Anandasankar Ray
- Department of Entomology, University of California, Riverside, CA 92521, USA.
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Roselino AC, Hrncir M, da Cruz Landim C, Giurfa M, Sandoz JC. Sexual dimorphism and phenotypic plasticity in the antennal lobe of a stingless bee,Melipona scutellaris. J Comp Neurol 2015; 523:1461-73. [DOI: 10.1002/cne.23744] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2014] [Revised: 12/03/2014] [Accepted: 01/09/2015] [Indexed: 01/12/2023]
Affiliation(s)
- Ana Carolina Roselino
- Departamento de Biologia, Instituto de Biociências de Rio Claro; Universidade Estadual Paulista Júlio de Mesquita Filho; Rio Claro São Paulo 13506-900 Brazil
- Faculté des Sciences d'Orsay; Université Paris-Sud; Orsay cedex 91405 France
- Evolution, Genomes, Behavior and Ecology Lab; CNRS, Université Paris-Sud, IRD (UMR 9191); Gif-sur-Yvette 91198 France
| | - Michael Hrncir
- Departamento de Ciências Animais; Universidade Federal Rural do Semi-Árido; Mossoró 59625-900 Brazil
| | - Carminda da Cruz Landim
- Departamento de Biologia, Instituto de Biociências de Rio Claro; Universidade Estadual Paulista Júlio de Mesquita Filho; Rio Claro São Paulo 13506-900 Brazil
| | - Martin Giurfa
- Centre National de la Recherche Scientifique (CNRS); Centre de Recherches sur la Cognition Animale; 31062 Toulouse cedex 9 France
- Université de Toulouse (UPS); Centre de Recherches sur la Cognition Animale; 31062 Toulouse cedex 9 France
| | - Jean-Christophe Sandoz
- Evolution, Genomes, Behavior and Ecology Lab; CNRS, Université Paris-Sud, IRD (UMR 9191); Gif-sur-Yvette 91198 France
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Si-CSP9 regulates the integument and moulting process of larvae in the red imported fire ant, Solenopsis invicta. Sci Rep 2015; 5:9245. [PMID: 25784646 PMCID: PMC4363891 DOI: 10.1038/srep09245] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2014] [Accepted: 02/25/2015] [Indexed: 01/18/2023] Open
Abstract
Chemosensory proteins (CSPs) have been predicted to be involved in development;
however, direct evidence for their involvement is lacking, and genetic basis is
largely unknown. To determine the function of the chemosensory protein 9
(Si-CSP9) gene in Solenopsis invicta, we used RNA interference to
silence Si-CSP9 in 3rd-instar larvae. The 3rd-instar larvae failed to shed
their cuticle after being fed Si-CSP9-directed siRNA, and expression
profiling of RNAi-treated and untreated control larvae showed that 375 genes were
differentially expressed. Pathway enrichment analysis revealed that 4 pathways
associated with larval development were significantly enriched. Blast analysis
revealed that one fatty acid amide hydrolase (FAAH) gene was up-regulated and
4 fatty acid synthase (FAT) genes and one protein kinase DC2 gene
(PKA) were down-regulated in the enriched pathways. Significantly higher
expression of these genes was found in 4th-instar larvae, and Pearson correlation
analysis of the expression patterns revealed significant relationships among
Si-CSP9, PKA, FAAH, and FAT1-4. Moreover, we confirmed that
expression levels of Si-CSP9, FAAH, and FAT1-4 were significantly
reduced and that the development of 3rd-instar larvae was halted with PKA
silencing. These results suggest that Si-CSP9 and PKA may be involved
in the network that contributes to development of 3rd-instar larvae.
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Ilieş I, Muscedere ML, Traniello JF. Neuroanatomical and Morphological Trait Clusters in the Ant Genus Pheidole: Evidence for Modularity and Integration in Brain Structure. BRAIN, BEHAVIOR AND EVOLUTION 2015; 85:63-76. [DOI: 10.1159/000370100] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2014] [Accepted: 08/28/2014] [Indexed: 11/19/2022]
Abstract
A central question in brain evolution concerns how selection has structured neuromorphological variation to generate adaptive behavior. In social insects, brain structures differ between reproductive and sterile castes, and worker behavioral specializations related to morphology, age, and ecology are associated with intra- and interspecific variation in investment in functionally different brain compartments. Workers in the hyperdiverse ant genus Pheidole are morphologically and behaviorally differentiated into minor and major subcastes that exhibit distinct species-typical patterns of brain compartment size variation. We examined integration and modularity in brain organization and its developmental patterning in three ecotypical Pheidole species by analyzing intra- and interspecific morphological and neuroanatomical covariation. Our results identified two trait clusters, the first involving olfaction and social information processing and the second composed of brain regions regulating nonolfactory sensorimotor functions. Patterns of size covariation between brain compartments within subcastes were consistent with levels of behavioral differentiation between minor and major workers. Globally, brains of mature workers were more heterogeneous than brains of newly eclosed workers, suggesting diversified developmental trajectories underscore species- and subcaste-typical brain organization. Variation in brain structure associated with the striking worker polyphenism in our sample of Pheidole appears to originate from initially differentiated brain templates that further diverge through species- and subcaste-specific processes of maturation and behavioral development.
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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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31
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The trap of sex in social insects: From the female to the male perspective. Neurosci Biobehav Rev 2014; 46 Pt 4:519-33. [DOI: 10.1016/j.neubiorev.2014.09.014] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2014] [Revised: 09/14/2014] [Accepted: 09/22/2014] [Indexed: 01/27/2023]
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López-Riquelme GO. Representación odotópica de la organización glomerular del lóbulo antenal en los cuerpos fungiformes de las hormigas (Hymenoptera: Formicidae): Comparaciones entre dos especies. TIP REVISTA ESPECIALIZADA EN CIENCIAS QUÍMICO-BIOLÓGICAS 2014. [DOI: 10.1016/s1405-888x(14)70317-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022] Open
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Kropf J, Kelber C, Bieringer K, Rössler W. Olfactory subsystems in the honeybee: sensory supply and sex specificity. Cell Tissue Res 2014; 357:583-95. [PMID: 24817103 PMCID: PMC4148592 DOI: 10.1007/s00441-014-1892-y] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2014] [Accepted: 04/08/2014] [Indexed: 12/21/2022]
Abstract
The antennae of honeybee (Apis mellifera) workers and drones differ in various aspects. One striking difference is the presence of Sensilla basiconica in (female) workers and their absence in (male) drones. We investigate the axonal projection patterns of olfactory receptor neurons (ORNs) housed in S. basiconica in honeybee workers by using selective anterograde labeling with fluorescent tracers and confocal-microscopy analysis of axonal projections in antennal lobe glomeruli. Axons of S. basiconica-associated ORNs preferentially projected into a specific glomerular cluster in the antennal lobe, namely the sensory input-tract three (T3) cluster. T3-associated glomeruli had previously been shown to be innervated by uniglomerular projection (output) neurons of the medial antennal lobe tract (mALT). As the number of T3 glomeruli is reduced in drones, we wished to determine whether this was associated with the reduction of glomeruli innervated by medial-tract projection neurons. We retrogradely traced mALT projection neurons in drones and counted the innervated glomeruli. The number of mALT-associated glomeruli was strongly reduced in drones compared with workers. The preferential projections of S. basiconica-associated ORNs in T3 glomeruli together with the reduction of mALT-associated glomeruli support the presence of a female (worker)-specific olfactory subsystem that is partly innervated by ORNs from S. basiconica and is associated with the T3 cluster of glomeruli and mALT projection neurons. We propose that this olfactory subsystem supports parallel olfactory processing related to worker-specific olfactory tasks such as the coding of colony odors, colony pheromones and/or odorants associated with foraging on floral resources.
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Affiliation(s)
- Jan Kropf
- Department of Behavioral Physiology and Sociobiology, Biozentrum, University of Würzburg, Am Hubland, 97074, Würzburg, Germany,
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Mysore K, Andrews E, Li P, Duman-Scheel M. Chitosan/siRNA nanoparticle targeting demonstrates a requirement for single-minded during larval and pupal olfactory system development of the vector mosquito Aedes aegypti. BMC DEVELOPMENTAL BIOLOGY 2014; 14:9. [PMID: 24552425 PMCID: PMC3936921 DOI: 10.1186/1471-213x-14-9] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/24/2014] [Accepted: 02/07/2014] [Indexed: 11/16/2022]
Abstract
Background Essentially nothing is known about the genetic regulation of olfactory system development in vector mosquitoes, which use olfactory cues to detect blood meal hosts. Studies in Drosophila melanogaster have identified a regulatory matrix of transcription factors that controls pupal/adult odorant receptor (OR) gene expression in olfactory receptor neurons (ORNs). However, it is unclear if transcription factors that function in the D. melanogaster regulatory matrix are required for OR expression in mosquitoes. Furthermore, the regulation of OR expression during development of the larval olfactory system, which is far less complex than that of pupae/adults, is not well understood in any insect, including D. melanogaster. Here, we examine the regulation of OR expression in the developing larval olfactory system of Aedes aegypti, the dengue vector mosquito. Results A. aegypti bears orthologs of eight transcription factors that regulate OR expression in D. melanogaster pupae/adults. These transcription factors are expressed in A. aegypti larval antennal sensory neurons, and consensus binding sites for these transcription factors reside in the 5’ flanking regions of A. aegypti OR genes. Consensus binding sites for Single-minded (Sim) are located adjacent to over half the A. aegypti OR genes, suggesting that this transcription factor functions as a major regulator of mosquito OR expression. To functionally test this hypothesis, chitosan/siRNA nanoparticles were used to target sim during larval olfactory development. These experiments demonstrated that Sim positively regulates expression of a large subset of OR genes, including orco, the obligate co-receptor in the assembly and function of heteromeric OR/Orco complexes. Decreased innervation of the antennal lobe was also noted in sim knockdown larvae. These OR expression and antennal lobe defects correlated with a larval odorant tracking behavioral defect. OR expression and antennal lobe defects were also observed in sim knockdown pupae. Conclusions The results of this investigation indicate that Sim has multiple functions during larval and pupal olfactory system development in A. aegypti.
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Affiliation(s)
| | | | | | - Molly Duman-Scheel
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, South Bend, IN 46617, United States of America.
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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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Mysore K, Flannery EM, Tomchaney M, Severson DW, Duman-Scheel M. Disruption of Aedes aegypti olfactory system development through chitosan/siRNA nanoparticle targeting of semaphorin-1a. PLoS Negl Trop Dis 2013; 7:e2215. [PMID: 23696908 PMCID: PMC3656119 DOI: 10.1371/journal.pntd.0002215] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2013] [Accepted: 04/02/2013] [Indexed: 11/19/2022] Open
Abstract
Despite the devastating impact of mosquito-borne illnesses on human health, surprisingly little is known about mosquito developmental biology, including development of the olfactory system, a tissue of vector importance. Analysis of mosquito olfactory developmental genetics has been hindered by a lack of means to target specific genes during the development of this sensory system. In this investigation, chitosan/siRNA nanoparticles were used to target semaphorin-1a (sema1a) during olfactory system development in the dengue and yellow fever vector mosquito Aedes aegypti. Immunohistochemical analyses and anterograde tracing of antennal sensory neurons, which were used to track the progression of olfactory development in this species, revealed antennal lobe defects in sema1a knockdown fourth instar larvae. These findings, which correlated with a larval odorant tracking behavioral phenotype, identified previously unreported roles for Sema1a in the developing insect larval olfactory system. Analysis of sema1a knockdown pupae also revealed a number of olfactory phenotypes, including olfactory receptor neuron targeting and projection neuron defects coincident with a collapse in the structure and shape of the antennal lobe and individual glomeruli. This study, which is to our knowledge the first functional genetic analysis of insect olfactory development outside of D. melanogaster, identified critical roles for Sema1a during Ae. aegypti larval and pupal olfactory development and advocates the use of chitosan/siRNA nanoparticles as an effective means of targeting genes during post-embryonic Ae. aegypti development. Use of siRNA nanoparticle methodology to understand sensory developmental genetics in mosquitoes will provide insight into the evolutionary conservation and divergence of key developmental genes which could be exploited in the development of both common and species-specific means for intervention.
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Affiliation(s)
- Keshava Mysore
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, South Bend, Indiana, United States of America
| | - Ellen M. Flannery
- Eck Institute for Global Health and Department of Biological Sciences, University of Notre Dame, Notre Dame, Indiana, United States of America
| | - Michael Tomchaney
- Eck Institute for Global Health and Department of Biological Sciences, University of Notre Dame, Notre Dame, Indiana, United States of America
| | - David W. Severson
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, South Bend, Indiana, United States of America
- Eck Institute for Global Health and Department of Biological Sciences, University of Notre Dame, Notre Dame, Indiana, United States of America
| | - Molly Duman-Scheel
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, South Bend, Indiana, United States of America
- Eck Institute for Global Health and Department of Biological Sciences, University of Notre Dame, Notre Dame, Indiana, United States of America
- * E-mail:
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Rössler W, Brill MF. Parallel processing in the honeybee olfactory pathway: structure, function, and evolution. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2013; 199:981-96. [PMID: 23609840 PMCID: PMC3824823 DOI: 10.1007/s00359-013-0821-y] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2013] [Revised: 04/10/2013] [Accepted: 04/11/2013] [Indexed: 12/21/2022]
Abstract
Animals face highly complex and dynamic olfactory stimuli in their natural environments, which require fast and reliable olfactory processing. Parallel processing is a common principle of sensory systems supporting this task, for example in visual and auditory systems, but its role in olfaction remained unclear. Studies in the honeybee focused on a dual olfactory pathway. Two sets of projection neurons connect glomeruli in two antennal-lobe hemilobes via lateral and medial tracts in opposite sequence with the mushroom bodies and lateral horn. Comparative studies suggest that this dual-tract circuit represents a unique adaptation in Hymenoptera. Imaging studies indicate that glomeruli in both hemilobes receive redundant sensory input. Recent simultaneous multi-unit recordings from projection neurons of both tracts revealed widely overlapping response profiles strongly indicating parallel olfactory processing. Whereas lateral-tract neurons respond fast with broad (generalistic) profiles, medial-tract neurons are odorant specific and respond slower. In analogy to “what-” and “where” subsystems in visual pathways, this suggests two parallel olfactory subsystems providing “what-” (quality) and “when” (temporal) information. Temporal response properties may support across-tract coincidence coding in higher centers. Parallel olfactory processing likely enhances perception of complex odorant mixtures to decode the diverse and dynamic olfactory world of a social insect.
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Affiliation(s)
- Wolfgang Rössler
- Behavioral Physiology and Sociobiology (Zoology II), Biozentrum, University of Würzburg, Am Hubland, 97074, Würzburg, Germany,
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Sakura M, Aonuma H. Aggressive behavior in the antennectomized male cricket Gryllus bimaculatus. ACTA ACUST UNITED AC 2013; 216:2221-8. [PMID: 23531830 DOI: 10.1242/jeb.079400] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Male crickets (Gryllus bimaculatus) exhibit intensively defensive aggressive behavior towards attacking males most often culminating in fighting. After the fight, the loser no longer exhibits aggressiveness in a second, separate encounter with another male; rather, the defeated male exhibits avoidance behavior. Here, we investigated the role of sensory input from the antennae in male defensive aggressive behavior. When we removed antennae from males (antennectomized males), we found that they showed little aggressiveness towards each other whereas they continued to exhibit typical fighting behavior towards an intact male. In addition, in a second encounter, antennectomized losers showed significantly higher aggressiveness towards another male than did intact losers. We further found that antennectomized crickets do not utilize visual or palpal sensory input to elicit aggressive behavior. In contrast, intact males showed aspects of aggressive behavior to male cuticular substances before and after winning a fight, and if they lost a fight they showed avoidance behavior. It thus appears that antennal sensory information is crucial in the mediation of aggressive and avoidance behaviors. However, sensory inputs from the antennae are not necessary to elicit defensive aggressive behavior but are necessary to discriminate conspecific males and initiate attacks against them.
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Affiliation(s)
- Midori Sakura
- Laboratory of Neurocybernetics, Research Institute for Electronic Science, Hokkaido University, Kita 12, Nishi 7, Sapporo, Hokkaido 060-0812, Japan.
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Zhou X, Slone JD, Rokas A, Berger SL, Liebig J, Ray A, Reinberg D, Zwiebel LJ. Phylogenetic and transcriptomic analysis of chemosensory receptors in a pair of divergent ant species reveals sex-specific signatures of odor coding. PLoS Genet 2012; 8:e1002930. [PMID: 22952454 PMCID: PMC3431598 DOI: 10.1371/journal.pgen.1002930] [Citation(s) in RCA: 153] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2012] [Accepted: 07/16/2012] [Indexed: 12/30/2022] Open
Abstract
Ants are a highly successful family of insects that thrive in a variety of habitats across the world. Perhaps their best-known features are complex social organization and strict division of labor, separating reproduction from the day-to-day maintenance and care of the colony, as well as strict discrimination against foreign individuals. Since these social characteristics in ants are thought to be mediated by semiochemicals, a thorough analysis of these signals, and the receptors that detect them, is critical in revealing mechanisms that lead to stereotypic behaviors. To address these questions, we have defined and characterized the major chemoreceptor families in a pair of behaviorally and evolutionarily distinct ant species, Camponotus floridanus and Harpegnathos saltator. Through comprehensive re-annotation, we show that these ant species harbor some of the largest yet known repertoires of odorant receptors (Ors) among insects, as well as a more modest number of gustatory receptors (Grs) and variant ionotropic glutamate receptors (Irs). Our phylogenetic analyses further demonstrate remarkably rapid gains and losses of ant Ors, while Grs and Irs have also experienced birth-and-death evolution to different degrees. In addition, comparisons of antennal transcriptomes between sexes identify many chemoreceptors that are differentially expressed between males and females and between species. We have also revealed an agonist for a worker-enriched OR from C. floridanus, representing the first case of a heterologously characterized ant tuning Or. Collectively, our analysis reveals a large number of ant chemoreceptors exhibiting patterns of differential expression and evolution consistent with sex/species-specific functions. These differentially expressed genes are likely associated with sex-based differences, as well as the radically different social lifestyles observed between C. floridanus and H. saltator, and thus are targets for further functional characterization. Our findings represent an important advance toward understanding the molecular basis of social interactions and the differential chemical ecologies among ant species.
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Affiliation(s)
- Xiaofan Zhou
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, United States of America
| | - Jesse D. Slone
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, United States of America
| | - Antonis Rokas
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, United States of America
| | - Shelley L. Berger
- Departments of Cell and Developmental Biology, Genetics, and Biology, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Jürgen Liebig
- School of Life Sciences, Arizona State University, Tempe, Arizona, United States of America
| | - Anandasankar Ray
- Department of Entomology, University of California Riverside, Riverside, California, United States of America
| | - Danny Reinberg
- Howard Hughes Medical Institute, Department of Biochemistry, New York University School of Medicine, New York, New York, United States of America
| | - Laurence J. Zwiebel
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, United States of America
- * E-mail:
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Nishikawa M, Watanabe H, Yokohari F. Higher brain centers for social tasks in worker ants, Camponotus japonicus. J Comp Neurol 2012; 520:1584-98. [PMID: 22102363 DOI: 10.1002/cne.23001] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Ants, eusocial insects, have highly elaborate chemical communication systems using a wide variety of pheromones. In the carpenter ant, Camponotus japonicus, workers and queens have the female-specific basiconic sensilla on antennae. The antennal lobe, the primary processing center, in female carpenter ants contains about 480 glomeruli, which are divided into seven groups (T1–T7 glomeruli) based on sensory afferent tracts. The axons of sensory neurons in basiconic sensilla are thought to project to female-specific T6 glomeruli. Therefore, these sensilla and glomeruli are thought to relate to female-specific social tasks in the ants. By using dye filling into local neurons (LNs) and projection neurons (PNs) in the antennal lobe, we neuroanatomically revealed the existence of an isolated processing system for signals probably relating to social tasks in the worker ant. In the antennal lobe, two categories of glomeruli, T6 glomeruli and non-T6 glomeruli, are clearly segregated by LNs. Furthermore, axon terminals of uniglomerular PNs from the respective categories of glomeruli (T6 uni-PNs and non-T6 uni-PNs) are also segregated in the secondary olfactory centers, the calyces of the mushroom body and the lateral horn: T6 uni-PNs terminate in the outer layers of the basal ring and lip of mushroom body calyces and in the posterior region of the lateral horn, whereas non-T6 uni-PNs terminate in the middle and inner layers of the basal ring and lip and in the anterior region of the lateral horn. These findings suggest that information probably relating to social tasks might be isolated from other olfactory information and processed in a separate subsystem.
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Affiliation(s)
- Michiko Nishikawa
- Department of Earth System Science, Fukuoka University, Fukuoka 814-0180, Japan.
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Lorenzi V, Grober MS. Immunohistochemical localization of serotonin in the brain during natural sex change in the hermaphroditic goby Lythrypnus dalli. Gen Comp Endocrinol 2012; 175:527-36. [PMID: 22214654 DOI: 10.1016/j.ygcen.2011.12.018] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/31/2011] [Revised: 12/07/2011] [Accepted: 12/15/2011] [Indexed: 11/29/2022]
Abstract
The neurotransmitter serotonin (5-HT) may play a central role in the inhibition of socially regulated sex change in fish because of its known modulation of both aggressive and reproductive behavior. This is the first study to use immunohistochemical techniques to examine the morphometry of serotonergic neurons at different times during sex change. Using a model species wherein sex change is socially regulated via agonistic social interactions (the bluebanded goby, Lythrypnus dalli), we sampled brains of males and females with different social status, and of females at different times during sex change. Consistent with previous studies on other teleosts, immunoreactive neurons were found in the posterior periventricular nucleus (NPPv), the nucleus of the lateral recess (NRL), the nucleus of the posterior recess (NRP) and in the raphe nucleus. We measured the total area of NPPv, NRL, NRP, and the number and mean cell area of serotonergic neurons in the raphe nucleus. There was no significant difference in any of the brain regions between males, females or sex changing fish, but there was a slight increase in the number of dorsal raphe neurons in the brain of sex changers 2h after male removal. The results show that in L. dalli the serotonergic system does not present any morphological sex and status differences, nor any dramatic modifications during sex change. These data, together with previous results, do not support the hypothesis that serotonin inhibits socially regulated sex change.
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Affiliation(s)
- Varenka Lorenzi
- Center for Behavioral Neuroscience, Department of Biology, Georgia State University, 24 Peachtree Center Avenue, Atlanta, GA 30303, USA.
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Brandstaetter AS, Kleineidam CJ. Distributed representation of social odors indicates parallel processing in the antennal lobe of ants. J Neurophysiol 2011; 106:2437-49. [PMID: 21849606 DOI: 10.1152/jn.01106.2010] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
In colonies of eusocial Hymenoptera cooperation is organized through social odors, and particularly ants rely on a sophisticated odor communication system. Neuronal information about odors is represented in spatial activity patterns in the primary olfactory neuropile of the insect brain, the antennal lobe (AL), which is analog to the vertebrate olfactory bulb. The olfactory system is characterized by neuroanatomical compartmentalization, yet the functional significance of this organization is unclear. Using two-photon calcium imaging, we investigated the neuronal representation of multicomponent colony odors, which the ants assess to discriminate friends (nestmates) from foes (nonnestmates). In the carpenter ant Camponotus floridanus, colony odors elicited spatial activity patterns distributed across different AL compartments. Activity patterns in response to nestmate and nonnestmate colony odors were overlapping. This was expected since both consist of the same components at differing ratios. Colony odors change over time and the nervous system has to constantly adjust for this (template reformation). Measured activity patterns were variable, and variability was higher in response to repeated nestmate than to repeated nonnestmate colony odor stimulation. Variable activity patterns may indicate neuronal plasticity within the olfactory system, which is necessary for template reformation. Our results indicate that information about colony odors is processed in parallel in different neuroanatomical compartments, using the computational power of the whole AL network. Parallel processing might be advantageous, allowing reliable discrimination of highly complex social odors.
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Affiliation(s)
- Andreas Simon Brandstaetter
- Department of Behavioral Physiology and Sociobiology (Zoology II), Biozentrum, University of Würzburg, Würzburg, Germany.
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Friends and foes from an ant brain's point of view--neuronal correlates of colony odors in a social insect. PLoS One 2011; 6:e21383. [PMID: 21731724 PMCID: PMC3121771 DOI: 10.1371/journal.pone.0021383] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2010] [Accepted: 06/01/2011] [Indexed: 12/02/2022] Open
Abstract
Background Successful cooperation depends on reliable identification of friends and foes. Social insects discriminate colony members (nestmates/friends) from foreign workers (non-nestmates/foes) by colony-specific, multi-component colony odors. Traditionally, complex processing in the brain has been regarded as crucial for colony recognition. Odor information is represented as spatial patterns of activity and processed in the primary olfactory neuropile, the antennal lobe (AL) of insects, which is analogous to the vertebrate olfactory bulb. Correlative evidence indicates that the spatial activity patterns reflect odor-quality, i.e., how an odor is perceived. For colony odors, alternatively, a sensory filter in the peripheral nervous system was suggested, causing specific anosmia to nestmate colony odors. Here, we investigate neuronal correlates of colony odors in the brain of a social insect to directly test whether they are anosmic to nestmate colony odors and whether spatial activity patterns in the AL can predict how odor qualities like “friend” and “foe” are attributed to colony odors. Methodology/Principal Findings Using ant dummies that mimic natural conditions, we presented colony odors and investigated their neuronal representation in the ant Camponotus floridanus. Nestmate and non-nestmate colony odors elicited neuronal activity: In the periphery, we recorded sensory responses of olfactory receptor neurons (electroantennography), and in the brain, we measured colony odor specific spatial activity patterns in the AL (calcium imaging). Surprisingly, upon repeated stimulation with the same colony odor, spatial activity patterns were variable, and as variable as activity patterns elicited by different colony odors. Conclusions Ants are not anosmic to nestmate colony odors. However, spatial activity patterns in the AL alone do not provide sufficient information for colony odor discrimination and this finding challenges the current notion of how odor quality is coded. Our result illustrates the enormous challenge for the nervous system to classify multi-component odors and indicates that other neuronal parameters, e.g., precise timing of neuronal activity, are likely necessary for attribution of odor quality to multi-component odors.
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Stieb SM, Kelber C, Wehner R, Rössler W. Antennal-Lobe Organization in Desert Ants of the Genus Cataglyphis. BRAIN, BEHAVIOR AND EVOLUTION 2011; 77:136-46. [DOI: 10.1159/000326211] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2010] [Accepted: 02/17/2011] [Indexed: 11/19/2022]
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Watanabe H, Nishino H, Nishikawa M, Mizunami M, Yokohari F. Complete mapping of glomeruli based on sensory nerve branching pattern in the primary olfactory center of the cockroach Periplaneta americana. J Comp Neurol 2010; 518:3907-30. [PMID: 20737592 DOI: 10.1002/cne.22452] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Glomeruli are structural and functional units in the primary olfactory center in vertebrates and insects. In the cockroach Periplaneta americana, axons of different types of sensory neurons housed in sensilla on antennae form dorsal and ventral antennal nerves and then project to a number of glomeruli. In this study, we identified all antennal lobe (AL) glomeruli based on detailed innervation patterns of sensory tracts in addition to the shape, size, and locations in the cockroach. The number of glomeruli is approximately 205, and no sex-specific difference is observed. Anterograde dye injections into the antennal nerves revealed that axons supplying the AL are divided into 10 sensory tracts (T1-T10). Each of T1-T3 innervates small, oval glomeruli in the anteroventral region of the AL, with sensory afferents invading each glomerulus from multiple directions, whereas each of T4-T10 innervates large glomeruli with various shapes in the posterodorsal region, with a bundle of sensory afferents invading each glomerulus from one direction. The topographic branching patterns of all these tracts are conserved among individuals. Sensory afferents in a sub-tract of T10 had axon terminals in the dorsal margin of the AL and the protocerebrum, where they form numerous small glomerular structures. Sensory nerve branching pattern should reflect developmental processes to determine spatial arrangement of glomeruli, and thus the complete map of glomeruli based on sensory nerve branching pattern should provide a basis for studying the functional significance of spatial arrangement of glomeruli and its developmental basis.
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Dacks AM, Nighorn AJ. The organization of the antennal lobe correlates not only with phylogenetic relationship, but also life history: a Basal hymenopteran as exemplar. Chem Senses 2010; 36:209-20. [PMID: 21059697 DOI: 10.1093/chemse/bjq121] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The structure of the brain is a consequence of selective pressures and the ancestral brain structures modified by those pressures. The Hymenoptera are one of the most behaviorally complex insect orders, and the olfactory system of honeybees (one of the most derived members) has been extensively studied. To understand the context in which the olfactory system of the Hymenoptera evolved, we performed a variety of immunocytochemical and anatomical labeling techniques on the antennal lobes (ALs) of one of its most primitive members, the sawflies, to provide a comparison between the honeybee and other insect model species. The olfactory receptor neurons project from the antennae to fill the entire glomerular volume but do not form distinct tracts as in the honeybee. Labeling of projection neurons revealed 5 output tracts similar to those in moths and immunolabeling for several transmitters revealed distinct populations of local interneurons and centrifugal neurons that were also similar to moths. There were, however, no histaminergic or dopaminergic AL neurons. The similarities between sawflies and moths suggest that along with the great radiation and increased complexity of behavioral repertoire of the Hymenoptera, there were extensive modifications of AL structure.
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Affiliation(s)
- Andrew M Dacks
- Department of Neuroscience, The University of Arizona, 1040 East 4th Street, Tucson, AZ 85721, USA.
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Mizunami M, Yamagata N, Nishino H. Alarm pheromone processing in the ant brain: an evolutionary perspective. Front Behav Neurosci 2010; 4:28. [PMID: 20676235 PMCID: PMC2912167 DOI: 10.3389/fnbeh.2010.00028] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2010] [Accepted: 05/10/2010] [Indexed: 11/13/2022] Open
Abstract
Social insects exhibit sophisticated communication by means of pheromones, one example of which is the use of alarm pheromones to alert nestmates for colony defense. We review recent advances in the understanding of the processing of alarm pheromone information in the ant brain. We found that information about formic acid and n-undecane, alarm pheromone components, is processed in a set of specific glomeruli in the antennal lobe of the ant Camponotus obscuripes. Alarm pheromone information is then transmitted, via projection neurons (PNs), to the lateral horn and the calyces of the mushroom body of the protocerebrum. In the lateral horn, we found a specific area where terminal boutons of alarm pheromone-sensitive PNs are more densely distributed than in the rest of the lateral horn. Some neurons in the protocerebrum responded specifically to formic acid or n-undecane and they may participate in the control of behavioral responses to each pheromone component. Other neurons, especially those originating from the mushroom body lobe, responded also to non-pheromonal odors and may play roles in integration of pheromonal and non-pheromonal signals. We found that a class of neurons receive inputs in the lateral horn and the mushroom body lobe and terminate in a variety of premotor areas. These neurons may participate in the control of aggressive behavior, which is sensitized by alarm pheromones and is triggered by non-pheromonal sensory stimuli associated with a potential enemy. We propose that the alarm pheromone processing system has evolved by differentiation of a part of general odor processing system.
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Affiliation(s)
- Makoto Mizunami
- Graduate School of Life Science, Hokkaido University Sapporo, Japan
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Yamagata N, Mizunami M. Spatial representation of alarm pheromone information in a secondary olfactory centre in the ant brain. Proc Biol Sci 2010; 277:2465-74. [PMID: 20375054 DOI: 10.1098/rspb.2010.0366] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Pheromones play major roles in intraspecific communication in many animals. Elaborated communication systems in eusocial insects provide excellent materials to study neural mechanisms for social pheromone processing. We previously reported that alarm pheromone information is processed in a specific cluster of glomeruli in the antennal lobe of the ant Camponotus obscuripes. However, representation of alarm pheromone information in a secondary olfactory centre is unknown in any animal. Olfactory information in the antennal lobe is transmitted to secondary olfactory centres, including the lateral horn, by projection neurons (PNs). In this study, we compared distributions of terminal boutons of alarm pheromone-sensitive and -insensitive PNs in the lateral horn of ants. Distributions of their dendrites largely overlapped, but there was a region where boutons of pheromone-sensitive PNs, but not those of pheromone-insensitive PNs, were significantly denser than in the rest of the lateral horn. Moreover, most of a major type of pheromone-sensitive efferent neurons from the lateral horn extended dendritic branches in this region, suggesting specialization of this region for alarm pheromone processing. This study is the first study to demonstrate the presence of specialized areas for the processing of a non-sexual, social pheromone in the secondary olfactory centre in any animal.
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Affiliation(s)
- Nobuhiro Yamagata
- Graduate School of Life Sciences, Tohoku University, Katahira 2-1-1, Aoba-ku, Sendai 980-8577, Japan
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