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Barbero F, Mannino G, Casacci LP. The Role of Biogenic Amines in Social Insects: With a Special Focus on Ants. INSECTS 2023; 14:386. [PMID: 37103201 PMCID: PMC10142254 DOI: 10.3390/insects14040386] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/12/2023] [Revised: 04/12/2023] [Accepted: 04/13/2023] [Indexed: 06/19/2023]
Abstract
Eusociality represents the higher degree of interaction in insects. This complex social structure is maintained through a multimodal communication system that allows colony members to be flexible in their responses, fulfilling the overall society's needs. The colony plasticity is supposedly achieved by combining multiple biochemical pathways through the neuromodulation of molecules such as biogenic amines, but the mechanisms through which these regulatory compounds act are far from being fully disentangled. Here, we review the potential function of major bioamines (dopamine, tyramine, serotine, and octopamine) on the behavioral modulation of principal groups of eusocial Hymenoptera, with a special focus on ants. Because functional roles are species- and context-dependent, identifying a direct causal relationship between a biogenic amine variation and behavioral changes is extremely challenging. We also used a quantitative and qualitative synthesis approach to summarize research trends and interests in the literature related to biogenic amines of social insects. Shedding light on the aminergic regulation of behavioral responses will pave the way for an entirely new approach to understanding the evolution of sociality in insects.
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Affiliation(s)
- Francesca Barbero
- Department of Life Sciences and Systems Biology, University of Turin, Via Accademia Albertina 13, 10123 Turin, Italy;
| | - Giuseppe Mannino
- Department of Life Sciences and Systems Biology, University of Turin, Via Gioacchino Quarello 15/A, 10135 Turin, Italy;
| | - Luca Pietro Casacci
- Department of Life Sciences and Systems Biology, University of Turin, Via Accademia Albertina 13, 10123 Turin, Italy;
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2
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Cressman A, Amsalem E. Impacts and mechanisms of CO2 narcosis in bumble bees: narcosis depends on dose, caste and mating status and is not induced by anoxia. J Exp Biol 2023; 226:286149. [PMID: 36541091 DOI: 10.1242/jeb.244746] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Accepted: 12/05/2022] [Indexed: 12/24/2022]
Abstract
Carbon dioxide (CO2) is commonly used to immobilize insects and to induce reproduction in bees. However, despite its wide use and potential off-target impacts, its underlying mechanisms are not fully understood. Here, we used Bombus impatiens to examine whether CO2 impacts are mediated by anoxia and whether these mechanisms differ between female castes or following mating in queens. We examined the behavior, physiology and gene expression of workers, mated queens and virgin queens following exposure to anoxia, hypoxia, full and partial hypercapnia, and controls. Hypercapnia and anoxia caused immobilization, but only hypercapnia resulted in behavioral, physiological and molecular impacts in bees. Recovery from hypercapnia resulted in increased abdominal contractions and took longer in queens. Additionally, hypercapnia activated the ovaries of queens, but inhibited those of workers in a dose-dependent manner and caused a depletion of fat-body lipids in both castes. All responses to hypercapnia were weaker following mating in queens. Analysis of gene expression related to hypoxia and hypercapnia supported the physiological findings in queens, demonstrating that the overall impacts of CO2, excluding virgin queen ovaries, were unique and were not induced by anoxia. This study contributes to our understanding of the impacts and the mechanistic basis of CO2 narcosis in insects and its impacts on bee physiology. This article has an associated ECR Spotlight interview with Anna Cressman.
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Affiliation(s)
- Anna Cressman
- Department of Entomology, Center for Chemical Ecology, Center for Pollination Research, Huck Institutes of the Life Sciences, Pennsylvania State University, University Park, PA 16802, USA
| | - Etya Amsalem
- Department of Entomology, Center for Chemical Ecology, Center for Pollination Research, Huck Institutes of the Life Sciences, Pennsylvania State University, University Park, PA 16802, USA
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3
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Knapp RA, Norman VC, Rouse JL, Duncan EJ. Environmentally responsive reproduction: neuroendocrine signalling and the evolution of eusociality. CURRENT OPINION IN INSECT SCIENCE 2022; 53:100951. [PMID: 35863739 PMCID: PMC9586883 DOI: 10.1016/j.cois.2022.100951] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Revised: 07/06/2022] [Accepted: 07/11/2022] [Indexed: 05/12/2023]
Abstract
Eusociality is a rare but successful life-history strategy that is defined by the reproductive division of labour. In eusocial species, most females forgo their own reproduction to support that of a dominant female or queen. In many eusocial insects, worker reproduction is inhibited via dominance hierarchies or by pheromones produced by the queen and her brood. Here, we consider whether these cues may act as generic 'environmental signals', similar to temperature or nutrition stress, which induce a state of reproductive dormancy in some solitary insects. We review the recent findings regarding the mechanisms of reproductive dormancy in insects and highlight key gaps in our understanding of how environmental cues inhibit reproduction.
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Affiliation(s)
- Rosemary A Knapp
- School of Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK
| | - Victoria C Norman
- School of Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK
| | - James L Rouse
- School of Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK
| | - Elizabeth J Duncan
- School of Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK.
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4
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Sasaki K, Okada Y, Shimoji H, Aonuma H, Miura T, Tsuji K. Social Evolution With Decoupling of Multiple Roles of Biogenic Amines Into Different Phenotypes in Hymenoptera. Front Ecol Evol 2021. [DOI: 10.3389/fevo.2021.659160] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Convergent evolution of eusociality with the division of reproduction and its plastic transition in Hymenoptera has long attracted the attention of researchers. To explain the evolutionary scenario of the reproductive division of labor, several hypotheses had been proposed. Among these, we focus on the most basic concepts, i.e., the ovarian ground plan hypothesis (OGPH) and the split-function hypothesis (SFH). The OGPH assumes the physiological decoupling of ovarian cycles and behavior into reproductive and non-reproductive individuals, whereas the SFH assumes that the ancestral reproductive function of juvenile hormone (JH) became split into a dual function. Here, we review recent progress in the understanding of the neurohormonal regulation of reproduction and social behavior in eusocial hymenopterans, with an emphasis on biogenic amines. Biogenic amines are key substances involved in the switching of reproductive physiology and modulation of social behaviors. Dopamine has a pivotal role in the formation of reproductive skew irrespective of the social system, whereas octopamine and serotonin contribute largely to non-reproductive social behaviors. These decoupling roles of biogenic amines are seen in the life cycle of a single female in a solitary species, supporting OGPH. JH promotes reproduction with dopamine function in primitively eusocial species, whereas it regulates non-reproductive social behaviors with octopamine function in advanced eusocial species. The signal transduction networks between JH and the biogenic amines have been rewired in advanced eusocial species, which could regulate reproduction in response to various social stimuli independently of JH action.
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5
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Measurement of natural variation of neurotransmitter tissue content in red harvester ant brains among different colonies. Anal Bioanal Chem 2020; 412:6167-6175. [PMID: 31912181 DOI: 10.1007/s00216-019-02355-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2019] [Revised: 12/03/2019] [Accepted: 12/13/2019] [Indexed: 10/25/2022]
Abstract
Colonies of the red harvester ant, Pogonomyrmex barbatus, regulate foraging activity based on food availability and local conditions. Colony variation in foraging behavior is thought to be linked to biogenic amine signaling and metabolism. Measurements of differences in neurotransmitters have not been made among ant colonies in a natural environment. Here, for the first time, we quantified tissue content of 4 biogenic amines (dopamine, serotonin, octopamine, and tyramine) in single forager brains from 9 red harvester ant colonies collected in the field. Capillary electrophoresis coupled with fast-scan cyclic voltammetry (CE-FSCV) was used to separate and detect the amines in individual ant brains. Low levels of biogenic amines were detected using field-amplified sample stacking by preparing a single brain tissue sample in acetonitrile and perchloric acid. The method provides low detection limits: 1 nM for dopamine, 2 nM for serotonin, 5 nM for octopamine, and 4 nM for tyramine. Overall, the content of dopamine (47 ± 9 pg/brain) was highest, followed by octopamine (36 ± 10 pg/brain), serotonin (20 ± 4 pg/brain), and tyramine (14 ± 3 pg/brain). Relative standard deviations were high, but there was less variation within a colony than among colonies, so the neurotransmitter content of each colony might change with environmental conditions. This study demonstrates that CE-FSCV is a useful method for investigating natural variation in neurotransmitter content in single ant brains and could be useful for future studies correlating tissue content with colony behavior such as foraging. Graphical abstract.
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Giehr J, Czaczkes TJ, Heinze J. Sanitary behavior in queenright and queenless ant colonies. Behav Processes 2019; 164:86-90. [DOI: 10.1016/j.beproc.2019.04.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Revised: 04/29/2019] [Accepted: 04/29/2019] [Indexed: 10/26/2022]
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Calkins TL, Tamborindeguy C, Pietrantonio PV. GPCR annotation, G proteins, and transcriptomics of fire ant (Solenopsis invicta) queen and worker brain: An improved view of signaling in an invasive superorganism. Gen Comp Endocrinol 2019; 278:89-103. [PMID: 30576645 DOI: 10.1016/j.ygcen.2018.12.008] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Revised: 12/13/2018] [Accepted: 12/17/2018] [Indexed: 10/27/2022]
Abstract
Knowledge of G protein-coupled receptors (GPCRs) and their signaling modalities is crucial to advancing insect endocrinology, specifically in highly successful invasive social insects, such as the red imported fire ant, Solenopsis invicta Buren. In the first published draft genome of S. invicta, emphasis was placed on the annotation of olfactory receptors, and only the number of predicted GPCR genes was reported. Without an organized and curated resource for GPCRs, it will be difficult to test hypotheses on the endocrine role of neuropeptide hormones, or the function of neurotransmitters and neuromodulators. Therefore, we mined the S. invicta genome for GPCRs and found 324 predicted transcripts encoded by 125 predicted loci and improved the annotation of 55 of these loci. Among them are sixteen GPCRs that are currently annotated as "uncharacterized proteins". Further, the phylogenetic analysis of class A neuropeptide receptors presented here and the comparative listing of GPCRs in the hymenopterans S. invicta, Apis mellifera (both eusocial), Nasonia vitripennis (solitary), and the solitary model dipteran Drosophila melanogaster will facilitate comparative endocrinological studies related to social insect evolution and diversity. We compiled the 24 G protein transcripts predicted (15 α, 7 β, and 2 γ) from 12 G protein genes (5 α, 5 β, and 2 γ). Reproductive division of labor is extreme in this ant species, therefore, we compared GPCR and G protein gene expression among worker, mated queen and alate virgin queen ant brain transcriptomes. Transcripts for ten GPCRs and two G proteins were differentially expressed between queen and worker brains. The differentially expressed GPCRs are candidate receptors to explore hypotheses on division of labor in this species.
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Affiliation(s)
- Travis L Calkins
- Department of Entomology, Texas A&M University, College Station, TX 77843-2475, USA
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Cohanim AB, Amsalem E, Saad R, Shoemaker D, Privman E. Evolution of Olfactory Functions on the Fire Ant Social Chromosome. Genome Biol Evol 2018; 10:2947-2960. [PMID: 30239696 PMCID: PMC6279166 DOI: 10.1093/gbe/evy204] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/14/2018] [Indexed: 12/16/2022] Open
Abstract
Understanding the molecular evolutionary basis of social behavior is a major challenge in evolutionary biology. Social insects evolved a complex language of chemical signals to coordinate thousands of individuals. In the fire ant Solenopsis invicta, chemical signals are involved in the determination of a polymorphic social organization. Single-queen (monogyne) or multiqueen (polygyne) social structure is determined by the "social chromosome," a nonrecombining region containing ∼504 genes with two distinct haplotypes, SB and Sb. Monogyne queens are always SBB, while polygyne queens are always SBb. Workers discriminate monogyne from polygyne queens based on olfactory cues. Here, we took an evolutionary genomics approach to search for candidate genes in the social chromosome that could be responsible for this discrimination. We compared the SB and Sb haplotypes and analyzed the evolutionary rates since their divergence. Notably, we identified a cluster of 23 odorant receptors in the nonrecombining region of the social chromosome that stands out in terms of nonsynonymous changes in both haplotypes. The cluster includes twelve genes formed by recent Solenopsis-specific duplications. We found evidence for positive selection on several tree branches and significant differences between the SB and Sb haplotypes of these genes. The most dramatic difference is the complete deletion of two of these genes in Sb. These results suggest that the evolution of polygyne social organization involved adaptations in olfactory genes and opens the way for functional studies of the molecular mechanisms underlying social behavior.
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Affiliation(s)
- Amir B Cohanim
- Department of Evolutionary and Environmental Biology, Institute of Evolution, University of Haifa, Israel
| | - Etya Amsalem
- Department of Entomology, Huck Institutes of the Life Sciences, Pennsylvania State University
| | - Rana Saad
- Department of Evolutionary and Environmental Biology, Institute of Evolution, University of Haifa, Israel
| | - DeWayne Shoemaker
- Department of Entomology and Plant Pathology, University of Tennessee
| | - Eyal Privman
- Department of Evolutionary and Environmental Biology, Institute of Evolution, University of Haifa, Israel
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Felden A, Paris CI, Chapple DG, Haywood J, Suarez AV, Tsutsui ND, Lester PJ, Gruber MAM. Behavioural variation and plasticity along an invasive ant introduction pathway. J Anim Ecol 2018; 87:1653-1666. [DOI: 10.1111/1365-2656.12886] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2018] [Accepted: 06/28/2018] [Indexed: 11/28/2022]
Affiliation(s)
- Antoine Felden
- Centre for Biodiversity and Restoration Ecology; School of Biological Sciences; Victoria University of Wellington; Wellington New Zealand
| | - Carolina I. Paris
- Departamento Ecología, Genética y Evolución; Universidad de Buenos Aires; Buenos Aires Argentina
| | - David G. Chapple
- School of Biological Sciences; Monash University; Clayton Victoria Australia
| | - John Haywood
- School of Mathematics and Statistics; Victoria University of Wellington; Wellington New Zealand
| | - Andrew V. Suarez
- Department of Animal Biology and Department of Entomology; University of Illinois; Urbana Illinois
| | - Neil D. Tsutsui
- Department of Environmental Science, Policy and Management; University of California - Berkeley; Berkeley California
| | - Philip J. Lester
- Centre for Biodiversity and Restoration Ecology; School of Biological Sciences; Victoria University of Wellington; Wellington New Zealand
| | - Monica A. M. Gruber
- Centre for Biodiversity and Restoration Ecology; School of Biological Sciences; Victoria University of Wellington; Wellington New Zealand
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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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12
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Momohara Y, Aonuma H, Nagayama T. Tyraminergic modulation of agonistic outcomes in crayfish. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2018; 204:465-473. [PMID: 29488014 DOI: 10.1007/s00359-018-1255-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2017] [Revised: 02/03/2018] [Accepted: 02/23/2018] [Indexed: 01/05/2023]
Abstract
Octopamine, a biogenic amine, modulates various behaviors, ranging from locomotion and aggression to learning and memory in invertebrates. Several studies recently demonstrated that tyramine, the biological precursor of octopamine, also affects behaviors independent of octopamine. Here we investigated the involvement of tyramine in agonistic interaction of the male crayfish Procambarus clarkii. When male crayfish fight, larger animals (3-7% difference in body length) are more likely to win. By contrast, direct injection of tyramine or octopamine counteracted the physical advantage of larger animals. Tyramine or octopamine-injected naive large animals were mostly beaten by untreated smaller naive animals. This pharmacological effect was similar to the loser effect in which subordinate larger animals are frequently beaten by smaller animals. Furthermore, loser effects were partly eliminated by either injection of epinastine, an octopamine blocker, or yohimbine, a tyramine blocker, and significantly diminished by injection of a mixture of both blockers. We also observed that tyramine levels in the subesophageal ganglion were remarkably increased in subordinate crayfish after losing a fight. These results suggest that tyramine modulates aggressive levels of crayfish and contributes to the loser effect in parallel with octopamine.
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Affiliation(s)
- Yuto Momohara
- Division of Biology, Graduate School of Science and Engineering, Yamagata University, Yamagata, 990-8560, Japan. .,Information Processing Biology Unit, Okinawa Institute of Science and Technology Graduate University, 1919-1 Tancha, Onna-son, Okinawa, Japan.
| | - Hitoshi Aonuma
- Research Center of Mathematics for Social Creativity, Research Institute for Electronic Science, Hokkaido University, Sapporo, 060-0811, Japan
| | - Toshiki Nagayama
- Department of Biology, Faculty of Science, Yamagata University, Yamagata, 990-8560, Japan
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Kamhi JF, Arganda S, Moreau CS, Traniello JFA. Origins of Aminergic Regulation of Behavior in Complex Insect Social Systems. Front Syst Neurosci 2017; 11:74. [PMID: 29066958 PMCID: PMC5641352 DOI: 10.3389/fnsys.2017.00074] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2017] [Accepted: 09/22/2017] [Indexed: 01/03/2023] Open
Abstract
Neuromodulators are conserved across insect taxa, but how biogenic amines and their receptors in ancestral solitary forms have been co-opted to control behaviors in derived socially complex species is largely unknown. Here we explore patterns associated with the functions of octopamine (OA), serotonin (5-HT) and dopamine (DA) in solitary ancestral insects and their derived functions in eusocial ants, bees, wasps and termites. Synthesizing current findings that reveal potential ancestral roles of monoamines in insects, we identify physiological processes and conserved behaviors under aminergic control, consider how biogenic amines may have evolved to modulate complex social behavior, and present focal research areas that warrant further study.
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Affiliation(s)
- J. Frances Kamhi
- Department of Biological Sciences, Macquarie University, Sydney, NSW, Australia
| | - Sara Arganda
- Department of Biology, Boston University, Boston, MA, United States
- Centre de Recherches sur la Cognition Animale, Centre de Biologie Intégrative, Université de Toulouse, CNRS, UPS, Toulouse, France
| | - Corrie S. Moreau
- Department of Science and Education, Field Museum of Natural History, Chicago, IL, United States
| | - James F. A. Traniello
- Department of Biology, Boston University, Boston, MA, United States
- Graduate Program for Neuroscience, Boston University, Boston, MA, United States
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Maximized complexity in miniaturized brains: morphology and distribution of octopaminergic, dopaminergic and serotonergic neurons in the parasitic wasp, Trichogramma evanescens. Cell Tissue Res 2017; 369:477-496. [PMID: 28597098 PMCID: PMC5579201 DOI: 10.1007/s00441-017-2642-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2016] [Accepted: 05/02/2017] [Indexed: 11/13/2022]
Abstract
The parasitic wasp, Trichogramma evanescens, is an extremely small insect, with a body length as small as 0.3 mm. To facilitate this miniaturization, their brains may have evolved to contain smaller neural components and/or reduced neural complexity than larger insects. Here, we study whether the size and number of neurons are reduced in the miniaturized brain of T. evanescens, focusing on neurons that express serotonin (5HT), octopamine (OA) and dopamine (DA). We provide the first description of the distribution, projection patterns and number of 5HT-, OA- and DA-like immunoreactive cell bodies in T. evanescens and compare our observations with descriptions of much larger insects. The brains of T. evanescens contain comparable numbers of monoaminergic neurons to those of larger insects. Serotonergic neurons appear to be especially conserved; most of the clusters contain a similar number of neurons to those described in Apis mellifera and Drosophila melanogaster. This maintained complexity may have been facilitated by miniaturization of neuron size. However, many dopaminergic and some octopaminergic neuron clusters in T. evanescens contain fewer neurons than in larger insects. Modification of the complexity of these monoaminergic systems may have been necessary to maintain neuron functionality during brain miniaturization in T. evanescens. Our results reveal some of the evolutionary adaptations that may enable behavioural and cognitive complexity with respect to miniaturized brains.
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Shimoji H, Aonuma H, Miura T, Tsuji K, Sasaki K, Okada Y. Queen contact and among-worker interactions dually suppress worker brain dopamine as a potential regulator of reproduction in an ant. Behav Ecol Sociobiol 2017. [DOI: 10.1007/s00265-016-2263-3] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Kamhi JF, Nunn K, Robson SKA, Traniello JFA. Polymorphism and division of labour in a socially complex ant: neuromodulation of aggression in the Australian weaver ant, Oecophylla smaragdina. Proc Biol Sci 2016; 282:rspb.2015.0704. [PMID: 26136448 DOI: 10.1098/rspb.2015.0704] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Complex social structure in eusocial insects can involve worker morphological and behavioural differentiation. Neuroanatomical variation may underscore worker division of labour, but the regulatory mechanisms of size-based task specialization in polymorphic species are unknown. The Australian weaver ant, Oecophylla smaragdina, exhibits worker polyphenism: larger major workers aggressively defend arboreal territories, whereas smaller minors nurse brood.Here, we demonstrate that octopamine (OA) modulates worker size-related aggression in O. smaragdina. We found that the brains of majors had significantly higher titres of OA than those of minors and that OA was positively and specifically correlated with the frequency of aggressive responses to non-nestmates, a key component of territorial defence. Pharmacological manipulations that effectively switched OA action in major and minor worker brains reversed levels of aggression characteristic of each worker size class. Results suggest that altering OA action is sufficient to produce differences in aggression characteristic of size-related social roles. Neuromodulators therefore may generate variation in responsiveness to task-related stimuli associated with worker size differentiation and collateral behavioural specializations, a significant component of division of labour in complex social systems.
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Muscedere ML, Helms Cahan S, Helms KR, Traniello JF. Geographic and life-history variation in ant queen colony founding correlates with brain amine levels. Behav Ecol 2015. [DOI: 10.1093/beheco/arv152] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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18
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Okada Y, Sasaki K, Miyazaki S, Shimoji H, Tsuji K, Miura T. Social dominance and reproductive differentiation mediated by dopaminergic signaling in a queenless ant. J Exp Biol 2015; 218:1091-8. [DOI: 10.1242/jeb.118414] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2014] [Accepted: 02/03/2015] [Indexed: 11/20/2022]
Abstract
ABSTRACT
In social Hymenoptera with no morphological caste, a dominant female becomes an egg layer, whereas subordinates become sterile helpers. The physiological mechanism that links dominance rank and fecundity is an essential part of the emergence of sterile females, which reflects the primitive phase of eusociality. Recent studies suggest that brain biogenic amines are correlated with the ranks in dominance hierarchy. However, the actual causality between aminergic systems and phenotype (i.e. fecundity and aggressiveness) is largely unknown due to the pleiotropic functions of amines (e.g. age-dependent polyethism) and the scarcity of manipulation experiments. To clarify the causality among dominance ranks, amine levels and phenotypes, we examined the dynamics of the aminergic system during the ontogeny of dominance hierarchy in the queenless ant Diacamma sp., which undergoes rapid physiological differentiation based on dominance interactions. Brain dopamine levels differed between dominants and subordinates at day 7 after eclosion, although they did not differ at day 1, reflecting fecundity but not aggressiveness. Topical applications of dopamine to the subordinate workers induced oocyte growth but did not induce aggressiveness, suggesting the gonadotropic effect of dopamine. Additionally, dopamine receptor transcripts (dopr1 and dopr2) were elevated in the gaster fat body of dominant females, suggesting that the fat body is a potential target of neurohormonal dopamine. Based on this evidence, we suggest that brain dopamine levels are elevated in dominants as a result of hierarchy formation, and differences in dopamine levels cause the reproductive differentiation, probably via stimulation of the fat body.
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Affiliation(s)
- Yasukazu Okada
- Department of General Systems Studies, Graduate School of Arts and Sciences, The University of Tokyo, Komaba, Tokyo 3-8-1, Japan
- Laboratory of Ecological Genetics, Graduate School of Environmental Science, Hokkaido University, Sapporo 060-0810, Japan
| | - Ken Sasaki
- Department of Bioresource Science, Tamagawa University, Machida, Tokyo 194-8610, Japan
| | - Satoshi Miyazaki
- Laboratory of Ecological Genetics, Graduate School of Environmental Science, Hokkaido University, Sapporo 060-0810, Japan
- Department of Hygiene and Public Health, Tokyo Women's Medical University, Shinjuku-ku, Tokyo 162-8666, Japan
| | - Hiroyuki Shimoji
- Laboratory of Ecological Genetics, Graduate School of Environmental Science, Hokkaido University, Sapporo 060-0810, Japan
| | - Kazuki Tsuji
- Department of Subtropical Agro-Environmental Sciences, Faculty of Agriculture, University of the Ryukyus, Nishihara, Okinawa 903-0213, Japan
| | - Toru Miura
- Laboratory of Ecological Genetics, Graduate School of Environmental Science, Hokkaido University, Sapporo 060-0810, Japan
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Kelstrup HC, Hartfelder K, Nascimento FS, Riddiford LM. The role of juvenile hormone in dominance behavior, reproduction and cuticular pheromone signaling in the caste-flexible epiponine wasp, Synoeca surinama. Front Zool 2014; 11:78. [PMID: 25371699 PMCID: PMC4219083 DOI: 10.1186/s12983-014-0078-5] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2014] [Accepted: 10/15/2014] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND The popular view on insect sociality is that of a harmonious division of labor among two morphologically distinct and functionally non-overlapping castes. But this is a highly derived state and not a prerequisite for a functional society. Rather, caste-flexibility is a central feature in many eusocial wasps, where adult females have the potential to become queens or workers, depending on the social environment. In non-swarming paper wasps (e.g., Polistes), prospective queens fight one another to assert their dominance, with losers becoming workers if they remain on the nest. This aggression is fueled by juvenile hormone (JH) and ecdysteroids, major factors involved in caste differentiation in most eusocial insects. We tested whether these hormones have conserved aggression-promoting functions in Synoeca surinama, a caste-flexible swarm-founding wasp (Epiponini) where reproductive competition is high and aggressive displays are common. RESULTS We observed the behavioral interactions of S. surinama females in field nests before and after we had removed the egg-laying queen(s). We measured the ovarian reproductive status, hemolymph JH and ecdysteroid titers, ovarian ecdysteroid content, and analyzed the cuticular hydrocarbon (CHC) composition of females engaged in competitive interactions in both queenright and queenless contexts. These data, in combination with hormone manipulation experiments, revealed that neither JH nor ecdysteroids are necessary for the expression of dominance behaviors in S. surinama. Instead, we show that JH likely functions as a gonadotropin and directly modifies the cuticular hydrocarbon blend of young workers to match that of a reproductive. Hemolymph ecdysteroids, in contrast, are not different between queens and workers despite great differences in ovarian ecdysteroid content. CONCLUSIONS The endocrine profile of S. surinama shows surprising differences from those of other caste-flexible wasps, although a rise in JH titers in replacement queens is a common theme. Extensive remodeling of hormone functions is also evident in the highly eusocial bees, which has been attributed to the evolution of morphologically defined castes. Our results show that hormones which regulate caste-plasticity can lose these roles even while caste-plasticity is preserved.
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Affiliation(s)
- Hans C Kelstrup
- />Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147 USA
- />Present address: Department of Botany and Zoology, Stellenbosch University, Private Bag XI, Matieland, 7602 South Africa
| | - Klaus Hartfelder
- />Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Universidade de São Paul, Av. Bandeirantes 3900, Ribeirão Preto, 14049-900 SP Brazil
| | - Fabio S Nascimento
- />Departamento de Biologia da Faculdade de Filosofia, Ciȇncias e Letras de Ribeirão Preto, Universidade de São Paulo, Av. Bandeirantes 3900, Ribeirão Preto, 14040-900 SP Brazil
| | - Lynn M Riddiford
- />Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147 USA
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Status discrimination through fertility signalling allows ants to regulate reproductive conflicts. Anim Behav 2014. [DOI: 10.1016/j.anbehav.2014.04.014] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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Penick CA, Brent CS, Dolezal K, Liebig J. Neurohormonal changes associated with ritualized combat and the formation of a reproductive hierarchy in the ant Harpegnathos saltator. ACTA ACUST UNITED AC 2014; 217:1496-503. [PMID: 24436385 DOI: 10.1242/jeb.098301] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Dominance rank in animal societies is correlated with changes in both reproductive physiology and behavior. In some social insects, dominance status is used to determine a reproductive division of labor, where a few colony members reproduce while most remain functionally sterile. Changes in reproduction and behavior in this context must be coordinated through crosstalk between the brain and the reproductive system. We investigated a role for biogenic amines in forming this connection in the ant Harpegnathos saltator. In this species, workers engage in an elaborate dominance tournament to establish a group of reproductive workers termed gamergates. We analyzed biogenic amine content in the brains of gamergates, inside-workers and foragers under stable colony conditions and found that gamergates had the highest levels of dopamine. Dopamine levels were also positively correlated with increased ovarian activity among gamergates. Next, we experimentally induced workers to compete in a reproductive tournament to determine how dopamine may be involved in the establishment of a new hierarchy. Dopamine levels rose in aggressive workers at the start of a tournament, while workers that were policed by their nestmates (a behavior that inhibits ovarian activity) showed a rapid decline in dopamine. In addition to dopamine, levels of serotonin and tyramine differed among castes, and these changes could contribute to differences in caste-specific behavioral patterns observed among non-reproductive workers. Overall, these results provide support that biogenic amines link changes in behavior and dominance with reproductive activity in H. saltator as well as drive differences in worker task performance.
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Affiliation(s)
- Clint A Penick
- School of Life Sciences, Arizona State University, Tempe, AZ 85287-4501, USA
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Biogenic amines are associated with worker task but not patriline in the leaf-cutting ant Acromyrmex echinatior. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2013; 199:1117-27. [PMID: 24072064 DOI: 10.1007/s00359-013-0854-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2013] [Revised: 08/31/2013] [Accepted: 09/02/2013] [Indexed: 10/26/2022]
Abstract
Division of labor among eusocial insect workers is a hallmark of advanced social organization, but its underlying neural mechanisms are not well understood. We investigated whether differences in whole-brain levels of the biogenic amines dopamine (DA), serotonin (5HT), and octopamine (OA) are associated with task specialization and genotype in similarly sized and aged workers of the leaf-cutting ant Acromyrmex echinatior, a polyandrous species in which genotype correlates with worker task specialization. We compared amine levels of foragers and waste management workers to test for an association with worker task, and young in-nest workers across patrilines to test for a genetic influence on brain amine levels. Foragers had higher levels of DA and OA and a higher OA:5HT ratio than waste management workers. Patrilines did not significantly differ in amine levels or their ratios, although patriline affected worker body size, which correlated with amine levels despite the small size range sampled. Levels of all three amines were correlated within individuals in both studies. Among patrilines, mean levels of DA and OA, and OA and 5HT were also correlated. Our results suggest that differences in biogenic amines could regulate worker task specialization, but may be not be significantly affected by genotype.
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Kamhi JF, Traniello JF. Biogenic Amines and Collective Organization in a Superorganism: Neuromodulation of Social Behavior in Ants. BRAIN, BEHAVIOR AND EVOLUTION 2013; 82:220-36. [DOI: 10.1159/000356091] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2013] [Accepted: 09/26/2013] [Indexed: 11/19/2022]
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Tanner CJ, Keller L. Nest distribution varies with dispersal method and familiarity-mediated aggression for two sympatric ants. Anim Behav 2012. [DOI: 10.1016/j.anbehav.2012.08.018] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Muscedere ML, Johnson N, Gillis BC, Kamhi JF, Traniello JFA. Serotonin modulates worker responsiveness to trail pheromone in the ant Pheidole dentata. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2011; 198:219-27. [PMID: 22134381 DOI: 10.1007/s00359-011-0701-2] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2011] [Revised: 11/15/2011] [Accepted: 11/16/2011] [Indexed: 11/24/2022]
Abstract
As social insect workers mature, outside-nest tasks associated with foraging and defense are typically performed at higher frequencies. Foraging in ants is often a pheromonally mediated collective action performed by mature workers; age-dependent differences in olfactory response thresholds may therefore proximately regulate task repertoire development. In the ant Pheidole dentata, foraging activity increases with chronological age in minor workers, and is chemically controlled. The onset of foraging in minor workers is accompanied by marked neuroanatomical and neurochemical changes, including synaptic remodeling in olfactory regions of the brain, proliferation of serotonergic neurons, and increased brain titers of monoamines, notably serotonin. We examined the linkage of serotonin and olfactory responsiveness by assaying trail-following performance in mature P. dentata minor workers with normal serotonin levels, or serotonin levels experimentally lowered by oral administration of the serotonin synthesis inhibitor α-methyltryptophan (AMTP). By assessing responsiveness to standardized pheromone trails, we demonstrate that trail-following behaviors are significantly reduced in serotonin-depleted workers. AMTP-treated individuals were less likely to initiate trail following, and oriented along pheromone trails for significantly shorter distances than untreated, similar-age workers. These results demonstrate for the first time that serotonin modulates olfactory processes and/or motor functions associated with cooperative foraging in ants.
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Blacher P, Lecoutey E, Fresneau D, Nowbahari E. Reproductive hierarchies and status discrimination in orphaned colonies of Pachycondyla apicalis ants. Anim Behav 2010. [DOI: 10.1016/j.anbehav.2009.10.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Seid MA, Goode K, Li C, Traniello JFA. Age- and subcaste-related patterns of serotonergic immunoreactivity in the optic lobes of the ant Pheidole dentata. Dev Neurobiol 2009; 68:1325-33. [PMID: 18666203 DOI: 10.1002/dneu.20663] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Serotonin, a biogenic amine known to be a neuromodulator of insect behavior, has recently been associated with age-related patterns of task performance in the ant Pheidole dentata. We identified worker age- and subcaste-related patterns of serotonergic activity within the optic lobes of the P. dentata brain to further examine its relationship to polyethism. We found strong immunoreactivity in the optic lobes of the brains of both minor and major workers. Serotonergic cell bodies in the optic lobes increased significantly in number as major and minor workers matured. Old major workers had greater numbers of serotonergic cell bodies than minors of a similar age. This age-related increase in serotonergic immunoreactivity, as well as the presence of diffuse serotonin networks in the mushroom bodies, antennal lobes, and central complex, occurs concomitantly with an increase in the size of worker task repertoires. Our results suggest that serotonin is associated with the development of the visual system, enabling the detection of task-related stimuli outside the nest, thus playing a significant role in worker behavioral development and colony-wide division of labor.
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Affiliation(s)
- Marc A Seid
- Department of Biology, Boston University, Boston, Massachusetts 02215, USA.
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Mailleux AC, Deneubourg JL, Detrain C. Food transport in ants: Do Lasius niger foragers maximize their individual load? C R Biol 2009; 332:500-6. [PMID: 19393982 DOI: 10.1016/j.crvi.2008.10.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2008] [Revised: 10/10/2008] [Accepted: 10/13/2008] [Indexed: 10/21/2022]
Abstract
The decision for a Lasius niger forager to lay a chemical trail and launch recruitment to a food source is governed by an internal individual threshold. The value of this threshold triggering chemical communication is not set by the maximal capacity of the crop. Actually, trail-laying ants are still able to drink additional food encountered on their homeward journey. The partial filling of the crop by trail-laying ants may be a means for the ants to shorten foraging trips and to speed up the information updating within the nest. Moreover, by partially filling their crop, foragers keep a potential for sampling resources and for tasting other encountered food sources.
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Division of labour and socially induced changes in response thresholds in associations of solitary halictine bees. Anim Behav 2008. [DOI: 10.1016/j.anbehav.2008.04.007] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Hunt GJ. Flight and fight: a comparative view of the neurophysiology and genetics of honey bee defensive behavior. JOURNAL OF INSECT PHYSIOLOGY 2007; 53:399-410. [PMID: 17379239 PMCID: PMC2606975 DOI: 10.1016/j.jinsphys.2007.01.010] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2006] [Revised: 01/10/2007] [Accepted: 01/16/2007] [Indexed: 05/08/2023]
Abstract
Honey bee nest defense involves guard bees that specialize in olfaction-based nestmate recognition and alarm-pheromone-mediated recruitment of nestmates to sting. Stinging is influenced by visual, tactile and olfactory stimuli. Both quantitative trait locus (QTL) mapping and behavioral studies point to guarding behavior as a key factor in colony stinging response. Results of reciprocal F1 crosses show that paternally inherited genes have a greater influence on colony stinging response than maternally inherited genes. The most active alarm pheromone component, isoamyl acetate (IAA) causes increased respiration and may induce stress analgesia in bees. IAA primes worker bees for 'fight or flight', possibly through actions of neuropeptides and/or biogenic amines. Studies of aggression in other species lead to an expectation that octopamine or 5-HT might play a role in honey bee defensive response. Genome sequence and QTL mapping identified 128 candidate genes for three regions known to influence defensive behavior. Comparative bioinformatics suggest possible roles of genes involved in neurogenesis and central nervous system (CNS) activity, and genes involved in sensory tuning through G-protein coupled receptors (GPCRs), such as an arrestin (AmArr4) and the metabotropic GABA(B) receptor (GABA-B-R1).
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Affiliation(s)
- G J Hunt
- Department of Entomology, Purdue University, 901 W. State St., West Lafayette, IN 47907, USA.
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