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Liu H, Robinson GE, Jakobsson E. Conservation in Mammals of Genes Associated with Aggression-Related Behavioral Phenotypes in Honey Bees. PLoS Comput Biol 2016; 12:e1004921. [PMID: 27359102 PMCID: PMC4928799 DOI: 10.1371/journal.pcbi.1004921] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2015] [Accepted: 04/17/2016] [Indexed: 01/11/2023] Open
Abstract
The emerging field of sociogenomics explores the relations between social behavior and genome structure and function. An important question is the extent to which associations between social behavior and gene expression are conserved among the Metazoa. Prior experimental work in an invertebrate model of social behavior, the honey bee, revealed distinct brain gene expression patterns in African and European honey bees, and within European honey bees with different behavioral phenotypes. The present work is a computational study of these previous findings in which we analyze, by orthology determination, the extent to which genes that are socially regulated in honey bees are conserved across the Metazoa. We found that the differentially expressed gene sets associated with alarm pheromone response, the difference between old and young bees, and the colony influence on soldier bees, are enriched in widely conserved genes, indicating that these differences have genomic bases shared with many other metazoans. By contrast, the sets of differentially expressed genes associated with the differences between African and European forager and guard bees are depleted in widely conserved genes, indicating that the genomic basis for this social behavior is relatively specific to honey bees. For the alarm pheromone response gene set, we found a particularly high degree of conservation with mammals, even though the alarm pheromone itself is bee-specific. Gene Ontology identification of human orthologs to the strongly conserved honey bee genes associated with the alarm pheromone response shows overrepresentation of protein metabolism, regulation of protein complex formation, and protein folding, perhaps associated with remodeling of critical neural circuits in response to alarm pheromone. We hypothesize that such remodeling may be an adaptation of social animals to process and respond appropriately to the complex patterns of conspecific communication essential for social organization.
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Affiliation(s)
- Hui Liu
- Center for Biophysics and Computational Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America
| | - Gene E. Robinson
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America
- Department of Entomology, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America
- Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America
| | - Eric Jakobsson
- Center for Biophysics and Computational Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America
- Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America
- National Center for Supercomputing Applications, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, Illinois, United States of America
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102
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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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103
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Sobotka JA, Daley M, Chandrasekaran S, Rubin BD, Thompson GJ. Structure and function of gene regulatory networks associated with worker sterility in honeybees. Ecol Evol 2016; 6:1692-701. [PMID: 26925214 PMCID: PMC4755009 DOI: 10.1002/ece3.1997] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2015] [Revised: 01/12/2016] [Accepted: 01/18/2016] [Indexed: 01/26/2023] Open
Abstract
A characteristic of eusocial bees is a reproductive division of labor in which one or a few queens monopolize reproduction, while her worker daughters take on reproductively altruistic roles within the colony. The evolution of worker reproductive altruism involves indirect selection for the coordinated expression of genes that regulate personal reproduction, but evidence for this type of selection remains elusive. In this study, we tested whether genes coexpressed under queen‐induced worker sterility show evidence of adaptive organization within a model brain transcriptional regulatory network (TRN). If so, this structured pattern would imply that indirect selection on nonreproductive workers has influenced the functional organization of genes within the network, specifically to regulate the expression of sterility. We found that literature‐curated sets of candidate genes for sterility, ranging in size from 18 to 267, show strong evidence of clustering within the three‐dimensional space of the TRN. This finding suggests that our candidate sets of genes for sterility form functional modules within the living bee brain's TRN. Moreover, these same gene sets colocate to a single, albeit large, region of the TRN's topology. This spatially organized and convergent pattern contrasts with a null expectation for functionally unrelated genes to be haphazardly distributed throughout the network. Our meta‐genomic analysis therefore provides first evidence for a truly “social transcriptome” that may regulate the conditional expression of honeybee worker sterility.
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Affiliation(s)
- Julia A Sobotka
- Biology Department Western University 1151 Richmond Street London ON N6A 5B7 Canada
| | - Mark Daley
- Biology Department Western University 1151 Richmond Street London ON N6A 5B7 Canada
| | - Sriram Chandrasekaran
- Harvard Society of Fellows Faculty of Arts and Sciences Harvard University 78 Mount Auburn Street Cambridge Massachusetts; The Broad Institute of MIT and Harvard 415 Main Street Cambridge Massachusetts
| | - Benjamin D Rubin
- Biology Department Western University 1151 Richmond Street London ON N6A 5B7 Canada
| | - Graham J Thompson
- Biology Department Western University 1151 Richmond Street London ON N6A 5B7 Canada
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104
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Bell AM, Bukhari SA, Sanogo YO. Natural variation in brain gene expression profiles of aggressive and nonaggressive individual sticklebacks. BEHAVIOUR 2016; 153:1723-1743. [PMID: 29046592 DOI: 10.1163/1568539x-00003393] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Within many species, some individuals are consistently more aggressive than others. We examine whether there are differences in brain gene expression between aggressive versus nonaggressive behavioural types of individuals within a natural population of male three-spined sticklebacks (Gasterosteus aculeatus). We compared gene expression profiles of aggressive male sticklebacks to nonaggressive males in four regions of the brain (brainstem, cerebellum, diencephalon and telencephalon). Relatively few genes were differentially expressed between behavioural types in telencephalon, cerebellum and diencephalon, but hundreds of genes were differentially expressed in brainstem, a brain area involved in detecting threats. Six genes that were differentially expressed in response to a territorial intrusion in a previous study were also differentially expressed between behavioural types in this study, implying primarily non-shared but some shared molecular mechanisms. Our findings offer new insights into the molecular causes and correlates of behavioural plasticity and individual variation in behaviour.
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Affiliation(s)
- Alison M Bell
- School of Integrative Biology, Program in Ecology, Evolution and Conservation, Program in Neuroscience, Carl R. Woese Institute for Genomic Biology, University of Illinois, Urbana Champaign, IL, USA
| | - Syed Abbas Bukhari
- Illinois Informatics Program, Carl R. Woese Institute for Genomic Biology, University of Illinois, Urbana Champaign, IL, USA
| | - Yibayiri Osee Sanogo
- Genomics Core, Lerner Research Institute, Cleveland Clinic Foundation, Cleveland, OH, USA
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105
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106
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107
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Gibson JD, Arechavaleta-Velasco ME, Tsuruda JM, Hunt GJ. Biased Allele Expression and Aggression in Hybrid Honeybees may be Influenced by Inappropriate Nuclear-Cytoplasmic Signaling. Front Genet 2015; 6:343. [PMID: 26648977 PMCID: PMC4664729 DOI: 10.3389/fgene.2015.00343] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2015] [Accepted: 11/20/2015] [Indexed: 11/15/2022] Open
Abstract
Hybrid effects are often exhibited asymmetrically between reciprocal families. One way this could happen is if silencing of one parent’s allele occurs in one lineage but not the other, which could affect the phenotypes of the hybrids asymmetrically by silencing that allele in only one of the hybrid families. We have previously tested for allele-specific expression biases in hybrids of European and Africanized honeybees and we found that there was an asymmetric overabundance of genes showing a maternal bias in the family with a European mother. Here, we further analyze allelic bias in these hybrids to ascertain whether they may underlie previously described asymmetries in metabolism and aggression in similar hybrid families and we speculate on what mechanisms may produce this biased allele usage. We find that there are over 500 genes that have some form of biased allele usage and over 200 of these are biased toward the maternal allele but only in the family with European maternity, mirroring the pattern observed for aggression and metabolic rate. This asymmetrically biased set is enriched for genes in loci associated with aggressive behavior and also for mitochondrial-localizing proteins. It contains many genes that play important roles in metabolic regulation. Moreover we find genes relating to the piwi-interacting RNA (piRNA) pathway, which is involved in chromatin modifications and epigenetic regulation and may help explain the mechanism underlying this asymmetric allele use. Based on these findings and previous work investigating aggression and metabolism in bees, we propose a novel hypothesis; that the asymmetric pattern of biased allele usage in these hybrids is a result of inappropriate use of piRNA-mediated nuclear-cytoplasmic signaling that is normally used to modulate aggression in honeybees. This is the first report of widespread asymmetric effects on allelic expression in hybrids and may represent a novel mechanism for gene regulation.
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Affiliation(s)
- Joshua D Gibson
- Department of Entomology, Purdue University, West Lafayette IN, USA
| | - Miguel E Arechavaleta-Velasco
- CENID-Fisiología y Mejoramiento Animal, Instituto Nacional de Investigaciones Forestales, Agrícolas y Pecuarias México, Mexico
| | | | - Greg J Hunt
- Department of Entomology, Purdue University, West Lafayette IN, USA
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108
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Bell AM, Dochtermann NA. Integrating molecular mechanisms into quantitative genetics to understand consistent individual differences in behavior. Curr Opin Behav Sci 2015; 6:111-114. [PMID: 26858967 DOI: 10.1016/j.cobeha.2015.10.014] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
It is now well appreciated that individual animals behave differently from one another and that individual differences in behaviors-personality differences-are maintained through time and across situations. Quantitative genetics has emerged as a conceptual basis for understanding the key ingredients of personality: (co)variation and plasticity. However, the results from quantitative genetic analyses are often divorced from underlying molecular or other proximate mechanisms. This disconnect has the potential to impede an integrated understanding of behavior and is a disconnect present throughout evolutionary ecology. Here we discuss some of the main conceptual connections between personality and quantitative genetics, the relationship of both with genomic tools, and areas that require integration. With its consideration of both trait variation and plasticity, the study of animal personality offers new opportunities to incorporate molecular mechanisms into both the trait partitioning and reaction norm frameworks provided by quantitative genetics.
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Affiliation(s)
- Alison M Bell
- School of Integrative Biology, Carl R. Woese Institute for Genomic Biology, Neuroscience Program and Program in Ecology, Evolution and Conservation
| | - Ned A Dochtermann
- Department of Biological Sciences, Dept. 2715, North Dakota State University, PO Box 6050, Fargo, ND 58108-6050
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109
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Shpigler HY, Robinson GE. Laboratory Assay of Brood Care for Quantitative Analyses of Individual Differences in Honey Bee (Apis mellifera) Affiliative Behavior. PLoS One 2015; 10:e0143183. [PMID: 26569402 PMCID: PMC4646683 DOI: 10.1371/journal.pone.0143183] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2015] [Accepted: 11/01/2015] [Indexed: 01/18/2023] Open
Abstract
Care of offspring is a form of affiliative behavior that is fundamental to studies of animal social behavior. Insects do not figure prominently in this topic because Drosophila melanogaster and other traditional models show little if any paternal or maternal care. However, the eusocial honey bee exhibits cooperative brood care with larvae receiving intense and continuous care from their adult sisters, but this behavior has not been well studied because a robust quantitative assay does not exist. We present a new laboratory assay that enables quantification of group or individual honey bee brood “nursing behavior” toward a queen larva. In addition to validating the assay, we used it to examine the influence of the age of the larva and the genetic background of the adult bees on nursing performance. This new assay also can be used in the future for mechanistic analyses of eusociality and comparative analyses of affilative behavior with other animals.
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Affiliation(s)
- Hagai Y Shpigler
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois, United State of America
| | - Gene E Robinson
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois, United State of America.,Department of Entomology and Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, Illinois, United State of America
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110
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Wheeler MM, Ament SA, Rodriguez-Zas SL, Southey B, Robinson GE. Diet and endocrine effects on behavioral maturation-related gene expression in the pars intercerebralis of the honey bee brain. ACTA ACUST UNITED AC 2015; 218:4005-14. [PMID: 26567353 DOI: 10.1242/jeb.119420] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2015] [Accepted: 10/22/2015] [Indexed: 01/05/2023]
Abstract
Nervous and neuroendocrine systems mediate environmental conditions to control a variety of life history traits. Our goal was to provide mechanistic insights as to how neurosecretory signals mediate division of labor in the honey bee (Apis mellifera). Worker division of labor is based on a process of behavioral maturation by individual bees, which involves performing in-hive tasks early in adulthood, then transitioning to foraging for food outside the hive. Social and nutritional cues converge on endocrine factors to regulate behavioral maturation, but whether neurosecretory systems are central to this process is not known. To explore this, we performed transcriptomic profiling of a neurosecretory region of the brain, the pars intercerebralis (PI). We first compared PI transcriptional profiles for bees performing in-hive tasks and bees engaged in foraging. Using these results as a baseline, we then performed manipulative experiments to test whether the PI is responsive to dietary changes and/or changes in juvenile hormone (JH) levels. Results reveal a robust molecular signature of behavioral maturation in the PI, with a subset of gene expression changes consistent with changes elicited by JH treatment. In contrast, dietary changes did not induce transcriptomic changes in the PI consistent with behavioral maturation or JH treatment. Based on these results, we propose a new verbal model of the regulation of division of labor in honey bees in which the relationship between diet and nutritional physiology is attenuated, and in its place is a relationship between social signals and nutritional physiology that is mediated by JH.
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Affiliation(s)
| | - Seth A Ament
- Institute for Systems Biology, Seattle, WA 98109, USA
| | | | - Bruce Southey
- Department of Animal Sciences, UIUC, Urbana, IL 61801, USA
| | - Gene E Robinson
- Department of Entomology, UIUC, Urbana, IL 61801, USA Institute for Genomic Biology, UIUC, Urbana, IL 61801, USA
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111
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Rittschof CC, Coombs CB, Frazier M, Grozinger CM, Robinson GE. Early-life experience affects honey bee aggression and resilience to immune challenge. Sci Rep 2015; 5:15572. [PMID: 26493190 PMCID: PMC4616062 DOI: 10.1038/srep15572] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2015] [Accepted: 09/29/2015] [Indexed: 11/23/2022] Open
Abstract
Early-life social experiences cause lasting changes in behavior and health for a variety of animals including humans, but it is not well understood how social information ''gets under the skin'' resulting in these effects. Adult honey bees (Apis mellifera) exhibit socially coordinated collective nest defense, providing a model for social modulation of aggressive behavior. Here we report for the first time that a honey bee's early-life social environment has lasting effects on individual aggression: bees that experienced high-aggression environments during pre-adult stages showed increased aggression when they reached adulthood relative to siblings that experienced low-aggression environments, even though all bees were kept in a common environment during adulthood. Unlike other animals including humans however, high-aggression honey bees were more, rather than less, resilient to immune challenge, assessed as neonicotinoid pesticide susceptibility. Moreover, aggression was negatively correlated with ectoparasitic mite presence. In honey bees, early-life social experience has broad effects, but increased aggression is decoupled from negative health outcomes. Because honey bees and humans share aspects of their physiological response to aggressive social encounters, our findings represent a step towards identifying ways to improve individual resiliency. Pre-adult social experience may be crucial to the health of the ecologically threatened honey bee.
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Affiliation(s)
- Clare C. Rittschof
- Carl R. Woese Institute for Genomic Biology, Department of Entomology and Neuroscience Program, University of Illinois Urbana-Champaign, Urbana, IL, 61801
- Department of Entomology, Center for Pollinator Research, The Pennsylvania State University, University Park, PA, 16802
| | - Chelsey B. Coombs
- Department of Molecular and Cellular Biology, University of Illinois Urbana-Champaign, Urbana, IL, 61801
| | - Maryann Frazier
- Department of Entomology, Center for Pollinator Research, The Pennsylvania State University, University Park, PA, 16802
| | - Christina M. Grozinger
- Department of Entomology, Center for Pollinator Research, The Pennsylvania State University, University Park, PA, 16802
| | - Gene E. Robinson
- Carl R. Woese Institute for Genomic Biology, Department of Entomology and Neuroscience Program, University of Illinois Urbana-Champaign, Urbana, IL, 61801
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112
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Transcriptomes of parents identify parenting strategies and sexual conflict in a subsocial beetle. Nat Commun 2015; 6:8449. [PMID: 26416581 PMCID: PMC4598741 DOI: 10.1038/ncomms9449] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2015] [Accepted: 08/21/2015] [Indexed: 11/23/2022] Open
Abstract
Parenting in the burying beetle Nicrophorus vespilloides is complex and, unusually, the sex and number of parents that can be present is flexible. Such flexibility is expected to involve specialized behaviour by the two sexes under biparental conditions. Here, we show that offspring fare equally well regardless of the sex or number of parents present. Comparing transcriptomes, we find a largely overlapping set of differentially expressed genes in both uniparental and biparental females and in uniparental males including vitellogenin, associated with reproduction, and takeout, influencing sex-specific mating and feeding behaviour. Gene expression in biparental males is similar to that in non-caring states. Thus, being ‘biparental’ in N. vespilloides describes the family social organization rather than the number of directly parenting individuals. There was no specialization; instead, in biparental families, direct male parental care appears to be limited with female behaviour unchanged. This should lead to strong sexual conflict. The burying beetle shows flexible parenting behaviour. Here, the authors show that offspring fare equally well regardless of the sex or number of parents present and find similar gene expression profiles in uniparental and biparental females and in uniparental males, which suggests no specialization in parenting.
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113
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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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114
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Liang ZS, Mattila HR, Rodriguez-Zas SL, Southey BR, Seeley TD, Robinson GE. Comparative brain transcriptomic analyses of scouting across distinct behavioural and ecological contexts in honeybees. Proc Biol Sci 2015; 281:rspb.2014.1868. [PMID: 25355476 DOI: 10.1098/rspb.2014.1868] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Individual differences in behaviour are often consistent across time and contexts, but it is not clear whether such consistency is reflected at the molecular level. We explored this issue by studying scouting in honeybees in two different behavioural and ecological contexts: finding new sources of floral food resources and finding a new nest site. Brain gene expression profiles in food-source and nest-site scouts showed a significant overlap, despite large expression differences associated with the two different contexts. Class prediction and 'leave-one-out' cross-validation analyses revealed that a bee's role as a scout in either context could be predicted with 92.5% success using 89 genes at minimum. We also found that genes related to four neurotransmitter systems were part of a shared brain molecular signature in both types of scouts, and the two types of scouts were more similar for genes related to glutamate and GABA than catecholamine or acetylcholine signalling. These results indicate that consistent behavioural tendencies across different ecological contexts involve a mixture of similarities and differences in brain gene expression.
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Affiliation(s)
- Zhengzheng S Liang
- Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Heather R Mattila
- Department of Biological Sciences, Wellesley College, Wellesley, MA 02481, USA
| | - Sandra L Rodriguez-Zas
- Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA Department of Animal Sciences, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Bruce R Southey
- Department of Animal Sciences, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Thomas D Seeley
- Department of Neurobiology and Behavior, Cornell University, Ithaca, NY 14853, USA
| | - Gene E Robinson
- Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA Department of Entomology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
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115
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Abstract
Parent-specific gene expression (PSGE) is little known outside of mammals and plants. PSGE occurs when the expression level of a gene depends on whether an allele was inherited from the mother or the father. Kin selection theory predicts that there should be extensive PSGE in social insects because social insect parents can gain inclusive fitness benefits by silencing parental alleles in female offspring. We searched for evidence of PSGE in honey bees using transcriptomes from reciprocal crosses between European and Africanized strains. We found 46 transcripts with significant parent-of-origin effects on gene expression, many of which overexpressed the maternal allele. Interestingly, we also found a large proportion of genes showing a bias toward maternal alleles in only one of the reciprocal crosses. These results indicate that PSGE may occur in social insects. The nonreciprocal effects could be largely driven by hybrid incompatibility between these strains. Future work will help to determine if these are indeed parent-of-origin effects that can modulate inclusive fitness benefits.
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116
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Rehan SM, Toth AL. Climbing the social ladder: the molecular evolution of sociality. Trends Ecol Evol 2015; 30:426-33. [PMID: 26051561 DOI: 10.1016/j.tree.2015.05.004] [Citation(s) in RCA: 105] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2015] [Revised: 05/11/2015] [Accepted: 05/12/2015] [Indexed: 11/24/2022]
Abstract
Genomic tools are allowing us to dissect the roles of genes and genetic architecture in social evolution, and eusocial insects are excellent models. Numerous hypotheses for molecular evolution of eusociality have been proposed, ranging from regulatory shifts in 'old' genes to rapid evolution of 'new' genes. A broad model to explain this major transition in evolution has been lacking. We provide a synthetic framework centered on the idea that different evolutionary processes dominate during different transitional stages, beginning with changes in gene regulation and culminating in novel genes later on. By considering multiple mechanisms as we 'climb the social ladder', we can test whether the transitions from solitary to simple sociality to complex sociality represent incremental changes or genetic revolutions.
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Affiliation(s)
- Sandra M Rehan
- Department of Biological Sciences, University of New Hampshire, Durham, NH 03824, USA.
| | - Amy L Toth
- Department of Evolution, Ecology, and Organismal Biology, and Department of Entomology, Iowa State University, Ames, IA 50011, USA
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117
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McNeill MS, Robinson GE. Voxel-based analysis of the immediate early gene, c-jun, in the honey bee brain after a sucrose stimulus. INSECT MOLECULAR BIOLOGY 2015; 24:377-390. [PMID: 25773289 DOI: 10.1111/imb.12165] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Immediate early genes (IEGs) have served as useful markers of brain neuronal activity in mammals, and more recently in insects. The mammalian canonical IEG, c-jun, is part of regulatory pathways conserved in insects and has been shown to be responsive to alarm pheromone in honey bees. We tested whether c-jun was responsive in honey bees to another behaviourally relevant stimulus, sucrose, in order to further identify the brain regions involved in sucrose processing. To identify responsive regions, we developed a new method of voxel-based analysis of c-jun mRNA expression. We found that c-jun is expressed in somata throughout the brain. It was rapidly induced in response to sucrose stimuli, and it responded in somata near the antennal and mechanosensory motor centre, mushroom body calices and lateral protocerebrum, which are known to be involved in sucrose processing. c-jun also responded to sucrose in somata near the lateral suboesophageal ganglion, dorsal optic lobe, ventral optic lobe and dorsal posterior protocerebrum, which had not been previously identified by other methods. These results demonstrate the utility of voxel-based analysis of mRNA expression in the insect brain.
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Affiliation(s)
- M S McNeill
- Department of Entomology, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA; Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA; Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA
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118
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Woodard SH, Lozier JD, Goulson D, Williams PH, Strange JP, Jha S. Molecular tools and bumble bees: revealing hidden details of ecology and evolution in a model system. Mol Ecol 2015; 24:2916-36. [PMID: 25865395 DOI: 10.1111/mec.13198] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2014] [Revised: 04/07/2015] [Accepted: 04/08/2015] [Indexed: 01/15/2023]
Abstract
Bumble bees are a longstanding model system for studies on behaviour, ecology and evolution, due to their well-studied social lifestyle, invaluable role as wild and managed pollinators, and ubiquity and diversity across temperate ecosystems. Yet despite their importance, many aspects of bumble bee biology have remained enigmatic until the rise of the genetic and, more recently, genomic eras. Here, we review and synthesize new insights into the ecology, evolution and behaviour of bumble bees that have been gained using modern genetic and genomic techniques. Special emphasis is placed on four areas of bumble bee biology: the evolution of eusociality in this group, population-level processes, large-scale evolutionary relationships and patterns, and immunity and resistance to pesticides. We close with a prospective on the future of bumble bee genomics research, as this rapidly advancing field has the potential to further revolutionize our understanding of bumble bees, particularly in regard to adaptation and resilience. Worldwide, many bumble bee populations are in decline. As such, throughout the review, connections are drawn between new molecular insights into bumble bees and our understanding of the causal factors involved in their decline. Ongoing and potential applications to bumble bee management and conservation are also included to demonstrate how genetics- and genomics-enabled research aids in the preservation of this threatened group.
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Affiliation(s)
- S Hollis Woodard
- Department of Integrative Biology, University of Texas, Austin, TX, 78712, USA.,Department of Entomology, University of California, Riverside, CA, 92521, USA
| | - Jeffrey D Lozier
- Department of Biological Sciences, University of Alabama, Tuscaloosa, AL, 35401, USA
| | - David Goulson
- Evolution, Behaviour & Environment, School of Life Sciences, University of Sussex, Falmer, East Sussex, BN1 9QG, UK
| | - Paul H Williams
- Department of Life Sciences, Natural History Museum, London, SW7 5BD, UK
| | - James P Strange
- USDA-ARS, Pollinating Insect Research Unit, Utah State University, Logan, UT, 84322, USA
| | - Shalene Jha
- Department of Integrative Biology, University of Texas, Austin, TX, 78712, USA
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Chandrasekaran S, Rittschof CC, Djukovic D, Gu H, Raftery D, Price ND, Robinson GE. Aggression is associated with aerobic glycolysis in the honey bee brain(1). GENES BRAIN AND BEHAVIOR 2015; 14:158-66. [PMID: 25640316 DOI: 10.1111/gbb.12201] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 09/19/2014] [Revised: 01/10/2015] [Accepted: 01/12/2015] [Indexed: 12/22/2022]
Abstract
Aerobic glycolysis involves increased glycolysis and decreased oxidative catabolism of glucose even in the presence of an ample oxygen supply. Aerobic glycolysis, a common metabolic pattern in cancer cells, was recently discovered in both the healthy and diseased human brain, but its functional significance is not understood. This metabolic pattern in the brain is surprising because it results in decreased efficiency of adenosine triphosphate (ATP) production in a tissue with high energetic demands. We report that highly aggressive honey bees (Apis mellifera) show a brain transcriptomic and metabolic state consistent with aerobic glycolysis, i.e. increased glycolysis in combination with decreased oxidative phosphorylation. Furthermore, exposure to alarm pheromone, which provokes aggression, causes a metabolic shift to aerobic glycolysis in the bee brain. We hypothesize that this metabolic state, which is associated with altered neurotransmitter levels, increased glycolytically derived ATP and a reduced cellular redox state, may lead to increased neuronal excitability and oxidative stress in the brain. Our analysis provides evidence for a robust, distinct and persistent brain metabolic response to aggression-inducing social cues. This finding for the first time associates aerobic glycolysis with naturally occurring behavioral plasticity, which has important implications for understanding both healthy and diseased brain function.
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Affiliation(s)
- S Chandrasekaran
- Institute for Systems Biology, Seattle, WA; Center for Biophysics and Computational Biology
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120
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Simões JM, Barata EN, Harris RM, O'Connell LA, Hofmann HA, Oliveira RF. Social odors conveying dominance and reproductive information induce rapid physiological and neuromolecular changes in a cichlid fish. BMC Genomics 2015; 16:114. [PMID: 25766511 PMCID: PMC4344806 DOI: 10.1186/s12864-015-1255-4] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2014] [Accepted: 01/19/2015] [Indexed: 01/01/2023] Open
Abstract
Background Social plasticity is a pervasive feature of animal behavior. Animals adjust the expression of their social behavior to the daily changes in social life and to transitions between life-history stages, and this ability has an impact in their Darwinian fitness. This behavioral plasticity may be achieved either by rewiring or by biochemically switching nodes of the neural network underlying social behavior in response to perceived social information. Independent of the proximate mechanisms, at the neuromolecular level social plasticity relies on the regulation of gene expression, such that different neurogenomic states emerge in response to different social stimuli and the switches between states are orchestrated by signaling pathways that interface the social environment and the genotype. Here, we test this hypothesis by characterizing the changes in the brain profile of gene expression in response to social odors in the Mozambique Tilapia, Oreochromis mossambicus. This species has a rich repertoire of social behaviors during which both visual and chemical information are conveyed to conspecifics. Specifically, dominant males increase their urination frequency during agonist encounters and during courtship to convey chemical information reflecting their dominance status. Results We recorded electro-olfactograms to test the extent to which the olfactory epithelium can discriminate between olfactory information from dominant and subordinate males as well as from pre- and post-spawning females. We then performed a genome-scale gene expression analysis of the olfactory bulb and the olfactory cortex homolog in order to identify the neuromolecular systems involved in processing these social stimuli. Conclusions Our results show that different olfactory stimuli from conspecifics’ have a major impact in the brain transcriptome, with different chemical social cues eliciting specific patterns of gene expression in the brain. These results confirm the role of rapid changes in gene expression in the brain as a genomic mechanism underlying behavioral plasticity and reinforce the idea of an extensive transcriptional plasticity of cichlid genomes, especially in response to rapid changes in their social environment. Electronic supplementary material The online version of this article (doi:10.1186/s12864-015-1255-4) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- José M Simões
- Unidade de Investigação em Eco-Etologia, ISPA - Instituto Universitário, Rua Jardim do Tabaco 34, 1149-041, Lisbon, Portugal. .,Integrative Behavioural Biology Lab, Instituto Gulbenkian de Ciência, Oeiras, Portugal. .,Champalimaud Neuroscience Programme, Champalimaud Foundation, Lisbon, Portugal.
| | - Eduardo N Barata
- CCMAR-CIMAR Laboratório Associado, Universidade do Algarve, Campus de Gambelas, 8005-139, Faro, Portugal. .,Departamento de Biologia, Universidade de Évora, Apartado 94, 7002-554, Évora, Portugal.
| | - Rayna M Harris
- Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin, TX, USA. .,Department of Integrative Biology, University of Texas at Austin, Austin, TX, USA.
| | - Lauren A O'Connell
- Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin, TX, USA. .,Department of Integrative Biology, University of Texas at Austin, Austin, TX, USA. .,Current address: FAS Center for Systems Biology, Harvard University, Cambridge, MA, USA.
| | - Hans A Hofmann
- Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin, TX, USA. .,Department of Integrative Biology, University of Texas at Austin, Austin, TX, USA. .,Institute for Neuroscience, University of Texas at Austin, Austin, TX, USA.
| | - Rui F Oliveira
- Unidade de Investigação em Eco-Etologia, ISPA - Instituto Universitário, Rua Jardim do Tabaco 34, 1149-041, Lisbon, Portugal. .,Integrative Behavioural Biology Lab, Instituto Gulbenkian de Ciência, Oeiras, Portugal. .,Champalimaud Neuroscience Programme, Champalimaud Foundation, Lisbon, Portugal.
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Mikheyev AS, Linksvayer TA. Genes associated with ant social behavior show distinct transcriptional and evolutionary patterns. eLife 2015; 4:e04775. [PMID: 25621766 PMCID: PMC4383337 DOI: 10.7554/elife.04775] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2014] [Accepted: 01/23/2015] [Indexed: 11/24/2022] Open
Abstract
Studies of the genetic basis and evolution of complex social behavior emphasize
either conserved or novel genes. To begin to reconcile these perspectives, we studied
how the evolutionary conservation of genes associated with social behavior depends on
regulatory context, and whether genes associated with social behavior exist in
distinct regulatory and evolutionary contexts. We identified modules of co-expressed
genes associated with age-based division of labor between nurses and foragers in the
ant Monomorium pharaonis, and we studied the relationship between
molecular evolution, connectivity, and expression. Highly connected and expressed
genes were more evolutionarily conserved, as expected. However, compared to the rest
of the genome, forager-upregulated genes were much more highly connected and
conserved, while nurse-upregulated genes were less connected and more evolutionarily
labile. Our results indicate that the genetic architecture of social behavior
includes both highly connected and conserved components as well as loosely connected
and evolutionarily labile components. DOI:http://dx.doi.org/10.7554/eLife.04775.001 Animal species vary widely in their degree of social behavior. Some species live
solitarily, and others, such as ants and humans, form large societies. Many
researchers have tried to understand the genetic changes underlying the evolution of
social behavior. Some researchers suggest that it involves recycling existing genes
that also have other conserved functions. Others propose that the evolution of social
behavior involves completely new genes that are not found in related but solitary
species. Ants are one of the best-studied social animals. An established colony can contain
many 1000s of individuals that live and work together and perform different roles.
The queen's job is to lay eggs, while the worker ants do everything else,
including collecting food, caring for the young, and protecting the colony. In some
species of ant—including the pharaoh ant—a worker's role changes
as it ages. Younger workers tend to stay in the nest and nurse the brood, while older
workers tend to leave the nest and forage for food. Mikheyev and Linksvayer asked: which genes are responsible for this age-based
division of labor? And how did this aspect of social behavior evolve? First, after
observing pharaoh ants from two colonies set up in the laboratory, they confirmed
that workers nursing the brood were on average almost a week younger than those seen
collecting food. Next Mikheyev and Linksvayer identified which genes were expressed
in ants of different ages, or ants engaged in different tasks. Specific sets of genes
were expressed more (or ‘up-regulated’) in nurse workers, while others
were up-regulated in foraging workers. Mikheyev and Linksvayer then investigated how rapidly these genes had evolved by
comparing them to related genes found in other social insects (fire ants and honey
bees). They also determined the ‘connectivity’ of these genes by asking
how many other genes showed similar expression patterns. In many organisms, how
rapidly a gene evolves depends on how tightly connected its expression is to the
expression of other genes; highly connected genes evolve more slowly. The genes that were expressed more in the older foraging workers were both more
highly connected and more evolutionarily conserved in the other social insects. Genes
that were up-regulated in the younger nurse workers were more loosely connected and
rapidly evolving. Mikheyev and Linksvayer's findings show that the evolution of social behavior
in animals involves both new genes, which tend to be loosely connected, and conserved
genes, which tend to be more highly connected. DOI:http://dx.doi.org/10.7554/eLife.04775.002
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Affiliation(s)
- Alexander S Mikheyev
- Ecology and Evolution Unit, Okinawa Institute of Science and Technology, Okinawa, Japan
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122
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How doth the little busy bee: unexpected metabolism. Trends Neurosci 2015; 38:1-2. [DOI: 10.1016/j.tins.2014.11.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2014] [Revised: 11/14/2014] [Accepted: 11/20/2014] [Indexed: 11/20/2022]
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123
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Whitney O, Pfenning AR, Howard JT, Blatti CA, Liu F, Ward JM, Wang R, Audet JN, Kellis M, Mukherjee S, Sinha S, Hartemink AJ, West AE, Jarvis ED. Core and region-enriched networks of behaviorally regulated genes and the singing genome. Science 2014; 346:1256780. [PMID: 25504732 DOI: 10.1126/science.1256780] [Citation(s) in RCA: 75] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Songbirds represent an important model organism for elucidating molecular mechanisms that link genes with complex behaviors, in part because they have discrete vocal learning circuits that have parallels with those that mediate human speech. We found that ~10% of the genes in the avian genome were regulated by singing, and we found a striking regional diversity of both basal and singing-induced programs in the four key song nuclei of the zebra finch, a vocal learning songbird. The region-enriched patterns were a result of distinct combinations of region-enriched transcription factors (TFs), their binding motifs, and presinging acetylation of histone 3 at lysine 27 (H3K27ac) enhancer activity in the regulatory regions of the associated genes. RNA interference manipulations validated the role of the calcium-response transcription factor (CaRF) in regulating genes preferentially expressed in specific song nuclei in response to singing. Thus, differential combinatorial binding of a small group of activity-regulated TFs and predefined epigenetic enhancer activity influences the anatomical diversity of behaviorally regulated gene networks.
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Affiliation(s)
- Osceola Whitney
- Department of Neurobiology, Howard Hughes Medical Institute, and Duke University Medical Center, Durham, NC 27710, USA.
| | - Andreas R Pfenning
- Department of Neurobiology, Howard Hughes Medical Institute, and Duke University Medical Center, Durham, NC 27710, USA. Computer Science and Artificial Intelligence Laboratory and the Broad Institute of MIT and Harvard, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
| | - Jason T Howard
- Department of Neurobiology, Howard Hughes Medical Institute, and Duke University Medical Center, Durham, NC 27710, USA
| | - Charles A Blatti
- Department of Computer Science, University of Illinois, Urbana-Champaign, IL, USA
| | - Fang Liu
- Department of Neurobiology, Duke University Medical Center, Durham, NC 27710, USA
| | - James M Ward
- Department of Neurobiology, Howard Hughes Medical Institute, and Duke University Medical Center, Durham, NC 27710, USA
| | - Rui Wang
- Department of Neurobiology, Howard Hughes Medical Institute, and Duke University Medical Center, Durham, NC 27710, USA
| | - Jean-Nicoles Audet
- Department of Biology, McGill University, Montreal, Quebec H3A 1B1, Canada
| | - Manolis Kellis
- Computer Science and Artificial Intelligence Laboratory and the Broad Institute of MIT and Harvard, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | | | - Saurabh Sinha
- Department of Computer Science, University of Illinois, Urbana-Champaign, IL, USA
| | | | - Anne E West
- Department of Neurobiology, Duke University Medical Center, Durham, NC 27710, USA.
| | - Erich D Jarvis
- Department of Neurobiology, Howard Hughes Medical Institute, and Duke University Medical Center, Durham, NC 27710, USA.
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124
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Rehan SM, Berens AJ, Toth AL. At the brink of eusociality: transcriptomic correlates of worker behaviour in a small carpenter bee. BMC Evol Biol 2014; 14:260. [PMID: 25514967 PMCID: PMC4276265 DOI: 10.1186/s12862-014-0260-6] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2014] [Accepted: 12/08/2014] [Indexed: 01/28/2023] Open
Abstract
Background There is great interest in understanding the genomic underpinnings of social evolution, in particular, the evolution of eusociality (caste-containing societies with non-reproductives that care for siblings). Subsociality is a key precursor for the evolution of eusociality and characterized by prolonged parental care and parent-offspring interaction. Here, we provide the first transcriptomic data for the small carpenter bee, Ceratina calcarata. This species is of special interest because it is subsocial and in the same family as the highly eusocial honey bee, Apis mellifera. In addition, some C. calcarata females demonstrate alloparental care without reproduction, which provides a unique opportunity to study worker behaviour in a non-eusocial species. Results We uncovered similar gene expression patterns related to maternal care and sibling care in different groups of females. This agrees with the maternal heterochrony hypothesis, specifically, that changes in timing of offspring care gene expression are related to worker behaviour in incipient insect societies. In addition, we also detected some similarity to caste-related gene expression patterns in highly eusocial honey bees, and uncovered large lifetime changes in gene expression that accompany shifts in reproductive and maternal care behaviour. Conclusions For Ceratina calcarata, we found that transcript expression profiles were most similar between sibling care and maternal care females. The maternal care behaviour exhibited post-reproductively by Ceratina mothers is concordant in terms of transcript expression with the alloparental care exhibited by workers. In line with theoretical predictions, our data are consistent with the maternal heterochrony hypothesis for the evolutionary development of worker behaviour in subsocial bees. Electronic supplementary material The online version of this article (doi:10.1186/s12862-014-0260-6) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Sandra M Rehan
- Department of Biological Sciences, University of New Hampshire, Durham, New Hampshire, USA.
| | - Ali J Berens
- Program in Bioinformatics and Computational Biology, Iowa State University, Ames, Iowa, USA. .,Department of Evolution, Ecology, and Organismal Biology, Iowa State University, Ames, Iowa, USA.
| | - Amy L Toth
- Program in Bioinformatics and Computational Biology, Iowa State University, Ames, Iowa, USA. .,Department of Evolution, Ecology, and Organismal Biology, Iowa State University, Ames, Iowa, USA. .,Department of Entomology, Iowa State University, Ames, Iowa, USA.
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125
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Bengston SE, Jandt JM. The development of collective personality: the ontogenetic drivers of behavioral variation across groups. Front Ecol Evol 2014. [DOI: 10.3389/fevo.2014.00081] [Citation(s) in RCA: 100] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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126
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Neuromolecular responses to social challenge: common mechanisms across mouse, stickleback fish, and honey bee. Proc Natl Acad Sci U S A 2014; 111:17929-34. [PMID: 25453090 DOI: 10.1073/pnas.1420369111] [Citation(s) in RCA: 120] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Certain complex phenotypes appear repeatedly across diverse species due to processes of evolutionary conservation and convergence. In some contexts like developmental body patterning, there is increased appreciation that common molecular mechanisms underlie common phenotypes; these molecular mechanisms include highly conserved genes and networks that may be modified by lineage-specific mutations. However, the existence of deeply conserved mechanisms for social behaviors has not yet been demonstrated. We used a comparative genomics approach to determine whether shared neuromolecular mechanisms could underlie behavioral response to territory intrusion across species spanning a broad phylogenetic range: house mouse (Mus musculus), stickleback fish (Gasterosteus aculeatus), and honey bee (Apis mellifera). Territory intrusion modulated similar brain functional processes in each species, including those associated with hormone-mediated signal transduction and neurodevelopment. Changes in chromosome organization and energy metabolism appear to be core, conserved processes involved in the response to territory intrusion. We also found that several homologous transcription factors that are typically associated with neural development were modulated across all three species, suggesting that shared neuronal effects may involve transcriptional cascades of evolutionarily conserved genes. Furthermore, immunohistochemical analyses of a subset of these transcription factors in mouse again implicated modulation of energy metabolism in the behavioral response. These results provide support for conserved genetic "toolkits" that are used in independent evolutions of the response to social challenge in diverse taxa.
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127
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Skaggs R, Jackson J, Toth A, Schneider S. The possible role of ritualized aggression in the vibration signal of the honeybee, Apis mellifera. Anim Behav 2014. [DOI: 10.1016/j.anbehav.2014.09.030] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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128
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Rosvall KA, Peterson MP. Behavioral effects of social challenges and genomic mechanisms of social priming: What's testosterone got to do with it? Curr Zool 2014; 60:791-803. [PMID: 27721823 DOI: 10.1093/czoolo/60.6.791] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Social challenges from rival conspecifics are common in the lives of animals, and changes in an animal's social environment can influence physiology and behavior in ways that appear to be adaptive in the face of continued social instability (i.e. social priming). Recently, it has become clear that testosterone, long thought to be the primary mediator of these effects, may not always change in response to social challenges, an observation that highlights gaps in our understanding of the proximate mechanisms by which animals respond to their social environment. Here, our goal is to address the degree to which testosterone mediates organismal responses to social cues. To this end, we review the behavioral and physiological consequences of social challenges, as well as their underlying hormonal and gene regulatory mechanisms. We also present a new case study from a wild songbird, the dark-eyed junco (Junco hyemalis), in which we find largely divergent genome-wide transcriptional changes induced by social challenges and testosterone, respectively, in muscle and liver tissue. Our review underscores the diversity of mechanisms that link the dynamic social environment with an organisms' genomic, hormonal, and behavioral state. This diversity among species, and even among tissues within an organism, reveals new insights into the pattern and process by which evolution may alter proximate mechanisms of social priming.
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Affiliation(s)
- Kimberly A Rosvall
- Indiana University, Department of Biology and Center for the Integrative Study of Animal Behavior
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129
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LeBoeuf AC, Grozinger CM. Me and we: the interplay between individual and group behavioral variation in social collectives. CURRENT OPINION IN INSECT SCIENCE 2014; 5:16-24. [PMID: 32846737 DOI: 10.1016/j.cois.2014.09.010] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2014] [Revised: 09/12/2014] [Accepted: 09/17/2014] [Indexed: 06/11/2023]
Abstract
In social insects, substantial behavioral variation exists among individuals and across colonies. Here, we discuss the role of individual variation in shaping behavioral tendencies of social groups, and highlight gaps in our knowledge about the role of the social group in modulating individual behavioral tendencies. We summarize our knowledge of the genetic mechanisms underpinning these processes, and describe the use of genomic tools to better understand the influence of social context on individuals. We discuss rapid collective phasic transitions, in which a group of individuals engages in a common novel behavior together, as a potentially highly informative model system in which to comprehensively investigate the interplay between individual and group variation.
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Affiliation(s)
- Adria C LeBoeuf
- Department of Ecology and Evolution, Center for Integrative Genomics, University of Lausanne, UNIL-Sorge, Batiment Biophore, CH-1015 Lausanne, Switzerland
| | - Christina M Grozinger
- Department of Entomology, Center for Pollinator Research, Center for Chemical Ecology, The Pennsylvania State University, 1 Chemical Ecology Lab, Orchard Road, University Park, PA 16802, USA.
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130
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Wnuk A, Kostowski W, Korczyńska J, Szczuka A, Symonowicz B, Bieńkowski P, Mierzejewski P, Godzińska EJ. Brain GABA and glutamate levels in workers of two ant species (Hymenoptera: Formicidae): interspecific differences and effects of queen presence/absence. INSECT SCIENCE 2014; 21:647-658. [PMID: 24174300 DOI: 10.1111/1744-7917.12076] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 10/10/2013] [Indexed: 06/02/2023]
Abstract
Presence of amino acid neurotransmitters gamma-aminobutyric acid (GABA) and glutamate (Glu) in ant brains was reported in very few studies. To learn more about factors influencing GABA and Glu levels in ant brains, we applied high-performance liquid chromatography to measure levels of these compounds in single brains of workers of 2 ant species, Myrmica ruginodis (subfamily Myrmicinae) and Formica polyctena (subfamily Formicinae) taken from queenright/queenless colony fragments and tested in dyadic aggression tests consisting of an encounter with a nestmate, an alien conspecific or a small cricket. Brain glutamate levels were higher than those of GABA in both tested species. Brain GABA levels (in μmol/brain) and GABA : Glu ratio were higher in M. ruginodis (a submissive species) than in F. polyctena (a dominant, aggressive species) in spite of smaller brain weight of M. ruginodis. Brain glutamate levels (in μmol/brain) did not differ between the tested species, which implies that glutamate concentration (in μmol/mg of brain tissue) was higher in M. ruginodis. Queen absence was associated with increased worker brain GABA levels in F. polyctena, but not in M. ruginodis. No significant effects of opponent type were discovered. As GABA agonists enhance friendly social behavior in rodents, we hypothesize that elevated brain GABA levels of orphaned workers of F. polyctena facilitate the adoption of a new queen. This is the first report providing information on GABA and glutamate levels in single ant brains and documenting the effects of queen presence/absence on brain levels of amino acid neurotransmitters in workers of social Hymenoptera.
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Affiliation(s)
- Andrzej Wnuk
- Laboratory of Ethology, Department of Neurophysiology, Nencki Institute of Experimental Biology PAS, Warsaw; Department of Pharmacology and Physiology of the Nervous System, Institute of Psychiatry and Neurology, Warsaw, Poland
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Li-Byarlay H, Rittschof CC, Massey JH, Pittendrigh BR, Robinson GE. Socially responsive effects of brain oxidative metabolism on aggression. Proc Natl Acad Sci U S A 2014; 111:12533-7. [PMID: 25092297 PMCID: PMC4151721 DOI: 10.1073/pnas.1412306111] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Despite ongoing high energetic demands, brains do not always use glucose and oxygen in a ratio that produces maximal ATP through oxidative phosphorylation. In some cases glucose consumption exceeds oxygen use despite adequate oxygen availability, a phenomenon known as aerobic glycolysis. Although metabolic plasticity seems essential for normal cognition, studying its functional significance has been challenging because few experimental systems link brain metabolic patterns to distinct behavioral states. Our recent transcriptomic analysis established a correlation between aggression and decreased whole-brain oxidative phosphorylation activity in the honey bee (Apis mellifera), suggesting that brain metabolic plasticity may modulate this naturally occurring behavior. Here we demonstrate that the relationship between brain metabolism and aggression is causal, conserved over evolutionary time, cell type-specific, and modulated by the social environment. Pharmacologically treating honey bees to inhibit complexes I or V in the oxidative phosphorylation pathway resulted in increased aggression. In addition, transgenic RNAi lines and genetic manipulation to knock down gene expression in complex I in fruit fly (Drosophila melanogaster) neurons resulted in increased aggression, but knockdown in glia had no effect. Finally, honey bee colony-level social manipulations that decrease individual aggression attenuated the effects of oxidative phosphorylation inhibition on aggression, demonstrating a specific effect of the social environment on brain function. Because decreased neuronal oxidative phosphorylation is usually associated with brain disease, these findings provide a powerful context for understanding brain metabolic plasticity and naturally occurring behavioral plasticity.
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Affiliation(s)
- Hongmei Li-Byarlay
- Department of Entomology, Department of Entomology, North Carolina State University, Raleigh, NC 27607
| | - Clare C Rittschof
- Department of Entomology, Institute for Genomic Biology, and Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, IL 61801; and
| | | | | | - Gene E Robinson
- Department of Entomology, Institute for Genomic Biology, and Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, IL 61801; and
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132
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Diet-dependent gene expression in honey bees: honey vs. sucrose or high fructose corn syrup. Sci Rep 2014; 4:5726. [PMID: 25034029 PMCID: PMC4103092 DOI: 10.1038/srep05726] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2014] [Accepted: 06/26/2014] [Indexed: 12/20/2022] Open
Abstract
Severe declines in honey bee populations have made it imperative to understand key factors impacting honey bee health. Of major concern is nutrition, as malnutrition in honey bees is associated with immune system impairment and increased pesticide susceptibility. Beekeepers often feed high fructose corn syrup (HFCS) or sucrose after harvesting honey or during periods of nectar dearth. We report that, relative to honey, chronic feeding of either of these two alternative carbohydrate sources elicited hundreds of differences in gene expression in the fat body, a peripheral nutrient-sensing tissue analogous to vertebrate liver and adipose tissues. These expression differences included genes involved in protein metabolism and oxidation-reduction, including some involved in tyrosine and phenylalanine metabolism. Differences between HFCS and sucrose diets were much more subtle and included a few genes involved in carbohydrate and lipid metabolism. Our results suggest that bees receive nutritional components from honey that are not provided by alternative food sources widely used in apiculture.
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133
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Giannoni-Guzmán MA, Giray T, Agosto-Rivera JL, Stevison BK, Freeman B, Ricci P, Brown EA, Abramson CI. Ethanol-induced effects on sting extension response and punishment learning in the western honey bee (Apis mellifera). PLoS One 2014; 9:e100894. [PMID: 24988309 PMCID: PMC4079248 DOI: 10.1371/journal.pone.0100894] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2013] [Accepted: 05/30/2014] [Indexed: 11/19/2022] Open
Abstract
Acute ethanol administration is associated with sedation and analgesia as well as behavioral disinhibition and memory loss but the mechanisms underlying these effects remain to be elucidated. During the past decade, insects have emerged as important model systems to understand the neural and genetic bases of alcohol effects. However, novel assays to assess ethanol's effects on complex behaviors in social or isolated contexts are necessary. Here we used the honey bee as an especially relevant model system since bees are typically exposed to ethanol in nature when collecting standing nectar crop of flowers, and there is recent evidence for independent biological significance of this exposure for social behavior. Bee's inhibitory control of the sting extension response (SER) and a conditioned-place aversion assay were used to study ethanol effects on analgesia, behavioral disinhibition, and associative learning. Our findings indicate that although ethanol, in a dose-dependent manner, increases SER thresholds (analgesic effects), it disrupts the ability of honey bees to inhibit SER and to associate aversive stimuli with their environment. These results suggest that ethanol's effects on analgesia, behavioral disinhibition and associative learning are common across vertebrates and invertebrates. These results add to the use of honey bees as an ethanol model to understand ethanol's effects on complex, socially relevant behaviors.
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Affiliation(s)
| | - Tugrul Giray
- Department of Biology, University of Puerto Rico Rio Piedras, San Juan, Puerto Rico
| | | | - Blake K. Stevison
- Laboratory of Behavioral Biology and Comparative Psychology, Oklahoma State University, Stillwater, Oklahoma, United States of America
| | - Brett Freeman
- Laboratory of Behavioral Biology and Comparative Psychology, Oklahoma State University, Stillwater, Oklahoma, United States of America
| | - Paige Ricci
- Laboratory of Behavioral Biology and Comparative Psychology, Oklahoma State University, Stillwater, Oklahoma, United States of America
| | - Erika A. Brown
- Laboratory of Behavioral Biology and Comparative Psychology, Oklahoma State University, Stillwater, Oklahoma, United States of America
| | - Charles I. Abramson
- Laboratory of Behavioral Biology and Comparative Psychology, Oklahoma State University, Stillwater, Oklahoma, United States of America
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134
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Swanson EM, Snell-Rood EC. A Molecular Signaling Approach to Linking Intraspecific Variation and Macro-evolutionary Patterns. Integr Comp Biol 2014; 54:805-21. [DOI: 10.1093/icb/icu057] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
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135
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Abstract
Researchers studying the adaptive significance of behaviour typically assume that genetic mechanisms will not inhibit evolutionary trajectories, an assumption commonly known as the 'phenotypic gambit'. Although the phenotypic gambit continues to be a useful heuristic for behavioural ecology, here we discuss how genomic methods provide new tools and conceptual approaches that are relevant to behavioural ecology. We first describe how the concept of a genetic toolkit for behaviour can allow behavioural ecologists to synthesize both genomic and ecological information when assessing behavioural adaptation. Then we show how gene expression profiles can be viewed as complex phenotypic measurements, used to (1) predict behaviour, (2) evaluate phenotypic plasticity and (3) devise methods to manipulate behaviour in order to test adaptive hypotheses. We propose that advances in genomics and bioinformatics may allow researchers to overcome some of the logistical obstacles that motivated the inception of the phenotypic gambit. Behavioural ecology and genomics are mutually informative, providing potential synergy that could lead to powerful advances in the field of animal behaviour.
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Affiliation(s)
- Clare C Rittschof
- Department of Entomology and Institute for Genomic Biology, Urbana, IL, U.S.A
| | - Gene E Robinson
- Department of Entomology and Institute for Genomic Biology, Urbana, IL, U.S.A
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136
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Fraser BA, Janowitz I, Thairu M, Travis J, Hughes KA. Phenotypic and genomic plasticity of alternative male reproductive tactics in sailfin mollies. Proc Biol Sci 2014; 281:20132310. [PMID: 24573842 PMCID: PMC3953829 DOI: 10.1098/rspb.2013.2310] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2013] [Accepted: 01/28/2014] [Indexed: 11/12/2022] Open
Abstract
A major goal of modern evolutionary biology is to understand the causes and consequences of phenotypic plasticity, the ability of a single genotype to produce multiple phenotypes in response to variable environments. While ecological and quantitative genetic studies have evaluated models of the evolution of adaptive plasticity, some long-standing questions about plasticity require more mechanistic approaches. Here, we address two of those questions: does plasticity facilitate adaptive evolution? And do physiological costs place limits on plasticity? We examine these questions by comparing genetically and plastically regulated behavioural variation in sailfin mollies (Poecilia latipinna), which exhibit striking variation in plasticity for male mating behaviour. In this species, some genotypes respond plastically to a change in the social environment by switching between primarily courting and primarily sneaking behaviour. In contrast, other genotypes have fixed mating strategies (either courting or sneaking) and do not display plasticity. We found that genetic and plastic variation in behaviour were accompanied by partially, but not completely overlapping changes in brain gene expression, in partial support of models that predict that plasticity can facilitate adaptive evolution. We also found that behavioural plasticity was accompanied by broader and more robust changes in brain gene expression, suggesting a substantial physiological cost to plasticity. We also observed that sneaking behaviour, but not courting, was associated with upregulation of genes involved in learning and memory, suggesting that sneaking is more cognitively demanding than courtship.
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Affiliation(s)
- Bonnie A. Fraser
- Department of Biological Science, Florida State University, Tallahassee, FL 32306, USA
- Max Plank Institute for Developmental Biology, Tuebingen 70276, Germany
| | - Ilana Janowitz
- Department of Biological Science, Florida State University, Tallahassee, FL 32306, USA
| | - Margaret Thairu
- Department of Biological Science, Florida State University, Tallahassee, FL 32306, USA
- Department of Entomology, University of Wisconsin, Madison, WI 53706, USA
| | - Joseph Travis
- Department of Biological Science, Florida State University, Tallahassee, FL 32306, USA
| | - Kimberly A. Hughes
- Department of Biological Science, Florida State University, Tallahassee, FL 32306, USA
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137
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Woodard SH, Bloch G, Band MR, Robinson GE. Social regulation of maternal traits in nest-founding bumble bee (Bombus terrestris) queens. ACTA ACUST UNITED AC 2014; 216:3474-82. [PMID: 23966589 DOI: 10.1242/jeb.087403] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
During the nest-founding phase of the bumble bee colony cycle, queens undergo striking changes in maternal care behavior. Early in the founding phase, prior to the emergence of workers in the nest, queens are reproductive and also provision and feed their offspring. However, later in the founding phase, queens reduce their feeding of larvae and become specialized on reproduction. This transition is synchronized with the emergence of workers in the colony, who assume the task of feeding their siblings. Using a social manipulation experiment with the bumble bee Bombus terrestris, we tested the hypothesis that workers regulate the transition from feeding brood to specialization on reproduction in nest-founding bumble bee queens. Consistent with this hypothesis, we found that early-stage nest-founding queens with workers prematurely added to their nests reduce their brood-feeding behavior and increase egg laying, and likewise, late-stage nest-founding queens increase their brood-feeding behavior and decrease egg-laying when workers are removed from their nests. Further, brood-feeding and egg-laying behaviors were negatively correlated. We used Agilent microarrays designed from B. terrestris brain expressed sequenced tags (ESTs) to explore a second hypothesis, that workers alter brain gene expression in nest-founding queens. We found evidence that brain gene expression in nest-founding queens is altered by the presence of workers, with the effect being much stronger in late-stage founding queens. This study provides new insights into how the transition from feeding brood to specialization on reproduction in queen bumble bees is regulated during the nest initiation phase of the colony cycle.
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Affiliation(s)
- S Hollis Woodard
- Program in Ecology, Evolution, and Conservation Biology, University of Illinois, Urbana, IL 61801, USA.
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138
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Woodard SH, Bloch GM, Band MR, Robinson GE. Molecular heterochrony and the evolution of sociality in bumblebees (Bombus terrestris). Proc Biol Sci 2014; 281:20132419. [PMID: 24552837 DOI: 10.1098/rspb.2013.2419] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Sibling care is a hallmark of social insects, but its evolution remains challenging to explain at the molecular level. The hypothesis that sibling care evolved from ancestral maternal care in primitively eusocial insects has been elaborated to involve heterochronic changes in gene expression. This elaboration leads to the prediction that workers in these species will show patterns of gene expression more similar to foundress queens, who express maternal care behaviour, than to established queens engaged solely in reproductive behaviour. We tested this idea in bumblebees (Bombus terrestris) using a microarray platform with approximately 4500 genes. Unlike the wasp Polistes metricus, in which support for the above prediction has been obtained, we found that patterns of brain gene expression in foundress and queen bumblebees were more similar to each other than to workers. Comparisons of differentially expressed genes derived from this study and gene lists from microarray studies in Polistes and the honeybee Apis mellifera yielded a shared set of genes involved in the regulation of related social behaviours across independent eusocial lineages. Together, these results suggest that multiple independent evolutions of eusociality in the insects might have involved different evolutionary routes, but nevertheless involved some similarities at the molecular level.
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Affiliation(s)
- S Hollis Woodard
- Department of Integrative Biology, University of Texas at Austin, , Austin, TX 78712, USA, Department of Ecology, Evolution and Behavior, Alexander Silberman Institute of Life Sciences, Hebrew University of Jerusalem, , Jerusalem 91904, Israel, W. M. Keck Center for Comparative and Functional Genomics, University of Illinois, , Urbana, IL 61801, USA, Department of Entomology, University of Illinois, , Urbana, IL 61801, USA, Institute for Genomic Biology, University of Illinois, , Urbana, IL 61801, USA, Neuroscience Program, University of Illinois, , Urbana, IL 61801, USA
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139
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Wyatt T. Introduction to Chemical Signaling in Vertebrates and Invertebrates. Front Neurosci 2014. [DOI: 10.1201/b16511-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
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140
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Toth AL, Tooker JF, Radhakrishnan S, Minard R, Henshaw MT, Grozinger CM. Shared genes related to aggression, rather than chemical communication, are associated with reproductive dominance in paper wasps (Polistes metricus). BMC Genomics 2014; 15:75. [PMID: 24472515 PMCID: PMC3922164 DOI: 10.1186/1471-2164-15-75] [Citation(s) in RCA: 72] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2013] [Accepted: 01/14/2014] [Indexed: 12/24/2022] Open
Abstract
BACKGROUND In social groups, dominant individuals may socially inhibit reproduction of subordinates using aggressive interactions or, in the case of highly eusocial insects, pheromonal communication. It has been hypothesized these two modes of reproductive inhibition utilize conserved pathways. Here, we use a comparative framework to investigate the chemical and genomic underpinnings of reproductive dominance in the primitively eusocial wasp Polistes metricus. Our goals were to first characterize transcriptomic and chemical correlates of reproductive dominance and second, to test whether dominance-associated mechanisms in paper wasps overlapped with aggression or pheromone-related gene expression patterns in other species. To explore whether conserved molecular pathways relate to dominance, we compared wasp transcriptomic data to previous studies of gene expression associated with pheromonal communication and queen-worker differences in honey bees, and aggressive behavior in bees, Drosophila, and mice. RESULTS By examining dominant and subordinate females from queen and worker castes in early and late season colonies, we found that cuticular hydrocarbon profiles and genome-wide patterns of brain gene expression were primarily associated with season/social environment rather than dominance status. In contrast, gene expression patterns in the ovaries were associated primarily with caste and ovary activation. Comparative analyses suggest genes identified as differentially expressed in wasp brains are not related to queen pheromonal communication or caste in bees, but were significantly more likely to be associated with aggression in other insects (bees, flies), and even a mammal (mice). CONCLUSIONS This study provides the first comprehensive chemical and molecular analysis of reproductive dominance in paper wasps. We found little evidence for a chemical basis for reproductive dominance in P. metricus, and our transcriptomic analyses suggest that different pathways regulate dominance in paper wasps and pheromone response in bees. Furthermore, there was a substantial impact of season/social environment on gene expression patterns, indicating the important role of external cues in shaping the molecular processes regulating behavior. Interestingly, genes associated with dominance in wasps were also associated with aggressive behavior in bees, solitary insects and mammals. Thus, genes involved in social regulation of reproduction in Polistes may have conserved functions associated with aggression in insects and other taxa.
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Affiliation(s)
- Amy L Toth
- Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, IA 50011, USA.
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141
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Moczek AP, Kijimoto T, Snell-Rood E, Rocha G, Pespeni M, Kafadar K. Evolutionary and Ecological Genomics of Developmental Plasticity: Novel Approaches and First Insights From the Study of Horned Beetles. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2014; 781:127-48. [DOI: 10.1007/978-94-007-7347-9_7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
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142
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Rosvall KA. Proximate perspectives on the evolution of female aggression: good for the gander, good for the goose? Philos Trans R Soc Lond B Biol Sci 2013; 368:20130083. [PMID: 24167313 PMCID: PMC3826212 DOI: 10.1098/rstb.2013.0083] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Female-female aggression often functions in competition over reproductive or social benefits, but the proximate mechanisms of this apparently adaptive behaviour are not well understood. The sex steroid hormone testosterone (T) and its metabolites are well-established mediators of male-male aggression, and several lines of evidence suggest that T-mediated mechanisms may apply to females as well. However, a key question is whether mechanisms of female aggression primarily reflect correlated evolutionary responses to selection acting on males, or whether direct selection acting on females has made modifications to these mechanisms that are adaptive in light of female life history. Here, I examine the degree to which female aggression is mediated at the level of T production, target tissue sensitivity to T, or downstream genomic responses in order to test the hypothesis that selection favours mechanisms that facilitate female aggression while minimizing the costs of systemically elevated T. I draw heavily from avian systems, including the dark-eyed junco (Junco hyemalis), as well as other organisms in which these mechanisms have been well studied from an evolutionary/ecological perspective in both sexes. Findings reveal that the sexes share many behavioural and hormonal mechanisms, though several patterns also suggest sex-specific adaptation. I argue that greater attention to multiple levels of analysis-from hormone to receptor to gene network, including analyses of individual variation that represents the raw material of evolutionary change-will be a fruitful path for understanding mechanisms of behavioural regulation and intersexual coevolution.
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Affiliation(s)
- Kimberly A. Rosvall
- Department of Biology, Center for the Integrative Study of Animal Behavior, Indiana University, Bloomington, IN 47405, USA
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143
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Flenniken ML, Andino R. Non-specific dsRNA-mediated antiviral response in the honey bee. PLoS One 2013; 8:e77263. [PMID: 24130869 PMCID: PMC3795074 DOI: 10.1371/journal.pone.0077263] [Citation(s) in RCA: 94] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2013] [Accepted: 09/01/2013] [Indexed: 12/22/2022] Open
Abstract
Honey bees are essential pollinators of numerous agricultural crops. Since 2006, honey bee populations have suffered considerable annual losses that are partially attributed to Colony Collapse Disorder (CCD). CCD is an unexplained phenomenon that correlates with elevated incidence of pathogens, including RNA viruses. Honey bees are eusocial insects that live in colonies of genetically related individuals that work in concert to gather and store nutrients. Their social organization provides numerous benefits, but also facilitates pathogen transmission between individuals. To investigate honey bee antiviral defense mechanisms, we developed an RNA virus infection model and discovered that administration of dsRNA, regardless of sequence, reduced virus infection. Our results suggest that dsRNA, a viral pathogen associated molecular pattern (PAMP), triggers an antiviral response that controls virus infection in honey bees.
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Affiliation(s)
- Michelle L. Flenniken
- Department of Microbiology and Immunology, University of California San Francisco, San Francisco, California, United States of America
- Department of Plant Sciences and Plant Pathology, Montana State University, Bozeman, Montana, United States of America
- * E-mail: (MLF); (RA)
| | - Raul Andino
- Department of Microbiology and Immunology, University of California San Francisco, San Francisco, California, United States of America
- * E-mail: (MLF); (RA)
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144
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Rittschof CC, Robinson GE. Manipulation of colony environment modulates honey bee aggression and brain gene expression. GENES BRAIN AND BEHAVIOR 2013; 12:802-11. [PMID: 24034579 DOI: 10.1111/gbb.12087] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2013] [Revised: 09/09/2013] [Accepted: 09/10/2013] [Indexed: 11/27/2022]
Abstract
The social environment plays an essential role in shaping behavior for most animals. Social effects on behavior are often linked to changes in brain gene expression. In the honey bee (Apis mellifera L.), social modulation of individual aggression allows colonies to adjust the intensity with which they defend their hive in response to predation threat. Previous research has showed social effects on both aggression and aggression-related brain gene expression in honey bees, caused by alarm pheromone and unknown factors related to colony genotype. For example, some bees from less aggressive genetic stock reared in colonies with genetic predispositions toward increased aggression show both increased aggression and more aggressive-like brain gene expression profiles. We tested the hypothesis that exposure to a colony environment influenced by high levels of predation threat results in increased aggression and aggressive-like gene expression patterns in individual bees. We assessed gene expression using four marker genes. Experimentally induced predation threats modified behavior, but the effect was opposite of our predictions: disturbed colonies showed decreased aggression. Disturbed colonies also decreased foraging activity, suggesting that they did not habituate to threats; other explanations for this finding are discussed. Bees in disturbed colonies also showed changes in brain gene expression, some of which paralleled behavioral findings. These results show that bee aggression and associated molecular processes are subject to complex social influences.
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Affiliation(s)
- C C Rittschof
- Department of Entomology and Institute for Genomic Biology, University of Illinois Urbana-Champaign, Urban, IL, USA
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145
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Wheeler MM, Ament SA, Rodriguez-Zas SL, Robinson GE. Brain gene expression changes elicited by peripheral vitellogenin knockdown in the honey bee. INSECT MOLECULAR BIOLOGY 2013; 22:562-573. [PMID: 23889463 DOI: 10.1111/imb.12043] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Vitellogenin (Vg) is best known as a yolk protein precursor. Vg also functions to regulate behavioural maturation in adult honey bee workers, but the underlying molecular mechanisms by which it exerts this novel effect are largely unknown. We used abdominal vitellogenin (vg) knockdown with RNA interference (RNAi) and brain transcriptomic profiling to gain insights into how Vg influences honey bee behavioural maturation. We found that vg knockdown caused extensive gene expression changes in the bee brain, with much of this transcriptional response involving changes in central biological functions such as energy metabolism. vg knockdown targeted many of the same genes that show natural, maturation-related differences, but the direction of change for the genes in these two contrasts was not correlated. By contrast, vg knockdown targeted many of the same genes that are regulated by juvenile hormone (JH) and there was a significant correlation for the direction of change for the genes in these two contrasts. These results indicate that the tight coregulatory relationship that exists between JH and Vg in the regulation of honey bee behavioural maturation is manifest at the genomic level and suggest that these two physiological factors act through common pathways to regulate brain gene expression and behaviour.
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Affiliation(s)
- M M Wheeler
- Department of Entomology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
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146
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Cingolani P, Cao X, Khetani RS, Chen CC, Coon M, Sammak A, Bollig-Fischer A, Land S, Huang Y, Hudson ME, Garfinkel MD, Zhong S, Robinson GE, Ruden DM. Intronic non-CG DNA hydroxymethylation and alternative mRNA splicing in honey bees. BMC Genomics 2013; 14:666. [PMID: 24079845 PMCID: PMC3850688 DOI: 10.1186/1471-2164-14-666] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2013] [Accepted: 09/22/2013] [Indexed: 11/20/2022] Open
Abstract
Background Previous whole-genome shotgun bisulfite sequencing experiments showed that DNA cytosine methylation in the honey bee (Apis mellifera) is almost exclusively at CG dinucleotides in exons. However, the most commonly used method, bisulfite sequencing, cannot distinguish 5-methylcytosine from 5-hydroxymethylcytosine, an oxidized form of 5-methylcytosine that is catalyzed by the TET family of dioxygenases. Furthermore, some analysis software programs under-represent non-CG DNA methylation and hydryoxymethylation for a variety of reasons. Therefore, we used an unbiased analysis of bisulfite sequencing data combined with molecular and bioinformatics approaches to distinguish 5-methylcytosine from 5-hydroxymethylcytosine. By doing this, we have performed the first whole genome analyses of DNA modifications at non-CG sites in honey bees and correlated the effects of these DNA modifications on gene expression and alternative mRNA splicing. Results We confirmed, using unbiased analyses of whole-genome shotgun bisulfite sequencing (BS-seq) data, with both new data and published data, the previous finding that CG DNA methylation is enriched in exons in honey bees. However, we also found evidence that cytosine methylation and hydroxymethylation at non-CG sites is enriched in introns. Using antibodies against 5-hydroxmethylcytosine, we confirmed that DNA hydroxymethylation at non-CG sites is enriched in introns. Additionally, using a new technique, Pvu-seq (which employs the enzyme PvuRts1l to digest DNA at 5-hydroxymethylcytosine sites followed by next-generation DNA sequencing), we further confirmed that hydroxymethylation is enriched in introns at non-CG sites. Conclusions Cytosine hydroxymethylation at non-CG sites might have more functional significance than previously appreciated, and in honey bees these modifications might be related to the regulation of alternative mRNA splicing by defining the locations of the introns.
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Affiliation(s)
- Pablo Cingolani
- Department of Obstetrics and Gynecology, Wayne State University, Detroit, MI 48201, USA.
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147
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Ugajin A, Kunieda T, Kubo T. Identification and characterization of an Egr ortholog as a neural immediate early gene in the European honeybee (Apis mellifera L.). FEBS Lett 2013; 587:3224-30. [PMID: 23994532 DOI: 10.1016/j.febslet.2013.08.014] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2013] [Revised: 08/19/2013] [Accepted: 08/19/2013] [Indexed: 10/26/2022]
Abstract
To date, there are only few reports of immediate early genes (IEGs) available in insects. Aiming at identifying a conserved IEG in insects, we characterized an Egr homolog of the honeybee (AmEgr: Apis mellifera Egr). AmEgr was transiently induced in whole worker brains after seizure induction. In situ hybridization for AmEgr indicated that neural activity of a certain mushroom body (a higher brain center) neuron subtype, which is the same as that we previously identified using another non-coding IEG, termed kakusei, is more enhanced in forager brains. These findings suggest that Egr can be utilized as an IEG in insects.
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Affiliation(s)
- Atsushi Ugajin
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
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148
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149
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Renn SC, Schumer ME. Genetic accommodation and behavioural evolution: insights from genomic studies. Anim Behav 2013. [DOI: 10.1016/j.anbehav.2013.02.012] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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150
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Ferreira PG, Patalano S, Chauhan R, Ffrench-Constant R, Gabaldón T, Guigó R, Sumner S. Transcriptome analyses of primitively eusocial wasps reveal novel insights into the evolution of sociality and the origin of alternative phenotypes. Genome Biol 2013; 14:R20. [PMID: 23442883 PMCID: PMC4053794 DOI: 10.1186/gb-2013-14-2-r20] [Citation(s) in RCA: 105] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2012] [Accepted: 02/26/2013] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND Understanding how alternative phenotypes arise from the same genome is a major challenge in modern biology. Eusociality in insects requires the evolution of two alternative phenotypes - workers, who sacrifice personal reproduction, and queens, who realize that reproduction. Extensive work on honeybees and ants has revealed the molecular basis of derived queen and worker phenotypes in highly eusocial lineages, but we lack equivalent deep-level analyses of wasps and of primitively eusocial species, the latter of which can reveal how phenotypic decoupling first occurs in the early stages of eusocial evolution. RESULTS We sequenced 20 Gbp of transcriptomes derived from brains of different behavioral castes of the primitively eusocial tropical paper wasp Polistes canadensis. Surprisingly, 75% of the 2,442 genes differentially expressed between phenotypes were novel, having no significant homology with described sequences. Moreover, 90% of these novel genes were significantly upregulated in workers relative to queens. Differential expression of novel genes in the early stages of sociality may be important in facilitating the evolution of worker behavioral complexity in eusocial evolution. We also found surprisingly low correlation in the identity and direction of expression of differentially expressed genes across similar phenotypes in different social lineages, supporting the idea that social evolution in different lineages requires substantial de novo rewiring of molecular pathways. CONCLUSIONS These genomic resources for aculeate wasps and first transcriptome-wide insights into the origin of castes bring us closer to a more general understanding of eusocial evolution and how phenotypic diversity arises from the same genome.
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