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Golian MJ, Friedman DA, Harrison M, McMahon DP, Buellesbach J. Chemical and transcriptomic diversity do not correlate with ascending levels of social complexity in the insect order Blattodea. Ecol Evol 2024; 14:e70063. [PMID: 39091327 PMCID: PMC11289792 DOI: 10.1002/ece3.70063] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2024] [Revised: 06/21/2024] [Accepted: 07/11/2024] [Indexed: 08/04/2024] Open
Abstract
Eusocial insects, such as ants and termites, are characterized by high levels of coordinated social organization. This is contrasted by solitary insects that display more limited forms of collective behavior. It has been hypothesized that this gradient in sociobehavioral sophistication is positively correlated with chemical profile complexity, due to a potentially increased demand for diversity in chemical communication mechanisms in insects with higher levels of social complexity. However, this claim has rarely been assessed empirically. Here, we compare different levels of chemical and transcriptomic complexity in selected species of the order Blattodea that represent different levels of social organization, from solitary to eusocial. We primarily focus on cuticular hydrocarbon (CHC) complexity, since it has repeatedly been demonstrated that CHCs are key signaling molecules conveying a wide variety of chemical information in solitary as well as eusocial insects. We assessed CHC complexity and divergence between our studied taxa of different social complexity levels as well as the differentiation of their respective repertoires of CHC biosynthesis gene transcripts. Surprisingly, we did not find any consistent pattern of chemical complexity correlating with social complexity, nor did the overall chemical divergence or transcriptomic repertoire of CHC biosynthesis genes reflect on the levels of social organization. Our results challenge the assumption that increasing social complexity is generally reflected in more complex chemical profiles and point toward the need for a more cautious and differentiated view on correlating complexity on a chemical, genetic, and social level.
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Affiliation(s)
- Marek J. Golian
- Institute for Evolution & BiodiversityUniversity of MünsterMünsterGermany
| | - Daniel A. Friedman
- Department of Entomology & NematologyUniversity of California – DavisDavisCaliforniaUSA
| | - Mark Harrison
- Institute for Evolution & BiodiversityUniversity of MünsterMünsterGermany
| | - Dino P. McMahon
- Institute of Biology – Zoology, Freie Universität BerlinBerlinGermany
- Department for Materials and EnvironmentBAM Federal Institute for Materials Research and TestingBerlinGermany
| | - Jan Buellesbach
- Institute for Evolution & BiodiversityUniversity of MünsterMünsterGermany
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2
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Oguchi K, Miura T. Body part-specific development in termite caste differentiation: crosstalk between hormonal actions and developmental toolkit genes. CURRENT OPINION IN INSECT SCIENCE 2024; 63:101183. [PMID: 38428818 DOI: 10.1016/j.cois.2024.101183] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2023] [Revised: 02/24/2024] [Accepted: 02/25/2024] [Indexed: 03/03/2024]
Abstract
In social insects, interactions among colony members trigger caste differentiation with morphological modifications. During caste differentiation in termites, body parts and caste-specific morphologies are modified during postembryonic development under endocrine controls such as juvenile hormone (JH) and ecdysone. In addition to endocrine factors, developmental toolkit genes such as Hox- and appendage-patterning genes also contribute to the caste-specific body part modifications. These toolkits are thought to provide spatial information for specific morphogenesis. During social evolution, the complex crosstalks between physiological and developmental mechanisms should be established, leading to the sophisticated caste systems. This article reviews recent studies on these mechanisms underlying the termite caste differentiation and addresses implications for the evolution of caste systems in termites.
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Affiliation(s)
- Kohei Oguchi
- Misaki Marine Biological Station, The University of Tokyo, Miura, Kanagawa 238-0225, Japan
| | - Toru Miura
- Misaki Marine Biological Station, The University of Tokyo, Miura, Kanagawa 238-0225, Japan.
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3
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Rau V, Flatt T, Korb J. The remoulding of dietary effects on the fecundity / longevity trade-off in a social insect. BMC Genomics 2023; 24:244. [PMID: 37147612 PMCID: PMC10163710 DOI: 10.1186/s12864-023-09335-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2022] [Accepted: 04/25/2023] [Indexed: 05/07/2023] Open
Abstract
BACKGROUND In many organisms increased reproductive effort is associated with a shortened life span. This trade-off is reflected in conserved molecular pathways that link nutrient-sensing with fecundity and longevity. Social insect queens apparently defy the fecundity / longevity trade-off as they are both, extremely long-lived and highly fecund. Here, we have examined the effects of a protein-enriched diet on these life-history traits and on tissue-specific gene expression in a termite species of low social complexity. RESULTS On a colony level, we did not observe reduced lifespan and increased fecundity, effects typically seen in solitary model organisms, after protein enrichment. Instead, on the individual level mortality was reduced in queens that consumed more of the protein-enriched diet - and partially also in workers - while fecundity seemed unaffected. Our transcriptome analyses supported our life-history results. Consistent with life span extension, the expression of IIS (insulin/insulin-like growth factor 1 signalling) components was reduced in fat bodies after protein enrichment. Interestingly, however, genes involved in reproductive physiology (e.g., vitellogenin) were largely unaffected in fat body and head transcriptomes. CONCLUSION These results suggest that IIS is decoupled from downstream fecundity-associated pathways, which can contribute to the remoulding of the fecundity/longevity trade-off in termites as compared to solitary insects.
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Affiliation(s)
- Veronika Rau
- Evolutionary Biology & Ecology, University of Freiburg, Hauptstrasse 1, 79104, Freiburg (Brsg.), Germany.
| | - Thomas Flatt
- Department of Biology, University of Fribourg, Chemin du Musée 10, CH-1700, Fribourg, Switzerland
| | - Judith Korb
- Evolutionary Biology & Ecology, University of Freiburg, Hauptstrasse 1, 79104, Freiburg (Brsg.), Germany.
- RIEL, Charles Darwin University Casuarina Campus, Ellengowan Drive, Darwin, NT0811, Australia.
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4
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Bai ZD, Shi CY, Sillam-Dussès D, Wang RW. Elusive workers are more likely to differentiate into replacement reproductives than aggressive workers in a lower termite. Curr Zool 2022. [DOI: 10.1093/cz/zoac040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Abstract
One of the most intriguing questions in eusocial insects is to understand how the overt reproductive conflict in the colony appears limited when queens or kings are senescent or lost, since the morphologically similar individuals in the colony are reproductively totipotent. Whether there are some individuals which preferentially differentiate into replacement reproductives or not has received little attention. The consistent individual behavioral differences (also termed ‘animal personality’) of individuals from the colony can shape cunningly their task and consequently affect the colony fitness but have been rarely investigated in eusocial insects. Here, we used the termite Reticulitermes labralis to investigate if variations in individual personalities (elusiveness and aggressiveness) may predict which individuals will perform reproductive differentiation within colonies. We observed that when we separately reared elusive and aggressive workers, elusive workers differentiate into reproductives significantly earlier than aggressive workers. When we reared them together in the proportions 12:3, 10:5 and 8:7 (aggressive workers:elusive workers), the first reproductives mostly differentiated from the elusive workers, and the reproductives differentiated from the elusive workers significantly earlier than from aggressive workers. Furthermore, we found that the number of workers participating in reproductive differentiation was significantly lower in the groups of both type of workers than in groups containing only elusive workers. Our results demonstrate that the elusiveness trait was a strong predictor of workers differentiation into replacement reproductives in R. labralis. Moreover, our results suggest that individual personalities within the insect society could play a key role in resolving the overt reproductive conflict.
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Affiliation(s)
- Zhuang-Dong Bai
- School of Ecology and Environment, Northwestern Polytechnical University, Xi’an 710072, China
| | - Chong-Yang Shi
- School of Ecology and Environment, Northwestern Polytechnical University, Xi’an 710072, China
| | - David Sillam-Dussès
- Laboratory of Experimental and Comparative Ethology, LEEC, UR 4443, University Sorbonne Paris Nord, Villetaneuse, France
| | - Rui-Wu Wang
- School of Ecology and Environment, Northwestern Polytechnical University, Xi’an 710072, China
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Padget RFB, Thompson FJ. Marking through molts: An evaluation of visible implant elastomer to permanently mark individuals in a lower termite species. Ecol Evol 2021; 11:12834-12844. [PMID: 34594542 PMCID: PMC8462160 DOI: 10.1002/ece3.8030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 07/12/2021] [Accepted: 07/26/2021] [Indexed: 12/02/2022] Open
Abstract
Advances in individual marking methods have facilitated detailed studies of animal populations and behavior as they allow tracking of individuals through time and space. Hemimetabolous insects, representing a wide range of commonly used model organisms, present a unique challenge to individual marking as they are not only generally small-bodied, but also molt throughout development, meaning that traditional surface marks are not persistent.Visible implant elastomer (VIE) offers a potential solution as small amounts of the inert polymer can be implanted under the skin or cuticle of an animal. VIE has proved useful for individually marking fish, crustaceans, and amphibians in both field and laboratory studies and has recently been successfully trialed in laboratory populations of worms and fly larvae. We trialed VIE in the single-piece nesting termite Zootermopsis angusticollis, a small hemimetabolous insect.We found that there was no effect of VIE on survival and that marks persisted following molting. However, we found some evidence that marked termites performed less allogrooming and trophallaxis than controls, although effect sizes were very small.Our study suggests that VIE is an effective technique for marking small hemimetabolous insects like termites but we advocate that caution is applied, particularly when behavioral observation is important.
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Affiliation(s)
- Rebecca F. B. Padget
- Centre for Ecology and ConservationCollege of Life and Environmental SciencesUniversity of ExeterCornwallUK
- Centre for Research in Animal BehaviourCollege of Life and Environmental SciencesUniversity of ExeterExeterUK
| | - Faye J. Thompson
- Centre for Ecology and ConservationCollege of Life and Environmental SciencesUniversity of ExeterCornwallUK
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6
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Korb J, Meusemann K, Aumer D, Bernadou A, Elsner D, Feldmeyer B, Foitzik S, Heinze J, Libbrecht R, Lin S, Majoe M, Monroy Kuhn JM, Nehring V, Negroni MA, Paxton RJ, Séguret AC, Stoldt M, Flatt T. Comparative transcriptomic analysis of the mechanisms underpinning ageing and fecundity in social insects. Philos Trans R Soc Lond B Biol Sci 2021; 376:20190728. [PMID: 33678016 PMCID: PMC7938167 DOI: 10.1098/rstb.2019.0728] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/04/2021] [Indexed: 12/13/2022] Open
Abstract
The exceptional longevity of social insect queens despite their lifelong high fecundity remains poorly understood in ageing biology. To gain insights into the mechanisms that might underlie ageing in social insects, we compared gene expression patterns between young and old castes (both queens and workers) across different lineages of social insects (two termite, two bee and two ant species). After global analyses, we paid particular attention to genes of the insulin/insulin-like growth factor 1 signalling (IIS)/target of rapamycin (TOR)/juvenile hormone (JH) network, which is well known to regulate lifespan and the trade-off between reproduction and somatic maintenance in solitary insects. Our results reveal a major role of the downstream components and target genes of this network (e.g. JH signalling, vitellogenins, major royal jelly proteins and immune genes) in affecting ageing and the caste-specific physiology of social insects, but an apparently lesser role of the upstream IIS/TOR signalling components. Together with a growing appreciation of the importance of such downstream targets, this leads us to propose the TI-J-LiFe (TOR/IIS-JH-Lifespan and Fecundity) network as a conceptual framework for understanding the mechanisms of ageing and fecundity in social insects and beyond. This article is part of the theme issue 'Ageing and sociality: why, when and how does sociality change ageing patterns?'
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Affiliation(s)
- Judith Korb
- Department of Evolutionary Biology and Ecology, Institute of Biology I (Zoology), University of Freiburg, Hauptstraße 1, D-79104 Freiburg (Breisgau), Germany
| | - Karen Meusemann
- Department of Evolutionary Biology and Ecology, Institute of Biology I (Zoology), University of Freiburg, Hauptstraße 1, D-79104 Freiburg (Breisgau), Germany
- Australian National Insect Collection, CSIRO National Research Collections Australia, Clunies Ross Street, Canberra, Acton 2601, Australia
| | - Denise Aumer
- Developmental Zoology, Molecular Ecology Research Group, Hoher Weg 4, D-06099 Halle (Saale), Germany
| | - Abel Bernadou
- Zoology/Evolutionary Biology, University of Regensburg, Universitätsstraße 31, D-93040 Regensburg, Germany
| | - Daniel Elsner
- Department of Evolutionary Biology and Ecology, Institute of Biology I (Zoology), University of Freiburg, Hauptstraße 1, D-79104 Freiburg (Breisgau), Germany
| | - Barbara Feldmeyer
- Senckenberg Biodiversity and Climate Research Centre (SBiK-F), Molecular Ecology, Senckenberg, Georg-Voigt-Straße 14-16, D-60325 Frankfurt, Germany
| | - Susanne Foitzik
- Institute of Organismic and Molecular Evolution (IOME), Johannes Gutenberg University Mainz, Hanns-Dieter-Hüsch-Weg 15, D-55128 Mainz, Germany
| | - Jürgen Heinze
- Zoology/Evolutionary Biology, University of Regensburg, Universitätsstraße 31, D-93040 Regensburg, Germany
| | - Romain Libbrecht
- Institute of Organismic and Molecular Evolution (IOME), Johannes Gutenberg University Mainz, Hanns-Dieter-Hüsch-Weg 15, D-55128 Mainz, Germany
| | - Silu Lin
- Department of Evolutionary Biology and Ecology, Institute of Biology I (Zoology), University of Freiburg, Hauptstraße 1, D-79104 Freiburg (Breisgau), Germany
| | - Megha Majoe
- Department of Evolutionary Biology and Ecology, Institute of Biology I (Zoology), University of Freiburg, Hauptstraße 1, D-79104 Freiburg (Breisgau), Germany
- Institute of Organismic and Molecular Evolution (IOME), Johannes Gutenberg University Mainz, Hanns-Dieter-Hüsch-Weg 15, D-55128 Mainz, Germany
| | - José Manuel Monroy Kuhn
- Department of Evolutionary Biology and Ecology, Institute of Biology I (Zoology), University of Freiburg, Hauptstraße 1, D-79104 Freiburg (Breisgau), Germany
| | - Volker Nehring
- Department of Evolutionary Biology and Ecology, Institute of Biology I (Zoology), University of Freiburg, Hauptstraße 1, D-79104 Freiburg (Breisgau), Germany
| | - Matteo A. Negroni
- Institute of Organismic and Molecular Evolution (IOME), Johannes Gutenberg University Mainz, Hanns-Dieter-Hüsch-Weg 15, D-55128 Mainz, Germany
| | - Robert J. Paxton
- Institute for Biology, Martin Luther University Halle-Wittenberg, Hoher Weg 8, 06120 Halle, Germany
| | - Alice C. Séguret
- Institute for Biology, Martin Luther University Halle-Wittenberg, Hoher Weg 8, 06120 Halle, Germany
- Institute for Evolution and Biodiversity, University of Münster, Hüfferstraße 1, 48149 Münster, Germany
| | - Marah Stoldt
- Institute of Organismic and Molecular Evolution (IOME), Johannes Gutenberg University Mainz, Hanns-Dieter-Hüsch-Weg 15, D-55128 Mainz, Germany
| | - Thomas Flatt
- Department of Biology, University of Fribourg, Chemin du Musée 10, CH-1700 Fribourg, Switzerland
| | - the So-Long consortium
- Department of Evolutionary Biology and Ecology, Institute of Biology I (Zoology), University of Freiburg, Hauptstraße 1, D-79104 Freiburg (Breisgau), Germany
- Australian National Insect Collection, CSIRO National Research Collections Australia, Clunies Ross Street, Canberra, Acton 2601, Australia
- Developmental Zoology, Molecular Ecology Research Group, Hoher Weg 4, D-06099 Halle (Saale), Germany
- Zoology/Evolutionary Biology, University of Regensburg, Universitätsstraße 31, D-93040 Regensburg, Germany
- Senckenberg Biodiversity and Climate Research Centre (SBiK-F), Molecular Ecology, Senckenberg, Georg-Voigt-Straße 14-16, D-60325 Frankfurt, Germany
- Institute of Organismic and Molecular Evolution (IOME), Johannes Gutenberg University Mainz, Hanns-Dieter-Hüsch-Weg 15, D-55128 Mainz, Germany
- Institute for Biology, Martin Luther University Halle-Wittenberg, Hoher Weg 8, 06120 Halle, Germany
- Institute for Evolution and Biodiversity, University of Münster, Hüfferstraße 1, 48149 Münster, Germany
- Department of Biology, University of Fribourg, Chemin du Musée 10, CH-1700 Fribourg, Switzerland
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7
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Lin S, Werle J, Korb J. Transcriptomic analyses of the termite, Cryptotermes secundus, reveal a gene network underlying a long lifespan and high fecundity. Commun Biol 2021; 4:384. [PMID: 33753888 PMCID: PMC7985136 DOI: 10.1038/s42003-021-01892-x] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2020] [Accepted: 02/19/2021] [Indexed: 01/31/2023] Open
Abstract
Organisms are typically characterized by a trade-off between fecundity and longevity. Notable exceptions are social insects. In insect colonies, the reproducing caste (queens) outlive their non-reproducing nestmate workers by orders of magnitude and realize fecundities and lifespans unparalleled among insects. How this is achieved is not understood. Here, we identified a single module of co-expressed genes that characterized queens in the termite species Cryptotermes secundus. It encompassed genes from all essential pathways known to be involved in life-history regulation in solitary model organisms. By manipulating its endocrine component, we tested the recent hypothesis that re-wiring along the nutrient-sensing/endocrine/fecundity axis can account for the reversal of the fecundity/longevity trade-off in social insect queens. Our data from termites do not support this hypothesis. However, they revealed striking links to social communication that offer new avenues to understand the re-modelling of the fecundity/longevity trade-off in social insects.
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Affiliation(s)
- Silu Lin
- grid.5963.9Evolutionary Biology and Ecology, University of Freiburg, Freiburg, Germany
| | - Jana Werle
- grid.5963.9Evolutionary Biology and Ecology, University of Freiburg, Freiburg, Germany
| | - Judith Korb
- grid.5963.9Evolutionary Biology and Ecology, University of Freiburg, Freiburg, Germany
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8
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Korb J, Greiner C, Foget M, Geiler A. How Can Termites Achieve Their Unparalleled Postembryonic Developmental Plasticity? A Test for the Role of Intermolt-Specific High Juvenile Hormone Titers. Front Ecol Evol 2021. [DOI: 10.3389/fevo.2021.619594] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Termites are “social cockroaches” and amongst the most phenotypically plastic insects. The different castes (i.e., two types of reproductives, workers, and soldiers) within termite societies are all encoded by a single genome and present the result of differential postembryonic development. Besides the default progressive development into winged sexuals of solitary hemimetabolous insects, termites have two postembryonic, non-terminal molts (stationary and regressive; i.e., molts associated, respectively, with no change or reduction of size/morphological differentiation) which allow them to retain workers, and two terminal developmental types to become soldiers and replacement reproductives. Despite this unique plasticity, especially the mechanisms underlying the non-terminal development are poorly understood. In 1982, Nijhout and Wheeler proposed a model how this diversity might have evolved. They proposed that varying juvenile hormone (JH) titers at the start, mid-phase, and end of each intermolt period account for the developmental diversity. We tested this rarely addressed model in the lower termite Cryptotermes secundus using phase-specific pharmacological manipulations of JH titers. Our results partially support the Nijhout and Wheeler model. These data are supplemented with gene expression studies of JH-related genes that characterize different postembryonic developmental trajectories. Our study provides new insights into the evolution of the unique postembryonic developmental plasticity of termites that constitutes the foundation of their social life.
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9
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Pull CD, McMahon DP. Superorganism Immunity: A Major Transition in Immune System Evolution. Front Ecol Evol 2020. [DOI: 10.3389/fevo.2020.00186] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
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10
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Sun Q, Hampton JD, Merchant A, Haynes KF, Zhou X. Cooperative policing behaviour regulates reproductive division of labour in a termite. Proc Biol Sci 2020; 287:20200780. [PMID: 32517622 DOI: 10.1098/rspb.2020.0780] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Reproductive conflicts are common in insect societies where helping castes retain reproductive potential. One of the mechanisms regulating these conflicts is policing, a coercive behaviour that reduces direct reproduction by other individuals. In eusocial Hymenoptera (ants, bees and wasps), workers or the queen act aggressively towards fertile workers, or destroy their eggs. In many termite species (order Blattodea), upon the death of the primary queen and king, workers and nymphs can differentiate into neotenic reproductives and inherit the breeding position. During this process, competition among neotenics is inevitable, but how this conflict is resolved remains unclear. Here, we report a policing behaviour that regulates reproductive division of labour in the eastern subterranean termite, Reticulitermes flavipes. Our results demonstrate that the policing behaviour is a cooperative effort performed sequentially by successful neotenics and workers. A neotenic reproductive initiates the attack of the fellow neotenic by biting and displays alarm behaviour. Workers are then recruited to cannibalize the injured neotenic. Furthermore, the initiation of policing is age-dependent, with older reproductives attacking younger ones, thereby inheriting the reproductive position. This study provides empirical evidence of policing behaviour in termites, which represents a convergent trait shared between eusocial Hymenoptera and Blattodea.
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Affiliation(s)
- Qian Sun
- Department of Entomology, Louisiana State University Agricultural Center, Baton Rouge, LA 70803, USA.,Department of Entomology, University of Kentucky, S-225 Agricultural Science Center North, Lexington, KY 40546-0091, USA
| | - Jordan D Hampton
- Department of Entomology, University of Kentucky, S-225 Agricultural Science Center North, Lexington, KY 40546-0091, USA
| | - Austin Merchant
- Department of Entomology, University of Kentucky, S-225 Agricultural Science Center North, Lexington, KY 40546-0091, USA
| | - Kenneth F Haynes
- Department of Entomology, University of Kentucky, S-225 Agricultural Science Center North, Lexington, KY 40546-0091, USA
| | - Xuguo Zhou
- Department of Entomology, University of Kentucky, S-225 Agricultural Science Center North, Lexington, KY 40546-0091, USA
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11
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Korb J. Chemical Fertility Signaling in Termites: Idiosyncrasies and Commonalities in Comparison with Ants. J Chem Ecol 2018; 44:818-826. [PMID: 29616376 DOI: 10.1007/s10886-018-0952-2] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2017] [Revised: 02/15/2018] [Accepted: 03/21/2018] [Indexed: 11/25/2022]
Abstract
Termites evolved eusociality independently from social Hymenoptera. As a common trait, reproductive monopoly is maintained through chemical communication. The queen (and in termites also a king) prevents workers from reproduction by conveying their reproductive status. In termites all soldiers are sterile, but workers' potential to reproduce differs between species. It ranges from totipotency in wood-dwelling lower termites where workers are a transient stage from which all other castes develop, to sterile workers in some higher termites. Intermediate are species in which workers can develop into replacement sexuals within the nest but not into winged sexuals. I summarize the patchy picture about fertility signaling that we currently have for termites, pointing also to potential conflicts over reproduction that differ from those in social Hymenoptera. Recent findings imply that, similar to many social Hymenoptera, wood-dwelling termites that live in confined nests use long-chain cuticular hydrocarbons (CHCs) as fertility signals. Yet other compounds are important as well, comprising proteinaceous secretions and especially volatiles. For a subterranean termite, two volatiles have been identified as primer pheromones that prevent reproductive differentiation of workers. It requires more data to test whether wood-dwelling termites use CHCs, while species with larger colonies and less confined nests use volatiles, or whether all species rely on multicomponent signals. Ultimately, we need more effort to model and test potential conflicts over reproduction between queens, kings and workers. Here results from social Hymenoptera cannot be transferred to termites as the latter are diploid and commonly inbred. This review illustrates promising future research avenues.
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Affiliation(s)
- Judith Korb
- Evolutionary Biology & Ecology, University of Freiburg, Hauptstrasse 1, D-79104, Freiburg, Germany.
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12
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Santos AA, de Oliveira BMS, Melo CR, Lima APS, Santana EDR, Blank AF, Picanço MC, Araújo APA, Cristaldo PF, Bacci L. Sub-lethal effects of essential oil of Lippia sidoides on drywood termite Cryptotermes brevis (Blattodea: Termitoidea). ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2017; 145:436-441. [PMID: 28778042 DOI: 10.1016/j.ecoenv.2017.07.057] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2017] [Revised: 07/18/2017] [Accepted: 07/24/2017] [Indexed: 06/07/2023]
Abstract
The drywood termite Cryptotermes brevis (Walker, 1853) (Kalotermitidae) is one of the most important wood structural pest in the world. Substances from the secondary metabolism of plants (e.g., essential oils) have been considered an environmentally safer form of control for urban pests, such as termites. In the present study, we analyzed the lethal and sub-lethal effects of essential oil of Lippia sidoides and its major components on C. brevis pseudergates in two routes of exposure (contact and fumigation). The essential oil of L. sidoides and thymol were more toxic to C. brevis pseudergates when applied by contact (LD50 = 9.33 and 8.20µgmg-1, respectively) and by fumigation (LC50 = 9.10 and 23.6µLL-1, respectively). In general, treatments changed the individual and collective behaviors of C. brevis pseudergates, as well as the displacement and walking speed. The essential oil of L. sidoides and its major components showed a high potential to control C. brevis pseudergates, due to the bioactivity in the two routes of exposure and the sub-lethal effects on the behavior and walking, important activities for the cohesion of C. brevis colonies.
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Affiliation(s)
- Abraão Almeida Santos
- Departamento de Engenharia Agronômica, and Departamento de Ecologia, Universidade Federal de Sergipe, São Cristóvão, Sergipe 49100-000, Brazil; Departamento de Entomologia, Universidade Federal de Viçosa, Viçosa, Minas Gerais 36570-900, Brazil
| | - Bruna Maria Santos de Oliveira
- Departamento de Engenharia Agronômica, and Departamento de Ecologia, Universidade Federal de Sergipe, São Cristóvão, Sergipe 49100-000, Brazil
| | - Carlisson Ramos Melo
- Departamento de Engenharia Agronômica, and Departamento de Ecologia, Universidade Federal de Sergipe, São Cristóvão, Sergipe 49100-000, Brazil
| | - Ana Paula Santana Lima
- Departamento de Engenharia Agronômica, and Departamento de Ecologia, Universidade Federal de Sergipe, São Cristóvão, Sergipe 49100-000, Brazil
| | - Emile Dayara Rabelo Santana
- Departamento de Engenharia Agronômica, and Departamento de Ecologia, Universidade Federal de Sergipe, São Cristóvão, Sergipe 49100-000, Brazil
| | - Arie Fitzgerald Blank
- Departamento de Engenharia Agronômica, and Departamento de Ecologia, Universidade Federal de Sergipe, São Cristóvão, Sergipe 49100-000, Brazil
| | - Marcelo Coutinho Picanço
- Departamento de Entomologia, Universidade Federal de Viçosa, Viçosa, Minas Gerais 36570-900, Brazil
| | - Ana Paula Albano Araújo
- Departamento de Engenharia Agronômica, and Departamento de Ecologia, Universidade Federal de Sergipe, São Cristóvão, Sergipe 49100-000, Brazil
| | - Paulo Fellipe Cristaldo
- Departamento de Engenharia Agronômica, and Departamento de Ecologia, Universidade Federal de Sergipe, São Cristóvão, Sergipe 49100-000, Brazil
| | - Leandro Bacci
- Departamento de Engenharia Agronômica, and Departamento de Ecologia, Universidade Federal de Sergipe, São Cristóvão, Sergipe 49100-000, Brazil.
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Vickruck JL, Richards MH. Nestmate discrimination based on familiarity but not relatedness in eastern carpenter bees. Behav Processes 2017; 145:73-80. [PMID: 29031812 DOI: 10.1016/j.beproc.2017.10.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2017] [Revised: 10/08/2017] [Accepted: 10/09/2017] [Indexed: 10/18/2022]
Abstract
How animals recognize conspecific individuals has important outcomes in many contexts, but interactions among group members are particularly important. Two recognition criteria are often implicated in these interactions: kin recognition is based on relatedness cues and nestmate recognition is based on familiarity. For social insects, both types of recognition are possible, as many nestmates are close kin and familiarity can develop among individuals that encounter each other repeatedly. To discern whether social insects use kin or nestmate recognition, it is necessary to simultaneously assess how relatedness and familiarity influence behaviour. The facultatively social eastern carpenter bee, Xylocopa virginica, offers an excellent opportunity to study how either nestmate or kin recognition (or both) may influence interactions among nestmates, as many females disperse from their natal nests in spring, and often attempt to join new colonies that may contain unrelated individuals. This leads to frequent behavioural interactions among females that may be related or unrelated, and familiar or unfamiliar. We used observation nests and microsatellite loci to assess the influence of familiarity and relatedness on behavioural interactions during the early phase of colony development, when females establish reproductive queues prior to brood production. Females were more likely to feed and were less aggressive to familiar rather than related nestmates, regardless of their relatedness. This suggests that eastern carpenter bees primarily use learned cues to discriminate among nestmates. Interactions with nestmates were also context-dependent, as females returning to the nest without food were the recipients of more aggression than those returning with food. If spring dispersal leads to reduced relatedness in X. virginica colonies, then nestmate recognition based on familiarity would be an important factor in maintaining group cohesion.
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Affiliation(s)
- J L Vickruck
- Department of Biological Sciences, Brock University, 1812 Sir Isaac Brock Way, St. Catharines, Ontario, Canada.
| | - M H Richards
- Department of Biological Sciences, Brock University, 1812 Sir Isaac Brock Way, St. Catharines, Ontario, Canada.
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Korb J, Belles X. Juvenile hormone and hemimetabolan eusociality: a comparison of cockroaches with termites. CURRENT OPINION IN INSECT SCIENCE 2017; 22:109-116. [PMID: 28805632 DOI: 10.1016/j.cois.2017.06.002] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2017] [Revised: 05/17/2017] [Accepted: 06/09/2017] [Indexed: 06/07/2023]
Abstract
Termites are social Dictyoptera that evolved eusociality independently from social Hymenoptera. They are characterized by unique developmental plasticity that is the basis of caste differentiation and social organization. As developmental plasticity is a result of endocrine regulation, in order to understand the evolution of termite sociality it is helpful to compare the endocrine underpinning of development between termites and cockroaches. Nijhout and Wheeler (1982) proposed that varying JH titers determine caste differentiation in termites. Based on current results, we extend this model by adding the importance of social interactions. High JH titers in the presence of soldiers lead to regressive development (decrease in body size, apparent regression in development), while an absence of soldiers induces (pre-)soldier differentiation. On the opposite side, low JH titers in colonies headed by reproductives result in progressive molts toward adults, while an absence of reproductives induces development of replacement reproductives. In cockroaches, transcription factors involved in JH signaling, including the adult specifier E93 (the co-called MEKRE93 pathway) regulate the morphogenetic transition between the nymph and the adult. In termites, we speculate that castes might be determined by social effects playing a modulatory action of JH in the MEKRE93 pathway.
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Affiliation(s)
- Judith Korb
- Evolutionary Biology & Ecology, University of Freiburg, Hauptstrasse 1, D-79104 Freiburg, Germany.
| | - Xavier Belles
- Institute of Evolutionary Biology, CSIC-Universitat Pompeu Fabra, Passeig Marítim 37, 08003 Barcelona, Spain
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15
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Abstract
The sterile worker castes found in the colonies of social insects are often cited as archetypal examples of altruism in nature. The challenge is to explain why losing the ability to mate has evolved as a superior strategy for transmitting genes into future generations. We propose that two conditions are necessary for the evolution of sterility: completely overlapping generations and monogamy. A review of the literature indicates that when these two conditions are met we consistently observe the evolution of sterile helpers. We explain the theory and evidence behind these ideas, and discuss the importance of ecology in predicting whether sterility will evolve using examples from social birds, mammals, and insects. In doing so, we offer an explanation for the extraordinary lifespans of some cooperative species which hint at ways in which we can unlock the secrets of long life.
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Korb J. Genes Underlying Reproductive Division of Labor in Termites, with Comparisons to Social Hymenoptera. Front Ecol Evol 2016. [DOI: 10.3389/fevo.2016.00045] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
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17
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Chak STC, Duffy JE, Rubenstein DR. Reproductive skew drives patterns of sexual dimorphism in sponge-dwelling snapping shrimps. Proc Biol Sci 2016; 282:20150342. [PMID: 26041357 DOI: 10.1098/rspb.2015.0342] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Sexual dimorphism is typically a result of strong sexual selection on male traits used in male-male competition and subsequent female choice. However, in social species where reproduction is monopolized by one or a few individuals in a group, selection on secondary sexual characteristics may be strong in both sexes. Indeed, sexual dimorphism is reduced in many cooperatively breeding vertebrates and eusocial insects with totipotent workers, presumably because of increased selection on female traits. Here, we examined the relationship between sexual dimorphism and sociality in eight species of Synalpheus snapping shrimps that vary in social structure and degree of reproductive skew. In species where reproduction was shared more equitably, most members of both sexes were physiologically capable of breeding. However, in species where reproduction was monopolized by a single individual, a large proportion of females--but not males--were reproductively inactive, suggesting stronger reproductive suppression and conflict among females. Moreover, as skew increased across species, proportional size of the major chela--the primary antagonistic weapon in snapping shrimps--increased among females and sexual dimorphism in major chela size declined. Thus, as reproductive skew increases among Synalpheus, female-female competition over reproduction appears to increase, resulting in decreased sexual dimorphism in weapon size.
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Affiliation(s)
- Solomon Tin Chi Chak
- Virginia Institute of Marine Science, The College of William and Mary, Gloucester Point, VA 23062, USA
| | - J Emmett Duffy
- Virginia Institute of Marine Science, The College of William and Mary, Gloucester Point, VA 23062, USA
| | - Dustin R Rubenstein
- Department of Ecology, Evolution and Environmental Biology, Columbia University, New York, NY 10027, USA
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Abstract
Why do most animals live solitarily, while complex social life is restricted to a few cooperatively breeding vertebrates and social insects? Here, we synthesize concepts and theories in social evolution and discuss its underlying ecological causes. Social evolution can be partitioned into (a) formation of stable social groups, (b) evolution of helping, and (c) transition to a new evolutionary level. Stable social groups rarely evolve due to competition over food and/or reproduction. Food competition is overcome in social insects with central-place foraging or bonanza-type food resources, whereas competition over reproduction commonly occurs because staying individuals are rarely sterile. Hence, the evolution of helping is shaped by direct and indirect fitness options and helping is only altruism if it reduces the helper's direct fitness. The helper's capability to gain direct fitness also creates within-colony conflict. This prevents transition to a new evolutionary level.
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Affiliation(s)
- Judith Korb
- Department of Evolutionary Biology & Ecology, University of Freiburg, D-79104 Freiburg, Germany;
| | - Jürgen Heinze
- Institute of Zoology/Evolutionary Biology, University of Regensburg, D-93040 Regensburg, Germany;
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Chak STC, Rubenstein DR, Duffy JE. Social Control of Reproduction and Breeding Monopolization in the Eusocial Snapping ShrimpSynalpheus elizabethae. Am Nat 2015; 186:660-8. [DOI: 10.1086/683132] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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20
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Hoffmann K, Gowin J, Hartfelder K, Korb J. The scent of royalty: a p450 gene signals reproductive status in a social insect. Mol Biol Evol 2014; 31:2689-96. [PMID: 25053804 DOI: 10.1093/molbev/msu214] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Cooperation requires communication; this applies to animals and humans alike. The main communication means differ between taxa and social insects (ants, termites, and some bees and wasps) lack the cognitive abilities of most social vertebrates. Central to the regulation of the reproductive harmony in insect societies is the production of a royalty scent which signals the fertility status of the reproducing queen to the nonreproducing workers. Here, we revealed a central genetic component underlying this hallmark of insect societies in the termite Cryptotermes secundus. Communication between queens and workers relied upon the expression of a gene, Neofem4, which belongs to the cytochrome P450 genes. We inhibited Neofem4 in queens by RNA interference. This resulted in the loss of the royalty scent in queens and the workers behaved as though the queen were absent. The queen's behavior was not generally affected by silencing Neofem4. This suggests that the lack of the royalty scent lead to workers not recognizing her anymore as queen. P450 genes are known to be involved in the production of chemical signals in cockroaches and their expression has been linked to a major fertility regulator, juvenile hormone. This makes P450 genes, both a suitable and available evolutionary substrate in the face of natural selection for production of a queen substance. Our data suggest that in an organism without elaborate cognitive abilities communication has been achieved by the exploitation of a central gene that links the fertility network with the chemical communication pathway. As termites and social Hymenoptera seem to share the same class of compounds in signaling fertility, this role of P450 genes might be more widespread across social insects.
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Affiliation(s)
| | - Johannes Gowin
- Behavioral Biology, University of Osnabrueck, Osnabrueck, Germany Evolutionary Biology & Ecology, University of Freiburg, Freiburg, Germany
| | - Klaus Hartfelder
- Departamento de Biologia Celular e Molecular e Bioagentes Patogênicos, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
| | - Judith Korb
- Behavioral Biology, University of Osnabrueck, Osnabrueck, Germany Evolutionary Biology & Ecology, University of Freiburg, Freiburg, Germany
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Hoffmann K, Foster KR, Korb J. Nest value mediates reproductive decision making within termite societies. Behav Ecol 2012. [DOI: 10.1093/beheco/ars103] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
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