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Kikuchi T, Hayashi Y, Fujito Y, Fujiwara-Tsujii N, Kawabata S, Sugawara K, Yamaoka R, Tsuji K. Test of the negative feedback hypothesis of colony size sensing in social insects. Biol Lett 2024; 20:20240102. [PMID: 38889776 DOI: 10.1098/rsbl.2024.0102] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2024] [Accepted: 04/18/2024] [Indexed: 06/20/2024] Open
Abstract
Social insects can sense colony size-even without visual information in a dark environment. How they achieve this is yet largely unknown. We empirically tested a hypothesis on the proximate mechanism using ant colonies. In Diacamma colonies, the monogynous queen is known to increase the effort devoted to queen pheromone transmission behaviour (patrolling) as the colony grows, as if she perceives colony size. The negative feedback hypothesis assumes that, through repeated physical contact with workers, the queen monitors the physiological state (fertility) of workers and increases her patrolling effort when she encounters more fertile workers. Supporting this hypothesis, we found that the queen increased her patrolling effort in response to a higher ratio of fertile workers under the experimental condition of constant colony size. Furthermore, chemical analyses and bioassays suggested that cuticular hydrocarbons have queen pheromone activity and can mediate the observed queen-worker communication of fertility state. Such a self-organizing mechanism of sensing colony size may also operate in other social insects living in small colonies.
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Grants
- 17657029, 18047017, 20033015, 23870003, 26249024, 15H02652, 16F16794, 17H01249, 22H02702, 23K18155 Japan Society for the Promotion of Science (KAKENHI)
- 4-1904, 4G-2301 The Environment Research and Technology Development Fund
- KAKENHI
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Affiliation(s)
- T Kikuchi
- Marine Biosystems Research Center, Chiba University, Tokawa 1 , Choshi City, Chiba 288-0014, Japan
| | - Y Hayashi
- Biomedical Sciences and Biomedical Engineering, School of Biological Sciences, University of Reading, Reading , Berkshire RG6 6AH, UK
| | - Y Fujito
- Division of Analytical and Measuring Instruments, Shimadzu Corporation, 1 Kuwabaracho Nishinokyo Nakagyo-ku , Kyoto 604-8511, Japan
| | - N Fujiwara-Tsujii
- Division of Core Technology for Pest Control Reserach, Institute for Plant Protection, National Agriculture and Food Research Organization , Tsukuba, Ibaraki 305-8666, Japan
| | - S Kawabata
- Department of Biology, Toyama University , Toyama 930-8555, Japan
| | - K Sugawara
- Department of Information Science, Faculty of Liberal Arts, Tohoku-gakuin University, 2-1-1, Tenjinzawa, Izumi , Sendai, Miyagi 981-3193, Japan
| | - R Yamaoka
- Division of Applied Biology, Graduate School of Science and Technology, Kyoto Institute of Technology (Emeritus) , Kyoto 606-8287, Japan
| | - Kazuki Tsuji
- Department of Subtropical Agro-Environmental Sciences, University of the Ryukyus , Nishihara, Okinawa 903-0213, Japan
- Environmental Sciences and Concervation Biology, The United Graduate School of Agricultural Sciences, Kagoshima University , Kagoshima 890-0065, Japan
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de Mendonça DMF, Caixeta MCS, Martins GL, Moreira CC, Kloss TG, Elliot SL. Low Virulence of the Fungi Escovopsis and Escovopsioides to a Leaf-Cutting Ant-Fungus Symbiosis. Front Microbiol 2021; 12:673445. [PMID: 34394025 PMCID: PMC8358438 DOI: 10.3389/fmicb.2021.673445] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2021] [Accepted: 07/06/2021] [Indexed: 01/22/2023] Open
Abstract
Eusocial insects interact with a diversity of parasites that can threaten their survival and reproduction. The amount of harm these parasites cause to their hosts (i.e., their virulence) can be influenced by numerous factors, such as the ecological context in which the parasite and its host are inserted. Leaf-cutting ants (genera Atta, Acromyrmex and Amoimyrmex, Attini: Formicidae) are an example of a eusocial insect whose colonies are constantly threatened by parasites. The fungi Escovopsis and Escovopsioides (Ascomycota: Hypocreales) are considered a highly virulent parasite and an antagonist, respectively, to the leaf-cutting ants' fungal cultivar, Leucoagaricus gongylophorus (Basidiomycota: Agaricales). Since Escovopsis and Escovopsioides are common inhabitants of healthy colonies that can live for years, we expect them to have low levels of virulence. However, this virulence could vary depending on ecological context. We therefore tested two hypotheses: (i) Escovopsis and Escovopsioides are of low virulence to colonies; (ii) virulence increases as colony complexity decreases. For this, we used three levels of complexity: queenright colonies (fungus garden with queen and workers), queenless colonies (fungus garden and workers, without queen) and fungus gardens (without any ants). Each was inoculated with extremely high concentrations of conidia of Escovopsis moelleri, Escovopsioides nivea, the mycoparasitic fungus Trichoderma longibrachiatum or a blank control. We found that these fungi were of low virulence to queenright colonies. The survival of queenless colonies was decreased by E. moelleri and fungus gardens were suppressed by all treatments. Moreover, E. nivea and T. longibrachiatum seemed to be less aggressive than E. moelleri, observed both in vivo and in vitro. The results highlight the importance of each element (queen, workers and fungus garden) in the leaf-cutting ant-fungus symbiosis. Most importantly, we showed that Escovopsis may not be virulent to healthy colonies, despite commonly being described as such, with the reported virulence of Escovopsis being due to poor colony conditions in the field or in laboratory experiments.
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Affiliation(s)
| | | | | | - Camila Costa Moreira
- Department of Entomology, Federal University of Viçosa, Viçosa, Brazil.,Department of Entomology and Acarology, Luiz de Queiroz College of Agriculture, University of São Paulo, Piracicaba, Brazil
| | - Thiago Gechel Kloss
- Department of Biological Sciences, Minas Gerais State University, Ubá, Brazil
| | - Simon Luke Elliot
- Department of Entomology, Federal University of Viçosa, Viçosa, Brazil
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Chiu MC, Wu WJ, Lai LC. Carriers and cutters: size-dependent caste polyethism in the tropical fire ant ( Solenopsis geminata). BULLETIN OF ENTOMOLOGICAL RESEARCH 2020; 110:388-396. [PMID: 31735176 DOI: 10.1017/s0007485319000750] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Body size is an important life-history trait in eusocial insects which plays a key role in colony fitness. The division of labour, represented by caste polyethism, correlates with divergent morphological traits. Size polymorphism has been noted in the tropical fire ant, Solenopsis geminata; however, little is known regarding the differences in the size distributions of workers performing foraging tasks. In the present study, task partitioning was observed in the foraging activities of S. geminata. Two subgroups among foraging workers of S. geminata were discovered using the Gaussian mixture model: a large worker group (head width ≥ 0.924 mm) and a small worker group (head width < 0.924 mm). The foraging worker population comprised two distinct groups - 25.64% were large workers and 74.36% were small workers. Larger workers delivered heavier seeds faster than smaller workers, but this difference became less apparent when lighter seeds were being carried. When large prey such as crickets was encountered during foraging, S. geminata partitioned their tasks into cutting and transportation. The large workers were observed to cut cricket prey into fragments with their longer mandibles, and the small workers then transported these fragments back to the nest. These results present evidence of task partitioning among tropical fire ants, with different tasks being performed by ants of different castes.
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Affiliation(s)
- Ming-Chung Chiu
- Department of Biology, Graduate School of Science, Kobe University, Kobe6578501, Japan
| | - Wen-Jer Wu
- Department of Entomology, National Taiwan University, 27, Lane 113, Sec. 4, Roosevelt Rd., Taipei10617, Taiwan
| | - Li-Chuan Lai
- Department of Ecological Humanities, Providence University, 200, Sec. 7, Taiwan Boulevard, Shalu Dist., Taichung City 43301, Taiwan
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Miller JS, Reeve HK. Feedback loops in the major evolutionary transition to eusociality: the status and potential of theoretical approaches. CURRENT OPINION IN INSECT SCIENCE 2019; 34:85-90. [PMID: 31247424 DOI: 10.1016/j.cois.2019.04.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Revised: 04/19/2019] [Accepted: 04/25/2019] [Indexed: 06/09/2023]
Abstract
In this review, we adopt a step-wise framework for the evolution a major evolutionary transition in light of eusocial insects. By focusing on the sequence of (1) group formation, (2) alignment of genetic interests, and finally (3) group integration to higher-level functioning, we highlight that these steps occasionally interact with each other through feedback. We summarize models that capture such feedback and identify cases where there is room for the development of between-step relationships. We suggest that life history traits may serve as a conduit for analyzing feedback between suites of correlated traits. Our review reveals that there are many relationships both within and between the above steps that await formal modeling.
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Affiliation(s)
- Julie S Miller
- Ecology & Evolutionary Biology, University of California, Los Angeles, 612 Charles E. Young Dr., Los Angeles, CA 90095, USA.
| | - Hudson Kern Reeve
- Neurobiology & Behavior, Cornell University, 215 Tower Rd., Ithaca, NY 14850, USA
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Nonacs P. Hamilton's rule is essential but insufficient for understanding monogamy's role in social evolution. ROYAL SOCIETY OPEN SCIENCE 2019; 6:180913. [PMID: 30800348 PMCID: PMC6366207 DOI: 10.1098/rsos.180913] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Accepted: 12/19/2018] [Indexed: 06/09/2023]
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Ohkubo Y, Yamamoto T, Ogusu N, Watanabe S, Murakami Y, Yagi N, Hasegawa E. The benefits of grouping as a main driver of social evolution in a halictine bee. SCIENCE ADVANCES 2018; 4:e1700741. [PMID: 30306126 PMCID: PMC6170040 DOI: 10.1126/sciadv.1700741] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/11/2017] [Accepted: 08/23/2018] [Indexed: 06/08/2023]
Abstract
Over the past decade, the cause of sociality has been much debated. Inclusive fitness [br in Hamilton's rule (br - c > 0)] has been criticized but is still useful in the organization of a framework by elucidating mechanisms through which br (benefit × relatedness) becomes larger than c (cost). The bee Lasioglossum baleicum is suitable for investigation of this issue because of the sympatric occurrence of both social and solitary nesting in its populations. We show that a large part (approximately 92%) of the inclusive fitness of a eusocial worker can be attributed to the benefits of grouping. A 1.5-fold relatedness asymmetry benefit in singly mated haplo-diploids explains a small part (approximately 8.5%) of the observed inclusive fitness. Sociality enables this species to conduct foraging and nest defense simultaneously, which is not the case in solitary nests. Our results indicate that this benefit of grouping is the main source of the increased inclusive fitness of eusocial workers.
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Affiliation(s)
- Yusaku Ohkubo
- Laboratory of Animal Ecology, Graduate School of Agriculture, Hokkaido University, Sapporo 060-8589, Japan
| | - Tatsuhiro Yamamoto
- Laboratory of Animal Ecology, Graduate School of Agriculture, Hokkaido University, Sapporo 060-8589, Japan
| | - Natsuki Ogusu
- Laboratory of Animal Ecology, Graduate School of Agriculture, Hokkaido University, Sapporo 060-8589, Japan
| | - Saori Watanabe
- Laboratory of Animal Ecology, Graduate School of Agriculture, Hokkaido University, Sapporo 060-8589, Japan
| | - Yuuka Murakami
- Graduate School of Medicine, Department of Neuropharmacology, Hokkaido University, Sapporo 060-8638, Japan
| | - Norihiro Yagi
- Laboratory of Animal Ecology, Graduate School of Agriculture, Hokkaido University, Sapporo 060-8589, Japan
| | - Eisuke Hasegawa
- Laboratory of Animal Ecology, Graduate School of Agriculture, Hokkaido University, Sapporo 060-8589, Japan
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Taylor D, Bentley MA, Sumner S. Social wasps as models to study the major evolutionary transition to superorganismality. CURRENT OPINION IN INSECT SCIENCE 2018; 28:26-32. [PMID: 30551764 DOI: 10.1016/j.cois.2018.04.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2018] [Revised: 04/03/2018] [Accepted: 04/05/2018] [Indexed: 06/09/2023]
Abstract
The major evolutionary transition to superorganismality has taken place several times in the insects. Although there has been much consideration of the ultimate evolutionary explanations for superorganismality, we know relatively little about what proximate mechanisms constrain or promote this major transition. Here, we propose that Vespid wasps represent an understudied, but potentially very useful, model system for studying the mechanisms underpinning superorganismality. We highlight how there is an abundance of behavioural data for many wasp species, confirming their utility in studies of social evolution; however, there is a sparsity of genomic data from which we can test proximate and ultimate hypotheses on this major evolutionary transition.
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Affiliation(s)
- Daisy Taylor
- Life Sciences Building, University of Bristol, 24 Tyndall Avenue, Bristol BS8 1TQ, United Kingdom
| | - Michael A Bentley
- Centre for Biodiversity & Environment Research, Department of Genetics, Evolution & Environment, University College London, Gower Street, London WC1E 6BT, United Kingdom
| | - Seirian Sumner
- Centre for Biodiversity & Environment Research, Department of Genetics, Evolution & Environment, University College London, Gower Street, London WC1E 6BT, United Kingdom.
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Queen Control or Queen Signal in Ants: What Remains of the Controversy 25 Years After Keller and Nonacs' Seminal Paper? J Chem Ecol 2018; 44:805-817. [PMID: 29858748 DOI: 10.1007/s10886-018-0974-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Revised: 04/05/2018] [Accepted: 05/25/2018] [Indexed: 10/14/2022]
Abstract
Ant queen pheromones (QPs) have long been known to affect colony functioning. In many species, QPs affect important reproductive functions such as diploid larvae sexualization and egg-laying by workers, unmated queens (gynes), or other queens. Until the 1990s, these effects were generally viewed to be the result of queen manipulation through the use of coercive or dishonest signals. However, in their seminal 1993 paper, Keller and Nonacs challenged this idea, suggesting that QPs had evolved as honest signals that informed workers and other colony members of the queen's presence and reproductive state. This paper has greatly influenced the study of ant QPs and inspired numerous attempts to identify fertility-related compounds and test their physiological and behavioral effects. In the present article, we review the literature on ant QPs in various contexts and pay special attention to the role of cuticular hydrocarbons (CHCs). Although the controversy generated by Keller and Nonacs' (Anim Behav 45:787-794, 1993) paper is currently less intensively debated, there is still no clear evidence which allows the rejection of the queen control hypothesis in favor of the queen signal hypothesis. We argue that important questions remain regarding the mode of action of QPs, and their targets which may help understanding their evolution.
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O’Donnell S, Fiocca K, Campbell M, Bulova S, Zelanko P, Velinsky D. Adult nutrition and reproductive physiology: a stable isotope analysis in a eusocial paper wasp (Mischocyttarus mastigophorus, Hymenoptera: Vespidae). Behav Ecol Sociobiol 2018. [DOI: 10.1007/s00265-018-2501-y] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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10
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Olejarz J, Veller C, Nowak MA. The evolution of queen control over worker reproduction in the social Hymenoptera. Ecol Evol 2017; 7:8427-8441. [PMID: 29075460 PMCID: PMC5648666 DOI: 10.1002/ece3.3324] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2017] [Revised: 07/12/2017] [Accepted: 07/20/2017] [Indexed: 02/06/2023] Open
Abstract
A trademark of eusocial insect species is reproductive division of labor, in which workers forego their own reproduction while the queen produces almost all offspring. The presence of the queen is key for maintaining social harmony, but the specific role of the queen in the evolution of eusociality remains unclear. A long‐discussed scenario is that a queen either behaviorally or chemically sterilizes her workers. However, the demographic and ecological conditions that enable such manipulation are still debated. We study a simple model of evolutionary dynamics based on haplodiploid genetics. Our model is set in the commonly observed case where workers have lost the ability to lay female (diploid) eggs by mating, but retain the ability to lay male (haploid) eggs. We consider a mutation that acts in a queen, causing her to control the reproductive behavior of her workers. Our mathematical analysis yields precise conditions for the evolutionary emergence and stability of queen‐induced worker sterility. These conditions do not depend on the queen's mating frequency. We find that queen control is always established if it increases colony reproductive efficiency, but can evolve even if it decreases colony efficiency. We further derive the conditions under which queen control is evolutionarily stable against invasion by mutant workers who have recovered the ability to lay male eggs.
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Affiliation(s)
- Jason Olejarz
- Program for Evolutionary Dynamics Harvard University Cambridge MA USA
| | - Carl Veller
- Program for Evolutionary Dynamics Harvard University Cambridge MA USA.,Department of Organismic and Evolutionary Biology Harvard University Cambridge MA USA
| | - Martin A Nowak
- Program for Evolutionary Dynamics Harvard University Cambridge MA USA.,Department of Organismic and Evolutionary Biology Harvard University Cambridge MA USA.,Department of Mathematics Harvard University Cambridge MA USA
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