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Carmona-Aldana F, Yong LW, Reinberg D, Desplan C. Phenomenon of reproductive plasticity in ants. CURRENT OPINION IN INSECT SCIENCE 2024; 63:101197. [PMID: 38583769 PMCID: PMC11139587 DOI: 10.1016/j.cois.2024.101197] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/24/2023] [Revised: 03/26/2024] [Accepted: 03/31/2024] [Indexed: 04/09/2024]
Abstract
Ant colonies are organized in castes with distinct behaviors that together allow the colony to strive. Reproduction relies on one or a few queens that stay in the nest producing eggs, while females of the worker caste do not reproduce and instead engage in colony maintenance and brood caretaking. Yet, in spite of this clear separation of functions, workers can become reproductive under defined circumstances. Here, we review the context in which workers become reproductive, exhibiting asexual or sexual reproduction depending on the species. Remarkably, the activation of reproduction in these workers can be quite stable, with changes that include behavior and a dramatic extension of lifespan. We compare these changes between species that do or do not have a queen caste. We discuss how the mechanisms underlying reproductive plasticity include changes in hormonal functions and in epigenetic configurations. Further studies are warranted to elucidate not only how reproductive functions have been gradually restricted to the queen caste during evolution but also how reproductive plasticity remains possible in workers of some species.
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Affiliation(s)
| | - Luok Wen Yong
- Department of Biology, New York University, NY 10003, USA
| | - Danny Reinberg
- Dr. John T. Macdonald Foundation Department of Human Genetics, University of Miami, Coral Gables, FL 33124, USA.
| | - Claude Desplan
- Department of Biology, New York University, NY 10003, USA; Center for Genomics and Systems Biology, New York University, Abu Dhabi 51133, United Arab Emirates.
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2
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Shimoji H, Dobata S. The build-up of dominance hierarchies in eusocial insects. Philos Trans R Soc Lond B Biol Sci 2022; 377:20200437. [PMID: 35000446 PMCID: PMC8743887 DOI: 10.1098/rstb.2020.0437] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Accepted: 11/08/2021] [Indexed: 12/11/2022] Open
Abstract
Reproductive division of labour is a hallmark of eusocial insects. However, its stability can often be hampered by the potential for reproduction by otherwise sterile nest-mates. Dominance hierarchy has a crucial role in some species in regulating which individuals reproduce. Compared with those in vertebrates, the dominance hierarchies in eusocial insects tend to involve many more individuals, and should require additional selective forces unique to them. Here, we provide an overview of a series of studies on dominance hierarchies in eusocial insects. Although reported from diverse eusocial taxa, dominance hierarchies have been extensively studied in paper wasps and ponerine ants. Starting from molecular physiological attributes of individuals, we describe how the emergence of dominance hierarchies can be understood as a kind of self-organizing process through individual memory and local behavioural interactions. The resulting global structures can be captured by using network analyses. Lastly, we argue the adaptive significance of dominance hierarchies from the standpoint of sterile subordinates. Kin selection, underpinned by relatedness between nest-mates, is key to the subordinates' acceptance of their positions in the hierarchies. This article is part of the theme issue 'The centennial of the pecking order: current state and future prospects for the study of dominance hierarchies'.
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Affiliation(s)
- Hiroyuki Shimoji
- School of Biological and Environmental Sciences, Kwansei Gakuin University, Sanda, Hyogo 669-1337, Japan
| | - Shigeto Dobata
- Department of General Systems Studies, Graduate School of Arts and Sciences, The University of Tokyo, Komaba, Meguro, Tokyo 153-8902, Japan
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3
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Steitz I, Paxton RJ, Schulz S, Ayasse M. Chemical Variation among Castes, Female Life Stages and Populations of the Facultative Eusocial Sweat Bee Halictus rubicundus (Hymenoptera: Halictidae). J Chem Ecol 2021; 47:406-419. [PMID: 33788128 PMCID: PMC8116247 DOI: 10.1007/s10886-021-01267-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Revised: 03/05/2021] [Accepted: 03/17/2021] [Indexed: 11/28/2022]
Abstract
In eusocial insects, chemical communication is crucial for mediating many aspects of social activities, especially the regulation of reproduction. Though queen signals are known to decrease ovarian activation of workers in highly eusocial species, little is known about their evolution. In contrast, some primitively eusocial species are thought to control worker reproduction through physical aggression by the queen rather than via pheromones, suggesting the evolutionary establishment of chemical signals with more derived sociality. However, studies supporting this hypothesis are largely missing. Socially polymorphic halictid bees, such as Halictus rubicundus, with social and solitary populations in both Europe and North America, offer excellent opportunities to illuminate the evolution of caste-specific signals. Here we compared the chemical profiles of social and solitary populations from both continents and tested whether (i) population or social level affect chemical dissimilarity and whether (ii) caste-specific patterns reflect a conserved queen signal. Our results demonstrate unique odor profiles of European and North American populations, mainly due to different isomers of n-alkenes and macrocyclic lactones; chemical differences may be indicative of phylogeographic drift in odor profiles. We also found common compounds overproduced in queens compared to workers in both populations, indicating a potential conserved queen signal. However, North American populations have a lower caste-specific chemical dissimilarity than European populations which raises the question if both use different mechanisms of regulating reproductive division of labor. Therefore, our study gives new insights into the evolution of eusocial behavior and the role of chemical communication in the inhibition of reproduction.
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Affiliation(s)
- Iris Steitz
- Institute of Evolutionary Ecology and Conservation Genomics, University of Ulm, Ulm, Germany.
| | - Robert J Paxton
- General Zoology, Institute for Biology, Martin Luther University Halle-Wittenberg, Halle (Saale), Germany
- German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Leipzig, Germany
| | - Stefan Schulz
- Departement of Life Sciences, Institute of Organic Chemistry, TU Braunschweig, Braunschweig, Germany
| | - Manfred Ayasse
- Institute of Evolutionary Ecology and Conservation Genomics, University of Ulm, Ulm, Germany
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4
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Abril S, Gómez C. Factors triggering queen executions in the Argentine ant. Sci Rep 2019; 9:10427. [PMID: 31320714 PMCID: PMC6639317 DOI: 10.1038/s41598-019-46972-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2019] [Accepted: 07/04/2019] [Indexed: 11/25/2022] Open
Abstract
Competition among queens in polygynous societies may result in queen executions or conflicts over personal reproduction. Understanding the factors that mediate the executions of ant queens should provide insight into how queen numbers are regulated in polygynous insect societies. The Argentine ant is a widespread invasive species that displays secondary polygyny, and workers execute 90% of their nestmate queens each spring. In this study, we investigated: (1) whether ambient temperature, queen number, and protein deprivation have an effect on queen executions and (2) whether workers select the queens slated for execution based on their cuticular hydrocarbon (CHC) profiles. We found that the percentage of queens executed was positively correlated with temperature and queen number but that protein deprivation did not play a role. As for queen fate, the levels of some CHCs were higher in surviving queens. One of these CHCs is associated with queen productivity (i.e egg-laying rate and ovarian index) suggesting that workers execute the least productive queens. Our findings suggest that chemical cues related to fertility signaling may mediate queen executions in Argentine ants.
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Affiliation(s)
- Sílvia Abril
- Department of Environmental Sciences, University of Girona, M. Aurèlia Campmany, 69, 17003, Girona, Spain.
| | - Crisanto Gómez
- Department of Environmental Sciences, University of Girona, M. Aurèlia Campmany, 69, 17003, Girona, Spain
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5
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Wang Q, Goodger JQD, Woodrow IE, Chang L, Elgar MA. Task-Specific Recognition Signals Are Located on the Legs in a Social Insect. Front Ecol Evol 2019. [DOI: 10.3389/fevo.2019.00227] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
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6
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Norman VC, Pamminger T, Nascimento F, Hughes WOH. The role of juvenile hormone in regulating reproductive physiology and dominance in Dinoponera quadriceps ants. PeerJ 2019; 7:e6512. [PMID: 30842903 PMCID: PMC6398374 DOI: 10.7717/peerj.6512] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2018] [Accepted: 01/24/2019] [Indexed: 12/18/2022] Open
Abstract
Unequal reproductive output among members of the same sex (reproductive skew) is a common phenomenon in a wide range of communally breeding animals. In such species, reproductive dominance is often acquired during antagonistic interactions between group members that establish a reproductive hierarchy in which only a few individuals reproduce. Rank-specific syndromes of behavioural and physiological traits characterize such hierarchies, but how antagonistic behavioural interactions translate into stable rank-specific syndromes remains poorly understood. The pleiotropic nature of hormones makes them prime candidates for generating such syndromes as they physiologically integrate environmental (social) information, and often affect reproduction and behaviour simultaneously. Juvenile hormone (JH) is one of several hormones that occupy such a central regulatory role in insects and has been suggested to regulate reproductive hierarchies in a wide range of social insects including ants. Here we use experimental manipulation to investigate the effect of JH levels on reproductive physiology and social dominance in high-ranked workers of the eusocial ant Dinoponera quadriceps, a species that has secondarily reverted to queenless, simple societies. We show that JH regulated reproductive physiology, with ants in which JH levels were experimentally elevated having more regressed ovaries. In contrast, we found no evidence of JH levels affecting dominance in social interactions. This could indicate that JH and ovary development are decoupled from dominance in this species, however only high-ranked workers were investigated. The results therefore confirm that the regulatory role of JH in reproductive physiology in this ant species is in keeping with its highly eusocial ancestors rather than its secondary reversion to simple societies, but more investigation is needed to disentangle the relationships between hormones, behaviour and hierarchies.
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Affiliation(s)
- Victoria C Norman
- School of Biology, University of Leeds, Leeds, United Kingdom.,School of Life Sciences, University of Sussex, Brighton, United Kingdom
| | - Tobias Pamminger
- School of Life Sciences, University of Sussex, Brighton, United Kingdom
| | - Fabio Nascimento
- Departamento de Biologia, Universidade de São Paulo, Ribeirão Preto, Brazil
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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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8
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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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9
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Abril S, Diaz M, Lenoir A, Ivon Paris C, Boulay R, Gómez C. Cuticular hydrocarbons correlate with queen reproductive status in native and invasive Argentine ants (Linepithema humile, Mayr). PLoS One 2018; 13:e0193115. [PMID: 29470506 PMCID: PMC5823440 DOI: 10.1371/journal.pone.0193115] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Accepted: 02/05/2018] [Indexed: 11/18/2022] Open
Abstract
In insect societies, chemical communication plays an important role in colony reproduction and individual social status. Many studies have indicated that cuticular hydrocarbons (CHCs) are the main chemical compounds encoding reproductive status. However, these studies have largely focused on queenless or monogynous species whose workers are capable of egg laying and have mainly explored the mechanisms underlying queen-worker or worker-worker reproductive conflicts. Less is known about what occurs in highly polygynous ant species with permanently sterile workers. Here, we used the Argentine ant as a model to examine the role of CHCs in communicating reproductive information in such insect societies. The Argentine ant is unicolonial, highly polygynous, and polydomous. We identified several CHCs whose presence and levels were correlated with queen age, reproductive status, and fertility. Our results also provide new insights into queen executions in the Argentine ant, a distinctive feature displayed by this species in its introduced range. Each spring, just before new sexuals appear, workers eliminate up to 90% of the mated queens in their colonies. We discovered that queens that survived execution had different CHC profiles from queens present before and during execution. More specifically, levels of some CHCs were higher in the survivors, suggesting that workers could eliminate queens based on their chemical profiles. In addition, queen CHC profiles differed based on season and species range (native vs. introduced). Overall, the results of this study provide new evidence that CHCs serve as queen signals and do more than just regulate worker reproduction.
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Affiliation(s)
- Sílvia Abril
- Departament de Ciències Ambientals, Universitat de Girona, Girona, Spain
- * E-mail:
| | - Mireia Diaz
- Departament de Ciències Ambientals, Universitat de Girona, Girona, Spain
| | - Alain Lenoir
- Institut de Recherche sur la Biologie de l’Insecte, Université François Rabelais de Tours, Tours, France
| | - Carolina Ivon Paris
- Departamento Ecología, Genética y Evolución, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Raphaël Boulay
- Institut de Recherche sur la Biologie de l’Insecte, Université François Rabelais de Tours, Tours, France
| | - Crisanto Gómez
- Departament de Ciències Ambientals, Universitat de Girona, Girona, Spain
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10
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Kohlmeier P, Negroni MA, Kever M, Emmling S, Stypa H, Feldmeyer B, Foitzik S. Intrinsic worker mortality depends on behavioral caste and the queens' presence in a social insect. Naturwissenschaften 2017; 104:34. [PMID: 28353195 DOI: 10.1007/s00114-017-1452-x] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2017] [Revised: 02/20/2017] [Accepted: 02/22/2017] [Indexed: 12/30/2022]
Abstract
According to the classic life history theory, selection for longevity depends on age-dependant extrinsic mortality and fecundity. In social insects, the common life history trade-off between fecundity and longevity appears to be reversed, as the most fecund individual, the queen, often exceeds workers in lifespan several fold. But does fecundity directly affect intrinsic mortality also in social insect workers? And what is the effect of task on worker mortality? Here, we studied how social environment and behavioral caste affect intrinsic mortality of ant workers. We compared worker survival between queenless and queenright Temnothorax longispinosus nests and demonstrate that workers survive longer under the queens' absence. Temnothorax ant workers fight over reproduction when the queen is absent and dominant workers lay eggs. Worker fertility might therefore increase lifespan, possibly due to a positive physiological link between fecundity and longevity, or better care for fertile workers. In social insects, division of labor among workers is age-dependant with young workers caring for the brood and old ones going out to forage. We therefore expected nurses to survive longer than foragers, which is what we found. Surprisingly, inactive inside workers showed a lower survival than nurses but comparable to that of foragers. The reduced longevity of inactive workers could be due to them being older than the nurses, or due to a positive effect of activity on lifespan. Overall, our study points to behavioral caste-dependent intrinsic mortality rates and a positive association between fertility and longevity not only in queens but also in ant workers.
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Affiliation(s)
- Philip Kohlmeier
- Institute of Organismic and Molecular Evolution, Johannes Gutenberg University Mainz, Johannes von Müller Weg 6, 55128, Mainz, Germany.
| | - Matteo Antoine Negroni
- Institute of Organismic and Molecular Evolution, Johannes Gutenberg University Mainz, Johannes von Müller Weg 6, 55128, Mainz, Germany
| | - Marion Kever
- Institute of Organismic and Molecular Evolution, Johannes Gutenberg University Mainz, Johannes von Müller Weg 6, 55128, Mainz, Germany
| | - Stefanie Emmling
- Institute of Organismic and Molecular Evolution, Johannes Gutenberg University Mainz, Johannes von Müller Weg 6, 55128, Mainz, Germany
| | - Heike Stypa
- Institute of Organismic and Molecular Evolution, Johannes Gutenberg University Mainz, Johannes von Müller Weg 6, 55128, Mainz, Germany
| | - Barbara Feldmeyer
- Senckenberg Biodiversity and Climate Research Centre, Senckenberg Gesellschaft für Naturforschung, Senckenberganlage 25, D-60325, Frankfurt am Main, Germany
| | - Susanne Foitzik
- Institute of Organismic and Molecular Evolution, Johannes Gutenberg University Mainz, Johannes von Müller Weg 6, 55128, Mainz, Germany
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11
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Padilla M, Amsalem E, Altman N, Hefetz A, Grozinger CM. Chemical communication is not sufficient to explain reproductive inhibition in the bumblebee Bombus impatiens. ROYAL SOCIETY OPEN SCIENCE 2016; 3:160576. [PMID: 27853577 PMCID: PMC5099002 DOI: 10.1098/rsos.160576] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2016] [Accepted: 09/12/2016] [Indexed: 05/29/2023]
Abstract
Reproductive division of labour is a hallmark of eusociality, but disentangling the underlying proximate mechanisms can be challenging. In bumblebees, workers isolated from the queen can activate their ovaries and lay haploid, male eggs. We investigated if volatile, contact, visual or behavioural cues produced by the queen or brood mediate reproductive dominance in Bombus impatiens. Exposure to queen-produced volatiles, brood-produced volatiles and direct contact with pupae did not reduce worker ovary activation; only direct contact with the queen could reduce ovary activation. We evaluated behaviour, physiology and gene expression patterns in workers that were reared in chambers with all stages of brood and a free queen, caged queen (where workers could contact the queen, but the queen was unable to initiate interactions) or no queen. Workers housed with a caged queen or no queen fully activated their ovaries, whereas ovary activation in workers housed with a free queen was completely inhibited. The caged queen marginally reduced worker aggression and expression of an aggression-associated gene relative to queenless workers. Thus, queen-initiated behavioural interactions appear necessary to establish reproductive dominance. Queen-produced chemical cues may function secondarily in a context-specific manner to augment behavioural cues, as reliable or honest signal.
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Affiliation(s)
- Mario Padilla
- Department of Entomology, Center for Pollinator Research, Center for Chemical Ecology, The Pennsylvania State University, University Park, PA 16802, USA
| | - Etya Amsalem
- Department of Entomology, Center for Pollinator Research, Center for Chemical Ecology, The Pennsylvania State University, University Park, PA 16802, USA
| | - Naomi Altman
- Department of Statistics, Huck Institutes of Life Sciences, Clinical and Translational Sciences Institute, The Pennsylvania State University, University Park, PA 16802, USA
| | - Abraham Hefetz
- Department of Zoology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Christina M. Grozinger
- Department of Entomology, Center for Pollinator Research, Center for Chemical Ecology, The Pennsylvania State University, University Park, PA 16802, USA
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12
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Sasaki T, Penick CA, Shaffer Z, Haight KL, Pratt SC, Liebig J. A Simple Behavioral Model Predicts the Emergence of Complex Animal Hierarchies. Am Nat 2016; 187:765-75. [PMID: 27172595 DOI: 10.1086/686259] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Social dominance hierarchies are widespread, but little is known about the mechanisms that produce nonlinear structures. In addition to despotic hierarchies, where a single individual dominates, shared hierarchies exist, where multiple individuals occupy a single rank. In vertebrates, these complex dominance relationships are thought to develop from interactions that require higher cognition, but similar cases of shared dominance have been found in social insects. Combining empirical observations with a modeling approach, we show that all three hierarchy structures-linear, despotic, and shared-can emerge from different combinations of simple interactions present in social insects. Our model shows that a linear hierarchy emerges when a typical winner-loser interaction (dominance biting) is present. A despotic hierarchy emerges when a policing interaction is added that results in the complete loss of dominance status for an attacked individual (physical policing). Finally, a shared hierarchy emerges with the addition of a winner-winner interaction that results in a positive outcome for both interactors (antennal dueling). Antennal dueling is an enigmatic ant behavior that has previously lacked a functional explanation. These results show how complex social traits can emerge from simple behaviors without requiring advanced cognition.
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13
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Motais de Narbonne M, van Zweden JS, Bello JE, Wenseleers T, Millar JG, d'Ettorre P. Biological activity of the enantiomers of 3-methylhentriacontane, a queen pheromone of the ant Lasius niger. ACTA ACUST UNITED AC 2016; 219:1632-8. [PMID: 26994182 DOI: 10.1242/jeb.136069] [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] [Received: 12/07/2015] [Accepted: 03/01/2016] [Indexed: 11/20/2022]
Abstract
Queen pheromones are essential for regulation of the reproductive division of labor in eusocial insect species. Although only the queen is able to lay fertilized eggs and produce females, in some cases workers may develop their ovaries and lay male-destined eggs, thus reducing the overall colony efficiency. As long as the queen is healthy, it is usually in the workers' collective interest to work for the colony and remain sterile. Queens signal their fertility via pheromones, which may have a primer effect, affecting the physiology of workers, or a releaser effect, influencing worker behavior. The queen pheromone of the ant Lasius niger was among the first queen pheromones of social insects to be identified. Its major component is 3-methylhentriacontane (3-MeC31), which is present in relatively large amounts on the queen's cuticle and on her eggs. 3-MeC31 regulates worker reproduction by inhibiting ovarian development. Most monomethyl-branched hydrocarbons can exist in two stereoisomeric forms. The correct stereochemistry is fundamental to the activity of most bioactive molecules, but this has rarely been investigated for methyl-branched hydrocarbons. Here, we tested the bioactivity of the (S)- and (R)-enantiomers of 3-MeC31, and found that whereas both enantiomers were effective in suppressing worker ovarian development, (S)-3-MeC31 appeared to be more effective at suppressing aggressive behavior by workers. This suggests that the natural pheromone may be a mixture of the two enantiomers. The enantiomeric ratio produced by queens remains unknown because of the small amounts of the compound available from each queen.
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Affiliation(s)
- Marine Motais de Narbonne
- Laboratory of Experimental and Comparative Ethology, University Paris 13, Sorbonne Paris Cité, Villetaneuse 93430, France
| | - Jelle S van Zweden
- Laboratory of Socioecology and Social Evolution, Department of Biology, KU Leuven, Naamsestraat 59 - Box 2466, Leuven 3000, Belgium
| | - Jan E Bello
- Departments of Entomology and Chemistry, University of California, 900 University Avenue, Riverside, CA 92521, USA
| | - Tom Wenseleers
- Laboratory of Socioecology and Social Evolution, Department of Biology, KU Leuven, Naamsestraat 59 - Box 2466, Leuven 3000, Belgium
| | - Jocelyn G Millar
- Departments of Entomology and Chemistry, University of California, 900 University Avenue, Riverside, CA 92521, USA
| | - Patrizia d'Ettorre
- Laboratory of Experimental and Comparative Ethology, University Paris 13, Sorbonne Paris Cité, Villetaneuse 93430, France
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14
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Andrade-Silva ACR, Nascimento FS. Reproductive regulation in an orchid bee: social context, fertility and chemical signalling. Anim Behav 2015. [DOI: 10.1016/j.anbehav.2015.05.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
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15
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Yagound B, Gouttefarde R, Leroy C, Belibel R, Barbaud C, Fresneau D, Chameron S, Poteaux C, Châline N. Fertility Signaling and Partitioning of Reproduction in the Ant Neoponera apicalis. J Chem Ecol 2015; 41:557-66. [PMID: 26018617 DOI: 10.1007/s10886-015-0591-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2015] [Revised: 03/30/2015] [Accepted: 05/19/2015] [Indexed: 11/30/2022]
Abstract
All individuals in social insect colonies benefit from being informed about the presence and fertility state of reproducers. This allows the established reproductive individuals to maintain their reproductive monopoly without the need for physical control, and the non-reproductive individuals to make appropriate reproductive choices. Here, we studied whether fertility signaling is responsible for the partitioning of reproduction in the ant Neoponera apicalis. This species forms small colonies from one single-mated queen, with workers establishing reproductive hierarchies when hopelessly queenless. Previous studies identified putative fertility signals, particularly the hydrocarbon 13-methylpentacosane (13-MeC25), and have shown that precise status discrimination based on these signals could be involved in the regulation of reproductive activities. Here, we extend these findings and reveal that all individuals, be they queens or workers, differ in their cuticular hydrocarbon profile according to fertility state. Proportions of 13-MeC25 were a strong predictor of an individual's ovarian activity, and could, thus, advertise the established reproducer(s) in both queenright and queenless conditions. Furthermore, this compound might play a key role in the establishment of the reproductive hierarchy, since workers with low fertility at the onset of hierarchy formation already have relatively high amounts of 13-MeC25. Dyadic encounters showed that individuals with experimentally increased amounts of 13-MeC25 triggered less agonistic interactions from top rankers, in accord with them "advertising" higher status. Thus, these bioassays supported the use of 13-MeC25 by competing ants. This simple recognition system potentially allows permanent regulation of partitioning of reproduction in this species.
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Affiliation(s)
- Boris Yagound
- Laboratoire d'Ethologie Expérimentale et Comparée, E.A. 4443, Université Paris 13, Sorbonne Paris Cité, 93430, Villetaneuse, France,
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Azevedo DO, de Paula SO, Zanuncio JC, Martinez LC, Serrão JE. Juvenile hormone downregulates vitellogenin production in Ectatomma tuberculatum (Hymenoptera: Formicidae) sterile workers. J Exp Biol 2015; 219:103-8. [DOI: 10.1242/jeb.127712] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2015] [Accepted: 11/02/2015] [Indexed: 11/20/2022]
Abstract
In the ant Ectatomma tuberculatum (Olivier, 1792), workers have active ovaries and lay trophic eggs that are eaten by the queen and larvae. Vitellogenins are the main proteins found in the eggs of insects and are the source of nutrients for the embryo in the fertilized eggs and for adults when in the trophic eggs. In social insects, vitellogenin titers vary between castes and affect reproductive social status, nursing, foraging, longevity, somatic maintenance, and immunity. In most insects, vitellogenin synthesis is mainly regulated by juvenile hormone. However, in non-reproductive worker ants, this relationship is poorly characterized. This study determined the effects of juvenile hormone on vitellogenin synthesis in non-reproductive E. tuberculatum workers. Juvenile hormone was topically applied onto workers, and the effect on vitellogenin synthesis in the fat body and vitellogenin titers in the haemolymph were analyzed by ELISA and qPCR. Juvenile hormone downregulated protein synthesis and reduced vitellogenin titers in the haemolymph, suggesting that in workers E. tuberculatum, juvenile hormone loses its gonadotrophic function.
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Affiliation(s)
| | | | - José Cola Zanuncio
- Departamento de Entomologia, Universidade Federal de Viçosa, 36570-000 Viçosa, MG, Brazil
| | - Luis Carlos Martinez
- Departamento de Biologia Geral, Universidade Federal de Viçosa, 36570-000 Viçosa, MG, Brazil
| | - José Eduardo Serrão
- Departamento de Biologia Geral, Universidade Federal de Viçosa, 36570-000 Viçosa, MG, Brazil
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17
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Status discrimination through fertility signalling allows ants to regulate reproductive conflicts. Anim Behav 2014. [DOI: 10.1016/j.anbehav.2014.04.014] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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18
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González-Forero M. AN EVOLUTIONARY RESOLUTION OF MANIPULATION CONFLICT. Evolution 2014; 68:2038-51. [DOI: 10.1111/evo.12420] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2013] [Accepted: 04/04/2014] [Indexed: 01/22/2023]
Affiliation(s)
- Mauricio González-Forero
- Department of Ecology and Evolutionary Biology; University of Tennessee; Knoxville Tennessee 37996-1610
- National Institute for Mathematical and Biological Synthesis (NIMBioS); Knoxville Tennessee 37996-3410
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Van Oystaeyen A, Oliveira RC, Holman L, van Zweden JS, Romero C, Oi CA, d'Ettorre P, Khalesi M, Billen J, Wäckers F, Millar JG, Wenseleers T. Conserved class of queen pheromones stops social insect workers from reproducing. Science 2014; 343:287-90. [PMID: 24436417 DOI: 10.1126/science.1244899] [Citation(s) in RCA: 248] [Impact Index Per Article: 24.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
A major evolutionary transition to eusociality with reproductive division of labor between queens and workers has arisen independently at least 10 times in the ants, bees, and wasps. Pheromones produced by queens are thought to play a key role in regulating this complex social system, but their evolutionary history remains unknown. Here, we identify the first sterility-inducing queen pheromones in a wasp, bumblebee, and desert ant and synthesize existing data on compounds that characterize female fecundity in 64 species of social insects. Our results show that queen pheromones are strikingly conserved across at least three independent origins of eusociality, with wasps, ants, and some bees all appearing to use nonvolatile, saturated hydrocarbons to advertise fecundity and/or suppress worker reproduction. These results suggest that queen pheromones evolved from conserved signals of solitary ancestors.
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Affiliation(s)
- Annette Van Oystaeyen
- Laboratory of Socioecology and Social Evolution, Zoological Institute, University of Leuven, Naamsestraat 59-Box 2466, 3000 Leuven, Belgium
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20
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van Zweden JS, Bonckaert W, Wenseleers T, d'Ettorre P. QUEEN SIGNALING IN SOCIAL WASPS. Evolution 2013; 68:976-86. [DOI: 10.1111/evo.12314] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2013] [Accepted: 10/10/2013] [Indexed: 11/29/2022]
Affiliation(s)
- Jelle S. van Zweden
- Centre for Social Evolution; University of Copenhagen; Universitetsparken 15 2100 Copenhagen Denmark
- Laboratory of Socioecology and Social Evolution; KU Leuven; Naamsestraat 59, box 2466 3000 Leuven Belgium
| | - Wim Bonckaert
- Laboratory of Socioecology and Social Evolution; KU Leuven; Naamsestraat 59, box 2466 3000 Leuven Belgium
| | - Tom Wenseleers
- Laboratory of Socioecology and Social Evolution; KU Leuven; Naamsestraat 59, box 2466 3000 Leuven Belgium
| | - Patrizia d'Ettorre
- Centre for Social Evolution; University of Copenhagen; Universitetsparken 15 2100 Copenhagen Denmark
- Laboratoire d'Ethologie Expérimentale et Comparée; Université Paris 13 99 avenue Jean-Baptiste Clément, 93430 Villetaneuse France
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21
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Tanner CJ, Keller L. Nest distribution varies with dispersal method and familiarity-mediated aggression for two sympatric ants. Anim Behav 2012. [DOI: 10.1016/j.anbehav.2012.08.018] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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22
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Holman L, Leroy C, Jørgensen C, Nielsen J, d’Ettorre P. Are queen ants inhibited by their own pheromone? Regulation of productivity via negative feedback. Behav Ecol 2012. [DOI: 10.1093/beheco/ars174] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
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23
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Experimental evidence that workers recognize reproductives through cuticular hydrocarbons in the ant Odontomachus brunneus. Behav Ecol Sociobiol 2012. [DOI: 10.1007/s00265-012-1380-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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24
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Holman L. Costs and constraints conspire to produce honest signaling: insights from an ant queen pheromone. Evolution 2012; 66:2094-105. [PMID: 22759287 DOI: 10.1111/j.1558-5646.2012.01603.x] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Signal costs and evolutionary constraints have both been proposed as ultimate explanations for the ubiquity of honest signaling, but the interface between these two factors is unclear. Here, I propose a pluralistic interpretation, and use game theory to demonstrate that evolutionary constraints determine whether signals evolve to be costly or cheap. Specifically, when the costs or benefits of signaling are strongly influenced by the sender's quality, low-cost signals evolve. The model reaffirms that cheap and costly signals can both be honest, and predicts that expensive signals should have more positive allometric slopes than cheap ones. The new framework is applied to an experimental study of an ant queen pheromone that honestly signals fecundity. Juvenile hormone was found to have opposing, dose-dependent effects on pheromone production and fecundity and was fatal at high doses, indicating that endocrine-mediated trade-offs preclude dishonesty. Several lines of evidence suggest that the realized cost of pheromone production may be nontrivial, and the antagonistic effects of juvenile hormone indicate the presence of significant evolutionary constraints. I conclude that the honesty of queen pheromones and other signals is likely enforced by both the cost of dishonesty and a suite of evolutionary constraints.
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Affiliation(s)
- Luke Holman
- Centre for Social Evolution, Department of Biology, University of Copenhagen, Universitetsparken 15, 2100 Copenhagen, Denmark.
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25
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Cooperation, Conflict, and the Evolution of Queen Pheromones. J Chem Ecol 2011; 37:1263-75. [DOI: 10.1007/s10886-011-0036-z] [Citation(s) in RCA: 83] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2011] [Revised: 10/16/2011] [Accepted: 10/28/2011] [Indexed: 01/08/2023]
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26
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Smith CR, Suarez AV, Tsutsui ND, Wittman SE, Edmonds B, Freauff A, Tillberg CV. Nutritional asymmetries are related to division of labor in a queenless ant. PLoS One 2011; 6:e24011. [PMID: 21886914 PMCID: PMC3160331 DOI: 10.1371/journal.pone.0024011] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2011] [Accepted: 08/02/2011] [Indexed: 11/19/2022] Open
Abstract
Eusocial species exhibit pronounced division of labor, most notably between reproductive and non-reproductive castes, but also within non-reproductive castes via morphological specialization and temporal polyethism. For species with distinct worker and queen castes, age-related differences in behavior among workers (e.g. within-nest tasks versus foraging) appear to result from physiological changes such as decreased lipid content. However, we know little about how labor is divided among individuals in species that lack a distinct queen caste. In this study, we investigated how fat storage varied among individuals in a species of ant (Dinoponera australis) that lacks a distinct queen caste and in which all individuals are morphologically similar and capable of reproduction (totipotent at birth). We distinguish between two hypotheses, 1) all individuals are physiologically similar, consistent with the possibility that any non-reproductive may eventually become reproductive, and 2) non-reproductive individuals vary in stored fat, similar to highly eusocial species, where depletion is associated with foraging and non-reproductives have lower lipid stores than reproducing individuals. Our data support the latter hypothesis. Location in the nest, the probability of foraging, and foraging effort, were all associated with decreased fat storage.
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Affiliation(s)
- Chris R Smith
- Department of Biology, Earlham College, Richmond, Indiana, United States of America.
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Tibbetts EA, Izzo A, Huang ZY. Behavioral and physiological factors associated with juvenile hormone in Polistes wasp foundresses. Behav Ecol Sociobiol 2010. [DOI: 10.1007/s00265-010-1126-6] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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28
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Holman L, Jørgensen CG, Nielsen J, d'Ettorre P. Identification of an ant queen pheromone regulating worker sterility. Proc Biol Sci 2010; 277:3793-800. [PMID: 20591861 DOI: 10.1098/rspb.2010.0984] [Citation(s) in RCA: 129] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
The selective forces that shape and maintain eusocial societies are an enduring puzzle in evolutionary biology. Ordinarily sterile workers can usually reproduce given the right conditions, so the factors regulating reproductive division of labour may provide insight into why eusociality has persisted over evolutionary time. Queen-produced pheromones that affect worker reproduction have been implicated in diverse taxa, including ants, termites, wasps and possibly mole rats, but to date have only been definitively identified in the honeybee. Using the black garden ant Lasius niger, we isolate the first sterility-regulating ant queen pheromone. The pheromone is a cuticular hydrocarbon that comprises the majority of the chemical profile of queens and their eggs, and also affects worker behaviour, by reducing aggression towards objects bearing the pheromone. We further show that the pheromone elicits a strong response in worker antennae and that its production by queens is selectively reduced following an immune challenge. These results suggest that the pheromone has a central role in colony organization and support the hypothesis that worker sterility represents altruistic self-restraint in response to an honest quality signal.
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Affiliation(s)
- Luke Holman
- Centre for Social Evolution, Department of Biology, University of Copenhagen, Universitetsparken 15, 2100 Copenhagen, Denmark.
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29
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The appeasement effect of sterility signaling in dominance contests among Bombus terrestris workers. Behav Ecol Sociobiol 2010. [DOI: 10.1007/s00265-010-0982-4] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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30
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Holman L, Dreier S, d'Ettorre P. Selfish strategies and honest signalling: reproductive conflicts in ant queen associations. Proc Biol Sci 2010; 277:2007-15. [PMID: 20181562 DOI: 10.1098/rspb.2009.2311] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Social insects offer unique opportunities to test predictions regarding the evolution of cooperation, life histories and communication. Colony founding by groups of unrelated queens, some of which are later killed, may select for selfish reproductive strategies, honest signalling and punishment. Here, we use a brood transfer experiment to test whether cofounding queens of the ant Lasius niger 'selfishly' adjust their productivity when sharing the nest with future competitors. We simultaneously analysed queen cuticular hydrocarbon (CHC) profiles to investigate whether queens honestly signal their reproductive output or produce dishonest, manipulative signals, providing a novel test of the evolutionary significance of queen pheromones. Queens produced fewer workers when their colony contained ample brood, but only in the presence of competitors, suggesting selfish conservation of resources. Several CHCs correlated with reproductive maturation, and to a lesser extent with productivity; the same hydrocarbons were more abundant on queens that were not killed, suggesting that workers select productive queens using these chemical cues. Our results highlight the role of honest signalling in the evolution of cooperation: whenever cheaters can be reliably identified, they may incur sanctions that reduce the incentive to be selfish.
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Affiliation(s)
- Luke Holman
- Department of Biology, Centre for Social Evolution, University of Copenhagen, Copenhagen, Denmark.
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31
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Izzo A, Wells M, Huang Z, Tibbetts E. Cuticular hydrocarbons correlate with fertility, not dominance, in a paper wasp, Polistes dominulus. Behav Ecol Sociobiol 2010. [DOI: 10.1007/s00265-010-0902-7] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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32
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Blacher P, Lecoutey E, Fresneau D, Nowbahari E. Reproductive hierarchies and status discrimination in orphaned colonies of Pachycondyla apicalis ants. Anim Behav 2010. [DOI: 10.1016/j.anbehav.2009.10.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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33
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Ichinose K, Lenoir A. Ontogeny of hydrocarbon profiles in the ant Aphaenogaster senilis and effects of social isolation. C R Biol 2009; 332:697-703. [DOI: 10.1016/j.crvi.2009.04.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2008] [Revised: 03/12/2009] [Accepted: 04/02/2009] [Indexed: 11/16/2022]
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34
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Cuticular hydrocarbon profiles indicate reproductive status in the termite Zootermopsis nevadensis. Behav Ecol Sociobiol 2009. [DOI: 10.1007/s00265-009-0807-5] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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35
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Smith AA, Hölldober B, Liebig J. Cuticular hydrocarbons reliably identify cheaters and allow enforcement of altruism in a social insect. Curr Biol 2009; 19:78-81. [PMID: 19135369 DOI: 10.1016/j.cub.2008.11.059] [Citation(s) in RCA: 107] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2008] [Revised: 11/25/2008] [Accepted: 11/26/2008] [Indexed: 11/25/2022]
Abstract
Cheaters are a threat to every society and therefore societies have established rules to punish these individuals in order to stabilize their social system. Recent models and observations suggest that enforcement of reproductive altruism (policing) in hymenopteran insect societies is a major force in maintaining high levels of cooperation. In order to be able to enforce altruism, reproductive cheaters need to be reliably identified. Strong correlational evidence indicates that cuticular hydrocarbons are the means of identifying cheaters, but direct proof is still missing. In the ant Aphaenogaster cockerelli, we mimicked reproductive cheaters by applying a synthetic compound typical of fertile individuals on nonreproductive workers. This treatment induced nestmate aggression in colonies where a queen was present. As expected, it failed to do so in colonies without a queen where workers had begun to reproduce. This provides the first direct evidence that cuticular hydrocarbons are the informational basis of policing behaviors, serving a major function in the regulation of reproduction in social insects. We suggest that even though cheaters would gain from suppressing these profiles, they are prevented from doing so through the mechanisms of hydrocarbon biosynthesis and its relation to reproductive physiology. Cheaters are identified through information that is inherently reliable.
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Affiliation(s)
- Adrian A Smith
- School of Life Sciences and Center for Social Dynamics and Complexity, Arizona State University, Tempe, AZ 85287-4501, USA
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Moxon S. Dominance as adaptive stressing and ranking of males, serving to allocate reproduction by differential self-suppressed fertility: towards a fully biological understanding of social systems. Med Hypotheses 2009; 73:5-14. [PMID: 19375872 DOI: 10.1016/j.mehy.2009.02.011] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2009] [Revised: 02/19/2009] [Accepted: 02/21/2009] [Indexed: 11/19/2022]
Abstract
Dominance is a biological concept of an asymmetric 'power' relationship between (any pair of) individuals, as a result of previous encounters with others biasing likelihood of contesting. That this requires dedicated neural structure shows that dominance is adaptive; and it is usually thought that fitness is increased through dominance (hierarchy) minimising mutually unproductive contest over resources, and/or determining access to or control over resources. But highly inconsistent data indicates that this operational definition is too wide, and given clear evidence that dominance is invariably same-sex, it would seem instead to function primarily to allocate reproduction. Dominance contest exposes individual differences in metabolic vigor especially, but also in various other, including sophisticated attributes; and by a self-organising process there is ranking of same-sex individuals in a hierarchy. But this achieves nothing in itself without an integral mechanism of corresponding individual variable self-suppression of the physiology re reproduction--and mate choice with rank as the criteria. Reproductive suppression would appear to vary along a continuum, from in some species (most 'cooperative breeders') a 100% reproductive skew with total suppression of all individuals bar the sole breeder to, in most others, a gradient down the length of the dominance hierarchy. The mechanism in most species is directly either hormonal or pheromonal, on top of an indirect consequence of the stress caused by relatively low rank. Dominance would seem to have evolved as a major instrument of the proposed 'genetic filter' function of the male, whereby in effect accumulated deleterious genetic material is 'quarantined' in the male half of the lineage from where it is purged, so as to keep this source of reproductive logjam away from females, thereby to avoid amplifying the problem of the female being necessarily the limiting factor in reproduction. The theory makes predictions mutually exclusive of the consensus model, that dominance/DH is: same-sex only; present whenever, within one or both sexes, there is potential conflict over reproduction, and there is no mechanism to preclude this, but otherwise is absent; always associated with some degree of differential physiological reproductive suppression. This new conceptualization of dominance has major implications for the social as well as biological sciences, in that resource-competition models of the basis of sociality will have to give way to a thoroughgoing biological understanding that places centre-stage not resources but reproduction; with consequent radical revision of notions of 'power'.
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van Zweden JS, Heinze J, Boomsma JJ, d'Ettorre P. Ant queen egg-marking signals: matching deceptive laboratory simplicity with natural complexity. PLoS One 2009; 4:e4718. [PMID: 19262683 PMCID: PMC2648039 DOI: 10.1371/journal.pone.0004718] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2008] [Accepted: 02/04/2009] [Indexed: 11/21/2022] Open
Abstract
Background Experiments under controlled laboratory conditions can produce decisive evidence for testing biological hypotheses, provided they are representative of the more complex natural conditions. However, whether this requirement is fulfilled is seldom tested explicitly. Here we provide a lab/field comparison to investigate the identity of an egg-marking signal of ant queens. Our study was based on ant workers resolving conflict over male production by destroying each other's eggs, but leaving queen eggs unharmed. For this, the workers need a proximate cue to discriminate between the two egg types. Earlier correlative evidence indicated that, in the ant Pachycondyla inversa, the hydrocarbon 3,11-dimethylheptacosane (3,11-diMeC27) is more abundant on the surface of queen-laid eggs. Methodology We first tested the hypothesis that 3,11-diMeC27 functions as a queen egg-marking pheromone using laboratory-maintained colonies. We treated worker-laid eggs with synthetic 3,11-diMeC27 and found that they were significantly more accepted than sham-treated worker-laid eggs. However, we repeated the experiment with freshly collected field colonies and observed no effect of treating worker-laid eggs with 3,11-diMeC27, showing that this compound by itself is not the natural queen egg-marking pheromone. We subsequently investigated the overall differences of entire chemical profiles of eggs, and found that queen-laid eggs in field colonies are more distinct from worker-laid eggs than in lab colonies, have more variation in profiles, and have an excess of longer-chain hydrocarbons. Conclusions Our results suggest that queen egg-marking signals are significantly affected by transfer to the laboratory, and that this change is possibly connected to reduced queen fertility as predicted by honest signaling theory. This change is reflected in the worker egg policing response under field and laboratory conditions.
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Affiliation(s)
- Jelle S van Zweden
- Centre for Social Evolution, Department of Biology, University of Copenhagen, Copenhagen, Denmark.
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38
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Malka O, Katzav-Gozansky T, Hefetz A. Uncoupling fertility from fertility-associated pheromones in worker honeybees (Apis mellifera). JOURNAL OF INSECT PHYSIOLOGY 2009; 55:205-209. [PMID: 19041321 DOI: 10.1016/j.jinsphys.2008.11.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2008] [Revised: 10/29/2008] [Accepted: 11/03/2008] [Indexed: 05/27/2023]
Abstract
Fertility-associated pheromones, chemical signals delineating ovarian development, were favourably selected in the course of evolution because it is in the best interest of both the signallers (in recruiting help from other colony members) and the receivers (in assisting them to reach an informed decision of how to maximize fitness). Such signals therefore should constitute honest, deception-proof indicators of ovarian development, suggesting, theoretically, that the processes of ovarian development and signal production are irreversibly coupled. Here we demonstrate that these processes can be uncoupled by treating queenless (QL) honeybee callow workers with methoprene, a juvenile hormone (JH) analog. While methoprene effectively inhibited ovarian development, it neither inhibited Dufour's fertility signal nor the mandibular glands' dominance signal. In fact, there was even a slight augmentation of both in the methoprene-treated bees. Thus, although fertility and fertility signals are tightly associated, they can be uncoupled by experimental manipulation. These results are consistent with the hypothesis that ovarian development and fertility-associated signal production are triggered by a common event/signal (e.g. queen pheromone disappearance) but comprise different regulatory systems. The evolutionary implication is that these two traits have evolved independently and may have been co-opted to emphasize the reproductive status of workers in the competition for reproduction.
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Affiliation(s)
- Osnat Malka
- Department of Zoology, Tel Aviv University, Ramat Aviv, 69978 Tel Aviv, Israel.
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39
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40
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Tannure-Nascimento IC, Nascimento FS, Zucchi R. The look of royalty: visual and odour signals of reproductive status in a paper wasp. Proc Biol Sci 2008; 275:2555-61. [PMID: 18682372 DOI: 10.1098/rspb.2008.0589] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Reproductive conflicts within animal societies occur when all females can potentially reproduce. In social insects, these conflicts are regulated largely by behaviour and chemical signalling. There is evidence that presence of signals, which provide direct information about the quality of the reproductive females would increase the fitness of all parties. In this study, we present an association between visual and chemical signals in the paper wasp Polistes satan. Our results showed that in nest-founding phase colonies, variation of visual signals is linked to relative fertility, while chemical signals are related to dominance status. In addition, experiments revealed that higher hierarchical positions were occupied by subordinates with distinct proportions of cuticular hydrocarbons and distinct visual marks. Therefore, these wasps present cues that convey reliable information of their reproductive status.
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Affiliation(s)
- Ivelize C Tannure-Nascimento
- Departamento de Biologia, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, São Paulo 14040-901, Brazil
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Newey PS, Robson SK, Crozier RH. Near-infrared spectroscopy as a tool in behavioural ecology: a case study of the weaver ant, Oecophylla smaragdina. Anim Behav 2008. [DOI: 10.1016/j.anbehav.2008.07.025] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Hydrocarbon Signals Explain the Pattern of Worker and Egg Policing in the Ant Aphaenogaster cockerelli. J Chem Ecol 2008; 34:1275-82. [DOI: 10.1007/s10886-008-9529-9] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2008] [Revised: 06/04/2008] [Accepted: 07/30/2008] [Indexed: 11/27/2022]
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Oettler J, Schmitt T, Herzner G, Heinze J. Chemical profiles of mated and virgin queens, egg-laying intermorphs and workers of the ant Crematogaster smithi. JOURNAL OF INSECT PHYSIOLOGY 2008; 54:672-679. [PMID: 18321526 DOI: 10.1016/j.jinsphys.2008.01.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2007] [Revised: 01/17/2008] [Accepted: 01/18/2008] [Indexed: 05/26/2023]
Abstract
Many colonies of the North American ant Crematogaster smithi contain a "third female caste" in addition to queens and workers. These "intermorphs" are morphological intermediate of queens and workers and have well-developed ovaries but lack a spermatheca for the storage of sperm. They are specialised for laying large numbers of unfertilised, viable eggs, most of which serve as food for larvae and adults, though a few may eventually develop into males. Based on the assumption that cuticular hydrocarbons (CHCs) in social insects honestly signal the reproductive status of an individual we investigated the CHC of mated mature queens, virgin queens, intermorphs and workers. We expected intermorphs to show chemical profiles intermediate between those of mated queens and non-reproductive workers. A discriminant analysis of the chemical profiles reliably separated queens, virgin queens, and workers, but failed to distinguish between queens and intermorphs even though workers were apparently capable of doing so.
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Affiliation(s)
- Jan Oettler
- Biologie I, Universität Regensburg, 93040 Regensburg, Germany.
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Denis D, Chameron S, Costille L, Pocheville A, Châline N, Fresneau D. Workers agonistic interactions in queenright and queenless nests of a polydomous ant society. Anim Behav 2008. [DOI: 10.1016/j.anbehav.2007.06.016] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Abstract
Social insect are profoundly influenced by primer pheromones (PPhs), which are efficient means for maintaining social harmony in the colony. PPhs act by affecting the physiology of the recipients with a subsequent shift in their behavior, and many PPhs have a releaser effect (i.e., changing the probability of performing a certain behavior upon perception). In this review we try to clarify the interplay between such dual pheromonal effects. Only a few PPhs have been identified, and we provide evidence for their existence in multiple species of social Hymenoptera, which is the most extensively studied of the social insects. We focus on the regulation of reproduction, social policing, and task allocation. Considering PPhs in a broad sense, we also discuss fertility signals and the role of cuticular hydrocarbons as putative PPhs. Identification of the underlying chemistry of PPhs offers insights into insect physiology and the evolution of social behavior. PPhs of the honey bee are used to demonstrate the complexity of pheromonal communication in social insects.
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Affiliation(s)
- Yves Le Conte
- INRA, UMR406 INRA-UAPV Ecologie des Invertébrés, Laboratoire de Biologie et Protection de l'Abeille, 84914, Avignon, France.
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Correlated changes in breeding status and polyunsaturated cuticular hydrocarbons: the chemical basis of nestmate recognition in the burying beetle Nicrophorus vespilloides? Behav Ecol Sociobiol 2007. [DOI: 10.1007/s00265-007-0532-x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Bocher A, Doums C, Millot L, Tirard C. Reproductive conflicts affect labor and immune defense in the queenless ant Diacamma sp. "nilgiri". Evolution 2007; 62:123-34. [PMID: 18067572 DOI: 10.1111/j.1558-5646.2007.00273.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
In many species of social Hymenoptera, totipotency of workers induces potential conflicts over reproduction. However, actual conflicts remain rare despite the existence of a high reproductive skew. One of the current hypotheses assumes that conflicts are costly and thus selected against. We studied the costs of conflicts in 20 colonies of the queenless ant Diacamma sp. "nilgiri" by testing the effects of conflicts on labor and worker immunocompetence, two parameters closely linked to the indirect fitness of workers. In this species, the dominant female is the only mated worker (gamergate) and monopolizes reproduction. We experimentally induced conflicts by splitting each colony into two groups, a control group containing the gamergate and an orphaned group displaying aggressions until a new dominant worker arises. Immunocompetence was assessed by the clearance of Escherichia coli bacteria that we injected into the ants. Time budget analysis revealed a lower rate of labor and especially brood care in orphaned groups, supporting the existence of a cost of conflicts on labor. Fifteen days after splitting, a lower immunocompetence was also found in orphaned groups, which concerned workers involved and not involved in conflicts. We propose that this immunosuppression induced by conflicts could stem from stress and not directly from aggression.
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Affiliation(s)
- Aurélie Bocher
- Laboratoire de Parasitologie Evolutive CNRS 7103, Université Pierre et Marie Curie, 7 quai Saint Bernard, 75005, Paris, France.
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Endler A, Hölldobler B, Liebig J. Lack of physical policing and fertility cues in egg-laying workers of the ant Camponotus floridanus. Anim Behav 2007. [DOI: 10.1016/j.anbehav.2006.10.031] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Boulay R, Hefetz A, Cerdá X, Devers S, Francke W, Twele R, Lenoir A. Production of sexuals in a fission-performing ant: dual effects of queen pheromones and colony size. Behav Ecol Sociobiol 2007. [DOI: 10.1007/s00265-007-0385-3] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Lommelen E, Johnson CA, Drijfhout FP, Billen J, Wenseleers T, Gobin B. Cuticular Hydrocarbons Provide Reliable Cues of Fertility in the Ant Gnamptogenys striatula. J Chem Ecol 2006; 32:2023-34. [PMID: 16902821 DOI: 10.1007/s10886-006-9126-8] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2006] [Revised: 02/21/2006] [Accepted: 04/06/2006] [Indexed: 10/24/2022]
Abstract
In ca. 150 species of queenless ants, a specialized queen caste is rare or absent, and mated workers take over the role of the queen in some or all of the colonies. Previously, it has been shown that reproduction in queenless ants is regulated by a combination of dominance behavior and chemical fertility signaling. It is unknown, however, whether chemical signals alone can sufficiently regulate reproduction. To investigate this possibility, we studied reproductive regulation in the facultatively queenless ant Gnamptogenys striatula, a species where dominance behavior is rare or absent. Active egg layers and infertile workers showed qualitative and quantitative differences in their cuticular hydrocarbon profile. Five long-chain methyl alkanes, 3,13- and 3,15-dimethyl pentriacontane, 3,13- and 3,15-dimethyl heptentriacontane, and 3,11,15-trimethyl heptentriacontane occurred only on the cuticles of virgin and mated egg layers. Pronounced quantitative differences were found in a further 27 alkenes; alkanes; and mono-, di-, and trimethyl alkanes. Workers that had recently stopped laying eggs had profiles similar to infertile workers, and mating status did not affect this chemical pattern. We conclude that the cuticular hydrocarbon profiles of G. striatula workers provide reliable information about their current fertility. In the interest of colony productivity, this allows reproduction to be regulated without the use of aggression.
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Affiliation(s)
- E Lommelen
- Zoological Institute, Catholic University of Leuven, Naamsestraat 59, B-3000, Leuven, Belgium.
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