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Pull CD. Social evolution: Limb amputation prevents infection in ants. Curr Biol 2024; 34:R677-R679. [PMID: 39043138 DOI: 10.1016/j.cub.2024.05.047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/25/2024]
Abstract
Social insect workers, renowned for their altruism, are frequently perceived as 'disposable'. A new study finds that ants amputate the limbs of nestmates, which saves them from infection, and indicates that worker care is as critical to colony success as sacrifice.
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2
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Ozan M, Helanterä H, d'Ettorre P, Sundström L. Queen fecundity, worker entourage and cuticular chemistry in the ant Formica fusca. Proc Biol Sci 2023; 290:20230861. [PMID: 37554034 PMCID: PMC10410219 DOI: 10.1098/rspb.2023.0861] [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: 04/12/2023] [Accepted: 07/06/2023] [Indexed: 08/10/2023] Open
Abstract
Cooperative breeding entails conflicts over reproductive shares that may be settled in different ways. In ants, where several queens simultaneously reproduce in a colony, both queens and workers may influence the reproductive apportionment and offspring quality. Queens may vary in their intrinsic fecundity, which may influence the size of the worker entourage attending individual queens, and this may eventually dictate the reproductive output of a queen. We tested whether the reproductive success of queens is affected by the size of their worker entourage, their fecundity at the onset of the reproductive season, and whether the queen cuticular hydrocarbon profile carries information on fecundity. We show that in the ant Formica fusca both queen fecundity and egg hatching success increase with the size of their entourage, and that newly hatched larvae produced by initially highly fecund queens are smaller. Furthermore, higher relatedness among workers increased queen fecundity. Finally, the queens that received a large worker entourage differed in the cuticular chemistry from those that received a small worker entourage. Our results thus show that workers play a pivotal role in determining queen fitness, that high intracolony relatedness among workers enhances the overall reproductive output in the colony, and that queen fecundity is reflected in their cuticular hydrocarbon profile.
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Affiliation(s)
- Martina Ozan
- Organismal and Evolutionary Biology, Faculty of Biological and Environmental Sciences, University of Helsinki, 00014, Finland
- Tvärminne Zoological Station, University of Helsinki, J.A. Palménintie 260, 10900 Hanko, Finland
| | - Heikki Helanterä
- Tvärminne Zoological Station, University of Helsinki, J.A. Palménintie 260, 10900 Hanko, Finland
- Faculty of Science, Ecology and Genetics Research Unit, University of Oulu, 90014, Finland
| | - Patrizia d'Ettorre
- Laboratoire d'Ethologie Expérimentale et Comparée, UR 4443, Université Sorbonne Paris Nord, Villetaneuse, France
- Institut Universitaire de France (IUF), Paris, France
| | - Liselotte Sundström
- Organismal and Evolutionary Biology, Faculty of Biological and Environmental Sciences, University of Helsinki, 00014, Finland
- Tvärminne Zoological Station, University of Helsinki, J.A. Palménintie 260, 10900 Hanko, Finland
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3
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Microstructures at the distal tip of ant chemosensory sensilla. Sci Rep 2022; 12:19328. [PMID: 36369461 PMCID: PMC9652420 DOI: 10.1038/s41598-022-21507-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2022] [Accepted: 09/28/2022] [Indexed: 11/13/2022] Open
Abstract
Ants and other eusocial insects emit and receive chemical signals to communicate important information within the colony. In ants, nestmate recognition, task allocation, and reproductive distribution of labor are largely mediated through the detection of cuticular hydrocarbons (CHCs) that cover the exoskeleton. With their large size and limited volatility, these CHCs are believed to be primarily detected through direct contact with the antennae during behavioral interactions. Here we first use scanning electron microscopy to investigate the unique morphological features of CHC-sensitive basiconic sensilla of two ant species, the black carpenter ant Camponotus pennsylvanicus and the Indian jumping ant Harpegnathos saltator. These basiconic sensilla possess an abundance of small pores typical of most insect olfactory sensilla, but also have a large concave depression at the terminal end. Basiconic sensilla are enriched at the distal segments of the antennae in both species, which aligns with their proposed role in contact chemosensation of CHCs. A survey of these sensilla across additional ant species shows varied microstructures at their tips, but each possess surface textures that would also increase sensory surface area. These unique ant chemosensory sensilla represent yet another example of how specialized structures have evolved to serve the functional requirements of eusocial communication.
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4
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Pulliainen U, Bos N, d'Ettorre P, Sundström L. The Scent of Ant Brood: Caste Differences in Surface Hydrocarbons of Formica exsecta Pupae. J Chem Ecol 2021; 47:513-524. [PMID: 33900528 PMCID: PMC8217064 DOI: 10.1007/s10886-021-01275-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: 06/26/2020] [Revised: 03/02/2021] [Accepted: 04/12/2021] [Indexed: 10/25/2022]
Abstract
Chemical communication is common across all organisms. Insects in particular use predominantly chemical stimuli in assessing their environment and recognizing their social counterparts. One of the chemical stimuli used for recognition in social insects, such as ants, is the suite of long-chain, cuticular hydrocarbons. In addition to providing waterproofing, these surface hydrocarbons serve as a signature mixture, which ants can perceive, and use to distinguish between strangers and colony mates, and to determine caste, sex, and reproductive status of another individual. They can be both environmentally and endogenously acquired. The surface chemistry of adult workers has been studied extensively in ants, yet the pupal stage has rarely been considered. Here we characterized the surface chemistry of pupae of Formica exsecta, and examine differences among sexes, castes (reproductive vs. worker), and types of sample (developing individual vs. cocoon envelope). We found quantitative and qualitative differences among both castes and types of sample, but male and female reproductives did not differ in their surface chemistry. We also found that the pupal surface chemistry was more complex than that of adult workers in this species. These results improve our understanding of the information on which ants base recognition, and highlights the diversity of surface chemistry in social insects across developmental stages.
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Affiliation(s)
- Unni Pulliainen
- Organismal and Evolutionary Biology Research Programme, Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland
- Tväminne Zoological Station, Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland
| | - Nick Bos
- Department of Biology, Faculty of Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Patrizia d'Ettorre
- Laboratory of Experimental and Comparative Ethology, University of Paris, 13, Sorbonne Paris Cité, Paris, France
| | - Liselotte Sundström
- Organismal and Evolutionary Biology Research Programme, Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland.
- Tväminne Zoological Station, Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland.
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5
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Abstract
Social behavior is one of the most fascinating and complex behaviors in humans and animals. A fundamental process of social behavior is communication among individuals. It relies on the capability of the nervous system to sense, process, and interpret various signals (e.g., pheromones) and respond with appropriate decisions and actions. Eusocial insects, including ants, some bees, some wasps, and termites, display intriguing cooperative social behavior. Recent advances in genetic and genomic studies have revealed key genes that are involved in pheromone synthesis, chemosensory perception, and physiological and behavioral responses to varied pheromones. In this review, we highlight the genes and pathways that regulate queen pheromone-mediated social communication, discuss the evolutionary changes in genetic systems, and outline prospects of functional studies in sociobiology.
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Affiliation(s)
- Hua Yan
- Department of Biology, University of Florida, Gainesville, Florida 32611, USA
- Center for Smell and Taste, University of Florida, Gainesville, Florida 32610, USA
| | - Jürgen Liebig
- School of Life Sciences, Arizona State University, Tempe, Arizona 85287, USA
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6
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Eyer PA, Salin J, Helms AM, Vargo EL. Distinct chemical blends produced by different reproductive castes in the subterranean termite Reticulitermes flavipes. Sci Rep 2021; 11:4471. [PMID: 33627740 PMCID: PMC7904765 DOI: 10.1038/s41598-021-83976-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Accepted: 02/10/2021] [Indexed: 11/13/2022] Open
Abstract
The production of royal pheromones by reproductives (queens and kings) enables social insect colonies to allocate individuals into reproductive and non-reproductive roles. In many termite species, nestmates can develop into neotenics when the primary king or queen dies, which then inhibit the production of additional reproductives. This suggests that primary reproductives and neotenics produce royal pheromones. The cuticular hydrocarbon heneicosane was identified as a royal pheromone in Reticulitermes flavipes neotenics. Here, we investigated the presence of this and other cuticular hydrocarbons in primary reproductives and neotenics of this species, and the ontogeny of their production in primary reproductives. Our results revealed that heneicosane was produced by most neotenics, raising the question of whether reproductive status may trigger its production. Neotenics produced six additional cuticular hydrocarbons absent from workers and nymphs. Remarkably, heneicosane and four of these compounds were absent in primary reproductives, and the other two compounds were present in lower quantities. Neotenics therefore have a distinct 'royal' blend from primary reproductives, and potentially over-signal their reproductive status. Our results suggest that primary reproductives and neotenics may face different social pressures. Future studies of these pressures should provide a more complete understanding of the mechanisms underlying social regulation in termites.
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Affiliation(s)
- Pierre-André Eyer
- Department of Entomology, 2143 TAMU, Texas A&M University, College Station, TX, 77843-2143, USA.
| | - Jared Salin
- Department of Entomology, 2143 TAMU, Texas A&M University, College Station, TX, 77843-2143, USA
| | - Anjel M Helms
- Department of Entomology, 2143 TAMU, Texas A&M University, College Station, TX, 77843-2143, USA
| | - Edward L Vargo
- Department of Entomology, 2143 TAMU, Texas A&M University, College Station, TX, 77843-2143, USA
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7
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Dominance Hierarchy, Ovarian Activity and Cuticular Hydrocarbons in the Primitively Eusocial Wasp Mischocyttarus cerberus (Vespidae, Polistinae, Mischocyttarini). J Chem Ecol 2020; 46:835-844. [PMID: 32789711 DOI: 10.1007/s10886-020-01206-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Revised: 06/22/2020] [Accepted: 07/30/2020] [Indexed: 10/23/2022]
Abstract
The dominance hierarchy in primitively eusocial insect societies has been shown to be mainly regulated through aggressive interactions. Females that are generally more dominant stand out and occupy the queen position, meaning that they monopolize reproduction while others perform other tasks. Chemical communication is important for maintaining social cohesion. Cuticular hydrocarbons are recognized as the main molecules responsible for mediating social interactions, especially nestmate recognition and queen signalling. Many highly eusocial groups have been studied in recent years, but primitively eusocial groups, which are key to understanding the evolution of social behavior, remain unexplored. In this study, we investigated the connection between cuticular hydrocarbons in females expressed in different social contexts in the primitively eusocial wasp Mischocyttarus cerberus. Colonies in two different ontogenetic phases, pre- and post-worker emergence, were used. We observed and categorized behavioral interactions between individual females and collected all individuals in a nest to obtain information on size, ovary activation and chemical composition. Furthermore, we conducted experiments in which the alpha (dominant) females were removed from nests to produce a new dominance hierarchy. We found that females in different hierarchical positions had small chemical difference corresponding with ovary activity. Our results support the hypothesis that cuticular hydrocarbons are associated with social context in this primitively eusocial species, with some compounds being associated with hierarchical position and ovarian activity.
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8
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Oi CA, Oliveira RC, van Zweden JS, Mateus S, Millar JG, Nascimento FS, Wenseleers T. Do Primitively Eusocial Wasps Use Queen Pheromones to Regulate Reproduction? A Case Study of the Paper Wasp Polistes satan. Front Ecol Evol 2019. [DOI: 10.3389/fevo.2019.00199] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
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9
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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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10
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Schultner E, Oettler J, Helanterä H. The Role of Brood in Eusocial Hymenoptera. QUARTERLY REVIEW OF BIOLOGY 2018; 92:39-78. [PMID: 29558609 DOI: 10.1086/690840] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Study of social traits in offspring traditionally reflects on interactions in simple family groups, with famous examples including parent-offspring conflict and sibling rivalry in birds and mammals. In contrast, studies of complex social groups such as the societies of ants, bees, and wasps focus mainly on adults and, in particular, on traits and interests of queens and workers. The social role of developing individuals in complex societies remains poorly understood. We attempt to fill this gap by illustrating that development in social Hymenoptera constitutes a crucial life stage with important consequences for the individual as well as the colony. We begin by describing the complex social regulatory network that modulates development in Hymenoptera societies. By highlighting the inclusive fitness interests of developing individuals, we show that they may differ from those of other colony members. We then demonstrate that offspring have evolved specialized traits that allow them to play a functional, cooperative role within colonies and give them the potential power to act toward increasing their inclusive fitness. We conclude by providing testable predictions for investigating the role of brood in colony interactions and giving a general outlook on what can be learned from studying offspring traits in hymenopteran societies.
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11
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Kay J, Menegazzi P, Mildner S, Roces F, Helfrich-Förster C. The Circadian Clock of the Ant Camponotus floridanus Is Localized in Dorsal and Lateral Neurons of the Brain. J Biol Rhythms 2018; 33:255-271. [PMID: 29589522 DOI: 10.1177/0748730418764738] [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] [Indexed: 12/16/2022]
Abstract
The circadian clock of social insects has become a focal point of interest for research, as social insects show complex forms of timed behavior and organization within their colonies. These behaviors include brood care, nest maintenance, foraging, swarming, defense, and many other tasks, of which several require social synchronization and accurate timing. Ants of the genus Camponotus have been shown to display a variety of daily timed behaviors such as the emergence of males from the nest, foraging, and relocation of brood. Nevertheless, circadian rhythms of isolated individuals have been studied in few ant species, and the circadian clock network in the brain that governs such behaviors remains completely uncharacterized. Here we show that isolated minor workers of Camponotus floridanus exhibit temperature overcompensated free-running locomotor activity rhythms under constant darkness. Under light-dark cycles, most animals are active during day and night, with a slight preference for the night. On the neurobiological level, we show that distinct cell groups in the lateral and dorsal brain of minor workers of C. floridanus are immunostained with an antibody against the clock protein Period (PER) and a lateral group additionally with an antibody against the neuropeptide pigment-dispersing factor (PDF). PER abundance oscillates in a daily manner, and PDF-positive neurites invade most parts of the brain, suggesting that the PER/PDF-positive neurons are bona fide clock neurons that transfer rhythmic signals into the relevant brain areas controlling rhythmic behavior.
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Affiliation(s)
- Janina Kay
- Neurobiology and Genetics, Biocenter, University of Würzburg, Würzburg, Germany
| | - Pamela Menegazzi
- Neurobiology and Genetics, Biocenter, University of Würzburg, Würzburg, Germany
| | - Stephanie Mildner
- Department of Behavioral Physiology and Sociobiology (Zoology II), Biocenter, University of Würzburg, Würzburg, Germany
| | - Flavio Roces
- Department of Behavioral Physiology and Sociobiology (Zoology II), Biocenter, University of Würzburg, Würzburg, Germany
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12
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Chomicki G, Renner SS. The interactions of ants with their biotic environment. Proc Biol Sci 2018; 284:rspb.2017.0013. [PMID: 28298352 DOI: 10.1098/rspb.2017.0013] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2017] [Accepted: 02/15/2017] [Indexed: 11/12/2022] Open
Abstract
This special feature results from the symposium 'Ants 2016: ant interactions with their biotic environments' held in Munich in May 2016 and deals with the interactions between ants and other insects, plants, microbes and fungi, studied at micro- and macroevolutionary levels with a wide range of approaches, from field ecology to next-generation sequencing, chemical ecology and molecular genetics. In this paper, we review key aspects of these biotic interactions to provide background information for the papers of this special feature After listing the major types of biotic interactions that ants engage in, we present a brief overview of ant/ant communication, ant/plant interactions, ant/fungus symbioses, and recent insights about ants and their endosymbionts. Using a large molecular clock-dated Formicidae phylogeny, we map the evolutionary origins of different ant clades' interactions with plants, fungi and hemiptera. Ants' biotic interactions provide ideal systems to address fundamental ecological and evolutionary questions about mutualism, coevolution, adaptation and animal communication.
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Affiliation(s)
- Guillaume Chomicki
- Systematic Botany and Mycology, University of Munich (LMU), Menzinger Strasse 67, 80638 Munich, Germany
| | - Susanne S Renner
- Systematic Botany and Mycology, University of Munich (LMU), Menzinger Strasse 67, 80638 Munich, Germany
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13
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Smith AA, Liebig J. The evolution of cuticular fertility signals in eusocial insects. CURRENT OPINION IN INSECT SCIENCE 2017; 22:79-84. [PMID: 28805643 DOI: 10.1016/j.cois.2017.05.017] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2017] [Revised: 05/17/2017] [Accepted: 05/19/2017] [Indexed: 05/19/2023]
Abstract
A reproductive division of labor is a definitive characteristic of eusocial insect societies and it requires a means through which colony members can assess the presence and productivity of reproductive individuals. Cuticular hydrocarbons are the primary means of doing so across eusocial hymenopterans. However, recent experimental work presents conflicting views on how these chemical signals function, are interpreted by workers, and evolve. These recent advances include demonstrations of hydrocarbons as evolutionarily conserved 'queen pheromones' and as species-divergent 'fertility signals' used by both queens and workers. In this review, we synthesize conflicting studies into an evolutionary framework suggesting a transition of reproductive communication from cue-like signature mixtures, to learned fertility signals, to innate queen pheromones that evolved across eusocial insects.
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Affiliation(s)
- Adrian A Smith
- Research & Collections, North Carolina Museum of Natural Sciences, 11 W. Jones St, Raleigh, NC 27601, USA; Department of Biological Sciences, North Carolina State University, Raleigh, NC, USA.
| | - Jürgen Liebig
- School of Life Sciences, Arizona State University, Tempe, AZ 85287, USA
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14
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Smith AA, Millar JG, Suarez AV. Comparative analysis of fertility signals and sex-specific cuticular chemical profiles of Odontomachus trap-jaw ants. ACTA ACUST UNITED AC 2016; 219:419-30. [PMID: 26847561 DOI: 10.1242/jeb.128850] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The lipid mixture that coats the insect cuticle contains a number of chemical signals. Mate choice in solitary insects is mediated by sexually dimorphic cuticular chemistry, whereas in eusocial insects, these profiles provide information through which colony members are identified and the fertility status of individuals is assessed. Profiles of queens and workers have been described for a number of eusocial species, but there have been few comparisons of fertility signals among closely related species. Additionally, sexual dimorphism in cuticular lipid profiles has only been reported in two species of ants. This study describes the cuticular chemical profiles of queens, workers and males of three species of Odontomachus trap-jaw ants: O. ruginodis, O. relictus and O. haematodus. These are compared with fertility signals and sexually dimorphic profiles already described from O. brunneus. We report that fertility signals are not conserved within this genus: chemical compounds that distinguish queens from workers vary in number and type among the species. Furthermore, the compounds that were most abundant in cuticular extracts of O. ruginodis queens relative to workers were novel 2,5-dialkyltetrahydrofurans. Bioassays of extracts of O. ruginodis queens indicate that the dialkyltetrahydrofuran and hydrocarbon fractions of the profile are likely to work synergistically in eliciting behavioral responses from workers. In contrast, cuticular lipids that distinguish males from females are more conserved across species, with isomeric and relative abundance variations comprising the main differences among species. Our results provide new insights into how these contact chemical signals may have arisen and evolved within eusocial insects.
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Affiliation(s)
- Adrian A Smith
- Research and Collections, North Carolina Museum of Natural Sciences, Raleigh, NC 27601, USA Department of Biological Sciences, North Carolina State University, Raleigh, NC 27695, USA
| | - Jocelyn G Millar
- Department of Entomology, University of California, Riverside, CA 92521, USA
| | - Andrew V Suarez
- Departments of Animal Biology and Entomology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
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15
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Grüter C, Keller L. Inter-caste communication in social insects. Curr Opin Neurobiol 2016; 38:6-11. [PMID: 26803006 DOI: 10.1016/j.conb.2016.01.002] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2015] [Revised: 01/04/2016] [Accepted: 01/04/2016] [Indexed: 01/02/2023]
Abstract
Social insect colonies function as highly integrated units despite consisting of many individuals. This requires the different functional parts of the colony (e.g. different castes) to exchange information that aid in colony functioning and ontogeny. Here we discuss inter-caste communication in three contexts, firstly, the communication between males and females during courtship, secondly, the communication between queens and workers that regulate reproduction and thirdly, the communication between worker castes that allows colonies to balance the number of different worker types. Some signals show surprising complexity in both their chemistry and function, whereas others are simple compounds that were probably already used as pheromones in the solitary ancestors of several social insect lineages.
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Affiliation(s)
- Christoph Grüter
- Department of Ecology and Evolution, Biophore, University of Lausanne, 1015 Lausanne, Switzerland.
| | - Laurent Keller
- Department of Ecology and Evolution, Biophore, University of Lausanne, 1015 Lausanne, Switzerland.
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16
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Ronai I, Vergoz V, Oldroyd B. The Mechanistic, Genetic, and Evolutionary Basis of Worker Sterility in the Social Hymenoptera. ADVANCES IN THE STUDY OF BEHAVIOR 2016. [DOI: 10.1016/bs.asb.2016.03.002] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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17
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Ebie JD, Hölldobler B, Liebig J. Larval regulation of worker reproduction in the polydomous ant Novomessor cockerelli. Naturwissenschaften 2015; 102:72. [DOI: 10.1007/s00114-015-1323-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2015] [Revised: 11/05/2015] [Accepted: 11/06/2015] [Indexed: 10/22/2022]
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18
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Sharma KR, Enzmann BL, Schmidt Y, Moore D, Jones GR, Parker J, Berger SL, Reinberg D, Zwiebel LJ, Breit B, Liebig J, Ray A. Cuticular Hydrocarbon Pheromones for Social Behavior and Their Coding in the Ant Antenna. Cell Rep 2015; 12:1261-71. [PMID: 26279569 DOI: 10.1016/j.celrep.2015.07.031] [Citation(s) in RCA: 90] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2015] [Revised: 07/10/2015] [Accepted: 07/15/2015] [Indexed: 01/08/2023] Open
Abstract
The sophisticated organization of eusocial insect societies is largely based on the regulation of complex behaviors by hydrocarbon pheromones present on the cuticle. We used electrophysiology to investigate the detection of cuticular hydrocarbons (CHCs) by female-specific olfactory sensilla basiconica on the antenna of Camponotus floridanus ants through the utilization of one of the largest family of odorant receptors characterized so far in insects. These sensilla, each of which contains multiple olfactory receptor neurons, are differentially sensitive to CHCs and allow them to be classified into three broad groups that collectively detect every hydrocarbon tested, including queen and worker-enriched CHCs. This broad-spectrum sensitivity is conserved in a related species, Camponotus laevigatus, allowing these ants to detect CHCs from both nestmates and non-nestmates. Behavioral assays demonstrate that these ants are excellent at discriminating CHCs detected by the antenna, including enantiomers of a candidate queen pheromone that regulates the reproductive division of labor.
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Affiliation(s)
- Kavita R Sharma
- Department of Entomology, University of California, Riverside, CA 92521, USA
| | | | - Yvonne Schmidt
- Institut für Organische Chemie, Albert-Ludwigs-Universität Freiburg, Albertstrasse 21, 79104 Freiburg im Breisgau, Germany
| | - Dani Moore
- School of Life Sciences, Arizona State University, Tempe, AZ 85287, USA
| | - Graeme R Jones
- Chemical Ecology Group, School of Physical and Geographical Sciences, Lennard-Jones Laboratory, Keele University, Staffordshire ST5 5GB, UK
| | - Jane Parker
- Chemical Ecology Group, School of Physical and Geographical Sciences, Lennard-Jones Laboratory, Keele University, Staffordshire ST5 5GB, UK
| | - Shelley L Berger
- Departments of Cell and Developmental Biology, Genetics, and Biology, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Danny Reinberg
- Department of Molecular Pharmacology and Biochemistry, New York University School of Medicine, New York, NY 10016, USA
| | - Laurence J Zwiebel
- Department of Biological Sciences, Vanderbilt University, Nashville, TN 37235, USA
| | - Bernhard Breit
- Institut für Organische Chemie, Albert-Ludwigs-Universität Freiburg, Albertstrasse 21, 79104 Freiburg im Breisgau, Germany
| | - Jürgen Liebig
- School of Life Sciences, Arizona State University, Tempe, AZ 85287, USA
| | - Anandasankar Ray
- Department of Entomology, University of California, Riverside, CA 92521, USA.
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19
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Villalta I, Angulo E, Devers S, Cerdá X, Boulay R. Regulation of worker egg laying by larvae in a fission-performing ant. Anim Behav 2015. [DOI: 10.1016/j.anbehav.2015.05.021] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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20
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Oi CA, van Zweden JS, Oliveira RC, Van Oystaeyen A, Nascimento FS, Wenseleers T. The origin and evolution of social insect queen pheromones: Novel hypotheses and outstanding problems. Bioessays 2015; 37:808-21. [PMID: 25916998 DOI: 10.1002/bies.201400180] [Citation(s) in RCA: 84] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Queen pheromones, which signal the presence of a fertile queen and induce daughter workers to remain sterile, are considered to play a key role in regulating the reproductive division of labor of insect societies. Although queen pheromones were long thought to be highly taxon-specific, recent studies have shown that structurally related long-chain hydrocarbons act as conserved queen signals across several independently evolved lineages of social insects. These results imply that social insect queen pheromones are very ancient and likely derived from an ancestral signalling system that was already present in their common solitary ancestors. Based on these new insights, we here review the literature and speculate on what signal precursors social insect queen pheromones may have evolved from. Furthermore, we provide compelling evidence that these pheromones should best be seen as honest signals of fertility as opposed to suppressive agents that chemically sterilize the workers against their own best interests.
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Affiliation(s)
- Cintia A Oi
- Department of Biology, Laboratory of Socioecology & Social Evolution, University of Leuven, Leuven, Belgium
| | - Jelle S van Zweden
- Department of Biology, Laboratory of Socioecology & Social Evolution, University of Leuven, Leuven, Belgium
| | - Ricardo C Oliveira
- Department of Biology, Laboratory of Socioecology & Social Evolution, University of Leuven, Leuven, Belgium
| | - Annette Van Oystaeyen
- Department of Biology, Laboratory of Socioecology & Social Evolution, University of Leuven, Leuven, Belgium
| | - Fabio S Nascimento
- Departamento de Biologia da Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Brazil
| | - Tom Wenseleers
- Department of Biology, Laboratory of Socioecology & Social Evolution, University of Leuven, Leuven, Belgium
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21
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Peso M, Elgar MA, Barron AB. Pheromonal control: reconciling physiological mechanism with signalling theory. Biol Rev Camb Philos Soc 2014; 90:542-59. [PMID: 24925630 DOI: 10.1111/brv.12123] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2012] [Revised: 05/07/2014] [Accepted: 05/13/2014] [Indexed: 11/28/2022]
Abstract
Pheromones are intraspecific chemical signals. They can have profound effects on the behaviour and/or physiology of the receiver, and it is still common to hear pheromones described as controlling of the behaviour of the receiver. The discussion of pheromonal control arose initially from a close association between hormones and pheromones in the comparative physiological literature, but the concept of a controlling pheromone is at odds with contemporary signal evolution theory, which predicts that a manipulative pheromonal signal negatively affecting the receiver's fitness should not be stable over evolutionary time. Here we discuss the meaning of pheromonal control, and the ecological circumstances by which it might be supported. We argue that in discussing pheromonal control it is important to differentiate between control applied to the effects of a pheromone on a receiver's physiology (proximate control), and control applied to the effects of a pheromone on a receiver's fitness (ultimate control). Critically, a pheromone signal affecting change in the receiver's behaviour or physiology need not necessarily manipulate the fitness of a receiver. In cases where pheromonal signalling does lead to a reduction in the fitness of the receiver, the signalling system would be stable if the pheromone were an honest signal of a social environment that disadvantages the receiver, and the physiological and behavioural changes observed in the receiver were an adaptive response to the new social circumstances communicated by the pheromone.
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Affiliation(s)
- Marianne Peso
- Department of Biological Sciences, Macquarie University, Building E8A, Eastern Road, North Ryde, New South Wales 2109, Australia
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22
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Holmes MJ, Tan K, Wang Z, Oldroyd BP, Beekman M. Why acquiesce? Worker reproductive parasitism in the Eastern honeybee (Apis cerana
). J Evol Biol 2014; 27:939-49. [DOI: 10.1111/jeb.12366] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2013] [Revised: 02/24/2014] [Accepted: 03/06/2014] [Indexed: 02/02/2023]
Affiliation(s)
- M. J. Holmes
- Behaviour and Genetics of Social Insects Laboratory; School of Biological Sciences; University of Sydney; Sydney NSW Australia
| | - K. Tan
- Key Laboratory of Tropical Forest Ecology; Xishuangbanna Tropical Botanical Garden; Chinese Academy of Science; Kunming China
- Eastern Bee Research Institute of Yunnan Agricultural University; Kunming China
| | - Z. Wang
- Eastern Bee Research Institute of Yunnan Agricultural University; Kunming China
| | - B. P. Oldroyd
- Behaviour and Genetics of Social Insects Laboratory; School of Biological Sciences; University of Sydney; Sydney NSW Australia
| | - M. Beekman
- Behaviour and Genetics of Social Insects Laboratory; School of Biological Sciences; University of Sydney; Sydney NSW Australia
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23
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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: 215] [Impact Index Per Article: 21.5] [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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24
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Rödel MO, Brede C, Hirschfeld M, Schmitt T, Favreau P, Stöcklin R, Wunder C, Mebs D. Chemical camouflage--a frog's strategy to co-exist with aggressive ants. PLoS One 2013; 8:e81950. [PMID: 24349157 PMCID: PMC3859521 DOI: 10.1371/journal.pone.0081950] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2013] [Accepted: 10/18/2013] [Indexed: 11/24/2022] Open
Abstract
Whereas interspecific associations receive considerable attention in evolutionary, behavioural and ecological literature, the proximate bases for these associations are usually unknown. This in particular applies to associations between vertebrates with invertebrates. The West-African savanna frog Phrynomantis microps lives in the underground nest of ponerine ants (Paltothyreus tarsatus). The ants usually react highly aggressively when disturbed by fiercely stinging, but the frog is not attacked and lives unharmed among the ants. Herein we examined the proximate mechanisms for this unusual association. Experiments with termites and mealworms covered with the skin secretion of the frog revealed that specific chemical compounds seem to prevent the ants from stinging. By HPLC-fractionation of an aqueous solution of the frogs' skin secretion, two peptides of 1,029 and 1,143 Da were isolated and found to inhibit the aggressive behaviour of the ants. By de novo sequencing using tandem mass spectrometry, the amino acid sequence of both peptides consisting of a chain of 9 and 11 residues, respectively, was elucidated. Both peptides were synthesized and tested, and exhibited the same inhibitory properties as the original frog secretions. These novel peptides most likely act as an appeasement allomone and may serve as models for taming insect aggression.
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Affiliation(s)
- Mark-Oliver Rödel
- Museum für Naturkunde Berlin, Leibniz Institute for Research on Evolution and Biodiversity, Berlin, Germany
- Theodor-Boveri-Institute (Biocenter of the University), Department of Animal Ecology and Tropical Biology (Zoology III), Würzburg, Germany
- * E-mail:
| | - Christian Brede
- Theodor-Boveri-Institute (Biocenter of the University), Department of Animal Ecology and Tropical Biology (Zoology III), Würzburg, Germany
- Medizinische Klinik und Poliklinik II, Zentrum für Experimentelle Molekulare Medizin, Würzburg, Germany
| | - Mareike Hirschfeld
- Museum für Naturkunde Berlin, Leibniz Institute for Research on Evolution and Biodiversity, Berlin, Germany
- Theodor-Boveri-Institute (Biocenter of the University), Department of Animal Ecology and Tropical Biology (Zoology III), Würzburg, Germany
| | - Thomas Schmitt
- Theodor-Boveri-Institute (Biocenter of the University), Department of Animal Ecology and Tropical Biology (Zoology III), Würzburg, Germany
- Ecological Networks, Biology, Technische Universität Darmstadt, Darmstadt, Germany
| | | | | | - Cora Wunder
- Institute of Legal Medicine, University of Frankfurt, Frankfurt/M., Germany
| | - Dietrich Mebs
- Institute of Legal Medicine, University of Frankfurt, Frankfurt/M., Germany
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25
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Chemical profiles of two pheromone glands are differentially regulated by distinct mating factors in honey bee queens (Apis mellifera L.). PLoS One 2013; 8:e78637. [PMID: 24236028 PMCID: PMC3827242 DOI: 10.1371/journal.pone.0078637] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2012] [Accepted: 09/21/2013] [Indexed: 11/21/2022] Open
Abstract
Pheromones mediate social interactions among individuals in a wide variety of species, from yeast to mammals. In social insects such as honey bees, pheromone communication systems can be extraordinarily complex and serve to coordinate behaviors among many individuals. One of the primary mediators of social behavior and organization in honey bee colonies is queen pheromone, which is produced by multiple glands. The types and quantities of chemicals produced differ significantly between virgin and mated queens, and recent studies have suggested that, in newly mated queens, insemination volume or quantity can affect pheromone production. Here, we examine the long-term impact of different factors involved during queen insemination on the chemical composition of the mandibular and Dufour's glands, two of the major sources of queen pheromone. Our results demonstrate that carbon dioxide (an anesthetic used in instrumental insemination), physical manipulation of genital tract (presumably mimicking the act of copulation), insemination substance (saline vs. semen), and insemination volume (1 vs. 8 µl) all have long-term effects on mandibular gland chemical profiles. In contrast, Dufour's gland chemical profiles were changed only upon insemination and were not influenced by exposure to carbon dioxide, manipulation, insemination substance or volume. These results suggest that the chemical contents of these two glands are regulated by different neuro-physiological mechanisms. Furthermore, workers responded differently to the different mandibular gland extracts in a choice assay. Although these studies must be validated in naturally mated queens of varying mating quality, our results suggest that while the chemical composition of Dufour's gland is associated with mating status, that of the mandibular glands is associated with both mating status and insemination success. Thus, the queen appears to be signaling both status and reproductive quality to the workers, which may impact worker behavior and physiology as well as social organization and productivity of the colony.
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26
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Smith AA, Vanderpool W, Millar JG, Hanks LM, Suarez AV. Conserved male-specific cuticular hydrocarbon patterns in the trap-jaw ant Odontomachus brunneus. CHEMOECOLOGY 2013. [DOI: 10.1007/s00049-013-0143-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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27
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Holmes MJ, Oldroyd BP, Duncan M, Allsopp MH, Beekman M. Cheaters sometimes prosper: targeted worker reproduction in honeybee (Apis mellifera) colonies during swarming. Mol Ecol 2013; 22:4298-4306. [PMID: 23889604 DOI: 10.1111/mec.12387] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2013] [Revised: 05/08/2013] [Accepted: 05/12/2013] [Indexed: 11/29/2022]
Abstract
Kin selection theory predicts that honeybee (Apis mellifera) workers should largely refrain from producing their own offspring, as the workers collectively have higher inclusive fitness if they rear the sons of their mother, the queen. Studies that have quantified levels of ovary activation and reproduction among workers have largely supported this prediction. We sampled pre-emergent male pupae and adult workers from seven colonies at regular intervals throughout the reproductive part of the season. We show that the overall contribution of workers to male (drone) production is 4.2%, nearly 40 times higher than is generally reported, and is highest during reproductive swarming, when an average of 6.2% of the males genotyped are worker-produced. Similarly, workers in our samples were 100 times more likely to have active ovaries than previously assumed. Worker reproduction is seasonally influenced and peaks when colonies are rearing new queens. Not all worker subfamilies contribute equally to reproduction. Instead, certain subfamilies are massively over-represented in drone brood. By laying eggs within the period in which many colonies produce virgin queens, these rare worker subfamilies increase their direct fitness via their well-timed sons.
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Affiliation(s)
- Michael J Holmes
- Behaviour and Genetics of Social Insects Laboratory, School of Biological Sciences, University of Sydney, Macleay A12, Science Road, Sydney, NSW, 2006, Australia
| | - Benjamin P Oldroyd
- Behaviour and Genetics of Social Insects Laboratory, School of Biological Sciences, University of Sydney, Macleay A12, Science Road, Sydney, NSW, 2006, Australia
| | - Michael Duncan
- Behaviour and Genetics of Social Insects Laboratory, School of Biological Sciences, University of Sydney, Macleay A12, Science Road, Sydney, NSW, 2006, Australia
| | - Michael H Allsopp
- Honeybee Research Section, ARC-Plant Protection Research Institute, Private Bag X5017, Stellenbosch, 7599, South Africa
| | - Madeleine Beekman
- Behaviour and Genetics of Social Insects Laboratory, School of Biological Sciences, University of Sydney, Macleay A12, Science Road, Sydney, NSW, 2006, Australia
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28
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Regional variation in queen and worker aggression in incipient colonies of the desert ant Messor pergandei. Behav Ecol Sociobiol 2013. [DOI: 10.1007/s00265-013-1568-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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29
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30
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Ruel C, Lenoir A, Cerdá X, Boulay R. Surface lipids of queen-laid eggs do not regulate queen production in a fission-performing ant. Naturwissenschaften 2012; 100:91-100. [DOI: 10.1007/s00114-012-0997-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2012] [Revised: 11/12/2012] [Accepted: 11/14/2012] [Indexed: 10/27/2022]
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31
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Asano E, Cassill DL. Modeling temperature-mediated fluctuation in colony size in the fire ant, Solenopsis invicta. J Theor Biol 2012; 305:70-7. [PMID: 22575550 DOI: 10.1016/j.jtbi.2012.03.011] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2011] [Revised: 01/21/2012] [Accepted: 03/12/2012] [Indexed: 10/28/2022]
Abstract
In the social insects, colony size is central to the survival of the queen. Two endogenous factors, worker longevity and queen's daily egg production, are known to determine maximum colony size. A third endogenous factor, duration of worker development from egg to adult, regulates the rate of colony growth. In this paper, we report findings from a simulation quantifying the effects of temperature on colony size in the fire ant, Solenopsis invicta. The monthly average temperature over a six year period for the panhandle of north Florida was interpolated to determine the effects of daily temperature on a queen's egg production, worker developmental time and worker longevity. Additional daily temperatures were simulated: 7°C higher and 7°C lower than daily temperatures for north Florida. As expected, colony size was the largest when annual temperatures were the highest across seasons, ranging from 57,000 to 187,000. Colony size at intermediate daily temperatures ranged from 14,000 to 103,000; small colonies recovered rapidly as temperatures warmed. Colony size at lower daily temperatures ranged from 14,000 to 21,000. Extended worker longevity at lower temperatures compensated for low egg production and longer developmental time. And vice versa, the queen's high rate of egg production and the shorter developmental time compensated for shorter worker longevity at high temperatures. Because the fire ant nest consists of a heat-collecting dome in which to incubate brood during cold weather, and deep chambers in which to cool workers during hot weather, colony size is likely to be higher and more stable than our simulation showed. The extended longevity of workers and queens at low temperatures, and perhaps their ability to hibernate below the permafrost, might explain the ability of ants to colonize habitats worldwide.
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Affiliation(s)
- Erika Asano
- Department of Environmental Science, Policy and Geography-Mathematics, University of South Florida, St. Petersburg, FL 33701, USA.
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32
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Konrad M, Pamminger T, Foitzik S. Two pathways ensuring social harmony. THE SCIENCE OF NATURE - NATURWISSENSCHAFTEN 2012; 99:627-36. [PMID: 22806253 DOI: 10.1007/s00114-012-0943-z] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2012] [Revised: 06/26/2012] [Accepted: 06/28/2012] [Indexed: 11/26/2022]
Abstract
Reproductive division of labour is a characteristic trait of social insects. The dominant reproductive individual, often the queen, uses chemical communication and/or behaviour to maintain her social status. Queens of many social insects communicate their fertility status via cuticle-bound substances. As these substances usually possess a low volatility, their range in queen-worker communication is potentially limited. Here, we investigate the range and impact of behavioural and chemical queen signals on workers of the ant Temnothorax longispinosus. We compared the behaviour and ovary development of workers subjected to three different treatments: workers with direct chemical and physical contact to the queen, those solely under the influence of volatile queen substances and those entirely separated from the queen. In addition to short-ranged queen signals preventing ovary development in workers, we discovered a novel secondary pathway influencing worker behaviour. Workers with no physical contact to the queen, but exposed to volatile substances, started to develop their ovaries, but did not change their behaviour compared to workers in direct contact to the queen. In contrast, workers in queen-separated groups showed both increased ovary development and aggressive dominance interactions. We conclude that T. longispinosus queens influence worker ovary development and behaviour via two independent signals, both ensuring social harmony within the colony.
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Affiliation(s)
- Matthias Konrad
- Institute of Science and Technology Austria (IST Austria), Klosterneuburg, Austria
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33
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Zanette LRS, Miller SDL, Faria CMA, Almond EJ, Huggins TJ, Jordan WC, Bourke AFG. Reproductive conflict in bumblebees and the evolution of worker policing. Evolution 2012. [PMID: 23206135 DOI: 10.1111/j.1558-5646.2012.01709.x] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Worker policing (mutual repression of reproduction) in the eusocial Hymenoptera represents a leading example of how coercion can facilitate cooperation. The occurrence of worker policing in "primitively" eusocial species with low mating frequencies, which lack relatedness differences conducive to policing, suggests that separate factors may underlie the origin and maintenance of worker policing. We tested this hypothesis by investigating conflict over male parentage in the primitively eusocial, monandrous bumblebee, Bombus terrestris. Using observations, experiments, and microsatellite genotyping, we found that: (a) worker- but not queen-laid male eggs are nearly all eaten (by queens, reproductive, and nonreproductive workers) soon after being laid, so accounting for low observed frequencies of larval and adult worker-produced males; (b) queen- and worker-laid male eggs have equal viabilities; (c) workers discriminate between queen- and worker-laid eggs using cues on eggs and egg cells that almost certainly originate from queens. The cooccurrence in B. terrestris of these three key elements of "classical" worker policing as found in the highly eusocial, polyandrous honeybees provides novel support for the hypothesis that worker policing can originate in the absence of relatedness differences maintaining it. Worker policing in B. terrestris almost certainly arose via reproductive competition among workers, that is, as "selfish" policing.
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Affiliation(s)
- Lorenzo R S Zanette
- School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, UK.
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34
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Johnson CA, Sundström L. Cuticular Chemistry of Two Social Forms in a Facultatively Polygyne Ant (Hymenoptera: Formicidae:Formica truncorum). ANN ZOOL FENN 2012. [DOI: 10.5735/086.049.0101] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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35
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Bonckaert W, Drijfhout FP, d’Ettorre P, Billen J, Wenseleers T. Hydrocarbon Signatures of Egg Maternity, Caste Membership and Reproductive Status in the Common Wasp. J Chem Ecol 2012; 38:42-51. [DOI: 10.1007/s10886-011-0055-9] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2011] [Revised: 11/07/2011] [Accepted: 12/27/2011] [Indexed: 01/28/2023]
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36
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Bos N, Dreier S, Jørgensen CG, Nielsen J, Guerrieri FJ, d'Ettorre P. Learning and perceptual similarity among cuticular hydrocarbons in ants. JOURNAL OF INSECT PHYSIOLOGY 2012; 58:138-146. [PMID: 22067290 DOI: 10.1016/j.jinsphys.2011.10.010] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/25/2011] [Revised: 10/24/2011] [Accepted: 10/25/2011] [Indexed: 05/31/2023]
Abstract
Nestmate recognition in ants is based on perceived differences in a multi-component blend of hydrocarbons that are present on the insect cuticle. Although supplementation experiments have shown that some classes of hydrocarbons, such as methyl branched alkanes and alkenes, have a salient role in nestmate recognition, there was basically no information available on how ants detect and perceive these molecules. We used a new conditioning procedure to investigate whether individual carpenter ants could associate a given hydrocarbon (linear or methyl-branched alkane) to sugar reward. We then studied perceptual similarity between a hydrocarbon previously associated with sugar and a novel hydrocarbon. Ants learnt all hydrocarbon-reward associations rapidly and with the same efficiency, regardless of the structure of the molecules. Ants could discriminate among a large number of pairs of hydrocarbons, but also generalised. Generalisation depended both on the structure of the molecule and the animal's experience. For linear alkanes, generalisation was observed when the novel molecule was smaller than the conditioned one. Generalisation between pairs of methyl-alkanes was high, while generalisation between hydrocarbons that differed in the presence or absence of a methyl group was low, suggesting that chain length and functional group might be coded independently by the ant olfactory system. Understanding variations in perception of recognition cues in ants is necessary for the general understanding of the mechanisms involved in social recognition processes based on chemical cues.
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Affiliation(s)
- Nick Bos
- Centre for Social Evolution, Department of Biology, University of Copenhagen, Universitetsparken 15, 2100 Copenhagen, Denmark.
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37
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Eliyahu D, Ross KG, Haight KL, Keller L, Liebig J. Venom alkaloid and cuticular hydrocarbon profiles are associated with social organization, queen fertility status, and queen genotype in the fire ant Solenopsis invicta. J Chem Ecol 2011; 37:1242-54. [PMID: 22095515 DOI: 10.1007/s10886-011-0037-y] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2010] [Revised: 10/10/2011] [Accepted: 11/04/2011] [Indexed: 11/27/2022]
Abstract
Queens in social insect colonies advertise their presence in the colony to: a) attract workers' attention and care; b) gain acceptance by workers as replacement or supplemental reproductives; c) prevent reproductive development in nestmates. We analyzed the chemical content of whole body surface extracts of adult queens of different developmental and reproductive stages, and of adult workers from monogyne (single colony queen) and polygyne (multiple colony queens) forms of the fire ant Solenopsis invicta. We found that the composition of the most abundant components, venom alkaloids, differed between queens and workers, as well as between reproductive and non-reproductive queens. Additionally, workers of the two forms could be distinguished by alkaloid composition. Finally, sexually mature, non-reproductive queens from polygyne colonies differed in their proportions of cis-piperidine alkaloids, depending on their Gp-9 genotype, although the difference disappeared once they became functional reproductives. Among the unsaturated cuticular hydrocarbons characteristic of queens, there were differences in amounts of alkenes/alkadienes between non-reproductive polygyne queens of different Gp-9 genotypes, between non-reproductive and reproductive queens, and between polygyne and monogyne reproductive queens, with the amounts increasing at a relatively higher rate through reproductive ontogeny in queens bearing the Gp-9 b allele. Given that the genotype-specific piperidine differences reflect differences in rates of reproductive maturation between queens, we speculate that these abundant and unique compounds have been co-opted to serve in fertility signaling, while the cuticular hydrocarbons now play a complementary role in regulation of social organization by signaling queen Gp-9 genotype.
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Affiliation(s)
- Dorit Eliyahu
- School of Life Sciences, Arizona State University, Tempe, USA
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38
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Brandstaetter AS, Kleineidam CJ. Distributed representation of social odors indicates parallel processing in the antennal lobe of ants. J Neurophysiol 2011; 106:2437-49. [PMID: 21849606 DOI: 10.1152/jn.01106.2010] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
In colonies of eusocial Hymenoptera cooperation is organized through social odors, and particularly ants rely on a sophisticated odor communication system. Neuronal information about odors is represented in spatial activity patterns in the primary olfactory neuropile of the insect brain, the antennal lobe (AL), which is analog to the vertebrate olfactory bulb. The olfactory system is characterized by neuroanatomical compartmentalization, yet the functional significance of this organization is unclear. Using two-photon calcium imaging, we investigated the neuronal representation of multicomponent colony odors, which the ants assess to discriminate friends (nestmates) from foes (nonnestmates). In the carpenter ant Camponotus floridanus, colony odors elicited spatial activity patterns distributed across different AL compartments. Activity patterns in response to nestmate and nonnestmate colony odors were overlapping. This was expected since both consist of the same components at differing ratios. Colony odors change over time and the nervous system has to constantly adjust for this (template reformation). Measured activity patterns were variable, and variability was higher in response to repeated nestmate than to repeated nonnestmate colony odor stimulation. Variable activity patterns may indicate neuronal plasticity within the olfactory system, which is necessary for template reformation. Our results indicate that information about colony odors is processed in parallel in different neuroanatomical compartments, using the computational power of the whole AL network. Parallel processing might be advantageous, allowing reliable discrimination of highly complex social odors.
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Affiliation(s)
- Andreas Simon Brandstaetter
- Department of Behavioral Physiology and Sociobiology (Zoology II), Biozentrum, University of Würzburg, Würzburg, Germany.
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Friends and foes from an ant brain's point of view--neuronal correlates of colony odors in a social insect. PLoS One 2011; 6:e21383. [PMID: 21731724 PMCID: PMC3121771 DOI: 10.1371/journal.pone.0021383] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2010] [Accepted: 06/01/2011] [Indexed: 12/02/2022] Open
Abstract
Background Successful cooperation depends on reliable identification of friends and foes. Social insects discriminate colony members (nestmates/friends) from foreign workers (non-nestmates/foes) by colony-specific, multi-component colony odors. Traditionally, complex processing in the brain has been regarded as crucial for colony recognition. Odor information is represented as spatial patterns of activity and processed in the primary olfactory neuropile, the antennal lobe (AL) of insects, which is analogous to the vertebrate olfactory bulb. Correlative evidence indicates that the spatial activity patterns reflect odor-quality, i.e., how an odor is perceived. For colony odors, alternatively, a sensory filter in the peripheral nervous system was suggested, causing specific anosmia to nestmate colony odors. Here, we investigate neuronal correlates of colony odors in the brain of a social insect to directly test whether they are anosmic to nestmate colony odors and whether spatial activity patterns in the AL can predict how odor qualities like “friend” and “foe” are attributed to colony odors. Methodology/Principal Findings Using ant dummies that mimic natural conditions, we presented colony odors and investigated their neuronal representation in the ant Camponotus floridanus. Nestmate and non-nestmate colony odors elicited neuronal activity: In the periphery, we recorded sensory responses of olfactory receptor neurons (electroantennography), and in the brain, we measured colony odor specific spatial activity patterns in the AL (calcium imaging). Surprisingly, upon repeated stimulation with the same colony odor, spatial activity patterns were variable, and as variable as activity patterns elicited by different colony odors. Conclusions Ants are not anosmic to nestmate colony odors. However, spatial activity patterns in the AL alone do not provide sufficient information for colony odor discrimination and this finding challenges the current notion of how odor quality is coded. Our result illustrates the enormous challenge for the nervous system to classify multi-component odors and indicates that other neuronal parameters, e.g., precise timing of neuronal activity, are likely necessary for attribution of odor quality to multi-component odors.
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Meunier J, Delémont O, Lucas C. Recognition in ants: social origin matters. PLoS One 2011; 6:e19347. [PMID: 21573235 PMCID: PMC3087756 DOI: 10.1371/journal.pone.0019347] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2011] [Accepted: 03/28/2011] [Indexed: 11/28/2022] Open
Abstract
The ability of group members to discriminate against foreigners is a keystone in the evolution of sociality. In social insects, colony social structure (number of queens) is generally thought to influence abilities of resident workers to discriminate between nestmates and non-nestmates. However, whether social origin of introduced individuals has an effect on their acceptance in conspecific colonies remains poorly explored. Using egg-acceptance bioassays, we tested the influence of social origin of queen-laid eggs on their acceptance by foreign workers in the ant Formica selysi. We showed that workers from both single- and multiple-queen colonies discriminated against foreign eggs from single-queen colonies, whereas they surprisingly accepted foreign eggs from multiple-queen colonies. Chemical analyses then demonstrated that social origins of eggs and workers could be discriminated on the basis of their chemical profiles, a signal generally involved in nestmate discrimination. These findings provide the first evidence in social insects that social origins of eggs interfere with nestmate discrimination and are encoded by chemical signatures.
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Affiliation(s)
- Joël Meunier
- Department of Ecology and Evolution, University of Lausanne, Lausanne, Switzerland.
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41
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Holman L. Queen pheromones: The chemical crown governing insect social life. Commun Integr Biol 2010; 3:558-60. [PMID: 21331238 DOI: 10.4161/cib.3.6.12976] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2010] [Accepted: 07/05/2010] [Indexed: 11/19/2022] Open
Abstract
Group-living species produce signals that alter the behavior and even the physiology of their social partners. Social insects possess especially sophisticated chemical communication systems that govern every aspect of colony life, including the defining feature of eusociality: reproductive division of labor. Current evidence hints at the central importance of queen pheromones, but progress has been hindered by the fact that such pheromones have only been isolated in honeybees. In a pair of papers on the ant Lasius niger, we identified and investigated a queen pheromone regulating worker sterility. The cuticular hydrocarbon 3-methylhentriacontane (3-MeC(31)) is correlated with queen maturity and fecundity and workers are also more likely to execute surplus queens that have low amounts of this chemical. Experiments with synthetic 3-MeC(31) found that it inhibits ovarian development in queenless workers and lowers worker aggression towards objects coated with it. Production of 3-MeC(31) by queens was depressed by an experimental immune challenge, and the same chemical was abundant on queenlaid eggs, suggesting that the workers' responses to the queen are conditional on her health and fecundity. Together with other studies, these results indicate that queen pheromones are honest signals of quality that simultaneously regulate multiple social behaviors.
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Affiliation(s)
- Luke Holman
- Centre for Social Evolution; Department of Biology; University of Copenhagen; Universitetsparken, Copenhagen Denmark
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42
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Dijkstra MB, van Zweden JS, Dirchsen M, Boomsma JJ. Workers of Acromyrmex echinatior leafcutter ants police worker-laid eggs, but not reproductive workers. Anim Behav 2010. [DOI: 10.1016/j.anbehav.2010.06.011] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Martin SJ, Helanterä H, Drijfhout FP. Is parasite pressure a driver of chemical cue diversity in ants? Proc Biol Sci 2010; 278:496-503. [PMID: 20610426 DOI: 10.1098/rspb.2010.1047] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Parasites and pathogens are possibly key evolutionary forces driving recognition systems. However, empirical evidence remains sparse. The ubiquitous pioneering ant Formica fusca is exploited by numerous socially parasitic ant species. We compared the chemical cue diversity, egg and nest mate recognition abilities in two Finnish and two UK populations where parasite pressure is high or absent, respectively. Finnish populations had excellent egg and nest mate discrimination abilities, which were lost in the UK populations. The loss of discrimination behaviour correlates with a loss in key recognition compounds (C(25)-dimethylalkanes). This was not owing to genetic drift or different ecotypes since neutral gene diversity was the same in both countries. Furthermore, it is known that the cuticular hydrocarbon profiles of non-host ant species remain stable between Finland and the UK. The most parsimonious explanation for the striking difference in the cue diversity (number of C(25)-dimethylalkanes isomers) between the UK and Finland populations is the large differences in parasite pressure experienced by F. fusca in the two countries. These results have strong parallels with bird (cuckoo) studies and support the hypothesis that parasites are driving recognition cue diversity.
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Affiliation(s)
- Stephen J Martin
- Department of Animal and Plant Sciences, University of Sheffield, Sheffield S10 2TN, UK.
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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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45
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Smith CR, Dolezal A, Eliyahu D, Holbrook CT, Gadau J. Ants (Formicidae): models for social complexity. Cold Spring Harb Protoc 2010; 2009:pdb.emo125. [PMID: 20147200 DOI: 10.1101/pdb.emo125] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
The family Formicidae (ants) is composed of more than 12,000 described species that vary greatly in size, morphology, behavior, life history, ecology, and social organization. Ants occur in most terrestrial habitats and are the dominant animals in many of them. They have been used as models to address fundamental questions in ecology, evolution, behavior, and development. The literature on ants is extensive, and the natural history of many species is known in detail. Phylogenetic relationships for the family, as well as within many subfamilies, are known, enabling comparative studies. Their ease of sampling and ecological variation makes them attractive for studying populations and questions relating to communities. Their sociality and variation in social organization have contributed greatly to an understanding of complex systems, division of labor, and chemical communication. Ants occur in colonies composed of tens to millions of individuals that vary greatly in morphology, physiology, and behavior; this variation has been used to address proximate and ultimate mechanisms generating phenotypic plasticity. Relatedness asymmetries within colonies have been fundamental to the formulation and empirical testing of kin and group selection theories. Genomic resources have been developed for some species, and a whole-genome sequence for several species is likely to follow in the near future; comparative genomics in ants should provide new insights into the evolution of complexity and sociogenomics. Future studies using ants should help establish a more comprehensive understanding of social life, from molecules to colonies.
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Affiliation(s)
- Chris R Smith
- School of Life Sciences, Arizona State University, Tempe, AZ 85287, USA.
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Johnson BR, Linksvayer TA. Deconstructing the superorganism: social physiology, groundplans, and sociogenomics. QUARTERLY REVIEW OF BIOLOGY 2010; 85:57-79. [PMID: 20337260 DOI: 10.1086/650290] [Citation(s) in RCA: 109] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Our understanding of insect societies is rapidly expanding due to an emphasis on integrative approaches. Emerging tools enabling the molecular dissection of social behavior, together with novel hypotheses for the evolution of eusociality, are emblematic of this progress. However, an obstacle to a truly integrative approach remains, as social physiology--the basis of group-level coordination--has generally been neglected by geneticists. In this paper, we begin a synthesis of these fields by first reviewing three classes of social insect organization that mark major transitions in increasing social complexity. We then develop an expansion of the superorganism concept in order to place eusociality into a broad evolutionary context, and we also interpret current molecular and genetic work on the evolution of eusociality. The ground plan hypothesis proposes that eusociality arose via simple changes in the regulation of ancestral gene sets affecting reproductive physiology and behavior, and we argue that this hypothesis is explanatory for the evolution of division of labor (social anatomy) but not for the regulatory systems that ensure group-level coordination of action (social physiology), which we propose is dependent on previously unrelated traits that are brought together into novel genetic networks. We conclude with a review of recent work in sociogenomics that supports our hypotheses.
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Affiliation(s)
- Brian R Johnson
- Department of Ecology, Behavior, and Evolution, University of California, San Diego, La Jolla, CA 92093-0116, USA.
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Mixed messages: fertility signaling interferes with nestmate recognition in the monogynous ant Camponotus floridanus. Behav Ecol Sociobiol 2010. [DOI: 10.1007/s00265-010-0916-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Keller L. Adaptation and the genetics of social behaviour. Philos Trans R Soc Lond B Biol Sci 2010; 364:3209-16. [PMID: 19805428 DOI: 10.1098/rstb.2009.0108] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
In recent years much progress has been made towards understanding the selective forces involved in the evolution of social behaviour including conflicts over reproduction among group members. Here, I argue that an important additional step necessary for advancing our understanding of the resolution of potential conflicts within insect societies is to consider the genetics of the behaviours involved. First, I discuss how epigenetic modifications of behaviour may affect conflict resolution within groups. Second, I review known natural polymorphisms of social organization to demonstrate that a lack of consideration of the genetic mechanisms involved may lead to erroneous explanations of the adaptive significance of behaviour. Third, I suggest that, on the basis of recent genetic studies of sexual conflict in Drosophila, it is necessary to reconsider the possibility of within-group manipulation by means of chemical substances (i.e. pheromones). Fourth, I address the issue of direct versus indirect genetic effects, which is of particular importance for the study of behaviour in social groups. Fifth, I discuss the issue of how a genetic influence on dominance hierarchies and reproductive division of labour can have secondary effects, for example in the evolution of promiscuity. Finally, because the same sets of genes (e.g. those implicated in chemical signalling and the responses that are triggered) may be used even in species as divergent as ants, cooperative breeding birds and primates, an integration of genetic mechanisms into the field of social evolution may also provide unifying ideas.
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Affiliation(s)
- Laurent Keller
- Department of Ecology and Evolution, University of Lausanne, Biophore, Lausanne 1015, Switzerland.
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49
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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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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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