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Kay T, Motes-Rodrigo A, Royston A, Richardson TO, Stroeymeyt N, Keller L. Ant social network structure is highly conserved across species. Proc Biol Sci 2024; 291:20240898. [PMID: 39079671 PMCID: PMC11288679 DOI: 10.1098/rspb.2024.0898] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2024] [Revised: 06/19/2024] [Accepted: 06/21/2024] [Indexed: 08/03/2024] Open
Abstract
The ecological success of social insects makes their colony organization fascinating to scientists studying collective systems. In recent years, the combination of automated behavioural tracking and social network analysis has deepened our understanding of many aspects of colony organization. However, because studies have typically worked with single species, we know little about interspecific variation in network structure. Here, we conduct a comparative network analysis across five ant species from five subfamilies, separated by more than 100 Myr of evolution. We find that social network structure is highly conserved across subfamilies. All species studied form modular networks, with two social communities, a similar distribution of individuals between the two communities, and equivalent mapping of task performance onto the communities. Against this backdrop of organizational similarity, queens of the different species occupied qualitatively distinct network positions. The deep conservation of the two community structure implies that the most fundamental behavioural division of labour in social insects is between workers that stay in the nest to rear brood, and those that leave the nest to forage. This division has parallels across the animal kingdom in systems of biparental care and probably represents the most readily evolvable form of behavioural division of labour.
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Affiliation(s)
- Tomas Kay
- Laboratory of Social Evolution and Behavior, The Rockefeller University, New York, NY, USA
- Department of Ecology and Evolution, University of Lausanne, Lausanne, Switzerland
| | - Alba Motes-Rodrigo
- Department of Ecology and Evolution, University of Lausanne, Lausanne, Switzerland
| | - Arthur Royston
- Department of Ecology and Evolution, University of Lausanne, Lausanne, Switzerland
| | | | | | - Laurent Keller
- Department of Ecology and Evolution, University of Lausanne, Lausanne, Switzerland
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Wiernasz DC, Cole BJ. The ontogeny of selection on genetic diversity in harvester ants. Proc Biol Sci 2022; 289:20220496. [PMID: 35673867 PMCID: PMC9174731 DOI: 10.1098/rspb.2022.0496] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Selection may favour traits throughout an individual's lifetime or at a particular life stage. In many species of social insects, established colonies that are more genetically diverse outperform less diverse colonies with respect to a variety of traits that contribute to fitness, but whether selection favours high diversity in small colonies is unknown. We tested the hypothesis that selection favours genetically diverse colonies during the juvenile period using a multi-year field experiment with the harvester ant, Pogonomyrmex occidentalis. We used controlled matings to generate colonies that varied in genetic diversity and transplanted them into the field. We monitored their survival for seven (the 2015 cohort, n = 149) and six (the 2016 cohort, n = 157) years. Genetically more diverse colonies had greater survival, resulting in significant viability selection. However, in both cohorts survival was not influenced by genetic diversity until colonies were three years old. We suggest that changes in their internal organization enabled colonies to use the benefits of multiple genotypes, and discuss possible mechanisms that can generate this pattern.
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Affiliation(s)
- Diane C. Wiernasz
- Department of Biology and Biochemistry, University of Houston, Houston, TX, 77204-5001, USA
| | - Blaine J. Cole
- Department of Biology and Biochemistry, University of Houston, Houston, TX, 77204-5001, USA
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Evans LJ, Smith KE, Raine NE. Fast learning in free-foraging bumble bees is negatively correlated with lifetime resource collection. Sci Rep 2017; 7:496. [PMID: 28356567 PMCID: PMC5428240 DOI: 10.1038/s41598-017-00389-0] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2016] [Accepted: 01/31/2017] [Indexed: 11/09/2022] Open
Abstract
Despite widespread interest in the potential adaptive value of individual differences in cognition, few studies have attempted to address the question of how variation in learning and memory impacts their performance in natural environments. Using a novel split-colony experimental design we evaluated visual learning performance of foraging naïve bumble bees (Bombus terrestris) in an ecologically relevant associative learning task under controlled laboratory conditions, before monitoring the lifetime foraging performance of the same individual bees in the field. We found appreciable variation among the 85 workers tested in both their learning and foraging performance, which was not predicted by colony membership. However, rather than finding that foragers benefited from enhanced learning performance, we found that fast and slow learners collected food at comparable rates and completed a similar number of foraging bouts per day in the field. Furthermore, bees with better learning abilities foraged for fewer days; suggesting a cost of enhanced learning performance in the wild. As a result, slower learning individuals collected more resources for their colony over the course of their foraging career. These results demonstrate that enhanced cognitive traits are not necessarily beneficial to the foraging performance of individuals or colonies in all environments.
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Affiliation(s)
- Lisa J Evans
- School of Biological Sciences, Royal Holloway University of London, Egham, Surrey, TW20 0EX, UK.
- The New Zealand Institute for Plant and Food Research, Hamilton, 3240, New Zealand.
| | - Karen E Smith
- School of Biological Sciences, Royal Holloway University of London, Egham, Surrey, TW20 0EX, UK
| | - Nigel E Raine
- School of Biological Sciences, Royal Holloway University of London, Egham, Surrey, TW20 0EX, UK
- School of Environmental Sciences, University of Guelph, Guelph, Ontario, N1G 2W1, Canada
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Slaa EJ, Chappell P, Hughes WOH. Colony genetic diversity affects task performance in the red ant Myrmica rubra. Behav Ecol Sociobiol 2014. [DOI: 10.1007/s00265-014-1703-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Jeanson R, Weidenmüller A. Interindividual variability in social insects - proximate causes and ultimate consequences. Biol Rev Camb Philos Soc 2013; 89:671-87. [PMID: 24341677 DOI: 10.1111/brv.12074] [Citation(s) in RCA: 151] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2013] [Revised: 11/15/2013] [Accepted: 11/19/2013] [Indexed: 12/20/2022]
Abstract
Individuals within social groups often show consistent differences in behaviour across time and context. Such interindividual differences and the evolutionary challenge they present have recently generated considerable interest. Social insects provide some of the most familiar and spectacular examples of social groups with large interindividual differences. Investigating these within-group differences has a long research tradition, and behavioural variability among the workers of a colony is increasingly regarded as fundamental for a key feature of social insects: division of labour. The goal of this review is to illustrate what we know about both the proximate mechanisms underlying behavioural variability among the workers of a colony and its ultimate consequences; and to highlight the many open questions in this research field. We begin by reviewing the literature on mechanisms that potentially introduce, maintain, and adjust the behavioural differentiation among workers. We highlight the fact that so far, most studies have focused on behavioural variability based on genetic variability, provided by e.g. multiple mating of the queen, while other mechanisms that may be responsible for the behavioural differentiation among workers have been largely neglected. These include maturational, nutritional and environmental influences. We further discuss how feedback provided by the social environment and learning and experience of adult workers provides potent and little-explored sources of differentiation. In a second part, we address what is known about the potential benefits and costs of increased behavioural variability within the workers of a colony. We argue that all studies documenting a benefit of variability so far have done so by manipulating genetic variability, and that a direct test of the effect of behavioural variability on colony productivity has yet to be provided. We emphasize that the costs associated with interindividual variability have been largely overlooked, and that a better knowledge of the cost/benefit balance of behavioural variability is crucial for our understanding of the evolution of the mechanisms underlying the social organization of insect societies. We conclude by highlighting what we believe to be promising but little-explored avenues for future research on how within-colony variability has evolved and is maintained. We emphasize the need for comparative studies and point out that, so far, most studies on interindividual variability have focused on variability in individual response thresholds, while the significance of variability in other parameters of individual response, such as probability and intensity of the response, has been largely overlooked. We propose that these parameters have important consequences for the colony response. Much more research is needed to understand if and how interindividual variability is modulated in order to benefit division of labour, homeostasis and ultimately colony fitness in social insects.
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Affiliation(s)
- Raphaël Jeanson
- Centre National de la Recherche Scientifique, Centre de Recherches sur la Cognition Animale, 118 Route de Narbonne, 31062 Cedex 9, Toulouse, France; Centre de Recherches sur la Cognition Animale, Université Paul Sabatier, 118 Route de Narbonne, 31062 Cedex 9, Toulouse, France
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6
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Eyer PA, Freyer J, Aron S. Genetic polyethism in the polyandrous desert ant Cataglyphis cursor. Behav Ecol 2012. [DOI: 10.1093/beheco/ars146] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Libbrecht R, Keller L. Genetic compatibility affects division of labor in the Argentine ant Linepithema humile. Evolution 2012; 67:517-24. [PMID: 23356622 DOI: 10.1111/j.1558-5646.2012.01792.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Division of labor is central to the organization of insect societies. Within-colony comparisons between subfamilies of workers (patrilines or matrilines) revealed genetic effects on division of labor in many social insect species. Although this has been taken as evidence for additive genetic effects on division of labor, it has never been experimentally tested. To determine the relative roles of additive and nonadditive genetic effects (e.g., genetic compatibility, epistasis, and parent-of-origin imprinting effects) on worker behavior, we performed controlled crosses using the Argentine ant Linepithema humile. Three of the measured behaviors (the efficiency to collect pupae, the foraging propensity, and the distance between non-brood-tenders and brood) were affected by the maternal genetic background and the two others (the efficiency to feed larvae and the distance between brood-tenders and brood) by the paternal genetic background. Moreover, there were significant interactions between the maternal and paternal genetic backgrounds for three of the five behaviors. These results are most consistent with parent-of-origin and genetic compatibility effects on division of labor. The finding of nonadditive genetic effects is in strong contrast with the current view and has important consequences for our understanding of division of labor in insect societies.
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Affiliation(s)
- Romain Libbrecht
- Department of Ecology and Evolution, Biophore Building, University of Lausanne, CH-1015 Lausanne, Switzerland.
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Gruber MAM, Hoffmann BD, Ritchie PA, Lester PJ. Genetic diversity is positively associated with fine-scale momentary abundance of an invasive ant. Ecol Evol 2012; 2:2091-105. [PMID: 23139870 PMCID: PMC3488662 DOI: 10.1002/ece3.313] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2012] [Revised: 06/07/2012] [Accepted: 06/12/2012] [Indexed: 11/11/2022] Open
Abstract
Many introduced species become invasive despite genetic bottlenecks that should, in theory, decrease the chances of invasion success. By contrast, population genetic bottlenecks have been hypothesized to increase the invasion success of unicolonial ants by increasing the genetic similarity between descendent populations, thus promoting co-operation. We investigated these alternate hypotheses in the unicolonial yellow crazy ant, Anoplolepis gracilipes, which has invaded Arnhem Land in Australia's Northern Territory. We used momentary abundance as a surrogate measure of invasion success, and investigated the relationship between A. gracilipes genetic diversity and its abundance, and the effect of its abundance on species diversity and community structure. We also investigated whether selected habitat characteristics contributed to differences in A. gracilipes abundance, for which we found no evidence. Our results revealed a significant positive association between A. gracilipes genetic diversity and abundance. Invaded communities were less diverse and differed in structure from uninvaded communities, and these effects were stronger as A. gracilipes abundance increased. These results contradict the hypothesis that genetic bottlenecks may promote unicoloniality. However, our A. gracilipes study population has diverged since its introduction, which may have obscured evidence of the bottleneck that would likely have occurred on arrival. The relative importance of genetic diversity to invasion success may be context dependent, and the role of genetic diversity may be more obvious in the absence of highly favorable novel ecological conditions.
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Affiliation(s)
- Monica A M Gruber
- School of Biological Sciences, Victoria University of Wellington PO Box 600, Wellington, 6140, New Zealand
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Duarte A, Weissing FJ, Pen I, Keller L. An Evolutionary Perspective on Self-Organized Division of Labor in Social Insects. ANNUAL REVIEW OF ECOLOGY EVOLUTION AND SYSTEMATICS 2011. [DOI: 10.1146/annurev-ecolsys-102710-145017] [Citation(s) in RCA: 122] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Ana Duarte
- Department of Theoretical Biology, Center for Ecological and Evolutionary Studies, University of Groningen, Groningen, 9747 AG The Netherlands; , ,
| | - Franz J. Weissing
- Department of Theoretical Biology, Center for Ecological and Evolutionary Studies, University of Groningen, Groningen, 9747 AG The Netherlands; , ,
| | - Ido Pen
- Department of Theoretical Biology, Center for Ecological and Evolutionary Studies, University of Groningen, Groningen, 9747 AG The Netherlands; , ,
| | - Laurent Keller
- Department of Ecology and Evolution, University of Lausanne, Lausanne, CH-1015 Switzerland;
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Tarapore D, Floreano D, Keller L. Task-dependent influence of genetic architecture and mating frequency on division of labour in social insect societies. Behav Ecol Sociobiol 2009. [DOI: 10.1007/s00265-009-0885-4] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Smith CR, Anderson KE, Tillberg CV, Gadau J, Suarez AV. Caste determination in a polymorphic social insect: nutritional, social, and genetic factors. Am Nat 2008; 172:497-507. [PMID: 18707530 DOI: 10.1086/590961] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
We examined how dietary, social, and genetic factors affect individual size and caste in the Florida harvester ant Pogonomyrmex badius, which has three discrete female castes. The diet that a larva consumed, as indicated by delta(13)C, delta(15)N, and C:N, varied with caste. Both N content and estimated trophic position of dietary input was higher for major than for minor workers and was highest for gynes (reproductive females). The size and resources of a colony affected the size of only minor workers, not that of gynes and major workers. Approximately 19% of patrilines showed a bias in which female caste they produced. There were significant genetic effects on female size, and the average sizes of a major worker and a gyne produced by a patriline were correlated, but neither was correlated with minor worker size. Thus, genetic factors influence both caste and size within caste. We conclude that environmental, social, and genetic variation interact to create morphological and physiological variation among females in P. badius. However, the relative importance of each type of factor affecting caste determination is caste specific.
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Affiliation(s)
- C R Smith
- Program in Ecology and Evolutionary Biology, University of Illinois Urbana-Champaign, Urbana, Illinois 61801, USA.
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WIERNASZ DIANEC, HINES JESSICA, PARKER DARAG, COLE BLAINEJ. Mating for variety increases foraging activity in the harvester ant, Pogonomyrmex occidentalis. Mol Ecol 2008; 17:1137-44. [DOI: 10.1111/j.1365-294x.2007.03646.x] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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14
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Genetic diversity, worker size polymorphism and division of labour in the polyandrous ant Cataglyphis cursor. Anim Behav 2008. [DOI: 10.1016/j.anbehav.2007.04.023] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Oldroyd BP, Fewell JH. Genetic diversity promotes homeostasis in insect colonies. Trends Ecol Evol 2007; 22:408-13. [PMID: 17573148 DOI: 10.1016/j.tree.2007.06.001] [Citation(s) in RCA: 182] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2007] [Revised: 04/25/2007] [Accepted: 06/01/2007] [Indexed: 11/29/2022]
Abstract
Although most insect colonies are headed by a singly mated queen, some ant, wasp and bee taxa have evolved high levels of multiple mating or 'polyandry'. We argue here that a contributing factor towards the evolution of polyandry is that the resulting genetic diversity within colonies provides them with a system of genetically based task specialization, enabling them to respond resiliently to environmental perturbation. An alternate view is that genetic contributions to task specialization are a side effect of multiple mating, which evolved through other causes, and that genetically based task specialization now makes little or no contribution to colony fitness.
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Affiliation(s)
- Benjamin P Oldroyd
- Behaviour and Genetics of Social Insects Laboratory, School of Biological Sciences A12, University of Sydney, NSW 2006, Australia.
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Seeley TD, Tarpy DR. Queen promiscuity lowers disease within honeybee colonies. Proc Biol Sci 2007; 274:67-72. [PMID: 17015336 PMCID: PMC1679871 DOI: 10.1098/rspb.2006.3702] [Citation(s) in RCA: 196] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2006] [Accepted: 08/13/2006] [Indexed: 11/12/2022] Open
Abstract
Most species of social insects have singly mated queens, but in some species each queen mates with numerous males to create a colony with a genetically diverse worker force. The adaptive significance of polyandry by social insect queens remains an evolutionary puzzle. Using the honeybee (Apis mellifera), we tested the hypothesis that polyandry improves a colony's resistance to disease. We established colonies headed by queens that had been artificially inseminated by either one or 10 drones. Later, we inoculated these colonies with spores of Paenibacillus larvae, the bacterium that causes a highly virulent disease of honeybee larvae (American foulbrood). We found that, on average, colonies headed by multiple-drone inseminated queens had markedly lower disease intensity and higher colony strength at the end of the summer relative to colonies headed by single-drone inseminated queens. These findings support the hypothesis that polyandry by social insect queens is an adaptation to counter disease within their colonies.
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Affiliation(s)
- Thomas D Seeley
- Department of Neurobiology and Behavior, Cornell University, Ithaca, NY 14853, USA.
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