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Yaguchi H, Kobayashi I, Maekawa K, Nalepa CA. Extra-pair paternity in the wood-feeding cockroach Cryptocercus punctulatus Scudder: Social but not genetic monogamy. Mol Ecol 2021; 30:6743-6758. [PMID: 34543485 DOI: 10.1111/mec.16185] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2020] [Revised: 08/25/2021] [Accepted: 09/08/2021] [Indexed: 11/29/2022]
Abstract
Subsocial Cryptocercus cockroaches are the sister group to termites and considered to be socially monogamous. Because genetic monogamy is a suggested requirement for evolution of cooperative breeding/eusociality, particularly in hymenopterans, clarification of the mating biology of Cryptocercus would help illuminate evolutionary trends in eusocial insects. To investigate possible extra-pair paternity in C. punctulatus, microsatellite markers were used to analyse offspring parentage, the stored sperm in females and results of experimental manipulation of sperm competition. Extra-pair paternity was common in field-collected families, but a lack of maternal alleles in several nymphs suggests sampling error or adoption. Isolating prereproductive pairs and assaying subsequently produced nymphs confirmed that nymphs lacked alleles from the pair male in 40% of families, with extra-pair male(s) siring 27%-77% of nymphs. Sperm of extra-pair males was detected in the spermatheca of 51% of paired prereproductive females. Mate switching and surgical manipulation of male mating ability indicated a tendency towards last male sperm precedence. Overall, the results demonstrate that about half of young females are serially monogamous during their maturational year, but bond, overwinter and produce their only set of offspring in company of the last mated male (=pair male). Repeated mating by the pair male increases the number of nymphs sired, but because many females use stored sperm of previous copulatory partners to fertilize eggs, pair males extend parental care to unrelated nymphs. The results suggest that genetic monogamy either developed in the termite ancestor after splitting from the Cryptocercus lineage, or that genetic monogamy may not be a strict prerequisite for the evolution of termite eusociality.
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Affiliation(s)
- Hajime Yaguchi
- Graduate School of Science and Engineering, University of Toyama, Toyama, Japan.,Department of Bioscience, School of Science and Technology, Kwansei Gakuin University, Sanda, Japan
| | - Itaru Kobayashi
- School of Science, University of Toyama, Toyama, Japan.,Graduate School of Science, The University of Tokyo, Tokyo, Japan
| | - Kiyoto Maekawa
- Faculty of Science, Academic Assembly, University of Toyama, Toyama, Japan
| | - Christine A Nalepa
- Department of Entomology and Plant Pathology, North Carolina State University, Raleigh, North Carolina, USA
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2
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Chiu MC, Wu WJ, Lai LC. Carriers and cutters: size-dependent caste polyethism in the tropical fire ant ( Solenopsis geminata). BULLETIN OF ENTOMOLOGICAL RESEARCH 2020; 110:388-396. [PMID: 31735176 DOI: 10.1017/s0007485319000750] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Body size is an important life-history trait in eusocial insects which plays a key role in colony fitness. The division of labour, represented by caste polyethism, correlates with divergent morphological traits. Size polymorphism has been noted in the tropical fire ant, Solenopsis geminata; however, little is known regarding the differences in the size distributions of workers performing foraging tasks. In the present study, task partitioning was observed in the foraging activities of S. geminata. Two subgroups among foraging workers of S. geminata were discovered using the Gaussian mixture model: a large worker group (head width ≥ 0.924 mm) and a small worker group (head width < 0.924 mm). The foraging worker population comprised two distinct groups - 25.64% were large workers and 74.36% were small workers. Larger workers delivered heavier seeds faster than smaller workers, but this difference became less apparent when lighter seeds were being carried. When large prey such as crickets was encountered during foraging, S. geminata partitioned their tasks into cutting and transportation. The large workers were observed to cut cricket prey into fragments with their longer mandibles, and the small workers then transported these fragments back to the nest. These results present evidence of task partitioning among tropical fire ants, with different tasks being performed by ants of different castes.
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Affiliation(s)
- Ming-Chung Chiu
- Department of Biology, Graduate School of Science, Kobe University, Kobe6578501, Japan
| | - Wen-Jer Wu
- Department of Entomology, National Taiwan University, 27, Lane 113, Sec. 4, Roosevelt Rd., Taipei10617, Taiwan
| | - Li-Chuan Lai
- Department of Ecological Humanities, Providence University, 200, Sec. 7, Taiwan Boulevard, Shalu Dist., Taichung City 43301, Taiwan
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Field J, Toyoizumi H. The evolution of eusociality: no risk-return tradeoff but the ecology matters. Ecol Lett 2019; 23:518-526. [PMID: 31884729 PMCID: PMC7027560 DOI: 10.1111/ele.13452] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2019] [Accepted: 12/02/2019] [Indexed: 11/27/2022]
Abstract
The origin of eusociality in the Hymenoptera is a question of major interest. Theory has tended to focus on genetic relatedness, but ecology can be just as important a determinant of whether eusociality evolves. Using the model of Fu et al. (2015), we show how ecological assumptions critically affect the conclusions drawn. Fu et al. inferred that eusociality rarely evolves because it faces a fundamental ‘risk‐return tradeoff’. The intuitive logic was that worker production represents an opportunity cost because it delays realising a reproductive payoff. However, making empirically justified assumptions that (1) workers take over egg‐laying following queen death and (2) productivity increases gradually with each additional worker, we find that the risk‐return tradeoff disappears. We then survey Hymenoptera with more specialised morphological castes, and show how the interaction between two common features of eusociality – saturating birth rates and group size‐dependent helping decisions – can determine whether eusociality outperforms other strategies.
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Affiliation(s)
- Jeremy Field
- Centre for Ecology and Conservation, University of Exeter, Penryn Campus, Cornwall, TR10 9EZ, UK
| | - Hiroshi Toyoizumi
- Graduate School of Accounting and Department of Applied Mathematics, Waseda University, Nishi-waseda 1-6-1, Shinjuku, Tokyo, 169-8050, Japan
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Nonacs P. Hamilton's rule is essential but insufficient for understanding monogamy's role in social evolution. ROYAL SOCIETY OPEN SCIENCE 2019; 6:180913. [PMID: 30800348 PMCID: PMC6366207 DOI: 10.1098/rsos.180913] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Accepted: 12/19/2018] [Indexed: 06/09/2023]
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Davies NG, Gardner A. Monogamy promotes altruistic sterility in insect societies. ROYAL SOCIETY OPEN SCIENCE 2018; 5:172190. [PMID: 29892408 PMCID: PMC5990772 DOI: 10.1098/rsos.172190] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/13/2017] [Accepted: 04/03/2018] [Indexed: 06/08/2023]
Abstract
Monogamy is associated with sibling-directed altruism in multiple animal taxa, including insects, birds and mammals. Inclusive-fitness theory readily explains this pattern by identifying high relatedness as a promoter of altruism. In keeping with this prediction, monogamy should promote the evolution of voluntary sterility in insect societies if sterile workers make for better helpers. However, a recent mathematical population-genetics analysis failed to identify a consistent effect of monogamy on voluntary worker sterility. Here, we revisit that analysis. First, we relax genetic assumptions, considering not only alleles of extreme effect-encoding either no sterility or complete sterility-but also alleles with intermediate effects on worker sterility. Second, we broaden the stability analysis-which focused on the invasibility of populations where either all workers are fully sterile or all workers are fully reproductive-to identify where intermediate pure or mixed evolutionarily stable states may occur. Third, we consider a broader range of demographically explicit ecological scenarios relevant to altruistic worker non-reproduction and to the evolution of eusociality more generally. We find that, in the absence of genetic constraints, monogamy always promotes altruistic worker sterility and may inhibit spiteful worker sterility. Our extended analysis demonstrates that an exact population-genetics approach strongly supports the prediction of inclusive-fitness theory that monogamy promotes sib-directed altruism in social insects.
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Affiliation(s)
| | - Andy Gardner
- School of Biology, University of St Andrews, St Andrews, UK
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Quiñones AE, Pen I. A unified model of Hymenopteran preadaptations that trigger the evolutionary transition to eusociality. Nat Commun 2017; 8:15920. [PMID: 28643786 PMCID: PMC5490048 DOI: 10.1038/ncomms15920] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2016] [Accepted: 05/12/2017] [Indexed: 11/09/2022] Open
Abstract
Explaining the origin of eusociality, with strict division of labour between workers and reproductives, remains one of evolutionary biology's greatest challenges. Specific combinations of genetic, behavioural and demographic traits in Hymenoptera are thought to explain their relatively high frequency of eusociality, but quantitative models integrating such preadaptations are lacking. Here we use mathematical models to show that the joint evolution of helping behaviour and maternal sex ratio adjustment can synergistically trigger both a behavioural change from solitary to eusocial breeding, and a demographic change from a life cycle with two reproductive broods to a life cycle in which an unmated cohort of female workers precedes a final generation of dispersing reproductives. Specific suits of preadaptations are particularly favourable to the evolution of eusociality: lifetime monogamy, bivoltinism with male generation overlap, hibernation of mated females and haplodiploidy with maternal sex ratio adjustment. The joint effects of these preadaptations may explain the abundance of eusociality in the Hymenoptera and its virtual absence in other haplodiploid lineages.
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Affiliation(s)
- Andrés E. Quiñones
- Theoretical Research in Evolutionary Life Sciences, Groningen Institute for Evolutionary Life Sciences, University of Groningen, P.O. Box 11103, 9700 CC Groningen, The Netherlands
| | - Ido Pen
- Theoretical Research in Evolutionary Life Sciences, Groningen Institute for Evolutionary Life Sciences, University of Groningen, P.O. Box 11103, 9700 CC Groningen, The Netherlands
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8
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Rodrigues AMM, Kokko H. Models of social evolution: can we do better to predict 'who helps whom to achieve what'? Philos Trans R Soc Lond B Biol Sci 2016; 371:20150088. [PMID: 26729928 DOI: 10.1098/rstb.2015.0088] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Models of social evolution and the evolution of helping have been classified in numerous ways. Two categorical differences have, however, escaped attention in the field. Models tend not to justify why they use a particular assumption structure about who helps whom: a large number of authors model peer-to-peer cooperation of essentially identical individuals, probably for reasons of mathematical convenience; others are inspired by particular cooperatively breeding species, and tend to assume unidirectional help where subordinates help a dominant breed more efficiently. Choices regarding what the help achieves (i.e. which life-history trait of the helped individual is improved) are similarly made without much comment: fecundity benefits are much more commonly modelled than survival enhancements, despite evidence that these may interact when the helped individual can perform life-history reallocations (load-lightening and related phenomena). We review our current theoretical understanding of effects revealed when explicitly asking 'who helps whom to achieve what', from models of mutual aid in partnerships to the very few models that explicitly contrast the strength of selection to help enhance another individual's fecundity or survival. As a result of idiosyncratic modelling choices in contemporary literature, including the varying degree to which demographic consequences are made explicit, there is surprisingly little agreement on what types of help are predicted to evolve most easily. We outline promising future directions to fill this gap.
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Affiliation(s)
- António M M Rodrigues
- Department of Zoology, University of Cambridge, Downing Street, Cambridge CB2 3EJ, UK Wolfson College, Barton Road, Cambridge CB3 9BB, UK
| | - Hanna Kokko
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
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9
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Rubenstein DR, Botero CA, Lacey EA. Discrete but variable structure of animal societies leads to the false perception of a social continuum. ROYAL SOCIETY OPEN SCIENCE 2016; 3:160147. [PMID: 27293796 PMCID: PMC4892458 DOI: 10.1098/rsos.160147] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/29/2016] [Accepted: 04/14/2016] [Indexed: 06/06/2023]
Abstract
Animal societies are typically divided into those in which reproduction within a group is monopolized by a single female versus those in which it is shared among multiple females. It remains controversial, however, whether these two forms of social structure represent distinct evolutionary outcomes or endpoints along a continuum of reproductive options. To address this issue and to determine whether vertebrates and insects exhibit the same patterns of variation in social structure, we examined the demographic and reproductive structures of 293 species of wasps, ants, birds and mammals. Using phylogenetically informed comparative analyses, we found strong evidence indicating that not all reproductive arrangements within social groups are viable in nature and that in societies with multiple reproductives, selection favours instead taxon-specific patterns of decrease in the proportion of breeders as a function of group size. These outcomes suggest that the selective routes to sociality differ depending upon whether monopolization of reproduction by one individual is possible and that variation within and among taxonomic groups may lead to the false perception of a continuum of social structures. Thus, the occurrence of very large societies may require either complete reproductive monopolization (monogyny/singular breeding) or the maintenance of a taxon-specific range of values for the proportional decrease in the number of breeders within a group (polygyny/plural breeding), both of which may reduce reproductive conflict among females.
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Affiliation(s)
- Dustin R Rubenstein
- Department of Ecology, Evolution and Environmental Biology, Columbia University, New York, NY 10027, USA; Center for Integrative Animal Behavior, Columbia University, New York, NY 10027, USA
| | - Carlos A Botero
- Department of Biology , Washington University in St Louis , St Louis, MO 63130 , USA
| | - Eileen A Lacey
- Museum of Vertebrate Zoology and Department of Integrative Biology , University of California , Berkeley, Berkeley, CA 94720 , USA
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10
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Elgar MA. Integrating insights across diverse taxa: challenges for understanding social evolution. Front Ecol Evol 2015. [DOI: 10.3389/fevo.2015.00124] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
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11
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Gardner MG, Pearson SK, Johnston GR, Schwarz MP. Group living in squamate reptiles: a review of evidence for stable aggregations. Biol Rev Camb Philos Soc 2015; 91:925-936. [PMID: 26052742 DOI: 10.1111/brv.12201] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2014] [Revised: 05/06/2015] [Accepted: 05/15/2015] [Indexed: 01/19/2023]
Abstract
How sociality evolves and is maintained remains a key question in evolutionary biology. Most studies to date have focused on insects, birds, and mammals but data from a wider range of taxonomic groups are essential to identify general patterns and processes. The extent of social behaviour among squamate reptiles is under-appreciated, yet they are a promising group for further studies. Living in aggregations is posited as an important step in the evolution of more complex sociality. We review data on aggregations among squamates and find evidence for some form of aggregations in 94 species across 22 families. Of these, 18 species across 7 families exhibited 'stable' aggregations that entail overlapping home ranges and stable membership in long-term (years) or seasonal aggregations. Phylogenetic analysis suggests that stable aggregations have evolved multiple times in squamates. We: (i) identify significant gaps in our understanding; (ii) outline key traits which should be the focus of future research; and (iii) outline the potential for utilising reproductive skew theory to provide insights into squamate sociality.
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Affiliation(s)
- Michael G Gardner
- School of Biological Sciences, Flinders University of South Australia, GPO Box 2100, Adelaide, 5001, Australia. .,South Australian Museum, North Terrace, Adelaide, 5000, Australia.
| | - Sarah K Pearson
- School of Biological Sciences, Flinders University of South Australia, GPO Box 2100, Adelaide, 5001, Australia
| | - Gregory R Johnston
- School of Biological Sciences, Flinders University of South Australia, GPO Box 2100, Adelaide, 5001, Australia.,South Australian Museum, North Terrace, Adelaide, 5000, Australia
| | - Michael P Schwarz
- School of Biological Sciences, Flinders University of South Australia, GPO Box 2100, Adelaide, 5001, Australia
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12
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Kramer KL, Russell AF. Kin-selected cooperation without lifetime monogamy: human insights and animal implications. Trends Ecol Evol 2014; 29:600-6. [PMID: 25267298 DOI: 10.1016/j.tree.2014.09.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2014] [Revised: 08/30/2014] [Accepted: 09/02/2014] [Indexed: 10/24/2022]
Abstract
Recent phylogenetic analyses suggest that monogamy precedes the evolution of cooperative breeding involving non-breeding helpers. The rationale: only through monogamy can helper-recipient relatedness coefficients match those of parent-offspring. Given that humans are cooperative breeders, these studies imply a monogamy bottleneck during hominin evolution. However, evidence from multiple sources is not compelling. In reconciliation, we propose that selection against cooperative breeding under alternative mating patterns will be mitigated by: (i) kin discrimination, (ii) reduced birth-intervals, and (iii) constraints on independent breeding, particularly for premature and post-fertile individuals. We suggest that such alternatives require consideration to derive a complete picture of the selection pressures acting on the evolution of cooperative breeding in humans and other animals.
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Affiliation(s)
- Karen L Kramer
- Department of Anthropology, University of Utah, Salt Lake City, UT 84112, USA; Department of Human Evolutionary Biology, Harvard University, Cambridge, MA 02138, USA
| | - Andrew F Russell
- Department of Human Evolutionary Biology, Harvard University, Cambridge, MA 02138, USA; Centre for Ecology and Conservation, College of Life and Environmental Sciences, University of Exeter, Penryn TR10 9FE, UK.
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