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Carmona-Aldana F, Yong LW, Reinberg D, Desplan C. Phenomenon of reproductive plasticity in ants. CURRENT OPINION IN INSECT SCIENCE 2024; 63:101197. [PMID: 38583769 PMCID: PMC11139587 DOI: 10.1016/j.cois.2024.101197] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/24/2023] [Revised: 03/26/2024] [Accepted: 03/31/2024] [Indexed: 04/09/2024]
Abstract
Ant colonies are organized in castes with distinct behaviors that together allow the colony to strive. Reproduction relies on one or a few queens that stay in the nest producing eggs, while females of the worker caste do not reproduce and instead engage in colony maintenance and brood caretaking. Yet, in spite of this clear separation of functions, workers can become reproductive under defined circumstances. Here, we review the context in which workers become reproductive, exhibiting asexual or sexual reproduction depending on the species. Remarkably, the activation of reproduction in these workers can be quite stable, with changes that include behavior and a dramatic extension of lifespan. We compare these changes between species that do or do not have a queen caste. We discuss how the mechanisms underlying reproductive plasticity include changes in hormonal functions and in epigenetic configurations. Further studies are warranted to elucidate not only how reproductive functions have been gradually restricted to the queen caste during evolution but also how reproductive plasticity remains possible in workers of some species.
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Affiliation(s)
| | - Luok Wen Yong
- Department of Biology, New York University, NY 10003, USA
| | - Danny Reinberg
- Dr. John T. Macdonald Foundation Department of Human Genetics, University of Miami, Coral Gables, FL 33124, USA.
| | - Claude Desplan
- Department of Biology, New York University, NY 10003, USA; Center for Genomics and Systems Biology, New York University, Abu Dhabi 51133, United Arab Emirates.
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Darras H, Berney C, Hasin S, Drescher J, Feldhaar H, Keller L. Obligate chimerism in male yellow crazy ants. Science 2023; 380:55-58. [PMID: 37023182 DOI: 10.1126/science.adf0419] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/08/2023]
Abstract
Multicellular organisms typically develop from a single fertilized egg and therefore consist of clonal cells. We report an extraordinary reproductive system in the yellow crazy ant. Males are chimeras of haploid cells from two divergent lineages: R and W. R cells are overrepresented in the males' somatic tissues, whereas W cells are overrepresented in their sperm. Chimerism occurs when parental nuclei bypass syngamy and divide separately within the same egg. When syngamy takes place, the diploid offspring either develops into a queen when the oocyte is fertilized by an R sperm or into a worker when fertilized by a W sperm. This study reveals a mode of reproduction that may be associated with a conflict between lineages to preferentially enter the germ line.
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Affiliation(s)
- H Darras
- Institute of Organismic and Molecular Evolution, Johannes Gutenberg University, Mainz, Germany
- Department of Ecology and Evolution, University of Lausanne, Lausanne, Switzerland
| | - C Berney
- Department of Ecology and Evolution, University of Lausanne, Lausanne, Switzerland
| | - S Hasin
- Valaya Alongkorn Rajabhat University, Pathum Thani, Thailand
| | - J Drescher
- Department of Animal Ecology, Göttingen University, Göttingen, Germany
| | - H Feldhaar
- Department of Animal Ecology, Göttingen University, Göttingen, Germany
- Animal Ecology I, University of Bayreuth, Bayreuth, Germany
| | - L Keller
- Department of Ecology and Evolution, University of Lausanne, Lausanne, Switzerland
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Cahan SH, Nguyen AD, Zhou Y. Population genomics supports multiple hybrid zone origins of socially hybridogenetic lineages of Pogonomyrmex harvester ants. Evolution 2022; 76:1016-1032. [PMID: 35365873 DOI: 10.1111/evo.14481] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Revised: 01/16/2022] [Accepted: 01/28/2022] [Indexed: 01/22/2023]
Abstract
Reproductive division of labor in the social insects is typically determined by environmental cues; however, genetic effects on caste have been discovered in a growing set of ant taxa. An extreme form of genetic caste determination is "social hybridogenesis," in which co-occurring genetic lineages obligately interbreed to produce workers, whereas daughter queens are of pure-lineage ancestry. In this study, we tested the hypothesis that social hybridogenesis in the genus Pogonomyrmex resulted from one or more interspecific hybridization events, and if so, whether individual lineages were of hybrid ancestry. We reconstructed evolutionary relationships of four lineage pairs to populations of two closely related non-hybridogenetic species, Pogonomyrmex barbatus and Pogonomyrmex rugosus, using nuclear SNP loci and mitochondrial sequencing. The nuclear phylogeny supported a hybridization hypothesis, with one member of each pair nested within P. rugosus, whereas the other was nested within P. barbatus. The source populations corresponded with two distinct geographic areas at the eastern and western edges of a zone of contact. Relatively little gene flow was detected between interbreeding lineages, either historically or currently. This suggests that shifts in reproductive caste determination may reinforce reproductive incompatibility, in a manner similar to the evolution of hybridogenesis in nonsocial systems.
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Affiliation(s)
- Sara Helms Cahan
- Department of Biology, University of Vermont, Burlington, Vermont, 05405
| | - Andrew D Nguyen
- Department of Biology, University of Vermont, Burlington, Vermont, 05405
| | - Yihong Zhou
- Department of Biology, University of Vermont, Burlington, Vermont, 05405
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Herrmann M, Cahan SH. Inter-genomic sexual conflict drives antagonistic coevolution in harvester ants. Proc Biol Sci 2014; 281:rspb.2014.1771. [PMID: 25355474 DOI: 10.1098/rspb.2014.1771] [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: 11/12/2022] Open
Abstract
The reproductive interests of males and females are not always aligned, leading to sexual conflict over parental investment, rate of reproduction and mate choice. Traits that increase the genetic interests of one sex often occur at the expense of the other, selecting for counter-adaptations leading to antagonistic coevolution. Reproductive conflict is not limited to intraspecific interactions; interspecific hybridization can produce pronounced sexual conflict between males and females of different species, but it is unclear whether such conflict can drive sexually antagonistic coevolution between reproductively isolated genomes. We tested for hybridization-driven sexually antagonistic adaptations in queens and males of the socially hybridogenetic 'J' lineages of Pogonomyrmex harvester ants, whose mating system promotes hybridization in queens but selects against it in males. We conducted no-choice mating assays to compare patterns of mating behaviour and sperm transfer between inter- and intra-lineage pairings. There was no evidence for mate discrimination on the basis of pair type, and the total quantity of sperm transferred did not differ between intra- and inter-lineage pairs; however, further dissection of the sperm transfer process into distinct mechanistic components revealed significant, and opposing, cryptic manipulation of copulatory investment by both sexes. Males of both lineages increased their rate of sperm transfer to high-fitness intra-lineage mates, with a stronger response in the rarer lineage for whom mating mistakes are the most likely. By contrast, the total duration of copulation for intra-lineage mating pairs was significantly shorter than for inter-lineage crosses, suggesting that queens respond to prevent excessive sperm loading by prematurely terminating copulation. These findings demonstrate that sexual conflict can lead to antagonistic coevolution in both intra-genomic and inter-genomic contexts. Indeed, the resolution of sexual conflict may be a key determinant of the long-term evolutionary potential of host-dependent reproductive strategies, counteracting the inherent instabilities arising from such systems.
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Affiliation(s)
- Michael Herrmann
- Department of Biology, University of Vermont, Burlington, VT 05405, USA
| | - Sara Helms Cahan
- Department of Biology, University of Vermont, Burlington, VT 05405, USA
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Sirviö A, Pamilo P, Johnson RA, Page RE, Gadau J. Origin and evolution of the dependent lineages in the genetic caste determination system of Pogonomyrmex ants. Evolution 2010; 65:869-84. [PMID: 21083661 DOI: 10.1111/j.1558-5646.2010.01170.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Hybridizing harvester ants of the Pogonomyrmex barbatus/rugosus complex have an exceptional genetic caste determination (GCD) mechanism. We combined computer simulations, population genomics, and linkage mapping using >1000 nuclear AFLP markers and a partial mtDNA sequence to explore the genetic architecture and origin of the dependent lineages. Our samples included two pairs of hybridizing lineages, and the mitochondrial and nuclear data showed contradicting affinities between them. Clustering of individual genotypes based on nuclear markers indicated some exceptions to the general GCD system, that is, interlineage hybrid genes as well as some pure-line workers. A genetic linkage map of P. rugosus showed one of the highest recombination rates ever measured in insects (14.0 cM/Mb), supporting the view that social insects are characterized by high recombination rates. The population data had 165 markers in which sibling pairs showed a significant genetic difference depending on the caste. The differences were scattered in the genome; 13 linkage groups had loci with F(ST)>0.9 between the hybridizing lineages J1 and J2.The mapping results and the population data indicate that the dependent lineages have been initially formed through hybridization at different points in time but the role of introgression has been insignificant in their later evolution.
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Affiliation(s)
- Anu Sirviö
- Department of Biology, University of Oulu 90014, Linnanmaa P.O. Box 3000, Finland.
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Curry MM, Wheeler DE, Yang K, Anderson KE. The potential for gene flow in a dependent lineage system of a harvester ant: fair meiosis in the F1 generation. J Hered 2009; 101:378-84. [PMID: 20022894 DOI: 10.1093/jhered/esp117] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
We investigated the potential for gene flow in a dependent lineage (DL) system of the harvester ant Pogonomyrmex. Each DL system is composed of 2 reproductively isolated lineages that are locked in an obligate mutualism. The genetic components that produce the worker phenotype are acquired by hybridizing with the partner lineage. In the mating flight, queens of both lineages mate with multiple males from each lineage. During colony growth and reproduction, eggs fertilized by partner-lineage sperm produce F(1) hybrid workers with interlineage genomes, whereas eggs fertilized by same-lineage sperm result in the development of new queens with intralineage genomes. New males are typically produced from unfertilized eggs laid by the pure-lineage queen but in her absence may be produced by interlineage F(1) workers. We investigated the potential for interlineage gene flow in this system using 2 classes of lineage-specific nuclear markers to identify hybrid genome combinations. We confirmed the production of viable interlineage F(1) reproductive females in field colonies, the occurrence of which is associated with the relative frequencies of each lineage in the population: interlineage F(1) queens occurred only in the rare lineage of the population with dramatically skewed lineage frequencies. In laboratory colonies, we detected fair meiosis in interlineage F(1) workers leading to the production of viable and haploid interlineage F(2) males. We conclude that the genomes of each lineage recombine freely, suggesting that extrinsic postzygotic selection maintains the integrity of each lineage genome. We compare our findings with those of the H1/H2 DL system.
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Affiliation(s)
- Meghan M Curry
- Department of Entomology, University of Arizona, Tucson, AZ, 85721, USA
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Suni SS, Gordon DM. Fine-scale genetic structure and dispersal distance in the harvester ant Pogonomyrmex barbatus. Heredity (Edinb) 2009; 104:168-73. [DOI: 10.1038/hdy.2009.124] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
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Helms Cahan S, Julian GE. Shift in frequency-dependent selection across the life-cycle in obligately interbreeding harvester ant lineages. Evol Ecol 2009. [DOI: 10.1007/s10682-009-9311-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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