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Miller S, Wilner D, Boldbaatar J, Bonduriansky R. Does ecology shape geographical parthenogenesis? Evidence from the facultatively parthenogenetic stick insect Megacrania batesii. Ecol Evol 2024; 14:e70145. [PMID: 39145042 PMCID: PMC11322659 DOI: 10.1002/ece3.70145] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2024] [Revised: 07/11/2024] [Accepted: 07/25/2024] [Indexed: 08/16/2024] Open
Abstract
Closely related sexual and parthenogenetic species often show distinct distribution patterns, known as geographical parthenogenesis. Similar patterns, characterized by the existence of separate sexual and parthenogenetic populations across their natural range, can also be found in facultative parthenogens - species in which every female is capable of both sexual and parthenogenetic reproduction. The underlying mechanisms driving this phenomenon in nature remain unclear. Features of the habitat, such as differences in host-plant phenotypes or niche breadth, could favour sexual or asexual reproductive modes and thus help to explain geographical parthenogenesis in natural insect populations. Megacrania batesii is a facultatively parthenogenetic stick insect that displays geographical parthenogenesis in the wild. We aimed to explore whether sexual and parthenogenetic populations of M. batesii displayed niche differentiation or variations in niche breadth that could explain the separation of the two population types. To do this, we sampled host plants from across the range of M. batesii and quantified phenotypic traits that might affect palatability or accessibility for M. batesii, including leaf thickness, toughness, spike size and density, plant height, and chemical composition. We also quantified host-plant density, which could affect M. batesii dispersal. We found little evidence of phenotypic differences between host plants supporting sexual versus asexual M. batesii populations, and no difference in host-plant density or niche breadth between the two population types. Our results suggest that habitat parameters do not play a substantial role in shaping patterns of geographical parthenogenesis in wild populations of M. batesii. Instead, population sex ratio variation could result from interactions between the sexes or dispersal dynamics.
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Affiliation(s)
- Soleille Miller
- Evolution & Ecology Research Centre, School of Biological, Earth and Environmental SciencesUNSW SydneySydneyNew South WalesAustralia
| | - Daniela Wilner
- Evolution & Ecology Research Centre, School of Biological, Earth and Environmental SciencesUNSW SydneySydneyNew South WalesAustralia
| | - Jigmidmaa Boldbaatar
- Evolution & Ecology Research Centre, School of Biological, Earth and Environmental SciencesUNSW SydneySydneyNew South WalesAustralia
| | - Russell Bonduriansky
- Evolution & Ecology Research Centre, School of Biological, Earth and Environmental SciencesUNSW SydneySydneyNew South WalesAustralia
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Machado G, Burns M. Reproductive biology of harvestmen (Arachnida: Opiliones): a review of a rapidly evolving research field. Curr Zool 2024; 70:115-135. [PMID: 38476141 PMCID: PMC10926269 DOI: 10.1093/cz/zoac102] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Accepted: 12/18/2022] [Indexed: 03/14/2024] Open
Abstract
Harvestmen are a major arachnid order that has experienced a dramatic increase in biological knowledge in the 21st century. The publication of the book Harvestmen: The Biology of Opiliones in 2007 stimulated the development of many behavioral studies. Although the book is relatively recent, our understanding of the reproductive biology of harvestmen is already outdated due to the fast accumulation of new data. Our goal is to provide an updated review of the subject to serve as a benchmark for the following years. In the pre-copulatory phase, we explore the evolution of facultative parthenogenesis, the factors that may affect the types of mating system, and the role of nuptial gifts in courtship. Regarding the copulatory phase, harvestmen are unique arachnids because they have aflagellate spermatozoa and a penis with complex morphology. We discuss the implications of these two features for sperm competition and cryptic female choice. In the post-copulatory phase, we connect oviposition site selection and climate conditions to the widespread occurrence of resource defense polygyny, alternative reproductive tactics, and sexual dimorphism in several clades of tropical harvestmen. Finally, we present the different forms of parental care in the order, and discuss the benefits and costs of this behavior, which can be performed either by females or males. Throughout the review, we indicate gaps in our knowledge and subjects that deserve further studies. Hopefully, the information synthesized here will stimulate researchers worldwide to embrace harvestmen as a study system and to improve our effort to unravel the mysteries of their reproductive biology.
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Affiliation(s)
- Glauco Machado
- LAGE do Departamento de Ecologia, Instituto de Biociências, Universidade de São Paulo, São Paulo, Brazil
| | - Mercedes Burns
- Department of Biological Sciences, University of Maryland, Baltimore County, Baltimore, MD, USA
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Miller SM, Stuart KC, Burke NW, Rollins LA, Bonduriansky R. Genetic and Phenotypic Consequences of Local Transitions between Sexual and Parthenogenetic Reproduction in the Wild. Am Nat 2024; 203:73-91. [PMID: 38207137 DOI: 10.1086/727511] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2024]
Abstract
AbstractTransitions from sexual to asexual reproduction have occurred in numerous lineages, but it remains unclear why asexual populations rarely persist. In facultatively parthenogenetic animals, all-female populations can arise when males are absent or become extinct, and such populations could help to understand the genetic and phenotypic changes that occur in the initial stages of transitions to asexuality. We investigated a naturally occurring spatial mosaic of mixed-sex and all-female populations of the facultatively parthenogenetic Australian phasmid Megacrania batesii. Analysis of single-nucleotide polymorphisms indicated multiple independent transitions between reproductive modes. All-female populations had much lower heterozygosity and allelic diversity than mixed-sex populations, but we found few consistent differences in fitness-related traits between population types. All-female populations exhibited more frequent and severe deformities in their (flight-incapable) wings but did not show higher rates of appendage loss. All-female populations also harbored more ectoparasites in swamp (but not beach) habitats. Reproductive mode explained little variation in female body size, fecundity, or egg hatch rate. Our results suggest that transitions to parthenogenetic reproduction can lead to dramatic genetic changes with little immediate effect on performance. All-female M. batesii populations appear to consist of high-fitness genotypes that might be able to thrive for many generations in relatively constant and benign environments but could be vulnerable to environmental challenges, such as increased parasite abundance.
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Fyon F, Berbel-Filho WM, Schlupp I, Wild G, Úbeda F. Why do hybrids turn down sex? Evolution 2023; 77:2186-2199. [PMID: 37459230 DOI: 10.1093/evolut/qpad129] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Revised: 05/19/2023] [Accepted: 07/05/2023] [Indexed: 10/05/2023]
Abstract
Asexual reproduction is ancestral in prokaryotes; the switch to sexuality in eukaryotes is one of the major transitions in the history of life. The study of the maintenance of sex in eukaryotes has raised considerable interest for decades and is still one of evolutionary biology's most prominent question. The observation that many asexual species are of hybrid origin has led some to propose that asexuality in hybrids results from sexual processes being disturbed because of incompatibilities between the two parental species' genomes. However, in some cases, failure to produce asexual F1s in the lab may indicate that this mechanism is not the only road to asexuality in hybrid species. Here, we present a mathematical model and propose an alternative, adaptive route for the evolution of asexuality from previously sexual hybrids. Under some reproductive alterations, we show that asexuality can evolve to rescue hybrids' reproduction. Importantly, we highlight that when incompatibilities only affect the fusion of sperm and egg's genomes, the two traits that characterize asexuality, namely unreduced meiosis and the initiation of embryogenesis without the incorporation of the sperm's pronucleus, can evolve separately, greatly facilitating the overall evolutionary route. Taken together, our results provide an alternative, potentially complementary explanation for the link between asexuality and hybridization.
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Affiliation(s)
- Frédéric Fyon
- Department of Biology, Royal Holloway University of London, Egham, United Kingdom
| | | | - Ingo Schlupp
- Department of Biology, University of Oklahoma, Norman, OK, United States
| | - Geoff Wild
- Department of Applied Mathematics, University of Western Ontario, London, ON, Canada
| | - Francisco Úbeda
- Department of Biology, Royal Holloway University of London, Egham, United Kingdom
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Ye Z, Jiang X, Pfrender ME, Lynch M. Genome-Wide Allele-Specific Expression in Obligately Asexual Daphnia pulex and the Implications for the Genetic Basis of Asexuality. Genome Biol Evol 2021; 13:6415829. [PMID: 34726699 PMCID: PMC8598174 DOI: 10.1093/gbe/evab243] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/24/2021] [Indexed: 01/17/2023] Open
Abstract
Although obligately asexual lineages are thought to experience selective disadvantages associated with reduced efficiency of fixing beneficial mutations and purging deleterious mutations, such lineages are phylogenetically and geographically widespread. However, despite several genome-wide association studies, little is known about the genetic elements underlying the origin of obligate asexuality and how they spread. Because many obligately asexual lineages have hybrid origins, it has been suggested that asexuality is caused by the unbalanced expression of alleles from the hybridizing species. Here, we investigate this idea by identifying genes with allele-specific expression (ASE) in a Daphnia pulex population, in which obligate parthenogens (OP) and cyclical parthenogens (CP) coexist, with the OP clones having been originally derived from hybridization between CP D. pulex and its sister species, Daphnia pulicaria. OP D. pulex have significantly more ASE genes (ASEGs) than do CP D. pulex. Whole-genomic comparison of OP and CP clones revealed ∼15,000 OP-specific markers and 42 consistent ASEGs enriched in marker-defined regions. Ten of the 42 ASEGs have alleles coding for different protein sequences, suggesting functional differences between the products of the two parental alleles. At least three of these ten genes appear to be directly involved in meiosis-related processes, for example, RanBP2 can cause abnormal chromosome segregation in anaphase I, and the presence of Wee1 in immature oocytes leads to failure to enter meiosis II. These results provide a guide for future molecular resolution of the genetic basis of the transition to ameiotic parthenogenesis.
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Affiliation(s)
- Zhiqiang Ye
- Center for Mechanisms of Evolution, Arizona State University, Tempe, Arizona
| | | | - Michael E Pfrender
- Department of Biological Sciences and Environmental Change Initiative, University of Notre Dame, Notre Dame, Indiana
| | - Michael Lynch
- Center for Mechanisms of Evolution, Arizona State University, Tempe, Arizona
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Phylogeographic reconstruction of the marbled crayfish origin. Commun Biol 2021; 4:1096. [PMID: 34535758 PMCID: PMC8448756 DOI: 10.1038/s42003-021-02609-w] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Accepted: 08/20/2021] [Indexed: 11/08/2022] Open
Abstract
The marbled crayfish (Procambarus virginalis) is a triploid and parthenogenetic freshwater crayfish species that has colonized diverse habitats around the world. Previous studies suggested that the clonal marbled crayfish population descended as recently as 25 years ago from a single specimen of P. fallax, the sexually reproducing parent species. However, the genetic, phylogeographic, and mechanistic origins of the species have remained enigmatic. We have now constructed a new genome assembly for P. virginalis to support a detailed phylogeographic analysis of the diploid parent species, Procambarus fallax. Our results strongly suggest that both parental haplotypes of P. virginalis were inherited from the Everglades subpopulation of P. fallax. Comprehensive whole-genome sequencing also detected triploid specimens in the same subpopulation, which either represent evolutionarily important intermediate genotypes or independent parthenogenetic lineages arising among the sexual parent population. Our findings thus clarify the geographic origin of the marbled crayfish and identify potential mechanisms of parthenogenetic speciation.
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Burke NW, Holwell GI. Increased male mating success in the presence of prey and rivals in a sexually cannibalistic mantis. Behav Ecol 2021. [DOI: 10.1093/beheco/arab022] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Abstract
Precopulatory sexual cannibalism—or cannibalism without mating—is expected to promote the evolution of male strategies that enhance mating success and reduce the risk of cannibalism, such as preferentially approaching feeding females. Sexual selection on male competitiveness has the potential to alter male mating decisions in the face of cannibalism risk, but such effects are poorly understood. We investigated the effect of prey availability and male–male competition on mating incidence in the highly cannibalistic Springbok mantis, Miomantis caffra. We found that matings were initiated more rapidly and more often in the presence of prey, suggesting that females distracted with foraging may be less of a threat. Competition between males also hastened the onset of copulation and led to higher mating success, with very large effects occurring in the presence of both prey and competitors, indicating that intrasexual competition may intensify attraction to foraging females. Taken together, our results suggest that precopulatory cannibalism has selected for male preference for foraging females and that males adjust their mating strategy to both the risk of competition and the threat of cannibalism.
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Affiliation(s)
- Nathan W Burke
- School of Biological Sciences, University of Auckland, 3A Symonds St, 1010 Auckland, New Zealand
| | - Gregory I Holwell
- School of Biological Sciences, University of Auckland, 3A Symonds St, 1010 Auckland, New Zealand
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Brown TA, Tsurusaki N, Burns M. Genomic Determination of Reproductive Mode in Facultatively Parthenogenetic Opiliones. J Hered 2021; 112:34-44. [PMID: 33448304 DOI: 10.1093/jhered/esaa045] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Accepted: 11/03/2020] [Indexed: 01/15/2023] Open
Abstract
Sexual reproduction may pose myriad short-term costs to females. Despite these costs, sexual reproduction is near ubiquitous. Facultative parthenogenesis is theorized to mitigate some of the costs of sex, as individuals can participate in occasional sex to limit costs while obtaining many benefits. However, most theoretical models assume sexual reproduction is fixed following mating, with no possibility of clutches of mixed reproductive ontogeny. Therefore, we asked: if coercive males are present at high frequency in a population of facultative parthenogens, will their clutches be solely sexually produced, or will there be evidence of sexually and asexually-produced offspring? How will their offspring production compare to conspecifics in low-frequency male populations? We addressed our questions by collecting females and egg clutches of the facultatively parthenogenetic Opiliones species Leiobunum manubriatum and L. globosum. In L. manubriatum, females from populations with few males were not significantly more fecund than females from populations with higher male relative frequency, despite the potential release of the former from sexual conflict. We used 3 genotyping methods along with a custom set of DNA capture probes to reveal that offspring of L. manubriatum from these high male populations were primarily produced via asexual reproduction. This is surprising because sex ratios in these southern populations approach equality, increasing the probability for females to encounter mates and produce offspring sexually. We additionally found evidence for reproductive polymorphisms within populations. Rapid and accurate SNP genotyping data will continue to allow us to address broader evolutionary questions regarding the role of facultative reproductive modes in the maintenance of sex.
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Affiliation(s)
- Tyler A Brown
- Department of Biological Sciences, University of Maryland, Baltimore County, Baltimore, MD
| | - Nobuo Tsurusaki
- Laboratory of Biodiversity and Taxonomy, Department of Agricultural, Life, and Environmental Sciences, Faculty of Agriculture, Tottori University, Tottori, Japan
| | - Mercedes Burns
- Department of Biological Sciences, University of Maryland, Baltimore County, Baltimore, MD
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Fields C, Levin M. Why isn't sex optional? Stem-cell competition, loss of regenerative capacity, and cancer in metazoan evolution. Commun Integr Biol 2020; 13:170-183. [PMID: 33403054 PMCID: PMC7746248 DOI: 10.1080/19420889.2020.1838809] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Revised: 10/14/2020] [Accepted: 10/15/2020] [Indexed: 12/15/2022] Open
Abstract
Animals that can reproduce vegetatively by fission or budding and also sexually via specialized gametes are found in all five primary animal lineages (Bilateria, Cnidaria, Ctenophora, Placozoa, Porifera). Many bilaterian lineages, including roundworms, insects, and most chordates, have lost the capability of vegetative reproduction and are obligately gametic. We suggest a developmental explanation for this evolutionary phenomenon: obligate gametic reproduction is the result of germline stem cells winning a winner-take-all competition with non-germline stem cells for control of reproduction and hence lineage survival. We develop this suggestion by extending Hamilton's rule, which factors the relatedness between parties into the cost/benefit analysis that underpins cooperative behaviors, to include similarity of cellular state. We show how coercive or deceptive cell-cell signaling can be used to make costly cooperative behaviors appear less costly to the cooperating party. We then show how competition between stem-cell lineages can render an ancestral combination of vegetative reproduction with facultative sex unstable, with one or the other process driven to extinction. The increased susceptibility to cancer observed in obligately-sexual lineages is, we suggest, a side-effect of deceptive signaling that is exacerbated by the loss of whole-body regenerative abilities. We suggest a variety of experimental approaches for testing our predictions.
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Affiliation(s)
| | - Michael Levin
- Allen Discovery Center at Tufts University, Medford, MA, USA
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