1
|
Fisher DN, Bechsgaard J, Bilde T. Exploring changes in social spider DNA methylation profiles in all cytosine contexts following infection. Heredity (Edinb) 2024:10.1038/s41437-024-00724-y. [PMID: 39266675 DOI: 10.1038/s41437-024-00724-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2024] [Revised: 08/27/2024] [Accepted: 08/27/2024] [Indexed: 09/14/2024] Open
Abstract
Living at high density and with low genetic diversity are factors that should both increase the susceptibility of organisms to disease. Therefore, group living organisms, especially those that are inbred, should be especially vulnerable to infection and therefore have particular strategies to cope with infection. Phenotypic plasticity, underpinned by epigenetic changes, could allow group living organisms to rapidly respond to infection challenges. To explore the potential role of epigenetic modifications in the immune response to a group-living species with low genetic diversity, we compared the genome-wide DNA methylation profiles of five colonies of social spiders (Stegodyphus dumicola) in their natural habitat in Namibia at the point just before they succumbed to infection to a point at least six months previously where they were presumably healthier. We found increases in genome- and chromosome-wide methylation levels in the CpG, CHG, and CHH contexts, although the genome-wide changes were not clearly different from zero. These changes were most prominent in the CHG context, especially at a narrow region of chromosome 13, hinting at an as-of-yet unsuspected role of this DNA methylation context in phenotypic plasticity. However, there were few clear patterns of differential methylation at the base level, and genes with a known immune function in spiders had mean methylation changes close to zero. Our results suggest that DNA methylation may change with infection at large genomic scales, but that this type of epigenetic change is not necessarily integral to the immune response of social spiders.
Collapse
Affiliation(s)
- David N Fisher
- School of Biological Sciences, University of Aberdeen, King's College, Aberdeen, UK.
| | - Jesper Bechsgaard
- Department of Biology, Section for Genetic Ecology and Evolution, Centre for Ecological Genetics, Aarhus University, Aarhus, Denmark
| | - Trine Bilde
- Department of Biology, Section for Genetic Ecology and Evolution, Centre for Ecological Genetics, Aarhus University, Aarhus, Denmark
| |
Collapse
|
2
|
Aagaard A, Bechsgaard J, Sørensen JG, Sandfeld T, Settepani V, Bird TL, Lund MB, Malmos KG, Falck-Rasmussen K, Darolti I, Nielsen KL, Johannsen M, Vosegaard T, Tregenza T, Verhoeven KJF, Mank JE, Schramm A, Bilde T. Molecular Mechanisms of Temperature Tolerance Plasticity in an Arthropod. Genome Biol Evol 2024; 16:evae165. [PMID: 39058286 DOI: 10.1093/gbe/evae165] [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: 05/28/2024] [Accepted: 07/11/2024] [Indexed: 07/28/2024] Open
Abstract
How species thrive in a wide range of environments is a major focus of evolutionary biology. For many species, limited genetic diversity or gene flow among habitats means that phenotypic plasticity must play an important role in their capacity to tolerate environmental heterogeneity and to colonize new habitats. However, we have a limited understanding of the molecular components that govern plasticity in ecologically relevant phenotypes. We examined this hypothesis in a spider species (Stegodyphus dumicola) with extremely low species-wide genetic diversity that nevertheless occupies a broad range of thermal environments. We determined phenotypic responses to temperature stress in individuals from four climatic zones using common garden acclimation experiments to disentangle phenotypic plasticity from genetic adaptations. Simultaneously, we created data sets on multiple molecular modalities: the genome, the transcriptome, the methylome, the metabolome, and the bacterial microbiome to determine associations with phenotypic responses. Analyses of phenotypic and molecular associations reveal that acclimation responses in the transcriptome and metabolome correlate with patterns of phenotypic plasticity in temperature tolerance. Surprisingly, genes whose expression seemed to be involved in plasticity in temperature tolerance were generally highly methylated contradicting the idea that DNA methylation stabilizes gene expression. This suggests that the function of DNA methylation in invertebrates varies not only among species but also among genes. The bacterial microbiome was stable across the acclimation period; combined with our previous demonstrations that the microbiome is temporally stable in wild populations, this is convincing evidence that the microbiome does not facilitate plasticity in temperature tolerance. Our results suggest that population-specific variation in temperature tolerance among acclimation temperatures appears to result from the evolution of plasticity in mainly gene expression.
Collapse
Affiliation(s)
- Anne Aagaard
- Section for Genetics, Ecology and Evolution, Centre for EcoGenetics, Department of Biology, Aarhus University, Aarhus C, Denmark
| | - Jesper Bechsgaard
- Section for Genetics, Ecology and Evolution, Centre for EcoGenetics, Department of Biology, Aarhus University, Aarhus C, Denmark
| | - Jesper Givskov Sørensen
- Section for Genetics, Ecology and Evolution, Centre for EcoGenetics, Department of Biology, Aarhus University, Aarhus C, Denmark
| | - Tobias Sandfeld
- Section for Microbiology, Department of Biology, Aarhus University, Aarhus C, Denmark
| | - Virginia Settepani
- Section for Genetics, Ecology and Evolution, Centre for EcoGenetics, Department of Biology, Aarhus University, Aarhus C, Denmark
| | - Tharina L Bird
- General Entomology, DITSONG: National Museum of Natural History, Pretoria, South Africa
- Department of Zoology and Entomology, University of Pretoria, Pretoria, South Africa
- Department of Arachnology and Myriapodology, National Museum of Namibia, Windhoek, Namibia
| | - Marie Braad Lund
- Section for Microbiology, Department of Biology, Aarhus University, Aarhus C, Denmark
| | - Kirsten Gade Malmos
- Interdisciplinary Nanoscience Center (iNANO), Aarhus University, Aarhus C, Denmark
| | - Kasper Falck-Rasmussen
- Section for Genetics, Ecology and Evolution, Centre for EcoGenetics, Department of Biology, Aarhus University, Aarhus C, Denmark
| | - Iulia Darolti
- Department of Zoology and Biodiversity Research Centre, University of British Columbia, Vancouver, British Columbia, Canada
- Department of Ecology and Evolution, University of Lausanne, Lausanne, Switzerland
| | | | - Mogens Johannsen
- Department of Forensic Medicine, Aarhus University, Aarhus N, Denmark
| | - Thomas Vosegaard
- Interdisciplinary Nanoscience Center (iNANO), Aarhus University, Aarhus C, Denmark
- Department of Chemistry, Aarhus University, Aarhus C, Denmark
| | - Tom Tregenza
- Centre for Ecology and Conservation, University of Exeter, Penryn Campus, Penryn TR109FE, UK
| | - Koen J F Verhoeven
- Terrestrial Ecology Department, Netherlands Institute of Ecology (NIOO-KNAW), Wageningen 6708 PB, The Netherlands
| | - Judith E Mank
- Department of Zoology and Biodiversity Research Centre, University of British Columbia, Vancouver, British Columbia, Canada
| | - Andreas Schramm
- Section for Microbiology, Department of Biology, Aarhus University, Aarhus C, Denmark
| | - Trine Bilde
- Section for Genetics, Ecology and Evolution, Centre for EcoGenetics, Department of Biology, Aarhus University, Aarhus C, Denmark
- Centre for Ecology and Conservation, University of Exeter, Penryn Campus, Penryn TR109FE, UK
| |
Collapse
|
3
|
Awosile B, Crasto C, Rahman MK, Daniel I, Boggan S, Steuer A, Fritzler J. Fecal Microbial Diversity of Coyotes and Wild Hogs in Texas Panhandle, USA. Microorganisms 2023; 11:1137. [PMID: 37317111 DOI: 10.3390/microorganisms11051137] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2023] [Revised: 04/24/2023] [Accepted: 04/25/2023] [Indexed: 06/16/2023] Open
Abstract
The ecology of infectious diseases involves wildlife, yet the wildlife interface is often neglected and understudied. Pathogens related to infectious diseases are often maintained within wildlife populations and can spread to livestock and humans. In this study, we explored the fecal microbiome of coyotes and wild hogs in the Texas panhandle using polymerase chain reactions and 16S sequencing methods. The fecal microbiota of coyotes was dominated by members of the phyla Bacteroidetes, Firmicutes, and Proteobacteria. At the genus taxonomic level, Odoribacter, Allobaculum, Coprobacillus, and Alloprevotella were the dominant genera of the core fecal microbiota of coyotes. While for wild hogs, the fecal microbiota was dominated by bacterial members of the phyla Bacteroidetes, Spirochaetes, Firmicutes, and Proteobacteria. Five genera, Treponema, Prevotella, Alloprevotella, Vampirovibrio, and Sphaerochaeta, constitute the most abundant genera of the core microbiota of wild hogs in this study. Functional profile of the microbiota of coyotes and wild hogs identified 13 and 17 human-related diseases that were statistically associated with the fecal microbiota, respectively (p < 0.05). Our study is a unique investigation of the microbiota using free-living wildlife in the Texas Panhandle and contributes to awareness of the role played by gastrointestinal microbiota of wild canids and hogs in infectious disease reservoir and transmission risk. This report will contribute to the lacking information on coyote and wild hog microbial communities by providing insights into their composition and ecology which may likely be different from those of captive species or domesticated animals. This study will contribute to baseline knowledge for future studies on wildlife gut microbiomes.
Collapse
Affiliation(s)
- Babafela Awosile
- School of Veterinary Medicine, Texas Tech University, Amarillo, TX 79106, USA
| | - Chiquito Crasto
- Center for Biotechnology and Genomics, Texas Tech University, Lubbock, TX 79409, USA
| | - Md Kaisar Rahman
- School of Veterinary Medicine, Texas Tech University, Amarillo, TX 79106, USA
| | - Ian Daniel
- School of Veterinary Medicine, Texas Tech University, Amarillo, TX 79106, USA
| | - SaraBeth Boggan
- School of Veterinary Medicine, Texas Tech University, Amarillo, TX 79106, USA
| | - Ashley Steuer
- School of Veterinary Medicine, Texas Tech University, Amarillo, TX 79106, USA
| | - Jason Fritzler
- School of Veterinary Medicine, Texas Tech University, Amarillo, TX 79106, USA
| |
Collapse
|
4
|
Durkin ES, Cassidy ST, Leyva A, Keiser CN. Population differences in the aggregation and collective foraging behavior of fragmented social spider colonies. Ethology 2023. [DOI: 10.1111/eth.13360] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Affiliation(s)
- Emily S. Durkin
- Department of Biology University of Florida Gainesville Florida USA
- Department of Biology University of Tampa Tampa Florida USA
| | | | - Arletys Leyva
- Department of Biology University of Florida Gainesville Florida USA
| | - Carl N. Keiser
- Department of Biology University of Florida Gainesville Florida USA
| |
Collapse
|
5
|
Bechsgaard J, Jorgensen TH, Jønsson AK, Schou M, Bilde T. Impaired immune function accompanies social evolution in spiders. Biol Lett 2022; 18:20220331. [PMID: 36541093 PMCID: PMC9768628 DOI: 10.1098/rsbl.2022.0331] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
An efficient immune system is essential to the survival of many animals. Sociality increases risk of pathogen transmission, which should select for enhanced immune function. However, two hypotheses instead predict a weakened immune function: relaxed selection caused by social immunity/protection, and reduced efficacy of selection due to inbreeding, reproductive skew and female bias in social species that reduce effective population size and accelerate genetic drift. We assessed the effect of social evolution on immune function in a comparative study of two social spider species and their closely related subsocial sister species (genus Stegodyphus). The haemolymph of social species was less efficient in inhibiting bacterial growth of the potentially pathogenic bacteria Bacillus subtilis than that of subsocial species. Reduced efficacy of selection in social species was supported by comparative genomic analysis showing substantially elevated non-synonymous substitutions in immune genes in one of the social species. We propose that impaired immune function results from reduced efficacy of selection because the evolution of sociality in spiders is accompanied by demographic processes that elevate genetic drift. Positive feedback between pathogen-induced local extinctions and the resulting elevation of genetic drift may further weaken responses to selection by pathogens, and threaten species persistence.
Collapse
Affiliation(s)
| | | | | | - Mads Schou
- Department of Biology, Lund University, Lund, Sweden
| | - Trine Bilde
- Department of Biology, Aarhus University, Aarhus, Denmark
| |
Collapse
|
6
|
Tong C, Avilés L, Rayor LS, Mikheyev AS, Linksvayer TA. Genomic signatures of recent convergent transitions to social life in spiders. Nat Commun 2022; 13:6967. [PMID: 36414623 PMCID: PMC9681848 DOI: 10.1038/s41467-022-34446-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Accepted: 10/25/2022] [Indexed: 11/24/2022] Open
Abstract
The transition from solitary to social life is a major phenotypic innovation, but its genetic underpinnings are largely unknown. To identify genomic changes associated with this transition, we compare the genomes of 22 spider species representing eight recent and independent origins of sociality. Hundreds of genes tend to experience shifts in selection during the repeated transition to social life. These genes are associated with several key functions, such as neurogenesis, behavior, and metabolism, and include genes that previously have been implicated in animal social behavior and human behavioral disorders. In addition, social species have elevated genome-wide rates of molecular evolution associated with relaxed selection caused by reduced effective population size. Altogether, our study provides unprecedented insights into the genomic signatures of social evolution and the specific genetic changes that repeatedly underpin the evolution of sociality. Our study also highlights the heretofore unappreciated potential of transcriptomics using ethanol-preserved specimens for comparative genomics and phylotranscriptomics.
Collapse
Affiliation(s)
- Chao Tong
- Department of Biology, University of Pennsylvania, Philadelphia, PA, 19104, USA.
- Department of Biological Sciences, Texas Tech University, Lubbock, TX, 79409, USA.
| | - Leticia Avilés
- Department of Zoology, University of British Columbia, Vancouver, British Columbia, V6T 1Z4, Canada
| | - Linda S Rayor
- Department of Entomology, Cornell University, Ithaca, NY, 14853, USA
| | - Alexander S Mikheyev
- Evolutionary Genomics Group, Research School of Biology, Australian National University, Canberra, 0200, Australia
| | - Timothy A Linksvayer
- Department of Biology, University of Pennsylvania, Philadelphia, PA, 19104, USA.
- Department of Biological Sciences, Texas Tech University, Lubbock, TX, 79409, USA.
| |
Collapse
|
7
|
Charmouh AP, Reid JM, Bilde T, Bocedi G. Eco-evolutionary extinction and recolonization dynamics reduce genetic load and increase time to extinction in highly inbred populations. Evolution 2022; 76:2482-2497. [PMID: 36117269 PMCID: PMC9828521 DOI: 10.1111/evo.14620] [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: 03/24/2022] [Revised: 06/01/2022] [Accepted: 07/11/2022] [Indexed: 01/22/2023]
Abstract
Understanding how genetic and ecological effects can interact to shape genetic loads within and across local populations is key to understanding ongoing persistence of systems that should otherwise be susceptible to extinction through mutational meltdown. Classic theory predicts short persistence times for metapopulations comprising small local populations with low connectivity, due to accumulation of deleterious mutations. Yet, some such systems have persisted over evolutionary time, implying the existence of mechanisms that allow metapopulations to avoid mutational meltdown. We first hypothesize a mechanism by which the combination of stochasticity in the numbers and types of mutations arising locally (genetic stochasticity), resulting local extinction, and recolonization through evolving dispersal facilitates metapopulation persistence. We then test this mechanism using a spatially and genetically explicit individual-based model. We show that genetic stochasticity in highly structured metapopulations can result in local extinctions, which can favor increased dispersal, thus allowing recolonization of empty habitat patches. This causes fluctuations in metapopulation size and transient gene flow, which reduces genetic load and increases metapopulation persistence over evolutionary time. Our suggested mechanism and simulation results provide an explanation for the conundrum presented by the continued persistence of highly structured populations with inbreeding mating systems that occur in diverse taxa.
Collapse
Affiliation(s)
- Anders P. Charmouh
- School of Biological SciencesUniversity of AberdeenAberdeenAB24 2TZUnited Kingdom
| | - Jane M. Reid
- School of Biological SciencesUniversity of AberdeenAberdeenAB24 2TZUnited Kingdom,Centre for Biodiversity DynamicsInstitutt for Biologi, NTNUTrondheim7491Norway
| | - Trine Bilde
- Department of BiologyAarhus UniversityAarhus C8000Denmark
| | - Greta Bocedi
- School of Biological SciencesUniversity of AberdeenAberdeenAB24 2TZUnited Kingdom
| |
Collapse
|
8
|
Aagaard A, Liu S, Tregenza T, Braad Lund M, Schramm A, Verhoeven KJF, Bechsgaard J, Bilde T. Adapting to climate with limited genetic diversity: Nucleotide, DNA methylation and microbiome variation among populations of the social spider Stegodyphus dumicola. Mol Ecol 2022; 31:5765-5783. [PMID: 36112081 PMCID: PMC9827990 DOI: 10.1111/mec.16696] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2022] [Revised: 09/01/2022] [Accepted: 09/06/2022] [Indexed: 02/06/2023]
Abstract
Understanding the role of genetic and nongenetic variants in modulating phenotypes is central to our knowledge of adaptive responses to local conditions and environmental change, particularly in species with such low population genetic diversity that it is likely to limit their evolutionary potential. A first step towards uncovering the molecular mechanisms underlying population-specific responses to the environment is to carry out environmental association studies. We associated climatic variation with genetic, epigenetic and microbiome variation in populations of a social spider with extremely low standing genetic diversity. We identified genetic variants that are associated strongly with environmental variation, particularly with average temperature, a pattern consistent with local adaptation. Variation in DNA methylation in many genes was strongly correlated with a wide set of climate parameters, thereby revealing a different pattern of associations than that of genetic variants, which show strong correlations to a more restricted range of climate parameters. DNA methylation levels were largely independent of cis-genetic variation and of overall genetic population structure, suggesting that DNA methylation can work as an independent mechanism. Microbiome composition also correlated with environmental variation, but most strong associations were with precipitation-related climatic factors. Our results suggest a role for both genetic and nongenetic mechanisms in shaping phenotypic responses to local environments.
Collapse
Affiliation(s)
- Anne Aagaard
- Section for Genetics, Ecology & Evolution, Department of BiologyAarhus UniversityAarhus CDenmark
| | - Shenglin Liu
- Section for Genetics, Ecology & Evolution, Department of BiologyAarhus UniversityAarhus CDenmark
| | - Tom Tregenza
- Centre for Ecology & Conservation, School of BiosciencesUniversity of ExeterPenryn CampusUK
| | - Marie Braad Lund
- Section for Microbiology, Department of BiologyAarhus UniversityAarhus CDenmark
| | - Andreas Schramm
- Section for Microbiology, Department of BiologyAarhus UniversityAarhus CDenmark
| | - Koen J. F. Verhoeven
- Terrestrial Ecology DepartmentNetherlands Institute of Ecology (NIOO‐KNAW)WageningenThe Netherlands
| | - Jesper Bechsgaard
- Section for Genetics, Ecology & Evolution, Department of BiologyAarhus UniversityAarhus CDenmark
| | - Trine Bilde
- Section for Genetics, Ecology & Evolution, Department of BiologyAarhus UniversityAarhus CDenmark
| |
Collapse
|
9
|
Genomic signatures of selection associated with benzimidazole drug treatments in Haemonchus contortus field populations. Int J Parasitol 2022; 52:677-689. [PMID: 36113620 DOI: 10.1016/j.ijpara.2022.07.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2022] [Revised: 07/19/2022] [Accepted: 07/19/2022] [Indexed: 11/22/2022]
Abstract
Genome-wide methods offer a powerful approach to detect signatures of drug selection. However, limited availability of suitable reference genomes and the difficulty of obtaining field populations with well-defined, distinct drug treatment histories mean there is little information on the signatures of selection in parasitic nematodes and on how best to detect them. This study addresses these knowledge gaps by using field populations of Haemonchus contortus with well-defined benzimidazole treatment histories, leveraging a recently completed chromosomal-scale reference genome assembly. We generated a panel of 49,393 genomic markers to genotype 20 individual adult worms from each of four H. contortus populations: two from closed sheep flocks with an approximate 20 year history of frequent benzimidazole treatment, and two populations with a history of little or no treatment. Sampling occurred in the same geographical region to limit genetic differentiation and maximise the detection sensitivity. A clear signature of selection was detected on chromosome I, centred on the isotype-1 β-tubulin gene. Two additional, but weaker, signatures of selection were detected; one near the middle of chromosome I spanning 3.75 Mbp and 259 annotated genes, and one on chromosome II spanning a region of 3.3 Mbp and 206 annotated genes, including the isotype-2 β-tubulin locus. We also assessed how sensitivity was impacted by sequencing depth, worm number, and pooled versus individual worm sequence data. This study provides the first known direct genome-wide evidence for any parasitic nematode, that the isotype-1 β-tubulin gene is quantitatively the single most important benzimidazole resistance locus. It also identified two additional genomic regions that likely contain benzimidazole resistance loci of secondary importance. This study provides an experimental framework to maximise the power of genome-wide approaches to detect signatures of selection driven by anthelmintic drug treatments in field populations of parasitic nematodes.
Collapse
|
10
|
Chak STC, Harris SE, Hultgren KM, Duffy JE, Rubenstein DR. Demographic inference provides insights into the extirpation and ecological dominance of eusocial snapping shrimps. J Hered 2022; 113:552-562. [PMID: 35921239 DOI: 10.1093/jhered/esac035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Accepted: 07/27/2022] [Indexed: 11/14/2022] Open
Abstract
Although eusocial animals often achieve ecological dominance in the ecosystems where they occur, many populations are unstable, resulting in local extinction. Both patterns may be linked to the characteristic demography of eusocial species-high reproductive skew and reproductive division of labor support stable effective population sizes that make eusocial groups more competitive in some species, but also lower effective population sizes that increase susceptibility to population collapse in others. Here, we examine the relationship between demography and social organization in Synalpheus snapping shrimps, a group in which eusociality has evolved recently and repeatedly. We show using coalescent demographic modelling that eusocial species have had lower but more stable effective population sizes across 100,000 generations. Our results are consistent with the idea that stable population sizes may enable competitive dominance in eusocial shrimps, but they also suggest that recent population declines are likely caused by eusocial shrimps' heightened sensitivity to environmental changes, perhaps as a result of their low effective population sizes and localized dispersal. Thus, although the unique life histories and demography of eusocial shrimps have likely contributed to their persistence and ecological dominance over evolutionary timescales, these social traits may also make them vulnerable to contemporary environmental change.
Collapse
Affiliation(s)
- Solomon T C Chak
- Department of Ecology, Evolution and Environmental Biology, Columbia University, New York, NY, USA.,Department of Biological Sciences, New Jersey Institute of Technology, Newark, NJ, USA.,Department of Biological Sciences, SUNY College at Old Westbury, Old Westbury, NY, USA
| | - Stephen E Harris
- Department of Ecology, Evolution and Environmental Biology, Columbia University, New York, NY, USA.,Biology Department, SUNY Purchase College, Purchase, NY, USA
| | | | - J Emmett Duffy
- Tennenbaum Marine Observatories Network, Smithsonian Institution, Edgewater, MD, USA
| | - Dustin R Rubenstein
- Department of Ecology, Evolution and Environmental Biology, Columbia University, New York, NY, USA
| |
Collapse
|
11
|
Sandfeld T, Malmos KG, Nielsen CB, Lund MB, Aagaard A, Bechsgaard J, Wurster M, Lalk M, Johannsen M, Vosegaard T, Bilde T, Schramm A. Metabolite Profiling of the Social Spider Stegodyphus dumicola Along a Climate Gradient. Front Ecol Evol 2022. [DOI: 10.3389/fevo.2022.841490] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Animals experience climatic variation in their natural habitats, which may lead to variation in phenotypic responses among populations through local adaptation or phenotypic plasticity. In ectotherm arthropods, the expression of thermoprotective metabolites such as free amino acids, sugars, and polyols, in response to temperature stress, may facilitate temperature tolerance by regulating cellular homeostasis. If populations experience differences in temperatures, individuals may exhibit population-specific metabolite profiles through differential accumulation of metabolites that facilitate thermal tolerance. Such thermoprotective metabolites may originate from the animals themselves or from their associated microbiome, and hence microbial symbionts may contribute to shape the thermal niche of their host. The social spider Stegodyphus dumicola has extremely low genetic diversity, yet it occupies a relatively broad temperature range occurring across multiple climate zones in Southern Africa. We investigated whether the metabolome, including thermoprotective metabolites, differs between populations, and whether population genetic structure or the spider microbiome may explain potential differences. To address these questions, we assessed metabolite profiles, phylogenetic relationships, and microbiomes in three natural populations along a temperature gradient. The spider microbiomes in three genetically distinct populations of S. dumicola showed no significant population-specific pattern, and none of its dominating genera (Borrelia, Diplorickettsia, and Mycoplasma) are known to facilitate thermal tolerance in hosts. These results do not support a role of the microbiome in shaping the thermal niche of S. dumicola. Metabolite profiles of the three spider populations were significantly different. The variation was driven by multiple metabolites that can be linked to temperature stress (e.g., lactate, succinate, or xanthine) and thermal tolerance (e.g., polyols, trehalose, or glycerol): these metabolites had higher relative abundance in spiders from the hottest geographic region. These distinct metabolite profiles are consistent with a potential role of the metabolome in temperature response.
Collapse
|
12
|
Busck MM, Lund MB, Bird TL, Bechsgaard JS, Bilde T, Schramm A. Temporal and spatial microbiome dynamics across natural populations of the social spider Stegodyphus dumicola. FEMS Microbiol Ecol 2022; 98:6526868. [PMID: 35147190 DOI: 10.1093/femsec/fiac015] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Revised: 01/07/2022] [Accepted: 02/09/2022] [Indexed: 11/13/2022] Open
Abstract
Host symbiont interactions may form obligatory or facultative associations that are context dependent. Long-term studies on microbiome composition from wild populations should assess the temporal and spatial dynamics of host-microbe associations. We characterized the temporal and spatial variation in the bacterial microbiome composition in six populations of the social spider Stegodyphus dumicola for 2.5 years, using 16S rRNA gene amplicon sequencing of whole spiders. Individuals within a nest exhibit highly similar microbiomes, which remain stable over several generations and are not predictably affected by seasonal variation in temperature or humidity. This stability in nest microbiome is likely due to social transmission, whereas drift-like processes during new nest foundations explain variation in host microbiomes between nests. This is supported by the lack of obligate symbionts (i.e. no symbionts are present in all spider individuals). Quantitative PCR analyses showed that the bacterial load of individual spiders is stable in healthy nests but can increase dramatically in perishing nests. These increases are not driven by specific bacterial taxa but likely caused by loss of host immune control under deteriorating conditions. Spider nests show an annual survival rate of approximately 45%, but nest death is not correlated to microbiome composition, and the bacteria found in S. dumicola are not considered to be high virulence pathogens.
Collapse
Affiliation(s)
- Mette M Busck
- Section for Microbiology, Department of Biology, Aarhus University, Aarhus, Denmark
| | - Marie B Lund
- Section for Microbiology, Department of Biology, Aarhus University, Aarhus, Denmark
| | - Tharina L Bird
- Department of Biological Sciences and Biotechnology, Botswana International University of Science and Technology (BIUST), Botswana.,Section for Genetics, Ecology and Evolution, Department of Biology, Aarhus University, Aarhus, Denmark.,General Entomology, Ditsong National Museum of Natural History, Pretoria, South Africa.,Department of Zoology and Entomology, University of Pretoria, Pretoria, South Africa
| | - Jesper S Bechsgaard
- Section for Genetics, Ecology and Evolution, Department of Biology, Aarhus University, Aarhus, Denmark
| | - Trine Bilde
- Section for Genetics, Ecology and Evolution, Department of Biology, Aarhus University, Aarhus, Denmark
| | - Andreas Schramm
- Section for Microbiology, Department of Biology, Aarhus University, Aarhus, Denmark
| |
Collapse
|
13
|
Ortiz D, Pekár S, Dianat M. Phylogenomics and loci dropout patterns of deeply diverged Zodarion ant-eating spiders suggest a high potential of RAD-seq for genus-level spider phylogenetics. Cladistics 2021; 38:320-334. [PMID: 34699083 DOI: 10.1111/cla.12493] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/02/2021] [Indexed: 11/28/2022] Open
Abstract
RAD sequencing yields large amounts of genome-wide data at a relatively low cost and without requiring previous taxon-specific information, making it ideal for evolutionary studies of highly diversified and neglected organisms. However, concerns about information decay with phylogenetic distance have discouraged its use for assessing supraspecific relationships. Here, using Double Digest Restriction Associated DNA (ddRAD) data, we perform the first deep-level approach to the phylogeny of Zodarion, a highly diversified spider genus. We explore the impact of loci and taxon filtering across concatenated and multispecies coalescent reconstruction methods and investigate the patterns of information dropout in reference to both the time of divergence and the mitochondrial divergence between taxa. We found that relaxed loci-filtering and nested taxon-filtering strategies maximized the amount of molecular information and improved phylogenetic inference. As expected, there was a clear pattern of allele dropout towards deeper time and mitochondrial divergences, but the phylogenetic signal remained strong throughout the phylogeny. Therefore, we inferred topologies that were almost fully resolved, highly supported, and noticeably congruent between setups and inference methods, which highlights overall inconsistency in the taxonomy of Zodarion. Because Zodarion appears to be among the oldest and most mitochondrially diversified spider genera, our results suggest that ddRAD data show high potential for inferring intra-generic relationships across spiders and probably also in other taxonomic groups.
Collapse
Affiliation(s)
- David Ortiz
- Department of Botany and Zoology, Faculty of Science, Masaryk University, Kotlářská 2, 611 37 Brno, Czechia
| | - Stano Pekár
- Department of Botany and Zoology, Faculty of Science, Masaryk University, Kotlářská 2, 611 37 Brno, Czechia
| | - Malahat Dianat
- Department of Botany and Zoology, Faculty of Science, Masaryk University, Kotlářská 2, 611 37 Brno, Czechia
| |
Collapse
|
14
|
Parthasarathy B, Somanathan H, Wright J. Long‐Term Behavioural Syndrome in Subadult Indian Social Spiders But Not Over the Short‐Term or in Juveniles. Ethology 2021. [DOI: 10.1111/eth.13229] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
| | - Hema Somanathan
- School of Biology Indian Institute of Science Education and Research Thiruvananthapuram India
| | - Jonathan Wright
- Department of Biology Centre for Biodiversity Dynamics (CBD) Norwegian University of Science and Technology (NTNU) Trondheim Norway
| |
Collapse
|
15
|
Lammers A, Zweers H, Sandfeld T, Bilde T, Garbeva P, Schramm A, Lalk M. Antimicrobial Compounds in the Volatilome of Social Spider Communities. Front Microbiol 2021; 12:700693. [PMID: 34504476 PMCID: PMC8422909 DOI: 10.3389/fmicb.2021.700693] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Accepted: 07/31/2021] [Indexed: 11/24/2022] Open
Abstract
Social arthropods such as termites, ants, and bees are among others the most successful animal groups on earth. However, social arthropods face an elevated risk of infections due to the dense colony structure, which facilitates pathogen transmission. An interesting hypothesis is that social arthropods are protected by chemical compounds produced by the arthropods themselves, microbial symbionts, or plants they associate with. Stegodyphus dumicola is an African social spider species, inhabiting communal silk nests. Because of the complex three-dimensional structure of the spider nest antimicrobial volatile organic compounds (VOCs) are a promising protection against pathogens, because of their ability to diffuse through air-filled pores. We analyzed the volatilomes of S. dumicola, their nests, and capture webs in three locations in Namibia and assessed their antimicrobial potential. Volatilomes were collected using polydimethylsiloxane (PDMS) tubes and analyzed using GC/Q-TOF. We showed the presence of 199 VOCs and tentatively identified 53 VOCs. More than 40% of the tentatively identified VOCs are known for their antimicrobial activity. Here, six VOCs were confirmed by analyzing pure compounds namely acetophenone, 1,3-benzothiazole, 1-decanal, 2-decanone, 1-tetradecene, and docosane and for five of these compounds the antimicrobial activity were proven. The nest and web volatilomes had many VOCs in common, whereas the spider volatilomes were more differentiated. Clear differences were identified between the volatilomes from the different sampling sites which is likely justified by differences in the microbiomes of the spiders and nests, the plants, and the different climatic conditions. The results indicate the potential relevance of the volatilomes for the ecological success of S. dumicola.
Collapse
Affiliation(s)
- Alexander Lammers
- Department of Cellular Biochemistry and Metabolomics, University of Greifswald, Greifswald, Germany.,Department of Microbial Ecology, Netherlands Institute of Ecology (NIOO-KNAW), Wageningen, Netherlands
| | - Hans Zweers
- Department of Microbial Ecology, Netherlands Institute of Ecology (NIOO-KNAW), Wageningen, Netherlands
| | - Tobias Sandfeld
- Section for Microbiology, Department of Biology, Aarhus University, Aarhus, Denmark
| | - Trine Bilde
- Section for Genetics, Ecology and Evolution, Department of Biology, Aarhus University, Aarhus, Denmark
| | - Paolina Garbeva
- Department of Microbial Ecology, Netherlands Institute of Ecology (NIOO-KNAW), Wageningen, Netherlands
| | - Andreas Schramm
- Section for Microbiology, Department of Biology, Aarhus University, Aarhus, Denmark
| | - Michael Lalk
- Department of Cellular Biochemistry and Metabolomics, University of Greifswald, Greifswald, Germany
| |
Collapse
|
16
|
Tregenza T, Rodríguez-Muñoz R, Boonekamp JJ, Hopwood PE, Sørensen JG, Bechsgaard J, Settepani V, Hegde V, Waldie C, May E, Peters C, Pennington Z, Leone P, Munk EM, Greenrod STE, Gosling J, Coles H, Gruffydd R, Capria L, Potter L, Bilde T. Evidence for genetic isolation and local adaptation in the field cricket Gryllus campestris. J Evol Biol 2021; 34:1624-1636. [PMID: 34378263 DOI: 10.1111/jeb.13911] [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: 01/12/2021] [Accepted: 07/01/2021] [Indexed: 12/31/2022]
Abstract
Understanding how species can thrive in a range of environments is a central challenge for evolutionary ecology. There is strong evidence for local adaptation along large-scale ecological clines in insects. However, potential adaptation among neighbouring populations differing in their environment has been studied much less. We used RAD sequencing to quantify genetic divergence and clustering of ten populations of the field cricket Gryllus campestris in the Cantabrian Mountains of northern Spain, and an outgroup on the inland plain. Our populations were chosen to represent replicate high and low altitude habitats. We identified genetic clusters that include both high and low altitude populations indicating that the two habitat types do not hold ancestrally distinct lineages. Using common-garden rearing experiments to remove environmental effects, we found evidence for differences between high and low altitude populations in physiological and life-history traits. As predicted by the local adaptation hypothesis, crickets with parents from cooler (high altitude) populations recovered from periods of extreme cooling more rapidly than those with parents from warmer (low altitude) populations. Growth rates also differed between offspring from high and low altitude populations. However, contrary to our prediction that crickets from high altitudes would grow faster, the most striking difference was that at high temperatures, growth was fastest in individuals from low altitudes. Our findings reveal that populations a few tens of kilometres apart have independently evolved adaptations to their environment. This suggests that local adaptation in a range of traits may be commonplace even in mobile invertebrates at scales of a small fraction of species' distributions.
Collapse
Affiliation(s)
- Tom Tregenza
- Centre for Ecology & Conservation, School of Biosciences, University of Exeter, Penryn, UK
| | | | - Jelle J Boonekamp
- Centre for Ecology & Conservation, School of Biosciences, University of Exeter, Penryn, UK.,Institute of Biodiversity, Animal Health & Comparative Medicine, University of Glasgow, Glasgow, UK
| | - Paul E Hopwood
- Centre for Ecology & Conservation, School of Biosciences, University of Exeter, Penryn, UK
| | - Jesper Givskov Sørensen
- Genetics, Ecology & Evolution Section, Department of Biology, Aarhus University, Aarhus C, Denmark
| | - Jesper Bechsgaard
- Genetics, Ecology & Evolution Section, Department of Biology, Aarhus University, Aarhus C, Denmark
| | - Virginia Settepani
- Genetics, Ecology & Evolution Section, Department of Biology, Aarhus University, Aarhus C, Denmark
| | - Vinayaka Hegde
- Centre for Ecology & Conservation, School of Biosciences, University of Exeter, Penryn, UK
| | - Callum Waldie
- Centre for Ecology & Conservation, School of Biosciences, University of Exeter, Penryn, UK
| | - Emma May
- Centre for Ecology & Conservation, School of Biosciences, University of Exeter, Penryn, UK
| | - Caleb Peters
- Centre for Ecology & Conservation, School of Biosciences, University of Exeter, Penryn, UK
| | - Zinnia Pennington
- Centre for Ecology & Conservation, School of Biosciences, University of Exeter, Penryn, UK
| | - Paola Leone
- Centre for Ecology & Conservation, School of Biosciences, University of Exeter, Penryn, UK
| | - Emil M Munk
- Genetics, Ecology & Evolution Section, Department of Biology, Aarhus University, Aarhus C, Denmark
| | - Samuel T E Greenrod
- Genetics, Ecology & Evolution Section, Department of Biology, Aarhus University, Aarhus C, Denmark
| | - Joe Gosling
- Centre for Ecology & Conservation, School of Biosciences, University of Exeter, Penryn, UK
| | - Harry Coles
- Centre for Ecology & Conservation, School of Biosciences, University of Exeter, Penryn, UK
| | - Rhodri Gruffydd
- Centre for Ecology & Conservation, School of Biosciences, University of Exeter, Penryn, UK
| | - Loris Capria
- Centre for Ecology & Conservation, School of Biosciences, University of Exeter, Penryn, UK
| | - Laura Potter
- Centre for Ecology & Conservation, School of Biosciences, University of Exeter, Penryn, UK
| | - Trine Bilde
- Genetics, Ecology & Evolution Section, Department of Biology, Aarhus University, Aarhus C, Denmark
| |
Collapse
|
17
|
The bacterial and fungal nest microbiomes in populations of the social spider Stegodyphus dumicola. Syst Appl Microbiol 2021; 44:126222. [PMID: 34146923 DOI: 10.1016/j.syapm.2021.126222] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Revised: 05/09/2021] [Accepted: 05/26/2021] [Indexed: 12/17/2022]
Abstract
Social spiders of the species Stegodyphus dumicola live in communal nests with hundreds of individuals and are characterized by extremely low species-wide genetic diversity. The lack of genetic diversity in combination with group living imposes a potential threat for infection by pathogens. We therefore proposed that specific microbial symbionts inhabiting the spider nests may provide antimicrobial defense. To compare the bacterial and fungal diversity in 17 nests from three different locations in Namibia, we used 16S rRNA gene and internal transcribed spacer (ITS2) sequencing. The nest microbiomes differed between geographically distinct spider populations and appeared largely determined by the local environment. Nevertheless, we identified a core microbiome consisting of four bacterial genera (Curtobacterium, Modestobacter, Sphingomonas, Massilia) and four fungal genera (Aureobasidium, Didymella, Alternaria, Ascochyta), which likely are selected from surrounding soil and plants by the nest environment. We did not find indications for a strain- or species-specific symbiosis in the nests. Isolation of bacteria and fungi from nest material retrieved a few bacterial strains with antimicrobial activity but a number of antimicrobial fungi, including members of the fungal core microbiome. The significance of antimicrobial taxa in the nest microbiome for host protection remains to be shown.
Collapse
|
18
|
Chak STC, Baeza JA, Barden P. Eusociality Shapes Convergent Patterns of Molecular Evolution across Mitochondrial Genomes of Snapping Shrimps. Mol Biol Evol 2021; 38:1372-1383. [PMID: 33211078 PMCID: PMC8480187 DOI: 10.1093/molbev/msaa297] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Eusociality is a highly conspicuous and ecologically impactful behavioral syndrome that has evolved independently across multiple animal lineages. So far, comparative genomic analyses of advanced sociality have been mostly limited to insects. Here, we study the only clade of animals known to exhibit eusociality in the marine realm-lineages of socially diverse snapping shrimps in the genus Synalpheus. To investigate the molecular impact of sociality, we assembled the mitochondrial genomes of eight Synalpheus species that represent three independent origins of eusociality and analyzed patterns of molecular evolution in protein-coding genes. Synonymous substitution rates are lower and potential signals of relaxed purifying selection are higher in eusocial relative to noneusocial taxa. Our results suggest that mitochondrial genome evolution was shaped by eusociality-linked traits-extended generation times and reduced effective population sizes that are hallmarks of advanced animal societies. This is the first direct evidence of eusociality impacting genome evolution in marine taxa. Our results also strongly support the idea that eusociality can shape genome evolution through profound changes in life history and demography.
Collapse
Affiliation(s)
- Solomon T C Chak
- Department of Biological Sciences, New Jersey Institute of Technology, Newark, NJ
- Department of Biological Sciences, SUNY College at Old Westbury, Old Westbury, NY
| | - Juan Antonio Baeza
- Department of Biological Sciences, Clemson University, Clemson, SC
- Smithsonian Institution, Smithsonian Marine Station at Fort Pierce, Fort Pierce, FL
- Departamento de Biología Marina, Facultad de Ciencias del Mar, Universidad Católica del Norte, Coquimbo, Chile
| | - Phillip Barden
- Department of Biological Sciences, New Jersey Institute of Technology, Newark, NJ
- Division of Invertebrate Zoology, American Museum of Natural History, New York, NY
| |
Collapse
|
19
|
Yang H, Lyu B, Yin HQ, Li SQ. Comparative transcriptomics highlights convergent evolution of energy metabolic pathways in group-living spiders. Zool Res 2021; 42:195-206. [PMID: 33709634 PMCID: PMC7995277 DOI: 10.24272/j.issn.2095-8137.2020.281] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Although widely thought to be aggressive, solitary, and potentially cannibalistic, some spider species have evolved group-living behaviors. The distinct transition provides the framework to uncover group-living evolution. Here, we conducted a comparative transcriptomic study and examined patterns of molecular evolution in two independently evolved group-living spiders and twelve solitary species. We report that positively selected genes among group-living spider lineages are significantly enriched in nutrient metabolism and autophagy pathways. We also show that nutrient-related genes of group-living spiders convergently experience amino acid substitutions and accelerated relative evolutionary rates. These results indicate adaptive convergence of nutrient metabolism that may ensure energy supply in group-living spiders. The decelerated evolutionary rate of autophagy-related genes in group-living lineages is consistent with an increased constraint on energy homeostasis as would be required in a group-living environment. Together, the results show that energy metabolic pathways play an important role in the transition to group-living in spiders.
Collapse
Affiliation(s)
- Han Yang
- Key Laboratory of Zoological Systematics and Evolution, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China.,College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Bin Lyu
- Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu, Sichuan 610041, China
| | - Hai-Qiang Yin
- College of Life Science, Hunan Normal University, Changsha, Hunan 410081, China. E-mail:
| | - Shu-Qiang Li
- Key Laboratory of Zoological Systematics and Evolution, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China.,College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100049, China. E-mail:
| |
Collapse
|
20
|
An antimicrobial Staphylococcus sciuri with broad temperature and salt spectrum isolated from the surface of the African social spider, Stegodyphus dumicola. Antonie Van Leeuwenhoek 2021; 114:325-335. [PMID: 33543432 DOI: 10.1007/s10482-021-01526-6] [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: 01/13/2021] [Accepted: 01/22/2021] [Indexed: 10/22/2022]
Abstract
Some social arthropods engage in mutualistic symbiosis with antimicrobial compound-producing microorganisms that provide protection against pathogens. Social spiders live in communal nests and contain specific endosymbionts with unknown function. Bacteria are also found on the spiders' surface, including prevalent staphylococci, which may have protective potential. Here we present the genomic and phenotypic characterization of strain i1, isolated from the surface of the social spider Stegodyphus dumicola. Phylogenomic analysis identified i1 as novel strain of Staphylococcus sciuri within subgroup 2 of three newly defined genomic subgroups. Further phenotypic investigations showed that S. sciuri i1 is an extremophile that can grow at a broad range of temperatures (4 °C-45 °C), high salt concentrations (up to 27%), and has antimicrobial activity against closely related species. We identified a lactococcin 972-like bacteriocin gene cluster, likely responsible for the antimicrobial activity, and found it conserved in two of the three subgroups of S. sciuri. These features indicate that S. sciuri i1, though not a specific symbiont, is well-adapted to survive on the surface of social spiders and may gain a competitive advantage by inhibiting closely related species.
Collapse
|
21
|
Double-digest RAD-sequencing: do pre- and post-sequencing protocol parameters impact biological results? Mol Genet Genomics 2021; 296:457-471. [PMID: 33469716 DOI: 10.1007/s00438-020-01756-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Accepted: 12/14/2020] [Indexed: 02/06/2023]
Abstract
Next-generation sequencing technologies have opened a new era of research in population genetics. Following these new sequencing opportunities, the use of restriction enzyme-based genotyping techniques, such as restriction site-associated DNA sequencing (RAD-seq) or double-digest RAD-sequencing (ddRAD-seq), has dramatically increased in the last decade. From DNA sampling to SNP calling, the laboratory and bioinformatic parameters of enzyme-based techniques have been investigated in the literature. However, the impact of those parameters on downstream analyses and biological results remains less documented. In this study, we investigated the effects of sevral pre- and post-sequencing settings on ddRAD-seq results for two biological systems: a complex of butterfly species (Coenonympha sp.) and several populations of common beech (Fagus sylvatica). Our results suggest that pre-sequencing parameters (i.e., DNA quantity, number of PCR cycles during library preparation) have a significant impact on the number of recovered reads and SNPs, on the number of unique alleles and on individual heterozygosity. In the same way, we found that post-sequencing settings (i.e., clustering and minimum coverage thresholds) influenced loci reconstruction (e.g., number of loci, mean coverage) and SNP calling (e.g., number of SNPs; heterozygosity) but had only a marginal impact on downstream analyses (e.g., measure of genetic differentiation, estimation of individual admixture, and demographic inferences). In addition, replication analyses confirmed the reproducibility of the ddRAD-seq procedure. Overall, this study assesses the degree of sensitivity of ddRAD-seq data to pre- and post-sequencing protocols, and illustrates its robustness when studying population genetics.
Collapse
|
22
|
Busck MM, Settepani V, Bechsgaard J, Lund MB, Bilde T, Schramm A. Microbiomes and Specific Symbionts of Social Spiders: Compositional Patterns in Host Species, Populations, and Nests. Front Microbiol 2020; 11:1845. [PMID: 32849442 PMCID: PMC7412444 DOI: 10.3389/fmicb.2020.01845] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Accepted: 07/14/2020] [Indexed: 12/18/2022] Open
Abstract
Social spiders have remarkably low species-wide genetic diversities, potentially increasing the relative importance of microbial symbionts for host fitness. Here we explore the bacterial microbiomes of three species of social Stegodyphus (S. dumicola, S. mimosarum, and S. sarasinorum), within and between populations, using 16S rRNA gene amplicon sequencing. The microbiomes of the three spider species were distinct but shared similarities in membership and structure. This included low overall diversity (Shannon index 0.5–1.7), strong dominance of single symbionts in individual spiders (McNaughton’s dominance index 0.68–0.93), and a core microbiome (>50% prevalence) consisting of 5–7 specific symbionts. The most abundant and prevalent symbionts were classified as Chlamydiales, Borrelia, and Mycoplasma, all representing novel, presumably Stegodyphus-specific lineages. Borrelia- and Mycoplasma-like symbionts were localized by fluorescence in situ hybridization (FISH) in the spider midgut. The microbiomes of individual spiders were highly similar within nests but often very different between nests from the same population, with only the microbiome of S. sarasinorum consistently reflecting host population structure. The weak population pattern in microbiome composition renders microbiome-facilitated local adaptation unlikely. However, the retention of specific symbionts across populations and species may indicate a recurrent acquisition from environmental vectors or an essential symbiotic contribution to spider phenotype.
Collapse
Affiliation(s)
- Mette Marie Busck
- Section for Microbiology, Department of Biology, Aarhus University, Aarhus, Denmark
| | - Virginia Settepani
- Section for Genetics, Ecology and Evolution, Department of Biology, Aarhus University, Aarhus, Denmark
| | - Jesper Bechsgaard
- Section for Genetics, Ecology and Evolution, Department of Biology, Aarhus University, Aarhus, Denmark
| | - Marie Braad Lund
- Section for Microbiology, Department of Biology, Aarhus University, Aarhus, Denmark
| | - Trine Bilde
- Section for Genetics, Ecology and Evolution, Department of Biology, Aarhus University, Aarhus, Denmark
| | - Andreas Schramm
- Section for Microbiology, Department of Biology, Aarhus University, Aarhus, Denmark
| |
Collapse
|
23
|
Predictors of colony extinction vary by habitat type in social spiders. Behav Ecol Sociobiol 2020; 74. [PMID: 32431472 DOI: 10.1007/s00265-019-2781-x] [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: 10/25/2022]
Abstract
Many animal societies are susceptible to mass mortality events and collapse. Elucidating how environmental pressures determine patterns of collapse is important for understanding how such societies function and evolve. Using the social spider Stegodyphus dumicola, we investigated the environmental drivers of colony extinction along two precipitation gradients across southern Africa, using the Namib and Kalahari deserts versus wetter savanna habitats to the north and east. We deployed experimental colonies (n = 242) along two ~ 800-km transects and returned to assess colony success in the field after 2 months. Specifically, we noted colony extinction events after the 2-month duration and collected environmental data on the correlates of those extinction events (e.g., evidence of ant attacks, no. of prey captured). We found that colony extinction events at desert sites were more frequently associated with attacks by predatory ants as compared with savanna sites, while colony extinctions in wetter savannas sites were more tightly associated with fungal outbreaks. Our findings support the hypothesis that environments vary in the selection pressures that they impose on social organisms, which may explain why different social phenotypes are often favored in each habitat.
Collapse
|
24
|
Najm GM, Pe A, Pruitt JN, Pinter-Wollman N. Physical and social cues shape nest-site preference and prey capture behavior in social spiders. Behav Ecol 2020; 31:627-632. [PMID: 32595269 PMCID: PMC7303816 DOI: 10.1093/beheco/araa003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2019] [Revised: 12/04/2019] [Accepted: 01/15/2020] [Indexed: 11/14/2022] Open
Abstract
Animals often face conflicting demands when making movement decisions. To examine the decision process of social animals, we evaluated nest-site preferences of the social spider Stegodyphus dumicola. Colonies engage in collective web building, constructing 3D nests and 2D capture webs on trees and fences. We examined how individuals and groups decide where to construct a nest based on habitat structure and conspecific presence. Individuals had a strong preference for 3D substrates and conspecific presence. Groups were then provided with conflicting options of 3D substrates versus 2D substrates with a conspecific. Groups preferred the 3D structures without presettled conspecifics over a 2D substrate with conspecifics. When a group fragmented and individuals settled on both substrates, the minority group eventually joined the majority. Before rejoining, the collective prey capture behavior of divided groups improved with the size of the majority fragment. The costs of slow responses to prey for split groups and weak conspecific attraction may explain why dispersal is rare in these spiders.
Collapse
Affiliation(s)
- Gabriella M Najm
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, CA, USA
| | - Angelika Pe
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, CA, USA
| | - Jonathan N Pruitt
- Department of Psychology, Neuroscience and Behaviour, McMaster University, Hamilton, Ontario, Canada
| | - Noa Pinter-Wollman
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, CA, USA
| |
Collapse
|
25
|
Pechmann M, Stollewerk A. Editorial. Dev Genes Evol 2020; 230:47-48. [PMID: 32124013 DOI: 10.1007/s00427-020-00658-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Affiliation(s)
- Matthias Pechmann
- School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London, E1 4NS, UK.
| | - Angelika Stollewerk
- School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London, E1 4NS, UK
| |
Collapse
|
26
|
Tong C, Najm GM, Pinter-Wollman N, Pruitt JN, Linksvayer TA. Comparative Genomics Identifies Putative Signatures of Sociality in Spiders. Genome Biol Evol 2020; 12:122-133. [PMID: 31960912 PMCID: PMC7108510 DOI: 10.1093/gbe/evaa007] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/15/2020] [Indexed: 12/15/2022] Open
Abstract
Comparative genomics has begun to elucidate the genomic basis of social life in insects, but insight into the genomic basis of spider sociality has lagged behind. To begin, to characterize genomic signatures associated with the evolution of social life in spiders, we performed one of the first spider comparative genomics studies including five solitary species and two social species, representing two independent origins of sociality in the genus Stegodyphus. We found that the two social spider species had a large expansion of gene families associated with transport and metabolic processes and an elevated genome-wide rate of molecular evolution compared with the five solitary spider species. Genes that were rapidly evolving in the two social species relative to the five solitary species were enriched for transport, behavior, and immune functions, whereas genes that were rapidly evolving in the solitary species were enriched for energy metabolism processes. Most rapidly evolving genes in the social species Stegodyphus dumicola were broadly expressed across four tissues and enriched for transport functions, but 12 rapidly evolving genes showed brain-specific expression and were enriched for social behavioral processes. Altogether, our study identifies putative genomic signatures and potential candidate genes associated with spider sociality. These results indicate that future spider comparative genomic studies, including broader sampling and additional independent origins of sociality, can further clarify the genomic causes and consequences of social life.
Collapse
Affiliation(s)
- Chao Tong
- Department of Biology, University of Pennsylvania
| | - Gabriella M Najm
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles
| | - Noa Pinter-Wollman
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles
| | - Jonathan N Pruitt
- Department of Psychology, Neurobiology & Behaviour, McMaster University, Hamilton, Ontario, Canada
| | | |
Collapse
|
27
|
Cordellier M, Schneider JM, Uhl G, Posnien N. Sex differences in spiders: from phenotype to genomics. Dev Genes Evol 2020; 230:155-172. [PMID: 32052129 PMCID: PMC7127994 DOI: 10.1007/s00427-020-00657-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Accepted: 01/31/2020] [Indexed: 01/26/2023]
Abstract
Sexual reproduction is pervasive in animals and has led to the evolution of sexual dimorphism. In most animals, males and females show marked differences in primary and secondary sexual traits. The formation of sex-specific organs and eventually sex-specific behaviors is defined during the development of an organism. Sex determination processes have been extensively studied in a few well-established model organisms. While some key molecular regulators are conserved across animals, the initiation of sex determination is highly diverse. To reveal the mechanisms underlying the development of sexual dimorphism and to identify the evolutionary forces driving the evolution of different sexes, sex determination mechanisms must thus be studied in detail in many different animal species beyond the typical model systems. In this perspective article, we argue that spiders represent an excellent group of animals in which to study sex determination mechanisms. We show that spiders are sexually dimorphic in various morphological, behavioral, and life history traits. The availability of an increasing number of genomic and transcriptomic resources and functional tools provides a great starting point to scrutinize the extensive sexual dimorphism present in spiders on a mechanistic level. We provide an overview of the current knowledge of sex determination in spiders and propose approaches to reveal the molecular and genetic underpinnings of sexual dimorphism in these exciting animals.
Collapse
Affiliation(s)
- Mathilde Cordellier
- Department of Biology, Institute of Zoology, Universität Hamburg, Martin-Luther-King Platz 3, 20146, Hamburg, Germany.
| | - Jutta M Schneider
- Department of Biology, Institute of Zoology, Universität Hamburg, Martin-Luther-King Platz 3, 20146, Hamburg, Germany.
| | - Gabriele Uhl
- Zoological Institute and Museum, Research Group General and Systematic Zoology, Universität Greifswald, Loitzer Straße 26, 17489, Greifswald, Germany.
| | - Nico Posnien
- Department of Developmental Biology, Göttingen Center for Molecular Biosciences (GZMB), University Göttingen, Justus-von-Liebig-Weg 11, 37077, Göttingen, Germany.
| |
Collapse
|
28
|
Jiménez‐Mena B, Le Moan A, Christensen A, van Deurs M, Mosegaard H, Hemmer‐Hansen J, Bekkevold D. Weak genetic structure despite strong genomic signal in lesser sandeel in the North Sea. Evol Appl 2020; 13:376-387. [PMID: 31993083 PMCID: PMC6976957 DOI: 10.1111/eva.12875] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2019] [Revised: 09/08/2019] [Accepted: 09/09/2019] [Indexed: 02/06/2023] Open
Abstract
Sandeels are an ecologically important group of fishes; they are a key part of the food chain serving as food for marine mammals, seabirds and fish. Sandeels are further targeted by a large industrial fishery, which has led to concern about ecosystem effects. In the North Sea, the lesser sandeel Ammodytes marinus is by far the most prevalent species of sandeel in the fishery. Management of sandeel in the North Sea plus the Kattegat is currently divided into seven geographical areas, based on subtle differences in demography, population dynamics and results from simulations of larval dispersal. However, little is known about the underlying genetic population structure. In this study, we used 2,522 SNPs derived from restriction site-associated DNA sequencing (RADseq) typed in 429 fish representing four main sandeel management areas. Our main results showed (a) a lack of a clear spatially defined genetic structure across the majority of genetic markers and (b) the existence of a group of at least 13 SNPs under strong linkage disequilibrium which together separate North Sea sandeel into three haplotype clusters, suggestive of one or more structural variants in the genome. Analyses of the spatial distribution of these putative structural variants suggest at least partial reproductive isolation of sandeel in the western management area along the Scottish coast, supporting a separate management. Our results highlight the importance of the application of a large number of markers to be able to detect weak patterns of differentiation. This study contributes to increasing the genetic knowledge of this important exploited species, and results can be used to improve our understanding of population dynamics and stock structure.
Collapse
Affiliation(s)
- Belén Jiménez‐Mena
- Section for Marine Living ResourcesNational Institute of Aquatic ResourcesTechnical University of DenmarkSilkeborgDenmark
| | - Alan Le Moan
- Section for Marine Living ResourcesNational Institute of Aquatic ResourcesTechnical University of DenmarkSilkeborgDenmark
| | - Asbjørn Christensen
- Section for Marine Living ResourcesNational Institute of Aquatic ResourcesTechnical University of DenmarkSilkeborgDenmark
| | - Mikael van Deurs
- Section for Marine Living ResourcesNational Institute of Aquatic ResourcesTechnical University of DenmarkSilkeborgDenmark
| | - Henrik Mosegaard
- Section for Marine Living ResourcesNational Institute of Aquatic ResourcesTechnical University of DenmarkSilkeborgDenmark
| | - Jakob Hemmer‐Hansen
- Section for Marine Living ResourcesNational Institute of Aquatic ResourcesTechnical University of DenmarkSilkeborgDenmark
| | - Dorte Bekkevold
- Section for Marine Living ResourcesNational Institute of Aquatic ResourcesTechnical University of DenmarkSilkeborgDenmark
| |
Collapse
|
29
|
Grinsted L, Schou MF, Settepani V, Holm C, Bird TL, Bilde T. Prey to predator body size ratio in the evolution of cooperative hunting-a social spider test case. Dev Genes Evol 2019; 230:173-184. [PMID: 31768622 DOI: 10.1007/s00427-019-00640-w] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2019] [Accepted: 10/30/2019] [Indexed: 11/30/2022]
Abstract
One of the benefits of cooperative hunting may be that predators can subdue larger prey. In spiders, cooperative, social species can capture prey many times larger than an individual predator. However, we propose that cooperative prey capture does not have to be associated with larger caught prey per se, but with an increase in the ratio of prey to predator body size. This can be achieved either by catching larger prey while keeping predator body size constant, or by evolving a smaller predator body size while maintaining capture of large prey. We show that within a genus of relatively large spiders, Stegodyphus, subsocial spiders representing the ancestral state of social species are capable of catching the largest prey available in the environment. Hence, within this genus, the evolution of cooperation would not provide access to otherwise inaccessible, large prey. Instead, we show that social Stegodyphus spiders are smaller than their subsocial counterparts, while catching similar sized prey, leading to the predicted increase in prey-predator size ratio with sociality. We further show that in a genus of small spiders, Anelosimus, the level of sociality is associated with an increased size of prey caught while predator size is unaffected by sociality, leading to a similar, predicted increase in prey-predator size ratio. In summary, we find support for our proposed 'prey to predator size ratio hypothesis' and discuss how relaxed selection on large body size in the evolution of social, cooperative living may provide adaptive benefits for ancestrally relatively large predators.
Collapse
Affiliation(s)
- Lena Grinsted
- School of Biological Sciences, Royal Holloway University of London, Egham, Surrey, TW20 0EX, UK
| | - Mads F Schou
- Department of Biology, Lund University, 22362, Lund, Sweden
| | - Virginia Settepani
- Department of Biology, Aarhus University, Ny Munkegade 114-116, 8000, Aarhus C, Denmark
| | - Christina Holm
- Department of Biology, Aarhus University, Ny Munkegade 114-116, 8000, Aarhus C, Denmark
| | - Tharina L Bird
- Department of Biological Sciences and Biotechnology, Botswana International University of Science and Technology (BIUST), Plot, 10071, Palapye, Botswana
| | - Trine Bilde
- Department of Biology, Aarhus University, Ny Munkegade 114-116, 8000, Aarhus C, Denmark.
| |
Collapse
|
30
|
Purcell J, Pruitt JN. Are personalities genetically determined? Inferences from subsocial spiders. BMC Genomics 2019; 20:867. [PMID: 31752670 PMCID: PMC6873478 DOI: 10.1186/s12864-019-6172-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2019] [Accepted: 10/02/2019] [Indexed: 11/25/2022] Open
Abstract
Background Recent research has revealed that polymorphic behavioral strategies shape intra-and interspecific interactions and contribute to fitness in many animal species. A better understanding of the proximate mechanisms underlying these behavioral syndromes will enhance our grasp this phenomenon. Spiders in the genus Anelosimus exhibit inter-individual behavioral variation on several axes: individuals have consistent responses to stimuli (e.g. bold vs. shy individuals) and they are subsocial (exhibiting extended maternal care and sibling cooperation) across most of their range, but they sometimes form permanent social groups in northern temperate regions. Here, we seek genetic variants associated with boldness and with social structure in a socially polymorphic population of the spider Anelosimus studiosus. We also develop preliminary genomic resources, including a genome assembly and linkage map, that support this and future genomic research on this group. Results Remarkably, we identify a small genomic scaffold (~ 1200 bp) that harbors seven single nucleotide polymorphisms (SNPs) associated with boldness. Moreover, heterozygotes are less common than expected based on Hardy-Weinberg equilibrium, suggesting that either assortative mating or selection against heterozygotes may be occurring in this system. We find no loci significantly associated with social organization. Our draft genome assembly allows us to localize SNPs of interest in this study and to carry out genetic comparisons with other published genomes, although it remains highly fragmented. Conclusions By identifying a locus associated with a well-studied animal personality trait, this study opens up avenues for future research to link behavioral studies of animal personality with genotype and fitness.
Collapse
Affiliation(s)
- Jessica Purcell
- Department of Entomology, University of California Riverside, 900 University Ave, Riverside, CA, 92521, USA.
| | - Jonathan N Pruitt
- Department of Psychology, Neuroscience and Behaviour, McMaster University, 1280 Main Street West, Hamilton, ON, L8S 4K1, Canada
| |
Collapse
|
31
|
Tuni C, Mestre L, Berger-Tal R, Lubin Y, Bilde T. Mate choice in naturally inbred spiders: testing the role of relatedness. Anim Behav 2019. [DOI: 10.1016/j.anbehav.2019.08.015] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
|
32
|
Junghanns A, Holm C, Schou MF, Overgaard J, Malte H, Uhl G, Bilde T. Physiological Adaptations to Extreme Maternal and Allomaternal Care in Spiders. Front Ecol Evol 2019. [DOI: 10.3389/fevo.2019.00305] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
|
33
|
Bechsgaard J, Schou MF, Vanthournout B, Hendrickx F, Knudsen B, Settepani V, Schierup MH, Bilde T. Evidence for Faster X Chromosome Evolution in Spiders. Mol Biol Evol 2019; 36:1281-1293. [PMID: 30912801 PMCID: PMC6526907 DOI: 10.1093/molbev/msz074] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
In species with chromosomal sex determination, X chromosomes are predicted to evolve faster than autosomes because of positive selection on recessive alleles or weak purifying selection. We investigated X chromosome evolution in Stegodyphus spiders that differ in mating system, sex ratio, and population dynamics. We assigned scaffolds to X chromosomes and autosomes using a novel method based on flow cytometry of sperm cells and reduced representation sequencing. We estimated coding substitution patterns (dN/dS) in a subsocial outcrossing species (S. africanus) and its social inbreeding and female-biased sister species (S. mimosarum), and found evidence for faster-X evolution in both species. X chromosome-to-autosome diversity (piX/piA) ratios were estimated in multiple populations. The average piX/piA estimates of S. africanus (0.57 [95% CI: 0.55-0.60]) was lower than the neutral expectation of 0.75, consistent with more hitchhiking events on X-linked loci and/or a lower X chromosome mutation rate, and we provide evidence in support of both. The social species S. mimosarum has a significantly higher piX/piA ratio (0.72 [95% CI: 0.65-0.79]) in agreement with its female-biased sex ratio. Stegodyphus mimosarum also have different piX/piA estimates among populations, which we interpret as evidence for recurrent founder events. Simulations show that recurrent founder events are expected to decrease the piX/piA estimates in S. mimosarum, thus underestimating the true effect of female-biased sex ratios. Finally, we found lower synonymous divergence on X chromosomes in both species, and the male-to-female substitution ratio to be higher than 1, indicating a higher mutation rate in males.
Collapse
Affiliation(s)
| | - Mads Fristrup Schou
- Department of Bioscience, Aarhus University, Aarhus C, Denmark.,Department of Biology, Lund University, SE-223 62 Lund, Sweden
| | - Bram Vanthournout
- Department of Bioscience, Aarhus University, Aarhus C, Denmark.,Evolution and Optics of Nanostructure Group (EON), Biology Department, Ghent University, Ghent, Belgium
| | - Frederik Hendrickx
- Royal Belgian Institute of Natural Sciences, Brussels, Belgium.,Terrestrial Ecology Unit (TEREC), Biology Department, Ghent University, Ghent, Belgium
| | | | | | - Mikkel Heide Schierup
- Department of Bioscience, Aarhus University, Aarhus C, Denmark.,Bioinformatics Research Centre (BiRC), Aarhus University, Aarhus C, Denmark
| | - Trine Bilde
- Department of Bioscience, Aarhus University, Aarhus C, Denmark
| |
Collapse
|
34
|
Vanthournout B, Busck MM, Bechsgaard J, Hendrickx F, Schramm A, Bilde T. Male spiders control offspring sex ratio through greater production of female-determining sperm. Proc Biol Sci 2019; 285:rspb.2017.2887. [PMID: 29563266 DOI: 10.1098/rspb.2017.2887] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2017] [Accepted: 02/26/2018] [Indexed: 01/07/2023] Open
Abstract
Sex allocation theory predicts that when sons and daughters have different reproductive values, parents should adjust offspring sex ratio towards the sex with the higher fitness return. Haplo-diploid species directly control offspring sex ratio, but species with chromosomal sex determination (CSD) were presumed to be constrained by Mendelian segregation. There is now increasing evidence that CSD species can adjust sex ratio strategically, but the underlying mechanism is not well understood. One hypothesis states that adaptive control is more likely to evolve in the heterogametic sex through a bias in gamete production. We investigated this hypothesis in males as the heterogametic sex in two social spider species that consistently show adaptive female-biased sex ratio and in one subsocial species that is characterized by equal sex ratio. We quantified the production of male (0) and female (X) determining sperm cells using flow cytometry, and show that males of social species produce significantly more X-carrying sperm than 0-sperm, on average 70%. This is consistent with the production of more daughters. Males of the subsocial species produced a significantly lower bias of 54% X-carrying sperm. We also investigated whether inter-genomic conflict between hosts and their endosymbionts may explain female bias. Next generation sequencing showed that five common genera of bacterial endosymbionts known to affect sex ratio are largely absent, ruling out that endosymbiont bacteria bias sex ratio in social spiders. Our study provides evidence for paternal control over sex allocation through biased gamete production as a mechanism by which the heterogametic sex in CSD species adaptively adjust offspring sex ratio.
Collapse
Affiliation(s)
- Bram Vanthournout
- Department of Bioscience, Section for Genetics, Ecology and Evolution, Aarhus University, Ny Munkegade 114, Building 1540, 8000 Aarhus C, Denmark.,Biology Department, Evolution and Optics of Nanostructures Group, Ghent University, K.L. Ledeganckstraat 35, 9000 Gent, Belgium
| | - Mette Marie Busck
- Department of Bioscience, Section for Microbiology, Aarhus University, Ny Munkegade 114, Building 1540, 8000 Aarhus C, Denmark
| | - Jesper Bechsgaard
- Department of Bioscience, Section for Genetics, Ecology and Evolution, Aarhus University, Ny Munkegade 114, Building 1540, 8000 Aarhus C, Denmark
| | - Frederik Hendrickx
- Biology Department, Terrestrial Ecology Unit, Ghent University, K.L. Ledeganckstraat 35, 9000 Gent, Belgium.,Entomology Department, Royal Belgian Institute of Natural Sciences, Vautierstraat 29, 1000 Brussels, Belgium
| | - Andreas Schramm
- Department of Bioscience, Section for Microbiology, Aarhus University, Ny Munkegade 114, Building 1540, 8000 Aarhus C, Denmark
| | - Trine Bilde
- Department of Bioscience, Section for Genetics, Ecology and Evolution, Aarhus University, Ny Munkegade 114, Building 1540, 8000 Aarhus C, Denmark
| |
Collapse
|
35
|
Smith C, Cotter A, Grinsted L, Bowolaksono A, Watiniasih NL, Agnarsson I. In a relationship: sister species in mixed colonies, with a description of new Chikunia species (Theridiidae). Zool J Linn Soc 2019. [DOI: 10.1093/zoolinnean/zly083] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Abstract
Group-living behaviour is rare in spiders but has evolved repeatedly, yielding several species, some showing cooperation among close kin, and others living in colonies where each female builds its own web and is territorial. The most frequent origins of group living are seen in the cobweb spiders (Theridiidae) that commonly build three-dimensional webs and show extensive maternal care, both putatively pre-adaptive traits to spider sociality. A very unusual behaviour was recently discovered in the theridiid genus Chikunia, where two distinct but related species occur in mixed-species colonies with potentially indiscriminate brood care. These mixed colonies consist of Chikunia nigra and a newly discovered species. Here, we describe the new species, Chikunia bilde sp. nov., and summarize the unique biology of this species pair. We also place the origin of mixed-species group living in a phylogenetic context, firmly confirming the placement of Chikunia within the clade (lost colulus clade) previously characterized as containing a concentration of independent origins of group living. The two Chikunia studied here are sister species, representing a rare case of close genetic and behavioural interspecific relationship. We conclude that the loss of aggression that accompanies group living and social behaviour in cobweb spiders might help to explain the origin of mixed-species colonies.
Collapse
Affiliation(s)
- Cassandra Smith
- Department of Biology, University of Vermont, Burlington, VT, USA
| | - Addie Cotter
- Department of Biology, University of Vermont, Burlington, VT, USA
| | - Lena Grinsted
- School of Biological Sciences, Royal Holloway University of London, Egham, Surrey, UK
| | - Anom Bowolaksono
- Department of Biology, Faculty of Mathematics and Sciences, University of Indonesia, Kampus UI Depok, Depok, Indonesia
| | - Ni Luh Watiniasih
- Department of Biology, Faculty of Mathematics and Natural Sciences, Udayana University, Kampus Bukit Jimbaran, Bali, Indonesia
| | - Ingi Agnarsson
- Department of Biology, University of Vermont, Burlington, VT, USA
| |
Collapse
|
36
|
Ballesteros JA, Sharma PP. A Critical Appraisal of the Placement of Xiphosura (Chelicerata) with Account of Known Sources of Phylogenetic Error. Syst Biol 2019; 68:896-917. [DOI: 10.1093/sysbio/syz011] [Citation(s) in RCA: 87] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Revised: 12/20/2018] [Accepted: 02/10/2019] [Indexed: 11/13/2022] Open
Abstract
AbstractHorseshoe crabs (Xiphosura) are traditionally regarded as sister group to the clade of terrestrial chelicerates (Arachnida). This hypothesis has been challenged by recent phylogenomic analyses, but the non-monophyly of Arachnida has consistently been disregarded as artifactual. We re-evaluated the placement of Xiphosura among chelicerates using the most complete phylogenetic data set to date, expanding outgroup sampling, and including data from whole genome sequencing projects. In spite of uncertainty in the placement of some arachnid clades, all analyses show Xiphosura consistently nested within Arachnida as the sister group to Ricinulei (hooded tick spiders). It is apparent that the radiation of arachnids is an old one and occurred over a brief period of time, resulting in several consecutive short internodes, and thus is a potential case for the confounding effects of incomplete lineage sorting (ILS). We simulated coalescent gene trees to explore the effects of increasing levels of ILS on the placement of horseshoe crabs. In addition, common sources of systematic error were evaluated, as well as the effects of fast-evolving partitions and the dynamics of problematic long branch orders. Our results indicated that the placement of horseshoe crabs cannot be explained by missing data, compositional biases, saturation, or ILS. Interrogation of the phylogenetic signal showed that the majority of loci favor the derived placement of Xiphosura over a monophyletic Arachnida. Our analyses support the inference that horseshoe crabs represent a group of aquatic arachnids, comparable to aquatic mites, breaking a long-standing paradigm in chelicerate evolution and altering previous interpretations of the ancestral transition to the terrestrial habitat. Future studies testing chelicerate relationships should approach the task with a sampling strategy where the monophyly of Arachnida is not held as the premise.
Collapse
Affiliation(s)
- Jesús A Ballesteros
- Department of Integrative Biology, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Prashant P Sharma
- Department of Integrative Biology, University of Wisconsin-Madison, Madison, WI 53706, USA
| |
Collapse
|
37
|
Liu S, Aageaard A, Bechsgaard J, Bilde T. DNA Methylation Patterns in the Social Spider, Stegodyphus dumicola. Genes (Basel) 2019; 10:E137. [PMID: 30759892 PMCID: PMC6409797 DOI: 10.3390/genes10020137] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2018] [Revised: 01/25/2019] [Accepted: 01/25/2019] [Indexed: 12/18/2022] Open
Abstract
Variation in DNA methylation patterns among genes, individuals, and populations appears to be highly variable among taxa, but our understanding of the functional significance of this variation is still incomplete. We here present the first whole genome bisulfite sequencing of a chelicerate species, the social spider Stegodyphus dumicola. We show that DNA methylation occurs mainly in CpG context and is concentrated in genes. This is a pattern also documented in other invertebrates. We present RNA sequence data to investigate the role of DNA methylation in gene regulation and show that, within individuals, methylated genes are more expressed than genes that are not methylated and that methylated genes are more stably expressed across individuals than unmethylated genes. Although no causal association is shown, this lends support for the implication of DNA CpG methylation in regulating gene expression in invertebrates. Differential DNA methylation between populations showed a small but significant correlation with differential gene expression. This is consistent with a possible role of DNA methylation in local adaptation. Based on indirect inference of the presence and pattern of DNA methylation in chelicerate species whose genomes have been sequenced, we performed a comparative phylogenetic analysis. We found strong evidence for exon DNA methylation in the horseshoe crab Limulus polyphemus and in all spider and scorpion species, while most Parasitiformes and Acariformes species seem to have lost DNA methylation.
Collapse
Affiliation(s)
- Shenglin Liu
- Department of Bioscience, Aarhus University, 8000 Aarhus C, Denmark.
| | | | | | | |
Collapse
|
38
|
Schendel V, Junghanns A, Bilde T, Uhl G. Comparative female genital morphology in Stegodyphus spiders (Araneae: Eresidae). ZOOL ANZ 2018. [DOI: 10.1016/j.jcz.2018.01.011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
|
39
|
Brooks KC, Maia R, Duffy JE, Hultgren KM, Rubenstein DR. Ecological generalism facilitates the evolution of sociality in snapping shrimps. Ecol Lett 2017; 20:1516-1525. [DOI: 10.1111/ele.12857] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2017] [Revised: 03/22/2017] [Accepted: 08/23/2017] [Indexed: 01/08/2023]
Affiliation(s)
- Katherine C. Brooks
- Department of Ecology, Evolution and Environmental Biology; Columbia University; New York NY 10027 USA
| | - Rafael Maia
- Department of Ecology, Evolution and Environmental Biology; Columbia University; New York NY 10027 USA
| | - J. Emmett Duffy
- Tennenbaum Marine Observatories Network; Smithsonian Institution; Washington DC 20013 USA
| | | | - 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
| |
Collapse
|