1
|
Mendel BM, Asselin AK, Johnson KN, McGuigan K. Effects of spontaneous mutations on survival and reproduction of Drosophila serrata infected with Drosophila C virus. Evolution 2024; 78:1661-1672. [PMID: 38934580 DOI: 10.1093/evolut/qpae101] [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: 04/07/2024] [Revised: 06/13/2024] [Accepted: 06/25/2024] [Indexed: 06/28/2024]
Abstract
The impact of selection on host immune function genes has been widely documented. However, it remains essentially unknown how mutation influences the quantitative immune traits that selection acts on. Applying a classical mutation accumulation (MA) experimental design in Drosophila serrata, we found the mutational variation in susceptibility (median time of death, LT50) to Drosophila C virus (DCV) was of similar magnitude to that reported for intrinsic survival traits. Mean LT50 did not change as mutations accumulated, suggesting no directional bias in mutational effects. Maintenance of genetic variance in immune function is hypothesized to be influenced by pleiotropic effects on immunity and other traits that contribute to fitness. To investigate this, we assayed female reproductive output for a subset of MA lines with relatively long or short survival times under DCV infection. Longer survival time tended to be associated with lower reproductive output, suggesting that mutations affecting susceptibility to DCV had pleiotropic effects on investment in reproductive fitness. Further studies are needed to uncover the general patterns of mutational effect on immune responses and other fitness traits, and to determine how selection might typically act on new mutations via their direct and pleiotropic effects.
Collapse
Affiliation(s)
- Bonita M Mendel
- School of the Environment, The University of Queensland, Brisbane, QLD, Australia
| | - Angelique K Asselin
- School of the Environment, The University of Queensland, Brisbane, QLD, Australia
| | - Karyn N Johnson
- School of the Environment, The University of Queensland, Brisbane, QLD, Australia
| | - Katrina McGuigan
- School of the Environment, The University of Queensland, Brisbane, QLD, Australia
| |
Collapse
|
2
|
Quevarec L, Morran LT, Dufourcq-Sekatcheff E, Armant O, Adam-Guillermin C, Bonzom JM, Réale D. Host defense alteration in Caenorhabditis elegans after evolution under ionizing radiation. BMC Ecol Evol 2024; 24:95. [PMID: 38982371 PMCID: PMC11234525 DOI: 10.1186/s12862-024-02282-7] [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: 01/10/2024] [Accepted: 07/01/2024] [Indexed: 07/11/2024] Open
Abstract
BACKGROUND Adaptation to a stressor can lead to costs on other traits. These costs play an unavoidable role on fitness and influence the evolutionary trajectory of a population. Host defense seems highly subject to these costs, possibly because its maintenance is energetically costly but essential to the survival. When assessing the ecological risk related to pollution, it is therefore relevant to consider these costs to evaluate the evolutionary consequences of stressors on populations. However, to the best of our knowledge, the effects of evolution in irradiate environment on host defense have never been studied. Using an experimental evolution approach, we analyzed fitness across 20 transfers (about 20 generations) in Caenorhabditis elegans populations exposed to 0, 1.4, and 50.0 mGy.h- 1 of 137Cs gamma radiation. Then, populations from transfer 17 were placed in the same environmental conditions without irradiation (i.e., common garden) for about 10 generations before being exposed to the bacterial parasite Serratia marcescens and their survival was estimated to study host defense. Finally, we studied the presence of an evolutionary trade-off between fitness of irradiated populations and host defense. RESULTS We found a lower fitness in both irradiated treatments compared to the control ones, but fitness increased over time in the 50.0 mGy.h- 1, suggesting a local adaptation of the populations. Then, the survival rate of C. elegans to S. marcescens was lower for common garden populations that had previously evolved under both irradiation treatments, indicating that evolution in gamma-irradiated environment had a cost on host defense of C. elegans. Furthermore, we showed a trade-off between standardized fitness at the end of the multigenerational experiment and survival of C. elegans to S. marcescens in the control treatment, but a positive correlation between the two traits for the two irradiated treatments. These results indicate that among irradiated populations, those most sensitive to ionizing radiation are also the most susceptible to the pathogen. On the other hand, other irradiated populations appear to have evolved cross-resistance to both stress factors. CONCLUSIONS Our study shows that adaptation to an environmental stressor can be associated with an evolutionary cost when a new stressor appears, even several generations after the end of the first stressor. Among irradiated populations, we observed an evolution of resistance to ionizing radiation, which also appeared to provide an advantage against the pathogen. On the other hand, some of the irradiated populations seemed to accumulate sensitivities to stressors. This work provides a new argument to show the importance of considering evolutionary changes in ecotoxicology and for ecological risk assessment.
Collapse
Affiliation(s)
- Loïc Quevarec
- Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PSE-ENV/SERPEN/LECO, Cadarache, Saint Paul Lez Durance, 13115, France.
| | - Levi T Morran
- Department of Biology, Emory University, Atlanta, GA, 30322, USA
| | - Elizabeth Dufourcq-Sekatcheff
- Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PSE-ENV/SERPEN/LECO, Cadarache, Saint Paul Lez Durance, 13115, France
| | - Olivier Armant
- Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PSE-ENV/SERPEN/LECO, Cadarache, Saint Paul Lez Durance, 13115, France
| | - Christelle Adam-Guillermin
- Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PSE-SANTE/SDOS/LMDN, Cadarache, Saint Paul Lez Durance, 13115, France
| | - Jean-Marc Bonzom
- Institut de Radioprotection et de Sûreté Nucléaire (IRSN), PSE-ENV/SERPEN/LECO, Cadarache, Saint Paul Lez Durance, 13115, France
| | - Denis Réale
- Département des sciences biologiques, Université du Québec à Montréal, Montréal, QC, Canada
| |
Collapse
|
3
|
Souto-Maior C, Serrano Negron YL, Harbison ST. Nonlinear expression patterns and multiple shifts in gene network interactions underlie robust phenotypic change in Drosophila melanogaster selected for night sleep duration. PLoS Comput Biol 2023; 19:e1011389. [PMID: 37561813 PMCID: PMC10443883 DOI: 10.1371/journal.pcbi.1011389] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Revised: 08/22/2023] [Accepted: 07/25/2023] [Indexed: 08/12/2023] Open
Abstract
All but the simplest phenotypes are believed to result from interactions between two or more genes forming complex networks of gene regulation. Sleep is a complex trait known to depend on the system of feedback loops of the circadian clock, and on many other genes; however, the main components regulating the phenotype and how they interact remain an unsolved puzzle. Genomic and transcriptomic data may well provide part of the answer, but a full account requires a suitable quantitative framework. Here we conducted an artificial selection experiment for sleep duration with RNA-seq data acquired each generation. The phenotypic results are robust across replicates and previous experiments, and the transcription data provides a high-resolution, time-course data set for the evolution of sleep-related gene expression. In addition to a Hierarchical Generalized Linear Model analysis of differential expression that accounts for experimental replicates we develop a flexible Gaussian Process model that estimates interactions between genes. 145 gene pairs are found to have interactions that are different from controls. Our method appears to be not only more specific than standard correlation metrics but also more sensitive, finding correlations not significant by other methods. Statistical predictions were compared to experimental data from public databases on gene interactions. Mutations of candidate genes implicated by our results affected night sleep, and gene expression profiles largely met predicted gene-gene interactions.
Collapse
Affiliation(s)
- Caetano Souto-Maior
- Laboratory of Systems Genetics, Systems Biology Center, National Heart Lung and Blood Institute, Bethesda, Maryland, United States of America
| | - Yazmin L. Serrano Negron
- Laboratory of Systems Genetics, Systems Biology Center, National Heart Lung and Blood Institute, Bethesda, Maryland, United States of America
| | - Susan T. Harbison
- Laboratory of Systems Genetics, Systems Biology Center, National Heart Lung and Blood Institute, Bethesda, Maryland, United States of America
| |
Collapse
|
4
|
Kutzer MAM, Gupta V, Neophytou K, Doublet V, Monteith KM, Vale PF. Intraspecific genetic variation in host vigour, viral load and disease tolerance during Drosophila C virus infection. Open Biol 2023; 13:230025. [PMID: 36854375 PMCID: PMC9974301 DOI: 10.1098/rsob.230025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/02/2023] Open
Abstract
Genetic variation for resistance and disease tolerance has been described in a range of species. In Drosophila melanogaster, genetic variation in mortality following systemic Drosophila C virus (DCV) infection is driven by large-effect polymorphisms in the restriction factor pastrel (pst). However, it is unclear if pst contributes to disease tolerance. We investigated systemic DCV challenges spanning nine orders of magnitude, in males and females of 10 Drosophila Genetic Reference Panel lines carrying either a susceptible (S) or resistant (R) pst allele. We find among-line variation in fly survival, viral load and disease tolerance measured both as the ability to maintain survival (mortality tolerance) and reproduction (fecundity tolerance). We further uncover novel effects of pst on host vigour, as flies carrying the R allele exhibited higher survival and fecundity even in the absence of infection. Finally, we found significant genetic variation in the expression of the JAK-STAT ligand upd3 and the epigenetic regulator of JAK-STAT G9a. However, while G9a has been previously shown to mediate tolerance of DCV infection, we found no correlation between the expression of either upd3 or G9a on fly tolerance or resistance. Our work highlights the importance of both resistance and tolerance in viral defence.
Collapse
Affiliation(s)
- Megan A. M. Kutzer
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, UK
| | - Vanika Gupta
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, UK
| | - Kyriaki Neophytou
- Institute of Immunology and Infection Research, School of Biological Sciences, University of Edinburgh, UK
| | - Vincent Doublet
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, UK
| | - Katy M. Monteith
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, UK
| | - Pedro F. Vale
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, UK
| |
Collapse
|
5
|
Jiranek J, Gibson A. Diet can alter the cost of resistance to a natural parasite in Caenorhabditis elegans. Ecol Evol 2023; 13:e9793. [PMID: 36789344 PMCID: PMC9911625 DOI: 10.1002/ece3.9793] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2023] [Revised: 01/07/2023] [Accepted: 01/16/2023] [Indexed: 02/12/2023] Open
Abstract
Resistance to parasites confers a fitness advantage, yet hosts show substantial variation in resistance in natural populations. Evolutionary theory indicates that resistant and susceptible genotypes can coexist if resistance is costly, but there is mixed evidence that resistant individuals have lower fitness in the absence of parasites. One explanation for this discrepancy is that the cost of resistance varies with environmental context. We tested this hypothesis using Caenorhabditis elegans and its natural microsporidian parasite, Nematocida ironsii. We used multiple metrics to compare the fitness of two near-isogenic host genotypes differing at regions associated with resistance to N. ironsii. To quantify the effect of the environment on the cost associated with these known resistance regions, we measured fitness on three microbial diets. We found that the cost of resistance varied with both diet and the measure of fitness. We detected no cost to resistance, irrespective of diet, when fitness was measured as fecundity. However, we detected a cost when fitness was measured in terms of population growth, and the magnitude of this cost varied with diet. These results provide a proof of concept that, by mediating the cost of resistance, environmental context may govern the rate and nature of resistance evolution in heterogeneous environments.
Collapse
Affiliation(s)
- Juliana Jiranek
- Department of BiologyUniversity of VirginiaCharlottesvilleVirginiaUSA
| | - Amanda Gibson
- Department of BiologyUniversity of VirginiaCharlottesvilleVirginiaUSA
| |
Collapse
|
6
|
Corbally MK, Regan JC. Fly immunity comes of age: The utility of Drosophila as a model for studying variation in immunosenescence. FRONTIERS IN AGING 2022; 3:1016962. [PMID: 36268532 PMCID: PMC9576847 DOI: 10.3389/fragi.2022.1016962] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Accepted: 09/20/2022] [Indexed: 11/05/2022]
Affiliation(s)
| | - Jennifer C. Regan
- Institute of Immunology and Infection Research, University of Edinburgh, Edinburgh, United Kingdom
| |
Collapse
|
7
|
Debray R, De Luna N, Koskella B. Historical contingency drives compensatory evolution and rare reversal of phage resistance. Mol Biol Evol 2022; 39:6673247. [PMID: 35994371 PMCID: PMC9447851 DOI: 10.1093/molbev/msac182] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Bacteria and lytic viruses (phages) engage in highly dynamic coevolutionary interactions over time, yet we have little idea of how transient selection by phages might shape the future evolutionary trajectories of their host populations. To explore this question, we generated genetically diverse phage-resistant mutants of the bacterium Pseudomonas syringae. We subjected the panel of mutants to prolonged experimental evolution in the absence of phages. Some populations re-evolved phage sensitivity, whereas others acquired compensatory mutations that reduced the costs of resistance without altering resistance levels. To ask whether these outcomes were driven by the initial genetic mechanisms of resistance, we next evolved independent replicates of each individual mutant in the absence of phages. We found a strong signature of historical contingency: some mutations were highly reversible across replicate populations, whereas others were highly entrenched. Through whole-genome sequencing of bacteria over time, we also found that populations with the same resistance gene acquired more parallel sets of mutations than populations with different resistance genes, suggesting that compensatory adaptation is also contingent on how resistance initially evolved. Our study identifies an evolutionary ratchet in bacteria–phage coevolution and may explain previous observations that resistance persists over time in some bacterial populations but is lost in others. We add to a growing body of work describing the key role of phages in the ecological and evolutionary dynamics of their host communities. Beyond this specific trait, our study provides a new insight into the genetic architecture of historical contingency, a crucial component of interpreting and predicting evolution.
Collapse
Affiliation(s)
- Reena Debray
- Department of Integrative Biology, University of California, Berkeley, Berkeley, CA, USA
| | - Nina De Luna
- Department of Immunology, Pennsylvania State University, State College, PA, USA
| | - Britt Koskella
- Department of Integrative Biology, University of California, Berkeley, Berkeley, CA, USA.,Chan Zuckerberg BioHub, San Francisco, CA, USA
| |
Collapse
|
8
|
Pathogen infection routes and host innate immunity: Lessons from insects. Immunol Lett 2022; 247:46-51. [PMID: 35667452 DOI: 10.1016/j.imlet.2022.05.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2022] [Revised: 05/19/2022] [Accepted: 05/30/2022] [Indexed: 11/23/2022]
Abstract
Recent advances in insect-pathogen interactions have started to reveal the role of insect tissues and organs as natural infection routes for parasites and microbial pathogens. Here we summarize this information highlighting the micro- and macro-parasites that enter insects through distinct infection routes and link them to innate immune activity. We also examine whether the infection route determines the insect immune response and if the resulting immunological and physiological processes underpinning these different routes of infection are clearly distinct. Understanding how the infection route is associated with the robustness in insect host defense will help us identify conserved evolutionary and ecological patterns in order to design novel strategies for the management of destructive agricultural pests and disease vectors.
Collapse
|
9
|
Prigot-Maurice C, Depeux C, Paulhac H, Braquart-Varnier C, Beltran-Bech S. Immune priming in Armadillidiumvulgare against Salmonellaenterica: direct or indirect costs on life history traits? Zookeys 2022; 1101:131-158. [PMID: 36760973 PMCID: PMC9848923 DOI: 10.3897/zookeys.1101.77216] [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] [Received: 10/28/2021] [Accepted: 02/08/2022] [Indexed: 11/12/2022] Open
Abstract
Invertebrate immune priming is defined as an enhanced protection against secondary pathogenic infections when individuals have been previously exposed to the same or a different pathogen. Immune priming can be energetically costly for individuals, thus impacting trade-offs between life-history traits, like reproduction, growth, and lifetime. Here, the reproductive cost(s) and senescence patterns of immune priming against S.enterica in the common woodlouse A.vulgare (Crustacea, Isopoda) were investigated. Four different groups of females were used that either (1) have never been injected (control), (2) were injected twice with S.enterica (7 days between infections), (3) were firstly injected with LB-broth, then with S.enterica, and (4) females injected only once with S.enterica. All females were allowed to breed with one non-infected male and were observed for eight months. Then, the number of clutches produced, the time taken to produce the clutch(es), the number of offspring in each clutch, the senescence biomarkers of females, and parameters of their haemocytes were compared. The result was that immune priming did not significantly impact reproductive abilities, senescence patterns, and haemocyte parameters of female A.vulgare, but had an indirect effect through body weight. The lighter immune primed females took less time to produce the first clutch, which contained less offspring, but they were more likely to produce a second clutch. The opposite effects were observed in the heavier immune primed females. By highlighting that immune priming was not as costly as expected in A.vulgare, these results provide new insights into the adaptive nature of this immune process.
Collapse
Affiliation(s)
- Cybèle Prigot-Maurice
- Université de Poitiers, Laboratoire Écologie et Biologie des Interactions, UMR CNRS 7267, 3 rue Jacques Fort, TSA 51106, F-86073 POITIERS Cedex 9, FranceUniversité de PoitiersPoitiersFrance
| | - Charlotte Depeux
- Université de Poitiers, Laboratoire Écologie et Biologie des Interactions, UMR CNRS 7267, 3 rue Jacques Fort, TSA 51106, F-86073 POITIERS Cedex 9, FranceUniversité de PoitiersPoitiersFrance
| | - Hélène Paulhac
- Université de Poitiers, Laboratoire Écologie et Biologie des Interactions, UMR CNRS 7267, 3 rue Jacques Fort, TSA 51106, F-86073 POITIERS Cedex 9, FranceUniversité de PoitiersPoitiersFrance
| | - Christine Braquart-Varnier
- Université de Poitiers, Laboratoire Écologie et Biologie des Interactions, UMR CNRS 7267, 3 rue Jacques Fort, TSA 51106, F-86073 POITIERS Cedex 9, FranceUniversité de PoitiersPoitiersFrance
| | - Sophie Beltran-Bech
- Université de Poitiers, Laboratoire Écologie et Biologie des Interactions, UMR CNRS 7267, 3 rue Jacques Fort, TSA 51106, F-86073 POITIERS Cedex 9, FranceUniversité de PoitiersPoitiersFrance
| |
Collapse
|
10
|
Ahlawat N, Maggu K, Jigisha, Arun MG, Meena A, Agarwala A, Prasad NG. No major cost of evolved survivorship in Drosophila melanogaster populations coevolving with Pseudomonas entomophila. Proc Biol Sci 2022; 289:20220532. [PMID: 35506222 PMCID: PMC9065972 DOI: 10.1098/rspb.2022.0532] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Rapid exaggeration of host and pathogen traits via arms race dynamics is one possible outcome of host-pathogen coevolution. However, the exaggerated traits are expected to incur costs in terms of resource investment in other life-history traits. The current study investigated the costs associated with evolved traits in a host-pathogen coevolution system. We used the Drosophila melanogaster (host)-Pseudomonas entomophila (pathogen) system to experimentally derive two selection regimes, one where the host and pathogen both coevolved, and the other, where only the host evolved against a non-evolving pathogen. After 17 generations of selection, we found that hosts from both selected populations had better post-infection survivorship than controls. Even though the coevolving populations tended to have better survivorship post-infection, we found no clear evidence that the two selection regimes were significantly different from each other. There was weak evidence for the coevolving pathogens being more virulent than the ancestral pathogen. We found no major cost of increased post-infection survivorship. The costs were not different between the coevolving hosts and the hosts evolving against a non-evolving pathogen. We found no evolved costs in the coevolving pathogens. Thus, our results suggest that increased host immunity and pathogen virulence may not be costly.
Collapse
Affiliation(s)
- Neetika Ahlawat
- Department of Biological Sciences, Indian Institute of Science Education and Research Mohali, Sector 81, SAS Nagar, Mohali 140306, India
| | - Komal Maggu
- Department of Biological Sciences, Indian Institute of Science Education and Research Mohali, Sector 81, SAS Nagar, Mohali 140306, India,Department of Evolutionary and Environmental Studies, University of Zürich, Zürich 8057, Switzerland
| | - Jigisha
- Department of Biological Sciences, Indian Institute of Science Education and Research Mohali, Sector 81, SAS Nagar, Mohali 140306, India,Department of Plant and Microbial Biology, University of Zürich, Zürich 8008, Switzerland
| | - Manas Geeta Arun
- Department of Biological Sciences, Indian Institute of Science Education and Research Mohali, Sector 81, SAS Nagar, Mohali 140306, India
| | - Abhishek Meena
- Department of Biological Sciences, Indian Institute of Science Education and Research Mohali, Sector 81, SAS Nagar, Mohali 140306, India,Department of Evolutionary and Environmental Studies, University of Zürich, Zürich 8057, Switzerland
| | - Amisha Agarwala
- Department of Biological Sciences, Indian Institute of Science Education and Research Mohali, Sector 81, SAS Nagar, Mohali 140306, India,Department of Biology, Syracuse University, Syracuse, NY 13210, USA
| | - Nagaraj Guru Prasad
- Department of Biological Sciences, Indian Institute of Science Education and Research Mohali, Sector 81, SAS Nagar, Mohali 140306, India
| |
Collapse
|
11
|
Letendre C, Duffield KR, Sadd BM, Sakaluk SK, House CM, Hunt J. Genetic covariance in immune measures and pathogen resistance in decorated crickets is sex and pathogen specific. J Anim Ecol 2022; 91:1471-1488. [PMID: 35470433 PMCID: PMC9545791 DOI: 10.1111/1365-2656.13709] [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: 12/18/2021] [Accepted: 03/21/2022] [Indexed: 12/05/2022]
Abstract
Insects are important models for studying immunity in an ecological and evolutionary context. Yet, most empirical work on the insect immune system has come from phenotypic studies meaning we have a limited understanding of the genetic architecture of immune function in the sexes. We use nine highly inbred lines to thoroughly examine the genetic relationships between a suite of commonly used immune assays (haemocyte count, implant encapsulation, total phenoloxidase activity, antibacterial zone of inhibition and pathogen clearance) and resistance to infection by three generalist insect pathogens (the gram‐negative bacterium Serratia marcescens, the gram‐positive bacterium Bacillus cereus and the fungus Metarhizium robertsii) in male and female Gryllodes sigillatus. There were consistent positive genetic correlations between haemocyte count, antibacterial and phenoloxidase activity and resistance to S. marcescens in both sexes, but these relationships were less consistent for resistance to B. cereus and M. robertsii. In addition, the clearance of S. marcescens was genetically correlated with the resistance to all three pathogens in both sexes. Genetic correlations between resistances to the different pathogen species were inconsistent, indicating that resistance to one pathogen does not necessarily mean resistance to another. Finally, while there is ample genetic (co)variance in immune assays and pathogen resistance, these genetic estimates differed across the sexes and many of these measures were not genetically correlated across the sexes, suggesting that these measures could evolve independently in the sexes. Our finding that the genetic architecture of immune function is sex and pathogen specific suggests that the evolution of immune function in male and female G. sigillatus is likely to be complex. Similar quantitative genetic studies that measure a large number of assays and resistance to multiple pathogens in both sexes are needed to ascertain if this complexity extends to other species.
Collapse
Affiliation(s)
- Corinne Letendre
- School of Science, Western Sydney University, Hawkesbury Campus, Locked Bag 1797, Richmond, New South Wales, Australia
| | - Kristin R Duffield
- School of Biological Sciences, Illinois State University, Normal, Illinois, United States of America.,Crop Bioprotection Research Unit, National Center for Agricultural Utilization Research, Peoria, IL, United States of America
| | - Ben M Sadd
- School of Biological Sciences, Illinois State University, Normal, Illinois, United States of America
| | - Scott K Sakaluk
- School of Biological Sciences, Illinois State University, Normal, Illinois, United States of America
| | - Clarissa M House
- School of Science, Western Sydney University, Hawkesbury Campus, Locked Bag 1797, Richmond, New South Wales, Australia
| | - John Hunt
- School of Science, Western Sydney University, Hawkesbury Campus, Locked Bag 1797, Richmond, New South Wales, Australia.,Centre for Ecology and Conservation, College of Life and Environmental Sciences, University of Exeter, Tremough Campus, Penryn, Cornwall, United Kingdom
| |
Collapse
|
12
|
Sharda S, Kawecki TJ, Hollis B. Adaptation to a bacterial pathogen in Drosophila melanogaster is not aided by sexual selection. Ecol Evol 2022; 12:e8543. [PMID: 35169448 PMCID: PMC8840902 DOI: 10.1002/ece3.8543] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Revised: 12/12/2021] [Accepted: 12/16/2021] [Indexed: 11/08/2022] Open
Abstract
Theory predicts that sexual selection should aid adaptation to novel environments, but empirical support for this idea is limited. Pathogens are a major driver of host evolution and, unlike abiotic selection pressures, undergo epidemiological and co-evolutionary cycles with the host involving adaptation and counteradaptation. Because of this, populations harbor ample genetic variation underlying immunity and the opportunity for sexual selection based on condition-dependent "good genes" is expected to be large. In this study, we evolved populations of Drosophila melanogaster in a 2-way factorial design manipulating sexual selection and pathogen presence, using a gram-negative insect pathogen Pseudomonas entomophila, for 14 generations. We then examined how the presence of sexual selection and the pathogen, as well as any potential interaction, affected the evolution of pathogen resistance. We found increased resistance to P. entomophila in populations that evolved under pathogen pressure, driven primarily by increased female survival after infection despite selection for resistance acting only on males over the course of experimental evolution. This result suggests that the genetic basis of resistance is in part shared between the sexes. We did not find any evidence of sexual selection aiding adaptation to pathogen, however, a finding contrary to the predictions of "good genes" theory. Our results therefore provide no support for a role for sexual selection in the evolution of immunity in this experimental system.
Collapse
Affiliation(s)
- Sakshi Sharda
- Department of Ecology and EvolutionUniversity of LausanneLausanneSwitzerland
| | - Tadeusz J. Kawecki
- Department of Ecology and EvolutionUniversity of LausanneLausanneSwitzerland
| | - Brian Hollis
- Department of Biological SciencesUniversity of South CarolinaColumbiaSouth CarolinaUSA
| |
Collapse
|
13
|
Prakash A, Agashe D, Khan I. The costs and benefits of basal infection resistance vs immune priming responses in an insect. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2022; 126:104261. [PMID: 34536466 DOI: 10.1016/j.dci.2021.104261] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Revised: 08/31/2021] [Accepted: 09/14/2021] [Indexed: 06/13/2023]
Abstract
In insects, basal pathogen resistance and immune priming can evolve as mutually exclusive strategies, with distinct infection outcomes. However, the evolutionary drivers of such diverse immune functions remain poorly understood. Here, we addressed this key issue by systematically analyzing the differential fitness costs and benefits of priming vs resistance evolution in Tribolium beetle populations infected with Bacillus thuringiensis. Surprisingly, resistant beetles had increased post-infection reproduction and a longer lifespan under both starving as well as fed conditions, with no other measurable costs. In contrast, priming reduced offspring early survival, development rate and reproduction. Priming did improve post-infection survival of offspring, but this added trans-generational benefit of immune priming might not compensate for its pervasive costs. Resistance was thus consistently more beneficial. Overall, our work demonstrates the evolutionary change in trans-generational priming response, and provides a detailed comparison of the complex fitness consequences of evolved priming vs resistance.
Collapse
Affiliation(s)
- Arun Prakash
- National Centre for Biological Sciences, GKVK Campus, Bellary Road, Bangalore, 560065, India
| | - Deepa Agashe
- National Centre for Biological Sciences, GKVK Campus, Bellary Road, Bangalore, 560065, India.
| | - Imroze Khan
- Ashoka University, Plot No. 2, Rajiv Gandhi Education City, P.O. Rai, Sonepat, Haryana, 131029, India.
| |
Collapse
|
14
|
Geeta Arun M, Agarwala A, Syed ZA, Jigisha, Kashyap M, Venkatesan S, Chechi TS, Gupta V, Prasad NG. Experimental evolution reveals sex-specific dominance for surviving bacterial infection in laboratory populations of Drosophila melanogaster. Evol Lett 2021; 5:657-671. [PMID: 34919096 PMCID: PMC8645198 DOI: 10.1002/evl3.259] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2021] [Revised: 08/11/2021] [Accepted: 08/13/2021] [Indexed: 01/14/2023] Open
Abstract
Males and females are subjected to distinct kinds of selection pressures, often leading to the evolution of sex‐specific genetic architecture, an example being sex‐specific dominance. Sex‐specific dominance reversals (SSDRs), where alleles at sexually antagonistic loci are at least partially dominant in the sex they benefit, have been documented in Atlantic salmon, rainbow trout, and seed beetles. Another interesting feature of many sexually reproducing organisms is the asymmetric inheritance pattern of X chromosomes, which often leads to distinct evolutionary outcomes on X chromosomes compared to autosomes. Examples include the higher efficacy of sexually concordant selection on X chromosomes, and X chromosomes being more conducive to the maintenance of sexually antagonistic polymorphisms under certain conditions. Immunocompetence is a trait that has been extensively investigated for sexual dimorphism with growing evidence for sex‐specific or sexually antagonistic variation. X chromosomes have been shown to harbor substantial immunity‐related genetic variation in the fruit fly, Drosophila melanogaster. Here, using interpopulation crosses and cytogenetic cloning, we investigated sex‐specific dominance and the role of the X chromosome in improved postinfection survivorship of laboratory populations of D. melanogaster selected against pathogenic challenge by Pseudomonas entomophila. We could not detect any contribution of the X chromosome to the evolved immunocompetence of our selected populations, as well as to within‐population variation in immunocompetence. However, we found strong evidence of sex‐specific dominance related to surviving bacterial infection. Our results indicate that alleles that confer a survival advantage to the selected populations are, on average, partially dominant in females but partially recessive in males. This could also imply an SSDR for overall fitness, given the putative evidence for sexually antagonistic selection affecting immunocompetence in Drosophila melanogaster. We also highlight sex‐specific dominance as a potential mechanism of sex differences in immunocompetence, with population‐level sex differences primarily driven by sex differences in heterozygotes.
Collapse
Affiliation(s)
- Manas Geeta Arun
- Department of Biological Sciences Indian Institute of Science Education and Research Mohali Mohali 140306 India
| | - Amisha Agarwala
- Department of Biological Sciences Indian Institute of Science Education and Research Mohali Mohali 140306 India.,Department of Biology Syracuse University Syracuse New York 13210
| | - Zeeshan Ali Syed
- Department of Biological Sciences Indian Institute of Science Education and Research Mohali Mohali 140306 India.,Department of Biology Syracuse University Syracuse New York 13210
| | - Jigisha
- Department of Biological Sciences Indian Institute of Science Education and Research Mohali Mohali 140306 India
| | - Mayank Kashyap
- Department of Biological Sciences Indian Institute of Science Education and Research Mohali Mohali 140306 India
| | - Saudamini Venkatesan
- Department of Biological Sciences Indian Institute of Science Education and Research Mohali Mohali 140306 India.,Institute of Evolutionary Biology, School of Biological Sciences, King's Buildings University of Edinburgh Edinburgh EH9 3FL United Kingdom
| | - Tejinder Singh Chechi
- Department of Biological Sciences Indian Institute of Science Education and Research Mohali Mohali 140306 India
| | - Vanika Gupta
- Department of Biological Sciences Indian Institute of Science Education and Research Mohali Mohali 140306 India.,Department of Entomology Cornell University Ithaca New York 14853
| | - Nagaraj Guru Prasad
- Department of Biological Sciences Indian Institute of Science Education and Research Mohali Mohali 140306 India
| |
Collapse
|
15
|
Shahrestani P, King E, Ramezan R, Phillips M, Riddle M, Thornburg M, Greenspan Z, Estrella Y, Garcia K, Chowdhury P, Malarat G, Zhu M, Rottshaefer SM, Wraight S, Griggs M, Vandenberg J, Long AD, Clark AG, Lazzaro BP. The molecular architecture of Drosophila melanogaster defense against Beauveria bassiana explored through evolve and resequence and quantitative trait locus mapping. G3-GENES GENOMES GENETICS 2021; 11:6371870. [PMID: 34534291 PMCID: PMC8664422 DOI: 10.1093/g3journal/jkab324] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Accepted: 08/17/2021] [Indexed: 12/02/2022]
Abstract
Little is known about the genetic architecture of antifungal immunity in natural populations. Using two population genetic approaches, quantitative trait locus (QTL) mapping and evolve and resequence (E&R), we explored D. melanogaster immune defense against infection with the fungus Beauveria bassiana. The immune defense was highly variable both in the recombinant inbred lines from the Drosophila Synthetic Population Resource used for our QTL mapping and in the synthetic outbred populations used in our E&R study. Survivorship of infection improved dramatically over just 10 generations in the E&R study, and continued to increase for an additional nine generations, revealing a trade-off with uninfected longevity. Populations selected for increased defense against B. bassiana evolved cross resistance to a second, distinct B. bassiana strain but not to bacterial pathogens. The QTL mapping study revealed that sexual dimorphism in defense depends on host genotype, and the E&R study indicated that sexual dimorphism also depends on the specific pathogen to which the host is exposed. Both the QTL mapping and E&R experiments generated lists of potentially causal candidate genes, although these lists were nonoverlapping.
Collapse
Affiliation(s)
- Parvin Shahrestani
- Department of Biological Science, California State University Fullerton, Fullerton CA, 92831, USA
| | - Elizabeth King
- Division of Biological Sciences, University of Missouri, Columbia MO, 65211, USA
| | - Reza Ramezan
- Department of Statistics and Actuarial Science, University of Waterloo, Waterloo ON, N2L 3G1, Canada
| | - Mark Phillips
- Department of Integrative Biology, Oregon State University, Corvallis OR, 97331, USA
| | - Melissa Riddle
- Department of Biological Science, California State University Fullerton, Fullerton CA, 92831, USA
| | - Marisa Thornburg
- Department of Biological Science, California State University Fullerton, Fullerton CA, 92831, USA
| | - Zachary Greenspan
- Department of Ecology and Evolutionary Biology, University of California Irvine, Irvine CA, 92692, USA
| | | | - Kelly Garcia
- Department of Entomology, Cornell University, Ithaca NY, 14853, USA
| | - Pratik Chowdhury
- Department of Entomology, Cornell University, Ithaca NY, 14853, USA
| | - Glen Malarat
- Department of Entomology, Cornell University, Ithaca NY, 14853, USA
| | - Ming Zhu
- Department of Entomology, Cornell University, Ithaca NY, 14853, USA
| | | | - Stephen Wraight
- USDA ARS Emerging Pets and Pathogens Research Unit, Robert W. Holley Center for Agriculture & Health, Ithaca NY, 14853, USA
| | - Michael Griggs
- USDA ARS Emerging Pets and Pathogens Research Unit, Robert W. Holley Center for Agriculture & Health, Ithaca NY, 14853, USA
| | - John Vandenberg
- USDA ARS Emerging Pets and Pathogens Research Unit, Robert W. Holley Center for Agriculture & Health, Ithaca NY, 14853, USA
| | - Anthony D Long
- Department of Ecology and Evolutionary Biology, University of California Irvine, Irvine CA, 92692, USA
| | - Andrew G Clark
- Department of Molecular Biology and Genetics, Cornell University, Ithaca NY, 14853, USA
| | - Brian P Lazzaro
- Department of Entomology, Cornell University, Ithaca NY, 14853, USA
| |
Collapse
|
16
|
Ahlawat N, Geeta Arun M, Maggu K, Prasad NG. Enemies make you stronger: Coevolution between fruit fly host and bacterial pathogen increases postinfection survivorship in the host. Ecol Evol 2021; 11:9563-9574. [PMID: 34306643 PMCID: PMC8293768 DOI: 10.1002/ece3.7774] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Revised: 05/01/2021] [Accepted: 05/11/2021] [Indexed: 11/16/2022] Open
Abstract
Multiple laboratory studies have evolved hosts against a nonevolving pathogen to address questions about evolution of immune responses. However, an ecologically more relevant scenario is one where hosts and pathogens can coevolve. Such coevolution between the antagonists, depending on the mutual selection pressure and additive variance in the respective populations, can potentially lead to a different pattern of evolution in the hosts compared to a situation where the host evolves against a nonevolving pathogen. In the present study, we used Drosophila melanogaster as the host and Pseudomonas entomophila as the pathogen. We let the host populations either evolve against a nonevolving pathogen or coevolve with the same pathogen. We found that the coevolving hosts on average evolved higher survivorship against the coevolving pathogen and ancestral (nonevolving) pathogen relative to the hosts evolving against a nonevolving pathogen. The coevolving pathogens evolved greater ability to induce host mortality even in nonlocal (novel) hosts compared to infection by an ancestral (nonevolving) pathogen. Thus, our results clearly show that the evolved traits in the host and the pathogen under coevolution can be different from one-sided adaptation. In addition, our results also show that the coevolving host-pathogen interactions can involve certain general mechanisms in the pathogen, leading to increased mortality induction in nonlocal or novel hosts.
Collapse
Affiliation(s)
- Neetika Ahlawat
- Department of Biological SciencesIndian Institute of Science Education and Research MohaliMohaliIndia
| | - Manas Geeta Arun
- Department of Biological SciencesIndian Institute of Science Education and Research MohaliMohaliIndia
| | - Komal Maggu
- Department of Biological SciencesIndian Institute of Science Education and Research MohaliMohaliIndia
| | - Nagaraj Guru Prasad
- Department of Biological SciencesIndian Institute of Science Education and Research MohaliMohaliIndia
| |
Collapse
|
17
|
Bartlett LJ, Visher E, Haro Y, Roberts KE, Boots M. The target of selection matters: An established resistance-development-time negative genetic trade-off is not found when selecting on development time. J Evol Biol 2020; 33:1109-1119. [PMID: 32390292 DOI: 10.1111/jeb.13639] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2019] [Revised: 04/22/2020] [Accepted: 05/02/2020] [Indexed: 11/30/2022]
Abstract
Trade-offs are fundamental to evolutionary outcomes and play a central role in eco-evolutionary theory. They are often examined by experimentally selecting on one life-history trait and looking for negative correlations in other traits. For example, populations of the moth Plodia interpunctella selected to resist viral infection show a life-history cost with longer development times. However, we rarely examine whether the detection of such negative genetic correlations depends on the trait on which we select. Here, we examine a well-characterized negative genotypic trade-off between development time and resistance to viral infection in the moth Plodia interpunctella and test whether selection on a phenotype known to be a cost of resistance (longer development time) leads to the predicted correlated increase in resistance. If there is tight pleiotropic relationship between genes that determine development time and resistance underpinning this trade-off, we might expect increased resistance when we select on longer development time. However, we show that selecting for longer development time in this system selects for reduced resistance when compared to selection for shorter development time. This shows how phenotypes typically characterized by a trade-off can deviate from that trade-off relationship, and suggests little genetic linkage between the genes governing viral resistance and those that determine response to selection on the key life-history trait. Our results are important for both selection strategies in applied biological systems and for evolutionary modelling of host-parasite interactions.
Collapse
Affiliation(s)
- Lewis J Bartlett
- Centre for Ecology and Conservation, College of Life and Environmental Sciences, University of Exeter, Penryn, UK
- Center for the Ecology of Infectious Diseases, University of Georgia, Athens, GA, USA
| | - Elisa Visher
- Department of Integrative Biology, University of California, Berkeley, CA, USA
| | | | - Katherine E Roberts
- Centre for Ecology and Conservation, College of Life and Environmental Sciences, University of Exeter, Penryn, UK
| | - Mike Boots
- Centre for Ecology and Conservation, College of Life and Environmental Sciences, University of Exeter, Penryn, UK
- Department of Integrative Biology, University of California, Berkeley, CA, USA
| |
Collapse
|
18
|
Joye P, Kawecki TJ. Sexual selection favours good or bad genes for pathogen resistance depending on males' pathogen exposure. Proc Biol Sci 2020; 286:20190226. [PMID: 31064300 DOI: 10.1098/rspb.2019.0226] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Resistance to pathogens is often invoked as an indirect benefit of female choice, but experimental evidence for links between father's sexual success and offspring resistance is scarce and equivocal. Two proposed mechanisms might generate such links. Under the first, heritable resistance to diverse pathogens depends on general immunocompetence; owing to shared condition dependence, male sexual traits indicate immunocompetence independently of the male's pathogen exposure. By contrast, other hypotheses (e.g. Hamilton-Zuk) assume that sexual traits only reveal heritable resistance if the males have been exposed to the pathogen. The distinction between the two mechanisms has been neglected by experimental studies. We show that Drosophila melanogaster males that are successful in mating contests (one female with two males) sire sons that are substantially more resistant to the intestinal pathogen Pseudomonas entomophila-but only if the males have themselves been exposed to the pathogen before the mating contest. By contrast, sons of males sexually successful in the absence of pathogen exposure are less resistant than sons of unsuccessful males. We detected no differences in daughters' resistance. Thus, while sexual selection may have considerable consequences for offspring resistance, these consequences may be sex-specific. Furthermore, contrary to the 'general immunocompetence' hypothesis, these consequences can be positive or negative depending on the epidemiological context under which sexual selection operates.
Collapse
Affiliation(s)
- Patrick Joye
- Department of Ecology and Evolution, University of Lausanne , 1015 Lausanne , Switzerland
| | - Tadeusz J Kawecki
- Department of Ecology and Evolution, University of Lausanne , 1015 Lausanne , Switzerland
| |
Collapse
|
19
|
Absence of reproduction-immunity trade-off in male Drosophila melanogaster evolving under differential sexual selection. BMC Evol Biol 2020; 20:13. [PMID: 31992187 PMCID: PMC6988192 DOI: 10.1186/s12862-019-1574-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Accepted: 12/30/2019] [Indexed: 11/24/2022] Open
Abstract
Background The theory of trade-off suggests that limited resources should lead to trade-off in resource intensive traits such as, immunity related and sexually selected traits in males. Alternatively, sexual exaggerations can also act as an honest indicator of underlying immunocompetence, leading to positive correlations between these traits. Evidences in support of either hypothesis in invertebrates are equivocal. Whereas several studies have addressed this question, few have used naturally occurring pathogens and realized post infection realized immunity (e.g., survivorship) to assay the fitness correlations between these two sets of traits. Results Adopting an experimental evolution approach, we evolved replicate populations of Drosophila melanogaster under high and low sexual selection regimes for over a hundred generations and found the following in virgin and mated males in three separate assays:
Post infection survivorship against two natural pathogens - Pseudomonas entomophila (Pe) and Staphylococcus succinus (Ss): Mated males survived better against Pe, but were no different than virgins against Ss. Bacterial clearance ability against a third natural pathogen Providencia rettgeri (Pr): Mated males had significantly lower CFUs than virgins.
However, sexual selection history had no effect on realized immunity of either virgin or mated males. Conclusion We show that while mating can affect realized immunity in a pathogen specific way, sexual selection did not affect the same. The results highlight that complex polygenic traits such as immunity and reproductive traits not necessarily evolve following a binary trade-off model. We also stress the importance natural pathogens while studying sexual selection-immunity correlations.
Collapse
|
20
|
Kawecki TJ. Sexual selection reveals a cost of pathogen resistance undetected in life-history assays. Evolution 2019; 74:338-348. [PMID: 31814118 PMCID: PMC7028033 DOI: 10.1111/evo.13895] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2019] [Accepted: 11/15/2019] [Indexed: 01/21/2023]
Abstract
Mechanisms of resistance to pathogens and parasites are thought to be costly and thus to lead to evolutionary trade‐offs between resistance and life‐history traits expressed in the absence of the infective agents. On the other hand, sexually selected traits are often proposed to indicate “good genes” for resistance, which implies a positive genetic correlation between resistance and success in sexual selection. Here I show that experimental evolution of improved resistance to the intestinal pathogen Pseudomonas entomophila in Drosophila melanogaster was associated with a reduction in male sexual success. Males from four resistant populations achieved lower paternity than males from four susceptible control populations in competition with males from a competitor strain, indicating an evolutionary cost of resistance in terms of mating success and/or sperm competition. In contrast, no costs were found in larval viability, larval competitive ability and population productivity assayed under nutritional limitation; together with earlier studies this suggests that the costs of P. entomophila resistance for nonsexual fitness components are negligible. Thus, rather than indicating heritable pathogen resistance, sexually selected traits expressed in the absence of pathogens may be sensitive to costs of resistance, even if no such costs are detected in other fitness traits.
Collapse
Affiliation(s)
- Tadeusz J Kawecki
- Department of Ecology and Evolution, University of Lausanne, CH 1015, Lausanne, Switzerland
| |
Collapse
|
21
|
Woestmann L, Stucki D, Saastamoinen M. Life history alterations upon oral and hemocoelic bacterial exposure in the butterfly Melitaea cinxia. Ecol Evol 2019; 9:10665-10680. [PMID: 31624574 PMCID: PMC6787844 DOI: 10.1002/ece3.5586] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Revised: 07/29/2019] [Accepted: 07/30/2019] [Indexed: 11/11/2022] Open
Abstract
Life history strategies often shape biological interactions by specifying the parameters for possible encounters, such as the timing, frequency, or way of exposure to parasites. Consequentially, alterations in life-history strategies are closely intertwined with such interaction processes. Understanding the connection between life-history alterations and host-parasite interactions can therefore be important to unveil potential links between adaptation to environmental change and changes in interaction processes. Here, we studied how two different host-parasite interaction processes, oral and hemocoelic exposure to bacteria, affect various life histories of the Glanville fritillary butterfly Melitaea cinxia. We either fed or injected adult butterflies with the bacterium Micrococcus luteus and observed for differences in immune defenses, reproductive life histories, and longevity, compared to control exposures. Our results indicate differences in how female butterflies adapt to the two exposure types. Orally infected females showed a reduction in clutch size and an earlier onset of reproduction, whereas a reduction in egg weight was observed for hemocoelically exposed females. Both exposure types also led to shorter intervals between clutches and a reduced life span. These results indicate a relationship between host-parasite interactions and changes in life-history strategies. This relationship could cast restrictions on the ability to adapt to new environments and consequentially influence the population dynamics of a species in changing environmental conditions.
Collapse
Affiliation(s)
- Luisa Woestmann
- Organismal and Evolutionary Biology Research ProgrammeFaculty of Biological and Environmental SciencesUniversity of HelsinkiHelsinkiFinland
| | - Dimitri Stucki
- Organismal and Evolutionary Biology Research ProgrammeFaculty of Biological and Environmental SciencesUniversity of HelsinkiHelsinkiFinland
| | - Marjo Saastamoinen
- Organismal and Evolutionary Biology Research ProgrammeFaculty of Biological and Environmental SciencesUniversity of HelsinkiHelsinkiFinland
| |
Collapse
|
22
|
Duxbury EML, Day JP, Maria Vespasiani D, Thüringer Y, Tolosana I, Smith SCL, Tagliaferri L, Kamacioglu A, Lindsley I, Love L, Unckless RL, Jiggins FM, Longdon B. Host-pathogen coevolution increases genetic variation in susceptibility to infection. eLife 2019; 8:e46440. [PMID: 31038124 PMCID: PMC6491035 DOI: 10.7554/elife.46440] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2019] [Accepted: 04/07/2019] [Indexed: 12/31/2022] Open
Abstract
It is common to find considerable genetic variation in susceptibility to infection in natural populations. We have investigated whether natural selection increases this variation by testing whether host populations show more genetic variation in susceptibility to pathogens that they naturally encounter than novel pathogens. In a large cross-infection experiment involving four species of Drosophila and four host-specific viruses, we always found greater genetic variation in susceptibility to viruses that had coevolved with their host. We went on to examine the genetic architecture of resistance in one host species, finding that there are more major-effect genetic variants in coevolved host-pathogen interactions. We conclude that selection by pathogens has increased genetic variation in host susceptibility, and much of this effect is caused by the occurrence of major-effect resistance polymorphisms within populations.
Collapse
Affiliation(s)
- Elizabeth ML Duxbury
- Department of GeneticsUniversity of CambridgeCambridgeUnited Kingdom
- School of Biological SciencesUniversity of East AngliaNorwichUnited Kingdom
| | - Jonathan P Day
- Department of GeneticsUniversity of CambridgeCambridgeUnited Kingdom
| | | | - Yannik Thüringer
- Department of GeneticsUniversity of CambridgeCambridgeUnited Kingdom
| | - Ignacio Tolosana
- Department of GeneticsUniversity of CambridgeCambridgeUnited Kingdom
| | - Sophia CL Smith
- Department of GeneticsUniversity of CambridgeCambridgeUnited Kingdom
| | - Lucia Tagliaferri
- Department of GeneticsUniversity of CambridgeCambridgeUnited Kingdom
| | - Altug Kamacioglu
- Department of GeneticsUniversity of CambridgeCambridgeUnited Kingdom
| | - Imogen Lindsley
- Department of GeneticsUniversity of CambridgeCambridgeUnited Kingdom
| | - Luca Love
- Department of GeneticsUniversity of CambridgeCambridgeUnited Kingdom
| | - Robert L Unckless
- Department of Molecular BiosciencesUniversity of KansasLawrenceUnited States
| | - Francis M Jiggins
- Department of GeneticsUniversity of CambridgeCambridgeUnited Kingdom
| | - Ben Longdon
- Department of GeneticsUniversity of CambridgeCambridgeUnited Kingdom
- Centre for Ecology and Conservation, BiosciencesUniversity of Exeter (Penryn Campus)CornwallUnited Kingdom
| |
Collapse
|
23
|
Faria VG, Martins NE, Schlötterer C, Sucena É. Readapting to DCV Infection without Wolbachia: Frequency Changes of Drosophila Antiviral Alleles Can Replace Endosymbiont Protection. Genome Biol Evol 2018; 10:1783-1791. [PMID: 29947761 PMCID: PMC6054199 DOI: 10.1093/gbe/evy137] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/25/2018] [Indexed: 12/19/2022] Open
Abstract
There is now ample evidence that endosymbionts can contribute to host adaptation to environmental challenges. However, how endosymbiont presence affects the adaptive trajectory and outcome of the host is yet largely unexplored. In Drosophila, Wolbachia confers protection to RNA virus infection, an effect that differs between Wolbachia strains and can be targeted by selection. Adaptation to RNA virus infections is mediated by both Wolbachia and the host, raising the question of whether adaptive genetic changes in the host vary with the presence/absence of the endosymbiont. Here, we address this question using a polymorphic D. melanogaster population previously adapted to DCV infection for 35 generations in the presence of Wolbachia, from which we removed the endosymbiont and followed survival over the subsequent 20 generations of infection. After an initial severe drop, survival frequencies upon DCV selection increased significantly, as seen before in the presence of Wolbachia. Whole-genome sequencing, revealed that the major genes involved in the first selection experiment, pastrel and Ubc-E2H, continued to be selected in Wolbachia-free D. melanogaster, with the frequencies of protective alleles being closer to fixation in the absence of Wolbachia. Our results suggest that heterogeneity in Wolbachia infection status may be sufficient to maintain polymorphisms even in the absence of costs.
Collapse
Affiliation(s)
- Vitor G Faria
- Instituto Gulbenkian de Ciência, Rua da quinta grande 6, 2780-156 Oeiras, Portugal.,Zoological Institute, Basel University, Basel, Switzerland
| | - Nelson E Martins
- Instituto Gulbenkian de Ciência, Rua da quinta grande 6, 2780-156 Oeiras, Portugal.,CNRS UPR9022, Institut de Biologie Moléculaire et Cellulaire, Université de Strasbourg, Strasbourg, France
| | - Christian Schlötterer
- Institut für Populationsgenetik, Vetmeduni Vienna, Veterinärplatz 1, 1210 Wien, Austria
| | - Élio Sucena
- Instituto Gulbenkian de Ciência, Rua da quinta grande 6, 2780-156 Oeiras, Portugal.,Departamento de Biologia Animal, edifício C2, Faculdade de Ciências, Universidade de Lisboa, Portugal
| |
Collapse
|
24
|
Penley MJ, Greenberg AB, Khalid A, Namburar SR, Morran LT. No measurable fitness cost to experimentally evolved host defence in the Caenorhabditis elegans-Serratia marcescens
host-parasite system. J Evol Biol 2018; 31:1976-1981. [DOI: 10.1111/jeb.13372] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2018] [Revised: 07/27/2018] [Accepted: 08/24/2018] [Indexed: 11/30/2022]
Affiliation(s)
| | | | - Arooj Khalid
- Department of Biology; Emory University; Atlanta GA USA
| | | | | |
Collapse
|
25
|
Khan I, Prakash A, Agashe D. Experimental evolution of insect immune memory versus pathogen resistance. Proc Biol Sci 2018; 284:rspb.2017.1583. [PMID: 29237849 DOI: 10.1098/rspb.2017.1583] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2017] [Accepted: 11/13/2017] [Indexed: 12/13/2022] Open
Abstract
Under strong pathogen pressure, insects often evolve resistance to infection. Many insects are also protected via immune memory (immune priming), whereby sublethal exposure to a pathogen enhances survival after secondary infection. Theory predicts that immune memory should evolve when the pathogen is highly virulent, or when pathogen exposure is relatively rare. However, there are no empirical tests of these hypotheses, and the adaptive benefits of immune memory relative to direct resistance against a pathogen are poorly understood. To determine the selective pressures and ecological conditions that shape immune evolution, we imposed strong pathogen selection on flour beetle (Tribolium castaneum) populations, infecting them with Bacillus thuringiensis (Bt) for 11 generations. Populations injected first with heat-killed and then live Bt evolved high basal resistance against multiple Bt strains. By contrast, populations injected only with a high dose of live Bt evolved a less effective but strain-specific priming response. Control populations injected with heat-killed Bt did not evolve priming; and in the ancestor, priming was effective only against a low Bt dose. Intriguingly, one replicate population first evolved priming and subsequently evolved basal resistance, suggesting the potential for dynamic evolution of different immune strategies. Our work is the first report showing that pathogens can select for rapid modulation of insect priming ability, allowing hosts to evolve divergent immune strategies (generalized resistance versus specific immune memory) with potentially distinct mechanisms.
Collapse
Affiliation(s)
- Imroze Khan
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, GKVK, Bellary Road, Bangalore 560065, India .,Ashoka University, Plot No. 2, Rajiv Gandhi Education City, National Capital Region, P.O. Rai, Sonepat, Haryana 131029, India
| | - Arun Prakash
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, GKVK, Bellary Road, Bangalore 560065, India
| | - Deepa Agashe
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, GKVK, Bellary Road, Bangalore 560065, India
| |
Collapse
|
26
|
Cross-Resistance: A Consequence of Bi-partite Host-Parasite Coevolution. INSECTS 2018; 9:insects9010028. [PMID: 29495405 PMCID: PMC5872293 DOI: 10.3390/insects9010028] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/28/2017] [Revised: 02/02/2018] [Accepted: 02/19/2018] [Indexed: 12/26/2022]
Abstract
Host-parasite coevolution can influence interactions of the host and parasite with the wider ecological community. One way that this may manifest is in cross-resistance towards other parasites, which has been observed to occur in some host-parasite evolution experiments. In this paper, we test for cross-resistance towards Bacillus thuringiensis and Pseudomonasentomophila in the red flour beetle Triboliumcastaneum, which was previously allowed to coevolve with the generalist entomopathogenic fungus Beauveriabassiana. We combine survival and gene expression assays upon infection to test for cross-resistance and underlying mechanisms. We show that larvae of T.castaneum that evolved with B.bassiana under coevolutionary conditions were positively cross-resistant to the bacterium B. thuringiensis, but not P.entomophila. Positive cross-resistance was mirrored at the gene expression level with markers that were representative of the oral route of infection being upregulated upon B.bassiana exposure. We find that positive cross-resistance towards B. thuringiensis evolved in T.castaneum as a consequence of its coevolutionary interactions with B.bassiana. This cross-resistance appears to be a consequence of resistance to oral toxicity. The fact that coevolution with B.bassiana results in resistance to B. thuringiensis, but not P.entomophila implies that B. thuringiensis and B.bassiana may share mechanisms of infection or toxicity not shared by P.entomophila. This supports previous suggestions that B.bassiana may possess Cry-like toxins, similar to those found in B. thuringiensis, which allow it to infect orally.
Collapse
|
27
|
Panchenko PL, Kornilova MB, Perfilieva KS, Markov AV. Contribution of symbiotic microbiota to adaptation of Drosophila melanogaster to an unfavorable growth medium. BIOL BULL+ 2017. [DOI: 10.1134/s1062359017040100] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
|
28
|
Complex Coding and Regulatory Polymorphisms in a Restriction Factor Determine the Susceptibility of Drosophila to Viral Infection. Genetics 2017. [PMID: 28630113 PMCID: PMC5560813 DOI: 10.1534/genetics.117.201970] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
It is common to find that major-effect genes are an important cause of variation in susceptibility to infection. Here we have characterized natural variation in a gene called pastrel that explains over half of the genetic variance in susceptibility to the Drosophila C virus (DCV) in populations of Drosophila melanogaster We found extensive allelic heterogeneity, with a sample of seven alleles of pastrel from around the world conferring four phenotypically distinct levels of resistance. By modifying candidate SNPs in transgenic flies, we show that the largest effect is caused by an amino acid polymorphism that arose when an ancestral threonine was mutated to alanine, greatly increasing resistance to DCV. Overexpression of the ancestral, susceptible allele provides strong protection against DCV; indicating that this mutation acted to improve an existing restriction factor. The pastrel locus also contains complex structural variation and cis-regulatory polymorphisms altering gene expression. We find that higher expression of pastrel is associated with increased survival after DCV infection. To understand why this variation is maintained in populations, we investigated genetic variation surrounding the amino acid variant that is causing flies to be resistant. We found no evidence of natural selection causing either recent changes in allele frequency or geographical variation in frequency, suggesting that this is an old polymorphism that has been maintained at a stable frequency. Overall, our data demonstrate how complex genetic variation at a single locus can control susceptibility to a virulent natural pathogen.
Collapse
|
29
|
Faria VG, Sucena É. From Nature to the Lab: Establishing Drosophila Resources for Evolutionary Genetics. Front Ecol Evol 2017. [DOI: 10.3389/fevo.2017.00061] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
|
30
|
Trinder M, Daisley BA, Dube JS, Reid G. Drosophila melanogaster as a High-Throughput Model for Host-Microbiota Interactions. Front Microbiol 2017; 8:751. [PMID: 28503170 PMCID: PMC5408076 DOI: 10.3389/fmicb.2017.00751] [Citation(s) in RCA: 57] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2017] [Accepted: 04/12/2017] [Indexed: 01/14/2023] Open
Abstract
Microbiota research often assumes that differences in abundance and identity of microorganisms have unique influences on host physiology. To test this concept mechanistically, germ-free mice are colonized with microbial communities to assess causation. Due to the cost, infrastructure challenges, and time-consuming nature of germ-free mouse models, an alternative approach is needed to investigate host–microbial interactions. Drosophila melanogaster (fruit flies) can be used as a high throughput in vivo screening model of host–microbiome interactions as they are affordable, convenient, and replicable. D. melanogaster were essential in discovering components of the innate immune response to pathogens. However, axenic D. melanogaster can easily be generated for microbiome studies without the need for ethical considerations. The simplified microbiota structure enables researchers to evaluate permutations of how each microbial species within the microbiota contribute to host phenotypes of interest. This enables the possibility of thorough strain-level analysis of host and microbial properties relevant to physiological outcomes. Moreover, a wide range of mutant D. melanogaster strains can be affordably obtained from public stock centers. Given this, D. melanogaster can be used to identify candidate mechanisms of host–microbe symbioses relevant to pathogen exclusion, innate immunity modulation, diet, xenobiotics, and probiotic/prebiotic properties in a high throughput manner. This perspective comments on the most promising areas of microbiota research that could immediately benefit from using the D. melanogaster model.
Collapse
Affiliation(s)
- Mark Trinder
- Centre for Human Microbiome and Probiotic Research, Lawson Health Research Institute, St. Joseph's Health Care London, LondonON, Canada.,Schulich School of Medicine and Dentistry, Department of Microbiology and Immunology, University of Western Ontario, LondonON, Canada
| | - Brendan A Daisley
- Centre for Human Microbiome and Probiotic Research, Lawson Health Research Institute, St. Joseph's Health Care London, LondonON, Canada.,Schulich School of Medicine and Dentistry, Department of Microbiology and Immunology, University of Western Ontario, LondonON, Canada
| | - Josh S Dube
- Centre for Human Microbiome and Probiotic Research, Lawson Health Research Institute, St. Joseph's Health Care London, LondonON, Canada.,Schulich School of Medicine and Dentistry, Department of Microbiology and Immunology, University of Western Ontario, LondonON, Canada
| | - Gregor Reid
- Centre for Human Microbiome and Probiotic Research, Lawson Health Research Institute, St. Joseph's Health Care London, LondonON, Canada.,Schulich School of Medicine and Dentistry, Department of Microbiology and Immunology, University of Western Ontario, LondonON, Canada.,Schulich School of Medicine and Dentistry, Department of Surgery, University of Western Ontario, LondonON, Canada
| |
Collapse
|
31
|
Martinez J, Cogni R, Cao C, Smith S, Illingworth CJR, Jiggins FM. Addicted? Reduced host resistance in populations with defensive symbionts. Proc Biol Sci 2016; 283:20160778. [PMID: 27335421 PMCID: PMC4936038 DOI: 10.1098/rspb.2016.0778] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2016] [Accepted: 05/20/2016] [Indexed: 12/28/2022] Open
Abstract
Heritable symbionts that protect their hosts from pathogens have been described in a wide range of insect species. By reducing the incidence or severity of infection, these symbionts have the potential to reduce the strength of selection on genes in the insect genome that increase resistance. Therefore, the presence of such symbionts may slow down the evolution of resistance. Here we investigated this idea by exposing Drosophila melanogaster populations to infection with the pathogenic Drosophila C virus (DCV) in the presence or absence of Wolbachia, a heritable symbiont of arthropods that confers protection against viruses. After nine generations of selection, we found that resistance to DCV had increased in all populations. However, in the presence of Wolbachia the resistant allele of pastrel-a gene that has a major effect on resistance to DCV-was at a lower frequency than in the symbiont-free populations. This finding suggests that defensive symbionts have the potential to hamper the evolution of insect resistance genes, potentially leading to a state of evolutionary addiction where the genetically susceptible insect host mostly relies on its symbiont to fight pathogens.
Collapse
Affiliation(s)
- Julien Martinez
- Department of Genetics, University of Cambridge, Cambridge, UK
| | - Rodrigo Cogni
- Department of Genetics, University of Cambridge, Cambridge, UK Departamento de Ecologia, Instituto de Biociências, Universidade de São Paulo, 05508 900 São Paulo, SP, Brazil
| | - Chuan Cao
- Department of Genetics, University of Cambridge, Cambridge, UK
| | - Sophie Smith
- Department of Genetics, University of Cambridge, Cambridge, UK
| | | | | |
Collapse
|
32
|
Sinam YM, Chatterjee A, Ranjini MS, Poojari A, Nagarajan A, Ramachandra NB, Nongthomba U. A newly evolved Drosophila Cytorace-9 shows trade-off between longevity and immune response. INFECTION GENETICS AND EVOLUTION 2016; 44:1-7. [PMID: 27306321 DOI: 10.1016/j.meegid.2016.06.025] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2015] [Revised: 06/02/2016] [Accepted: 06/09/2016] [Indexed: 10/21/2022]
Abstract
Species with an efficient immune system would be at an advantage to evade pathogenic challenges and adapt to an ever changing ecological niche. The upkeep of immunity is a costly affair, thus trade-offs between immunity and other life history traits are expected. However, studies on the relation between immunity and life span have yielded paradoxical results. Drosophila Cytoraces, being at different stages of evolutionary divergence, provide an excellent experimental model system to study how evolving populations gain novel traits in the absence of selection. We found that in the absence of pathogenic infections, the Cytorace-9 flies lived longer than those of Cytorace-3. However, when these Cytoraces were challenged with different pathogenic microbes, the trend was opposite. After infection with pathogens, the long-lived Cytorace-9 survived worse than the short lived Cytorace-3, which can be attributed to a reduction in its immune response. This study provides evidence to support the existence of a trade-off between life span and immunity.
Collapse
Affiliation(s)
- Yoirentomba Meetei Sinam
- Department of Molecular Reproduction, Development and Genetics, Indian Institute of Science, Bengaluru 560 012, India
| | - Arunita Chatterjee
- Department of Molecular Reproduction, Development and Genetics, Indian Institute of Science, Bengaluru 560 012, India
| | - Mysore S Ranjini
- Unit on Evolution and Genetics Laboratory, Department of Studies in Genetics and Genomics, University of Mysore, Manasagangotri, Mysuru 570 006, India
| | - Adarsh Poojari
- Unit on Evolution and Genetics Laboratory, Department of Studies in Genetics and Genomics, University of Mysore, Manasagangotri, Mysuru 570 006, India
| | - Aarthi Nagarajan
- Department of Molecular Reproduction, Development and Genetics, Indian Institute of Science, Bengaluru 560 012, India
| | - Nallur B Ramachandra
- Unit on Evolution and Genetics Laboratory, Department of Studies in Genetics and Genomics, University of Mysore, Manasagangotri, Mysuru 570 006, India
| | - Upendra Nongthomba
- Department of Molecular Reproduction, Development and Genetics, Indian Institute of Science, Bengaluru 560 012, India.
| |
Collapse
|
33
|
Gupta V, Venkatesan S, Chatterjee M, Syed ZA, Nivsarkar V, Prasad NG. No apparent cost of evolved immune response in Drosophila melanogaster. Evolution 2016; 70:934-43. [PMID: 26932243 DOI: 10.1111/evo.12896] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2015] [Revised: 02/19/2016] [Accepted: 02/22/2016] [Indexed: 11/28/2022]
Abstract
Maintenance and deployment of the immune system are costly and are hence predicted to trade-off with other resource-demanding traits, such as reproduction. We subjected this longstanding idea to test using laboratory experimental evolution approach. In the present study, replicate populations of Drosophila melanogaster were subjected to three selection regimes-I (Infection with Pseudomonas entomophila), S (Sham-infection with MgSO4 ), and U (Unhandled Control). After 30 generations of selection flies from the I regime had evolved better survivorship upon infection with P. entomophila compared to flies from U and S regimes. However, contrary to expectations and previous reports, we did not find any evidence of trade-offs between immunity and other life history related traits, such as longevity, fecundity, egg hatchability, or development time. After 45 generations of selection, the selection was relaxed for a set of populations. Even after 15 generations, the postinfection survivorship of populations under relaxed selection regime did not decline. We speculate that either there is a negligible cost to the evolved immune response or that trade-offs occur on traits such as reproductive behavior or other immune mechanisms that we have not investigated in this study. Our research suggests that at least under certain conditions, life-history trade-offs might play little role in maintaining variation in immunity.
Collapse
Affiliation(s)
- Vanika Gupta
- Indian Institute of Science Education and Research, P.O. Manauli, Mohali, Punjab, 140306, India
| | - Saudamini Venkatesan
- Indian Institute of Science Education and Research, P.O. Manauli, Mohali, Punjab, 140306, India
| | - Martik Chatterjee
- Indian Institute of Science Education and Research, P.O. Manauli, Mohali, Punjab, 140306, India
| | - Zeeshan A Syed
- Indian Institute of Science Education and Research, P.O. Manauli, Mohali, Punjab, 140306, India
| | - Vaishnavi Nivsarkar
- Indian Institute of Science Education and Research, P.O. Manauli, Mohali, Punjab, 140306, India
| | - Nagaraj G Prasad
- Indian Institute of Science Education and Research, P.O. Manauli, Mohali, Punjab, 140306, India.
| |
Collapse
|