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Kutzer MAM, Cornish B, Jamieson M, Zawistowska O, Monteith KM, Vale PF. Mitochondrial background can explain variable costs of immune deployment. J Evol Biol 2024:voae082. [PMID: 39145390 DOI: 10.1093/jeb/voae082] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/16/2024]
Abstract
Organismal health and survival depend on the ability to mount an effective immune response against infection. Yet immune defence may be energy-demanding, resulting in fitness costs if investment in immune function deprives other physiological processes of resources. While evidence of costly immunity resulting in reduced longevity and reproduction is common, the role of energy-producing mitochondria on the magnitude of these costs is unknown. Here, we employed Drosophila melanogaster cybrid lines, where several mitochondrial genotypes (mitotypes) were introgressed onto a single nuclear genetic background, to explicitly test the role of mitochondrial variation on the costs of immune stimulation. We exposed female flies carrying one of nine distinct mitotypes to either a benign, heat-killed bacterial pathogen (stimulating immune deployment while avoiding pathology) or to a sterile control and measured lifespan, fecundity, and locomotor activity. We observed mitotype-specific costs of immune stimulation and identified a positive genetic correlation in immune-stimulated flies between lifespan and the proportion of time cybrids spent moving while alive. Our results suggests that costs of immunity are highly variable depending on the mitochondrial genome, adding to a growing body of work highlighting the important role of mitochondrial variation in host-pathogen interactions.
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Affiliation(s)
- Megan A M Kutzer
- Institute of Ecology and Evolution, School of Biological Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Beth Cornish
- Institute of Ecology and Evolution, School of Biological Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Michael Jamieson
- Institute of Ecology and Evolution, School of Biological Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Olga Zawistowska
- Institute of Ecology and Evolution, School of Biological Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Katy M Monteith
- Institute of Ecology and Evolution, School of Biological Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Pedro F Vale
- Institute of Ecology and Evolution, School of Biological Sciences, University of Edinburgh, Edinburgh, United Kingdom
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2
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Basu A, Singh A, Ruchitha BG, Prasad NG. Experimental adaptation to pathogenic infection ameliorates negative effects of mating on host post-infection survival in Drosophila melanogaster. ZOOLOGY 2024; 166:126198. [PMID: 39173303 DOI: 10.1016/j.zool.2024.126198] [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: 01/14/2024] [Revised: 07/28/2024] [Accepted: 08/12/2024] [Indexed: 08/24/2024]
Abstract
Sexual activity (mating) negatively affects immune function in various insect species across both sexes. In Drosophila melanogaster females, mating increases susceptibility to pathogenic challenges and encourages within-host pathogen proliferation. This effect is pathogen and host genotype dependent. We tested if mating-induced increased susceptibility to infections is more, or less, severe in hosts experimentally adapted to pathogenic infection. We selected replicate D. melanogaster populations for increased post-infection survival following infection with a bacterial pathogen, Enterococcus faecalis. We found that females from the selected populations were better at surviving a pathogenic infection compared to the females from the control populations. This was true in the case of both the pathogen used for selection and other novel pathogens (i.e., pathogens the hosts have not encountered in recent history). Additionally, the negative effect of mating on post-infection survival was limited to only the females from control populations. Therefore, we have demonstrated that experimental selection for increased post-infection survival ameliorates negative effects of mating on host susceptibility to infections.
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Affiliation(s)
- Aabeer Basu
- Indian Institute of Science Education and Research (IISER), Mohali, India.
| | - Aparajita Singh
- Indian Institute of Science Education and Research (IISER), Mohali, India.
| | - B G Ruchitha
- Indian Institute of Science Education and Research (IISER), Mohali, India.
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3
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Prakash A, Monteith KM, Bonnet M, Vale PF. Duox and Jak/Stat signalling influence disease tolerance in Drosophila during Pseudomonas entomophila infection. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2023; 147:104756. [PMID: 37302730 DOI: 10.1016/j.dci.2023.104756] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2023] [Revised: 05/18/2023] [Accepted: 06/09/2023] [Indexed: 06/13/2023]
Abstract
Disease tolerance describes an infected host's ability to maintain health independently of the ability to clear microbe loads. The Jak/Stat pathway plays a pivotal role in humoral innate immunity by detecting tissue damage and triggering cellular renewal, making it a candidate tolerance mechanism. Here, we find that in Drosophila melanogaster infected with Pseudomonas entomophila disrupting ROS-producing dual oxidase (duox) or the negative regulator of Jak/Stat Socs36E, render male flies less tolerant. Another negative regulator of Jak/Stat, G9a - which has previously been associated with variable tolerance of viral infections - did not affect the rate of mortality with increasing microbe loads compared to flies with functional G9a, suggesting it does not affect tolerance of bacterial infection as in viral infection. Our findings highlight that ROS production and Jak/Stat signalling influence the ability of flies to tolerate bacterial infection sex-specifically and may therefore contribute to sexually dimorphic infection outcomes in Drosophila.
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Affiliation(s)
- Arun Prakash
- Institute of Ecology and Evolution, School of Biological Sciences, University of Edinburgh, UK.
| | - Katy M Monteith
- Institute of Ecology and Evolution, School of Biological Sciences, University of Edinburgh, UK
| | - Mickael Bonnet
- UFR De Biologie, Campus Universitaire Des Cezeaux, France
| | - Pedro F Vale
- Institute of Ecology and Evolution, School of Biological Sciences, University of Edinburgh, UK.
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4
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Wolf SE, Shalev I. The shelterin protein expansion of telomere dynamics: Linking early life adversity, life history, and the hallmarks of aging. Neurosci Biobehav Rev 2023; 152:105261. [PMID: 37268182 PMCID: PMC10527177 DOI: 10.1016/j.neubiorev.2023.105261] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2023] [Revised: 04/10/2023] [Accepted: 05/30/2023] [Indexed: 06/04/2023]
Abstract
Aging is characterized by functional decline occurring alongside changes to several hallmarks of aging. One of the hallmarks includes attrition of repeated DNA sequences found at the ends of chromosomes called telomeres. While telomere attrition is linked to morbidity and mortality, whether and how it causally contributes to lifelong rates of functional decline is unclear. In this review, we propose the shelterin-telomere hypothesis of life history, in which telomere-binding shelterin proteins translate telomere attrition into a range of physiological outcomes, the extent of which may be modulated by currently understudied variation in shelterin protein levels. Shelterin proteins may expand the breadth and timing of consequences of telomere attrition, e.g., by translating early life adversity into acceleration of the aging process. We consider how the pleiotropic roles of shelterin proteins provide novel insights into natural variation in physiology, life history, and lifespan. We highlight key open questions that encourage the integrative, organismal study of shelterin proteins that enhances our understanding of the contribution of the telomere system to aging.
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Affiliation(s)
- Sarah E Wolf
- Department of Biobehavioral Health, Penn State University, University Park, PA 16802, USA.
| | - Idan Shalev
- Department of Biobehavioral Health, Penn State University, University Park, PA 16802, USA
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5
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Hagen EH, Blackwell AD, Lightner AD, Sullivan RJ. Homo medicus: The transition to meat eating increased pathogen pressure and the use of pharmacological plants in Homo. AMERICAN JOURNAL OF BIOLOGICAL ANTHROPOLOGY 2023; 180:589-617. [PMID: 36815505 DOI: 10.1002/ajpa.24718] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Revised: 01/31/2023] [Accepted: 02/08/2023] [Indexed: 02/24/2023]
Abstract
The human lineage transitioned to a more carnivorous niche 2.6 mya and evolved a large body size and slower life history, which likely increased zoonotic pathogen pressure. Evidence for this increase includes increased zoonotic infections in modern hunter-gatherers and bushmeat hunters, exceptionally low stomach pH compared to other primates, and divergence in immune-related genes. These all point to change, and probably intensification, in the infectious disease environment of Homo compared to earlier hominins and other apes. At the same time, the brain, an organ in which immune responses are constrained, began to triple in size. We propose that the combination of increased zoonotic pathogen pressure and the challenges of defending a large brain and body from pathogens in a long-lived mammal, selected for intensification of the plant-based self-medication strategies already in place in apes and other primates. In support, there is evidence of medicinal plant use by hominins in the middle Paleolithic, and all cultures today have sophisticated, plant-based medical systems, add spices to food, and regularly consume psychoactive plant substances that are harmful to helminths and other pathogens. We propose that the computational challenges of discovering effective plant-based treatments, the consequent ability to consume more energy-rich animal foods, and the reduced reliance on energetically-costly immune responses helped select for increased cognitive abilities and unique exchange relationships in Homo. In the story of human evolution, which has long emphasized hunting skills, medical skills had an equal role to play.
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Affiliation(s)
- Edward H Hagen
- Department of Anthropology, Washington State University, Pullman, Washington, USA
| | - Aaron D Blackwell
- Department of Anthropology, Washington State University, Pullman, Washington, USA
| | - Aaron D Lightner
- Department of Anthropology, Washington State University, Pullman, Washington, USA
- Department of the Study of Religion, Aarhus University, Aarhus, Denmark
| | - Roger J Sullivan
- Department of Anthropology, California State University, Sacramento, California, USA
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6
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Weber JN, Steinel NC, Peng F, Shim KC, Lohman BK, Fuess LE, Subramanian S, Lisle SPD, Bolnick DI. Evolutionary gain and loss of a pathological immune response to parasitism. Science 2022; 377:1206-1211. [PMID: 36074841 PMCID: PMC9869647 DOI: 10.1126/science.abo3411] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Parasites impose fitness costs on their hosts. Biologists often assume that natural selection favors infection-resistant hosts. Yet, when the immune response itself is costly, theory suggests that selection may sometimes favor loss of resistance, which may result in alternative stable states where some populations are resistant and others are tolerant. Intraspecific variation in immune costs is rarely surveyed in a manner that tests evolutionary patterns, and there are few examples of adaptive loss of resistance. Here, we show that when marine threespine stickleback colonized freshwater lakes, they gained resistance to the freshwater-associated cestode Schistocephalus solidus. Extensive peritoneal fibrosis and inflammation are a commonly observed phenotype that contributes to suppression of cestode growth and viability but also imposes a substantial cost on fecundity. Combining genetic mapping and population genomics, we find that opposing selection generates immune system differences between tolerant and resistant populations, consistent with divergent optimization.
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Affiliation(s)
- Jesse N Weber
- Department of Integrative Biology, University of Texas at Austin, Austin, TX 78712, USA
| | - Natalie C Steinel
- Department of Integrative Biology, University of Texas at Austin, Austin, TX 78712, USA
| | - Foen Peng
- Department of Ecology and Evolutionary Biology, University of Connecticut, Storrs, CT 06269, USA
| | - Kum Chuan Shim
- Department of Integrative Biology, University of Texas at Austin, Austin, TX 78712, USA
| | - Brian K Lohman
- Department of Integrative Biology, University of Texas at Austin, Austin, TX 78712, USA
| | - Lauren E Fuess
- Department of Ecology and Evolutionary Biology, University of Connecticut, Storrs, CT 06269, USA
| | - Swapna Subramanian
- Department of Ecology and Evolutionary Biology, University of Connecticut, Storrs, CT 06269, USA
| | - Stephen P De Lisle
- Department of Ecology and Evolutionary Biology, University of Connecticut, Storrs, CT 06269, USA
| | - Daniel I Bolnick
- Department of Integrative Biology, University of Texas at Austin, Austin, TX 78712, USA.,Department of Ecology and Evolutionary Biology, University of Connecticut, Storrs, CT 06269, USA
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7
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Lund-Hansen KK, Kutzer MAM, Armitage SAO, Gornard S, Keilani H, Abbott JK. Female-limited X chromosome evolution reveals that lifespan is mainly modulated by interlocus rather than intralocus sexual conflict. Behav Ecol Sociobiol 2022; 76:120. [PMID: 35991525 PMCID: PMC9385781 DOI: 10.1007/s00265-022-03231-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2022] [Revised: 07/29/2022] [Accepted: 08/08/2022] [Indexed: 11/21/2022]
Abstract
Abstract Sexual dimorphism in somatic investment may be shaped by two distinct forms of sexual conflict; under intralocus sexual conflict (IASC), males and females have different optimal levels of somatic investment but are constrained from reaching their respective optima by their shared genome, while under interlocus sexual conflict (IRSC), males and females have different optimal sexual strategies, which could have direct or indirect effects on levels of somatic investment. We investigated effects of IASC and IRSC on two aspects of somatic investment, immune defence strategies and longevity, using previously established female-limited experimental evolution lines in Drosophila melanogaster. We found little evidence for any effect of either type of sexual conflict on investment in the immune defence resistance or tolerance. Nor did we find convincing evidence that longevity is subject to IASC in this species. However, we did find evidence that increased female control over mating rate had important and opposite effects on longevity between the sexes. Specifically, females that had adapted to high levels of female control over mating had a longer lifespan when kept in mixed-sex groups, while males had shorter longevity, perhaps due to increased investment in post-copulatory sexual selection. These novel results show that female control over mating rates may have important and unexpected effects on patterns of somatic investment. Significance statement Sexual conflict occurs between the two sexes over numerous life history traits, and it is complex to disentangle how these traits interact and affect each other. Here we use a long-term evolution experiment to investigate sexual dimorphism in somatic maintenance. We found no effect of feminising the X chromosome on female immune defence. However, we did find that increased female control over mating rate resulted in longer female lifespan, but reduced male lifespan, and that these effects were dependent on social context (isolated or in mixed-sex groups). Unlike previous studies on the effect of sexual conflict on longevity, our experiment did not manipulate environmental conditions nor the adult sex ratio, which is likely to reduce both pre- and post-copulatory sexual selection. Supplementary Information The online version contains supplementary material available at 10.1007/s00265-022-03231-4.
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8
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Decomposing virulence to understand bacterial clearance in persistent infections. Nat Commun 2022; 13:5023. [PMID: 36028497 PMCID: PMC9418333 DOI: 10.1038/s41467-022-32118-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Accepted: 07/15/2022] [Indexed: 11/08/2022] Open
Abstract
Following an infection, hosts cannot always clear the pathogen, instead either dying or surviving with a persistent infection. Such variation is ecologically and evolutionarily important because it can affect infection prevalence and transmission, and virulence evolution. However, the factors causing variation in infection outcomes, and the relationship between clearance and virulence are not well understood. Here we show that sustained persistent infection and clearance are both possible outcomes across bacterial species showing a range of virulence in Drosophila melanogaster. Variation in virulence arises because of differences in the two components of virulence: bacterial infection intensity inside the host (exploitation), and the amount of damage caused per bacterium (per parasite pathogenicity). As early-phase exploitation increased, clearance rates later in the infection decreased, whereas there was no apparent effect of per parasite pathogenicity on clearance rates. Variation in infection outcomes is thereby determined by how virulence - and its components - relate to the rate of pathogen clearance. Taken together we demonstrate that the virulence decomposition framework is broadly applicable and can provide valuable insights into host-pathogen interactions.
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9
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Buttemer WA, O'Dwyer TW, Astheimer LB, Klasing KC, Hoye BJ. No evidence of metabolic costs following adaptive immune activation or reactivation in house sparrows. Biol Lett 2022; 18:20220036. [PMID: 35702980 DOI: 10.1098/rsbl.2022.0036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The energy cost of adaptive immune activation in endotherms is typically quantified from changes in resting metabolic rate following exposure to a novel antigen. An implicit assumption of this technique is that all variation in energy costs following antigenic challenge is due solely to adaptive immunity, while ignoring potential changes in the energy demands of ongoing bodily functions. We critically assess this assumption by measuring both basal metabolic rate (BMR) and exercise-induced maximal metabolic rate (MMR) in house sparrows before and after the primary and two subsequent vaccinations with either saline (sham) or two novel antigens (keyhole limpet haemocyanin and sheep red blood cells; KLH and SRBC, respectively). We also examined the effect of inducing male breeding levels of testosterone (T) on immune responses and their metabolic costs in both males and females. Although there was a moderate decrease in KLH antibody formation in T-treated birds, there was no effect of T on BMR, MMR or immunity to SRBC. There was no effect of vaccination on BMR but, surprisingly, all vaccinated birds maintained MMR better than sham-treated birds as the experiment progressed. Our findings caution against emphasizing energy costs or nutrient diversion as being responsible for reported fitness reductions following activation of adaptive immunity.
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Affiliation(s)
- William A Buttemer
- School of Earth, Atmospheric and Life Sciences, University of Wollongong, Wollongong, NSW 2522, Australia
| | - Terence W O'Dwyer
- School of Earth, Atmospheric and Life Sciences, University of Wollongong, Wollongong, NSW 2522, Australia
| | - Lee B Astheimer
- School of Medicine, University of Wollongong, Wollongong, NSW 2522, Australia
| | - Kirk C Klasing
- Department of Animal Science, University of California, Davis, CA 95616-5270, USA
| | - Bethany J Hoye
- School of Earth, Atmospheric and Life Sciences, University of Wollongong, Wollongong, NSW 2522, Australia
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10
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Pham HT, Elgar MA, van Lieshout E, McNamara KB. Experimental immune challenges reduce the quality of male antennae and female pheromone output. Sci Rep 2022; 12:3578. [PMID: 35246550 PMCID: PMC8897396 DOI: 10.1038/s41598-022-07100-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2021] [Accepted: 02/01/2022] [Indexed: 11/17/2022] Open
Abstract
Sexual signalling is a key feature of reproductive investment, yet the effects of immune system activation on investment into chemical signalling, and especially signal receiver traits such as antennae, are poorly understood. We explore how upregulation of juvenile immunity affects male antennal functional morphology and female pheromone attractiveness in the gumleaf skeletonizer moth, Uraba lugens. We injected final-instar larvae with a high or low dose of an immune elicitor or a control solution and measured male antennal morphological traits, gonad investment and female pheromone attractiveness. Immune activation affected male and female signalling investment: immune challenged males had a lower density of antennal sensilla, and the pheromone of immune-challenged females was less attractive to males than their unchallenged counterparts. Immune challenge affected female investment into ovary development but not in a linear, dose-dependent manner. While there was no effect of immune challenge on testes size, there was a trade-off between male pre- and post-copulatory investment: male antennal length was negatively correlated with testes size. Our study highlights the costs of elaborate antennae and pheromone production and demonstrates the capacity for honest signalling in species where the costs of pheromone production were presumed to be trivial.
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Affiliation(s)
- Hieu T Pham
- School of BioSciences, The University of Melbourne, Parkville, VIC, 3010, Australia.,Department of Entomology, Faculty of Agronomy, Vietnam National University of Agriculture, Hanoi, Vietnam
| | - Mark A Elgar
- School of BioSciences, The University of Melbourne, Parkville, VIC, 3010, Australia
| | - Emile van Lieshout
- School of BioSciences, The University of Melbourne, Parkville, VIC, 3010, Australia
| | - Kathryn B McNamara
- School of BioSciences, The University of Melbourne, Parkville, VIC, 3010, Australia.
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11
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Limberger GM, Esteves KP, Halal LM, Nery LEM, da Fonseca DB. Chronic immune challenge is detrimental to female survival, feeding behavior, and reproduction in the field cricket Gryllus assimilis (Fabricius, 1775). J Comp Physiol B 2022; 192:423-434. [PMID: 35195757 DOI: 10.1007/s00360-022-01431-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Revised: 01/18/2022] [Accepted: 02/10/2022] [Indexed: 01/03/2023]
Abstract
Physiological trade-offs among expensive fitness-related traits, such as reproduction and immunity, are common in life histories of animals. An immune challenge can have different effects on female reproduction mediated by resource allocation and acquisition. In this study, employing a widely used method to challenge the insect immune system (nylon implant), we assessed the effects of mounting a chronic immune response simulating three successive immune assaults on survival and reproduction of mated females of Gryllus assimilis. We also verified feeding behavior following an implantation, which can be important in explaining trade-off dynamics in terms of energy acquisition. For this, three experimental groups were designed (Control, Sham, and Implant) with oviposition rates, egg morphometry, and nymph vigour observed over 3 weeks, at which ovarian mass and unlaid eggs were quantified from remaining individuals. The results showed that chronic implants were detrimental to female survival and reproduction throughout the experiments; Surgical Sham had no effect on survival compared to the control, but did on reproductive aspects such as oviposition rates and hatchling vigour. These negative effects on reproduction in Sham disappeared in the last experimental week, but still strong in the implanted females. Such immune challenge affected the feeding behavior of implanted females by reducing food consumption compared to control after infection, which is probably explained by illness-induced anorexia that takes place to maximize the immune system performance as a part of sickness behavior, exacerbating the adverse effects observed on reproduction (i.e., fewer and smaller eggs, and low vigour of nymphs) and survival.
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Affiliation(s)
- Guilherme Martins Limberger
- Programa de Pós-Graduação em Ciências Fisiológicas, Instituto de Ciências Biológicas, Universidade Federal do Rio Grande-FURG, Av. Itália, km 8, Rio Grande, RS, 96203-001, Brazil.
| | | | - Lamia Marques Halal
- Programa de Pós-Graduação em Ciências Fisiológicas, Instituto de Ciências Biológicas, Universidade Federal do Rio Grande-FURG, Av. Itália, km 8, Rio Grande, RS, 96203-001, Brazil
| | - Luiz Eduardo Maia Nery
- Programa de Pós-Graduação em Ciências Fisiológicas, Instituto de Ciências Biológicas, Universidade Federal do Rio Grande-FURG, Av. Itália, km 8, Rio Grande, RS, 96203-001, Brazil
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12
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Vincze O, Vágási CI, Pénzes J, Szabó K, Magonyi NM, Czirják GÁ, Pap PL. Sexual dimorphism in immune function and oxidative physiology across birds: The role of sexual selection. Ecol Lett 2022; 25:958-970. [PMID: 35106902 PMCID: PMC9305230 DOI: 10.1111/ele.13973] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2021] [Revised: 01/05/2022] [Accepted: 01/05/2022] [Indexed: 01/08/2023]
Abstract
Sex‐specific physiology is commonly reported in animals, often indicating lower immune indices and higher oxidative stress in males than in females. Sexual selection is argued to explain these differences, but empirical evidence is limited. Here, we explore sex differences in immunity, oxidative physiology and packed cell volume of wild, adult, breeding birds (97 species, 1997 individuals, 14 230 physiological measurements). We show that higher female immune indices are most common across birds (when bias is present), but oxidative physiology shows no general sex‐bias and packed cell volume is generally male‐biased. In contrast with predictions based on sexual selection, male‐biased sexual size dimorphism is associated with male‐biased immune measures. Sexual dichromatism, mating system and parental roles had no effect on sex‐specificity in physiology. Importantly, female‐biased immunity remained after accounting for sexual selection indices. We conclude that cross‐species differences in physiological sex‐bias are largely unrelated to sexual selection and alternative explanations should be explored.
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Affiliation(s)
- Orsolya Vincze
- Centre for Ecological Research, Institute of Aquatic Ecology, Debrecen, Hungary.,Evolutionary Ecology Group, Hungarian Department of Biology and Ecology, Babeş-Bolyai University, Cluj-Napoca, Romania
| | - Csongor I Vágási
- Evolutionary Ecology Group, Hungarian Department of Biology and Ecology, Babeş-Bolyai University, Cluj-Napoca, Romania
| | - Janka Pénzes
- Evolutionary Ecology Group, Hungarian Department of Biology and Ecology, Babeş-Bolyai University, Cluj-Napoca, Romania
| | - Krisztián Szabó
- Department of Ecology, University of Veterinary Medicine Budapest, Budapest, Hungary
| | - Nóra M Magonyi
- Doctoral School of Biology and Sportbiology, Faculty of Sciences, University of Pécs, Pécs, Hungary.,Centre for Agricultural Research, Plant Protection Institute, ELKH, Budapest, Hungary
| | - Gábor Á Czirják
- Department of Wildlife Diseases, Leibniz Institute for Zoo and Wildlife Research, Berlin, Germany
| | - Péter L Pap
- Evolutionary Ecology Group, Hungarian Department of Biology and Ecology, Babeş-Bolyai University, Cluj-Napoca, Romania.,Behavioural Ecology Research Group, Department of Evolutionary Zoology and Human Biology, University of Debrecen, Debrecen, Hungary
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13
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Rodrigues MA, Merckelbach A, Durmaz E, Kerdaffrec E, Flatt T. Transcriptomic evidence for a trade-off between germline proliferation and immunity in Drosophila. Evol Lett 2021; 5:644-656. [PMID: 34917403 PMCID: PMC8645197 DOI: 10.1002/evl3.261] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Revised: 09/07/2021] [Accepted: 09/12/2021] [Indexed: 11/08/2022] Open
Abstract
Life-history theory posits that investment into reproduction might occur at the expense of investment into somatic maintenance, including immune function. If so, reduced or curtailed reproductive effort might be expected to increase immunity. In support of this notion, work in Caenorhabditis elegans has shown that worms lacking a germline exhibit improved immunity, but whether the antagonistic relation between germline proliferation and immunity also holds for other organisms is less well understood. Here, we report that transgenic ablation of germ cells in late development or early adulthood in Drosophila melanogaster causes elevated baseline expression and increased induction of Toll and Imd immune genes upon bacterial infection, as compared to fertile flies with an intact germline. We also identify immune genes whose expression after infection differs between fertile and germline-less flies in a manner that is conditional on their mating status. We conclude that germline activity strongly impedes the expression and inducibility of immune genes and that this physiological trade-off might be evolutionarily conserved.
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Affiliation(s)
| | | | - Esra Durmaz
- Department of BiologyUniversity of FribourgCH‐1700 FribourgSwitzerland
| | - Envel Kerdaffrec
- Department of BiologyUniversity of FribourgCH‐1700 FribourgSwitzerland
| | - Thomas Flatt
- Department of BiologyUniversity of FribourgCH‐1700 FribourgSwitzerland
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14
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Erdos Z, Chandler D, Bass C, Raymond B. Controlling insecticide resistant clones of the aphid, Myzus persicae, using the entomopathogenic fungus Akanthomyces muscarius: fitness cost of resistance under pathogen challenge. PEST MANAGEMENT SCIENCE 2021; 77:5286-5293. [PMID: 34310830 DOI: 10.1002/ps.6571] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Accepted: 07/26/2021] [Indexed: 06/13/2023]
Abstract
BACKGROUND Biological control is a cornerstone of integrated pest management and could also play a key role in managing the evolution of insecticide resistance. Ecological theory predicts that the fitness cost of insecticide resistance can be increased under exposure to invertebrate natural enemies or pathogens, and can therefore increase the value of integrating biological control into pest management. In this study of the peach potato aphid, Myzus persicae, we aimed to identify whether insecticide resistance affected fitness and vulnerability of different aphid clones to the entomopathogenic fungus Akanthomyces muscarius. RESULTS Insecticide resistant clones were found to be slightly less susceptible to the pathogen than susceptible clones. However, this pattern could also be explained by the influence of length of laboratory culture, which was longer in susceptible clones and was positively correlated with susceptibility to fungi. Furthermore, resistance status did not affect aphid development time or intrinsic rate of increase of aphids. Finally, in a cage trial the application of fungus did not increase the competitive fitness of insecticide resistant clone 'O'. CONCLUSION We found no fitness cost in reproductive rate or pathogen susceptibility associated with chemical resistance in M. persicae. In contrast, some susceptible clones, particularly those subject to decades of laboratory rearing, showed enhanced susceptibility to a fungal pathogen, but not reduced reproductive fitness, an observation consistent with down-regulation of costly immune functions in culture. Overall, fungal pathogen control is compatible with insecticides and should not increase the selection pressure for resistance of M. persicae to chemical insecticides.
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Affiliation(s)
- Zoltan Erdos
- Centre for Ecology and Conservation, Biosciences, College of Life and Environmental Sciences, University of Exeter, Penryn, Exeter, UK
| | - David Chandler
- School of Life Sciences, The University of Warwick, Coventry, UK
| | - Chris Bass
- Centre for Ecology and Conservation, Biosciences, College of Life and Environmental Sciences, University of Exeter, Penryn, Exeter, UK
| | - Ben Raymond
- Centre for Ecology and Conservation, Biosciences, College of Life and Environmental Sciences, University of Exeter, Penryn, Exeter, UK
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Seal S, Dharmarajan G, Khan I. Evolution of pathogen tolerance and emerging infections: A missing experimental paradigm. eLife 2021; 10:e68874. [PMID: 34544548 PMCID: PMC8455132 DOI: 10.7554/elife.68874] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Accepted: 08/23/2021] [Indexed: 12/11/2022] Open
Abstract
Researchers worldwide are repeatedly warning us against future zoonotic diseases resulting from humankind's insurgence into natural ecosystems. The same zoonotic pathogens that cause severe infections in a human host frequently fail to produce any disease outcome in their natural hosts. What precise features of the immune system enable natural reservoirs to carry these pathogens so efficiently? To understand these effects, we highlight the importance of tracing the evolutionary basis of pathogen tolerance in reservoir hosts, while drawing implications from their diverse physiological and life-history traits, and ecological contexts of host-pathogen interactions. Long-term co-evolution might allow reservoir hosts to modulate immunity and evolve tolerance to zoonotic pathogens, increasing their circulation and infectious period. Such processes can also create a genetically diverse pathogen pool by allowing more mutations and genetic exchanges between circulating strains, thereby harboring rare alive-on-arrival variants with extended infectivity to new hosts (i.e., spillover). Finally, we end by underscoring the indispensability of a large multidisciplinary empirical framework to explore the proposed link between evolved tolerance, pathogen prevalence, and spillover in the wild.
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Affiliation(s)
| | - Guha Dharmarajan
- Savannah River Ecology Laboratory, University of GeorgiaAikenUnited States
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16
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Bagchi B, Corbel Q, Khan I, Payne E, Banerji D, Liljestrand-Rönn J, Martinossi-Allibert I, Baur J, Sayadi A, Immonen E, Arnqvist G, Söderhäll I, Berger D. Sexual conflict drives micro- and macroevolution of sexual dimorphism in immunity. BMC Biol 2021; 19:114. [PMID: 34078377 PMCID: PMC8170964 DOI: 10.1186/s12915-021-01049-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2021] [Accepted: 05/07/2021] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND Sexual dimorphism in immunity is believed to reflect sex differences in reproductive strategies and trade-offs between competing life history demands. Sexual selection can have major effects on mating rates and sex-specific costs of mating and may thereby influence sex differences in immunity as well as associated host-pathogen dynamics. Yet, experimental evidence linking the mating system to evolved sexual dimorphism in immunity are scarce and the direct effects of mating rate on immunity are not well established. Here, we use transcriptomic analyses, experimental evolution and phylogenetic comparative methods to study the association between the mating system and sexual dimorphism in immunity in seed beetles, where mating causes internal injuries in females. RESULTS We demonstrate that female phenoloxidase (PO) activity, involved in wound healing and defence against parasitic infections, is elevated relative to males. This difference is accompanied by concomitant sex differences in the expression of genes in the prophenoloxidase activating cascade. We document substantial phenotypic plasticity in female PO activity in response to mating and show that experimental evolution under enforced monogamy (resulting in low remating rates and reduced sexual conflict relative to natural polygamy) rapidly decreases female (but not male) PO activity. Moreover, monogamous females had evolved increased tolerance to bacterial infection unrelated to mating, implying that female responses to costly mating may trade off with other aspects of immune defence, an hypothesis which broadly accords with the documented sex differences in gene expression. Finally, female (but not male) PO activity shows correlated evolution with the perceived harmfulness of male genitalia across 12 species of seed beetles, suggesting that sexual conflict has a significant influence on sexual dimorphisms in immunity in this group of insects. CONCLUSIONS Our study provides insights into the links between sexual conflict and sexual dimorphism in immunity and suggests that selection pressures moulded by mating interactions can lead to a sex-specific mosaic of immune responses with important implications for host-pathogen dynamics in sexually reproducing organisms.
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Affiliation(s)
- Basabi Bagchi
- Department of Biology, Ashoka University, Sonipat, India
| | - Quentin Corbel
- Department of Ecology and Genetics, Program of Animal Ecology, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden
- Cavanilles Institute of Biodiversity and Evolutionary Biology, University of Valencia, Valencia, Spain
| | - Imroze Khan
- Department of Biology, Ashoka University, Sonipat, India
| | - Ellen Payne
- Department of Ecology and Genetics, Program of Animal Ecology, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden
| | | | - Johanna Liljestrand-Rönn
- Department of Ecology and Genetics, Program of Animal Ecology, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden
| | - Ivain Martinossi-Allibert
- Department of Ecology and Genetics, Program of Animal Ecology, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden
- Department of Organismal Biology, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden
| | - Julian Baur
- Department of Ecology and Genetics, Program of Animal Ecology, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden
| | - Ahmed Sayadi
- Department of Ecology and Genetics, Program of Animal Ecology, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden
- Department of Chemistry, Biochemistry, Uppsala University, Uppsala, Sweden
| | - Elina Immonen
- Department of Ecology and Genetics, Program of Evolutionary Biology, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden
| | - Göran Arnqvist
- Department of Ecology and Genetics, Program of Animal Ecology, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden
| | - Irene Söderhäll
- Department of Organismal Biology, Program of Comparative Physiology, Uppsala University, Uppsala, Sweden
| | - David Berger
- Department of Ecology and Genetics, Program of Animal Ecology, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden.
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Abstract
Whilst the immune system often varies seasonally and exhibits differences between males and females, the general patterns in seasonality and sex differences across taxa have remained controversial. Birds are excellent model organisms to assess these patterns, because the immune system of many species is well characterised. We conducted a meta-analysis using 41 wild bird species from 24 avian families to investigate sex differences and seasonal (breeding/non-breeding) variations in immune status, including white blood cell counts, phytohaemagglutinin (PHA) test, bacteria-killing ability (BKA), haemolysis and haemagglutination assays. We found male-biased macrophage concentration, BKA and haemolysis titers, but only during the breeding season. Sex-specific heterophil concentrations, heterophil/lymphocyte ratios and PHA responses differed between breeding and non-breeding, suggesting larger changes in males than in females. Importantly, sex differences in immune status are stronger during the breeding period than during the non-breeding period. Taken together, our study suggests that both seasonal variation and sex differences in immune system are common in birds, although their associations are more complex than previously thought.
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