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Hector TE, Shocket MS, Sgrò CM, Hall MD. Acclimation to warmer temperatures can protect host populations from both further heat stress and the potential invasion of pathogens. GLOBAL CHANGE BIOLOGY 2024; 30:e17341. [PMID: 38837568 DOI: 10.1111/gcb.17341] [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: 10/09/2023] [Revised: 04/15/2024] [Accepted: 04/20/2024] [Indexed: 06/07/2024]
Abstract
Thermal acclimation can provide an essential buffer against heat stress for host populations, while acting simultaneously on various life-history traits that determine population growth. In turn, the ability of a pathogen to invade a host population is intimately linked to these changes via the supply of new susceptible hosts, as well as the impact of warming on its immediate infection dynamics. Acclimation therefore has consequences for hosts and pathogens that extend beyond simply coping with heat stress-governing both population growth trajectories and, as a result, an inherent propensity for a disease outbreak to occur. The impact of thermal acclimation on heat tolerances, however, is rarely considered simultaneously with metrics of both host and pathogen population growth, and ultimately fitness. Using the host Daphnia magna and its bacterial pathogen, we investigated how thermal acclimation impacts host and pathogen performance at both the individual and population scales. We first tested the effect of maternal and direct thermal acclimation on the life-history traits of infected and uninfected individuals, such as heat tolerance, fecundity, and lifespan, as well as pathogen infection success and spore production. We then predicted the effects of each acclimation treatment on rates of host and pathogen population increase by deriving a host's intrinsic growth rate (rm) and a pathogen's basic reproductive number (R0). We found that direct acclimation to warming enhanced a host's heat tolerance and rate of population growth, despite a decline in life-history traits such as lifetime fecundity and lifespan. In contrast, pathogen performance was consistently worse under warming, with within-host pathogen success, and ultimately the potential for disease spread, severely hampered at higher temperatures. Our results suggest that hosts could benefit more from warming than their pathogens, but only by linking multiple individual traits to population processes can the full impact of higher temperatures on host and pathogen population dynamics be realised.
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Affiliation(s)
| | - Marta S Shocket
- Lancaster Environment Centre, Lancaster University, Lancaster, UK
| | - Carla M Sgrò
- School of Biological Sciences, Monash University, Melbourne, Victoria, Australia
| | - Matthew D Hall
- School of Biological Sciences, Monash University, Melbourne, Victoria, Australia
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2
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Halle S, Hirshberg O, Manzi F, Wolinska J, Ben-Ami F. Coinfection frequency in water flea populations is a mere reflection of parasite diversity. Commun Biol 2024; 7:559. [PMID: 38734859 PMCID: PMC11088698 DOI: 10.1038/s42003-024-06176-8] [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: 03/03/2023] [Accepted: 04/10/2024] [Indexed: 05/13/2024] Open
Abstract
In nature, parasite species often coinfect the same host. Yet, it is not clear what drives the natural dynamics of coinfection prevalence. The prevalence of coinfections might be affected by interactions among coinfecting species, or simply derive from parasite diversity. Identifying the relative impact of these parameters is crucial for understanding patterns of coinfections. We studied the occurrence and likelihood of coinfections in natural populations of water fleas (Daphnia magna). Coinfection prevalence was within the bounds expected by chance and parasite diversity had a strong positive effect on the likelihood of coinfections. Additionally, coinfection prevalence increased over the season and became as common as a single infection. Our results demonstrate how patterns of coinfection, and particularly their temporal variation, are affected by overlapping epidemics of different parasites. We suggest that monitoring parasite diversity can help predict where and when coinfection prevalence will be high, potentially leading to increased health risks to their hosts.
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Affiliation(s)
- Snir Halle
- School of Zoology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, 6997801, Israel.
| | - Ofir Hirshberg
- School of Zoology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, 6997801, Israel
| | - Florent Manzi
- Department of Evolutionary and Integrative Ecology, Leibniz Institute of Freshwater Ecology and Inland Fisheries, Berlin, Germany
| | - Justyna Wolinska
- Department of Evolutionary and Integrative Ecology, Leibniz Institute of Freshwater Ecology and Inland Fisheries, Berlin, Germany
- Department of Biology, Chemistry, Pharmacy, Institute of Biology, Freie Universität Berlin, Berlin, Germany
| | - Frida Ben-Ami
- School of Zoology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, 6997801, Israel
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3
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Trzebny A, Nahimova O, Dabert M. High temperatures and low humidity promote the occurrence of microsporidians (Microsporidia) in mosquitoes (Culicidae). Parasit Vectors 2024; 17:187. [PMID: 38605410 PMCID: PMC11008030 DOI: 10.1186/s13071-024-06254-0] [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: 10/26/2023] [Accepted: 03/20/2024] [Indexed: 04/13/2024] Open
Abstract
BACKGROUND In the context of climate change, a growing concern is that vector-pathogen or host-parasite interactions may be correlated with climatic factors, especially increasing temperatures. In the present study, we used a mosquito-microsporidian model to determine the impact of environmental factors such as temperature, humidity, wind and rainfall on the occurrence rates of opportunistic obligate microparasites (Microsporidia) in hosts from a family that includes important disease vectors (Culicidae). METHODS In our study, 3000 adult mosquitoes collected from the field over 3 years were analysed. Mosquitoes and microsporidia were identified using PCR and sequencing of the hypervariable V5 region of the small subunit ribosomal RNA gene and a shortened fragment of the cytochrome c oxidase subunit I gene, respectively. RESULTS DNA metabarcoding was used to identify nine mosquito species, all of which were hosts of 12 microsporidian species. The prevalence of microsporidian DNA across all mosquito samples was 34.6%. Microsporidian prevalence in mosquitoes was more frequent during warm months (> 19 °C; humidity < 65%), as was the co-occurrence of two or three microsporidian species in a single host individual. During warm months, microsporidian occurrence was noted 1.6-fold more often than during the cold periods. Among the microsporidians found in the mosquitoes, five (representing the genera Enterocytospora, Vairimorpha and Microsporidium) were positively correlated with an increase in temperature, whereas one (Hazardia sp.) was significantly correlated with a decrease in temperature. Threefold more microsporidian co-occurrences were recorded in the warm months than in the cold months. CONCLUSIONS These results suggest that the susceptibility of mosquitoes to parasite occurrence is primarily determined by environmental conditions, such as, for example, temperatures > 19 °C and humidity not exceeding 62%. Collectively, our data provide a better understanding of the effects of the environment on microsporidian-mosquito interactions.
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Affiliation(s)
- Artur Trzebny
- Molecular Biology Techniques Laboratory, Faculty of Biology, Adam Mickiewicz University, Poznan, Poland.
| | - Olena Nahimova
- Molecular Biology Techniques Laboratory, Faculty of Biology, Adam Mickiewicz University, Poznan, Poland
- Genetics and Cytology Department, School of Biology, V.N. Karazin Kharkiv National University, Kharkiv, Ukraine
| | - Miroslawa Dabert
- Molecular Biology Techniques Laboratory, Faculty of Biology, Adam Mickiewicz University, Poznan, Poland
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4
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O'Keeffe FE, Pendleton RC, Holland CV, Luijckx P. Increased virulence due to multiple infection in Daphnia leads to limited growth in 1 of 2 co-infecting microsporidian parasites. Parasitology 2024; 151:58-67. [PMID: 37981808 PMCID: PMC10941049 DOI: 10.1017/s0031182023001130] [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: 07/20/2023] [Revised: 11/14/2023] [Accepted: 11/15/2023] [Indexed: 11/21/2023]
Abstract
Recent outbreaks of various infectious diseases have highlighted the ever-present need to understand the drivers of the outbreak and spread of disease. Although much of the research investigating diseases focuses on single infections, natural systems are dominated by multiple infections. These infections may occur simultaneously, but are often acquired sequentially, which may alter the outcome of infection. Using waterfleas (Daphnia magna) as a model organism, we examined the outcome of sequential and simultaneous multiple infections with 2 microsporidian parasites (Ordospora colligata and Hamiltosporidium tvaerminnensis) in a fully factorial design with 9 treatments and 30 replicates. We found no differences between simultaneous and sequential infections. However, H. tvaerminnensis fitness was impeded by multiple infection due to increased host mortality, which gave H. tvaerminnensis less time to grow. Host fecundity was also reduced across all treatments, but animals infected with O. colligata at a younger age produced the fewest offspring. As H. tvaerminnensis is both horizontally and vertically transmitted, this reduction in offspring may have further reduced H. tvaerminnensis fitness in co-infected treatments. Our findings suggest that in natural populations where both species co-occur, H. tvaerminnensis may evolve to higher levels of virulence following frequent co-infection by O. colligata.
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Affiliation(s)
- Floriane E. O'Keeffe
- Department of Zoology, School of Natural Sciences, Trinity College Dublin, Dublin, Ireland
| | - Rebecca C. Pendleton
- Department of Zoology, School of Natural Sciences, Trinity College Dublin, Dublin, Ireland
| | - Celia V. Holland
- Department of Zoology, School of Natural Sciences, Trinity College Dublin, Dublin, Ireland
| | - Pepijn Luijckx
- Department of Zoology, School of Natural Sciences, Trinity College Dublin, Dublin, Ireland
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5
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Johnson PTJ, Merrill TS, Calhoun DM, McDevitt-Galles T, Hobart B. Into the danger zone: How the within-host distribution of parasites controls virulence. Ecol Lett 2024; 27:e14352. [PMID: 38115188 PMCID: PMC10872350 DOI: 10.1111/ele.14352] [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: 02/20/2023] [Revised: 05/30/2023] [Accepted: 06/01/2023] [Indexed: 12/21/2023]
Abstract
Despite the importance of virulence in epidemiological theory, the relative contributions of host and parasite to virulence outcomes remain poorly understood. Here, we use reciprocal cross experiments to disentangle the influence of host and parasite on core virulence components-infection and pathology-and understand dramatic differences in parasite-induced malformations in California amphibians. Surveys across 319 populations revealed that amphibians' malformation risk was 2.7× greater in low-elevation ponds, even while controlling for trematode infection load. Factorial experiments revealed that parasites from low-elevation sites induced higher per-parasite pathology (reduced host survival and growth), whereas there were no effects of host source on resistance or tolerance. Parasite populations also exhibited marked differences in within-host distribution: ~90% of low-elevation cysts aggregated around the hind limbs, relative to <60% from high-elevation. This offers a novel, mechanistic basis for regional variation in parasite-induced malformations while promoting a framework for partitioning host and parasite contributions to virulence.
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Affiliation(s)
| | - Tara Stewart Merrill
- Ecology and Evolutionary Biology, University of Colorado, Boulder, CO, USA
- Coastal and Marine Laboratory, Florida State University, St. Teresa, FL, 32358, USA
| | - Dana M. Calhoun
- Ecology and Evolutionary Biology, University of Colorado, Boulder, CO, USA
| | - Travis McDevitt-Galles
- Ecology and Evolutionary Biology, University of Colorado, Boulder, CO, USA
- Current address: USGS National Wildlife Health Center, Madison, WI, USA
| | - Brendan Hobart
- Ecology and Evolutionary Biology, University of Colorado, Boulder, CO, USA
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6
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Claar DC, Faiad SM, Mastick NC, Welicky RL, Williams MA, Sasser KT, Weber JN, Wood CL. Estimating the magnitude and sensitivity of energy fluxes for stickleback hosts and Schistocephalus solidus parasites using the metabolic theory of ecology. Ecol Evol 2023; 13:e10755. [PMID: 38053794 PMCID: PMC10694383 DOI: 10.1002/ece3.10755] [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: 05/21/2023] [Revised: 11/03/2023] [Accepted: 11/09/2023] [Indexed: 12/07/2023] Open
Abstract
Parasites are ubiquitous, yet their effects on hosts are difficult to quantify and generalize across ecosystems. One promising metric of parasitic impact uses the metabolic theory of ecology (MTE) to calculate energy flux, an estimate of energy lost to parasites. We investigated the feasibility of using metabolic scaling rules to compare the energetic burden of parasitism among individuals. Specifically, we found substantial sensitivity of energy flux estimates to input parameters used in the MTE equation when using available data from a model host-parasite system (Gasterosteus aculeatus and Schistocephalus solidus). Using literature values, size data from parasitized wild fish, and a respirometry experiment, we estimate that a single S. solidus tapeworm may extract up to 32% of its stickleback host's baseline metabolic energy requirement, and that parasites in multiple infections may collectively extract up to 46%. The amount of energy siphoned from stickleback to tapeworms is large but did not instigate an increase in respiration rate in the current study. This emphasizes the importance of future work focusing on how parasites influence ecosystem energetics. The approach of using the MTE to calculate energy flux provides great promise as a quantitative foundation for such estimates and provides a more concrete metric of parasite impact on hosts than parasite abundance alone.
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Affiliation(s)
- Danielle C. Claar
- Washington State Department of Natural ResourcesOlympiaWashingtonUSA
- School of Aquatic and Fishery SciencesUniversity of WashingtonSeattleWashingtonUSA
| | - Sara M. Faiad
- School of Aquatic and Fishery SciencesUniversity of WashingtonSeattleWashingtonUSA
| | - Natalie C. Mastick
- School of Aquatic and Fishery SciencesUniversity of WashingtonSeattleWashingtonUSA
| | - Rachel L. Welicky
- School of Aquatic and Fishery SciencesUniversity of WashingtonSeattleWashingtonUSA
- Unit for Environmental Sciences and ManagementNorth‐West UniversityPotchefstroomSouth Africa
- College of Arts and SciencesNeumann UniversityAstonPennsylvaniaUSA
| | - Maureen A. Williams
- School of Aquatic and Fishery SciencesUniversity of WashingtonSeattleWashingtonUSA
- Biology DepartmentMcDaniel CollegeWestminsterMarylandUSA
| | - Kristofer T. Sasser
- Department of Biological SciencesUniversity of Alaska AnchorageAnchorageAlaskaUSA
- Department of Integrative BiologyUniversity of Wisconsin MadisonMadisonWisconsinUSA
| | - Jesse N. Weber
- Department of Biological SciencesUniversity of Alaska AnchorageAnchorageAlaskaUSA
- Department of Integrative BiologyUniversity of Wisconsin MadisonMadisonWisconsinUSA
| | - Chelsea L. Wood
- School of Aquatic and Fishery SciencesUniversity of WashingtonSeattleWashingtonUSA
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7
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Aleuy OA, Peacock SJ, Molnár PK, Ruckstuhl KE, Kutz SJ. Local thermal adaptation and local temperature regimes drive the performance of a parasitic helminth under climate change: The case of Marshallagia marshalli from wild ungulates. GLOBAL CHANGE BIOLOGY 2023; 29:6217-6233. [PMID: 37615247 DOI: 10.1111/gcb.16918] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Revised: 07/24/2023] [Accepted: 07/26/2023] [Indexed: 08/25/2023]
Abstract
Across a species' range, populations are exposed to their local thermal environments, which on an evolutionary scale, may cause adaptative differences among populations. Helminths often have broad geographic ranges and temperature-sensitive life stages but little is known about whether and how local thermal adaptation can influence their response to climate change. We studied the thermal responses of the free-living stages of Marshallagia marshalli, a parasitic nematode of wild ungulates, along a latitudinal gradient. We first determine its distribution in wild sheep species in North America. Then we cultured M. marshalli eggs from different locations at temperatures from 5 to 38°C. We fit performance curves based on the metabolic theory of ecology to determine whether development and mortality showed evidence of local thermal adaptation. We used parameter estimates in life-cycle-based host-parasite models to understand how local thermal responses may influence parasite performance under general and location-specific climate-change projections. We found that M. marshalli has a wide latitudinal and host range, infecting wild sheep species from New Mexico to Yukon. Increases in mortality and development time at higher temperatures were most evident for isolates from northern locations. Accounting for location-specific parasite parameters primarily influenced the magnitude of climate change parasite performance, while accounting for location-specific climates primarily influenced the phenology of parasite performance. Despite differences in development and mortality among M. marshalli populations, when using site-specific climate change projections, there was a similar magnitude of impact on the relative performance of M. marshalli among populations. Climate change is predicted to decrease the expected lifetime reproductive output of M. marshalli in all populations while delaying its seasonal peak by approximately 1 month. Our research suggests that accurate projections of the impacts of climate change on broadly distributed species need to consider local adaptations of organisms together with local temperature profiles and climate projections.
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Affiliation(s)
- O Alejandro Aleuy
- Department of Biological Sciences, University of Calgary, Alberta, Calgary, Canada
- Department of Ecosystem and Public Health, Faculty of Veterinary Medicine, University of Calgary, Alberta, Calgary, Canada
| | - Stephanie J Peacock
- Department of Biological Sciences, University of Calgary, Alberta, Calgary, Canada
- Department of Ecosystem and Public Health, Faculty of Veterinary Medicine, University of Calgary, Alberta, Calgary, Canada
| | - Péter K Molnár
- Department of Ecology and Evolutionary Biology, University of Toronto, Ontario, Toronto, Canada
- Department of Biological Sciences, University of Toronto Scarborough, Ontario, Toronto, Canada
| | - Kathreen E Ruckstuhl
- Department of Biological Sciences, University of Calgary, Alberta, Calgary, Canada
| | - Susan J Kutz
- Department of Ecosystem and Public Health, Faculty of Veterinary Medicine, University of Calgary, Alberta, Calgary, Canada
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8
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Palmer-Young EC, Markowitz LM, Huang WF, Evans JD. High temperatures augment inhibition of parasites by a honey bee gut symbiont. Appl Environ Microbiol 2023; 89:e0102323. [PMID: 37791764 PMCID: PMC10617414 DOI: 10.1128/aem.01023-23] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2023] [Accepted: 08/02/2023] [Indexed: 10/05/2023] Open
Abstract
Temperature affects growth, metabolism, and interspecific interactions in microbial communities. Within animal hosts, gut bacterial symbionts can provide resistance to parasitic infections. Both infection and populations of symbionts can be shaped by the host body temperature. However, the effects of temperature on the antiparasitic activities of gut symbionts have seldom been explored. The Lactobacillus-rich gut microbiota of facultatively endothermic honey bees is subject to seasonal and ontogenetic changes in host temperature that could alter the effects of symbionts against parasites. We used cell cultures of a Lactobacillus symbiont and an important trypanosomatid gut parasite of honey bees to test the potential for temperature to shape parasite-symbiont interactions. We found that symbionts showed greater heat tolerance than parasites and chemically inhibited parasite growth via production of acids. Acceleration of symbiont growth and acid production at high temperatures resulted in progressively stronger antiparasitic effects across a temperature range typical of bee colonies. Consequently, the presence of symbionts reduced both the peak growth rate and heat tolerance of parasites. Substantial changes in parasite-symbiont interactions were evident over a temperature breadth that parallels changes in diverse animals exhibiting infection-related fevers and the amplitude of circadian temperature variation typical of endothermic birds and mammals, implying the frequent potential for temperature to alter symbiont-mediated resistance to parasites in endo- and ectothermic hosts. Results suggest that the endothermic behavior of honey bees could enhance the impacts of gut symbionts on parasites, implicating thermoregulation as a reinforcer of core symbioses and possibly microbiome-mediated antiparasitic defense. IMPORTANCE Two factors that shape the resistance of animals to infection are body temperature and gut microbiota. However, temperature can also alter interactions among microbes, raising the question of whether and how temperature changes the antiparasitic effects of gut microbiota. Honey bees are agriculturally important hosts of diverse parasites and infection-mitigating gut microbes. They can also socially regulate their body temperatures to an extent unusual for an insect. We show that high temperatures found in honey bee colonies augment the ability of a gut bacterial symbiont to inhibit the growth of a common bee parasite, reducing the parasite's ability to grow at high temperatures. This suggests that fluctuations in colony and body temperatures across life stages and seasons could alter the protective value of bees' gut microbiota against parasites, and that temperature-driven changes in gut microbiota could be an underappreciated mechanism by which temperature-including endothermy and fever-alters animal infection.
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Affiliation(s)
| | - Lindsey M. Markowitz
- USDA-ARS Bee Research Lab, Beltsville, Maryland, USA
- Department of Biology, University of Maryland, College Park, Maryland, USA
| | | | - Jay D. Evans
- USDA-ARS Bee Research Lab, Beltsville, Maryland, USA
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9
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Krichel L, Kirk D, Pencer C, Hönig M, Wadhawan K, Krkošek M. Short-term temperature fluctuations increase disease in a Daphnia-parasite infectious disease system. PLoS Biol 2023; 21:e3002260. [PMID: 37683040 PMCID: PMC10491407 DOI: 10.1371/journal.pbio.3002260] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2023] [Accepted: 07/18/2023] [Indexed: 09/10/2023] Open
Abstract
Climate change has profound effects on infectious disease dynamics, yet the impacts of increased short-term temperature fluctuations on disease spread remain poorly understood. We empirically tested the theoretical prediction that short-term thermal fluctuations suppress endemic infection prevalence at the pathogen's thermal optimum. This prediction follows from a mechanistic disease transmission model analyzed using stochastic simulations of the model parameterized with thermal performance curves (TPCs) from metabolic scaling theory and using nonlinear averaging, which predicts ecological outcomes consistent with Jensen's inequality (i.e., reduced performance around concave-down portions of a thermal response curve). Experimental observations of replicated epidemics of the microparasite Ordospora colligata in Daphnia magna populations indicate that temperature variability had the opposite effect of our theoretical predictions and instead increase endemic infection prevalence. This positive effect of temperature variability is qualitatively consistent with a published hypothesis that parasites may acclimate more rapidly to fluctuating temperatures than their hosts; however, incorporating hypothetical effects of delayed host acclimation into the mechanistic transmission model did not fully account for the observed pattern. The experimental data indicate that shifts in the distribution of infection burden underlie the positive effect of temperature fluctuations on endemic prevalence. The increase in disease risk associated with climate fluctuations may therefore result from disease processes interacting across scales, particularly within-host dynamics, that are not captured by combining standard transmission models with metabolic scaling theory.
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Affiliation(s)
- Leila Krichel
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Canada
| | - Devin Kirk
- Department of Biology, Stanford University, Stanford, California, United States of America
| | - Clara Pencer
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Canada
| | - Madison Hönig
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Canada
- Department of Anthropology, Washington State University, Pullman, Washington, United States of America
| | - Kiran Wadhawan
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Canada
- School of Biological Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Martin Krkošek
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Canada
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10
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Pile B, Warren D, Hassall C, Brown LE, Dunn AM. Biological Invasions Affect Resource Processing in Aquatic Ecosystems: The Invasive Amphipod Dikerogammarus villosus Impacts Detritus Processing through High Abundance Rather than Differential Response to Temperature. BIOLOGY 2023; 12:830. [PMID: 37372115 DOI: 10.3390/biology12060830] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2023] [Revised: 05/24/2023] [Accepted: 06/05/2023] [Indexed: 06/29/2023]
Abstract
Anthropogenic stressors such as climate warming and invasive species and natural stressors such as parasites exert pressures that can interact to impact the function of ecosystems. This study investigated how these stressors interact to impact the vital ecosystem process of shredding by keystone species in temperate freshwater ecosystems. We compared metabolic rates and rates of shredding at a range of temperatures up to extreme levels, from 5 °C to 30 °C, between invasive and native amphipods that were unparasitised or parasitised by a common acanthocephalan, Echinorhynchus truttae. Shredding results were compared using the relative impact potential (RIP) metric to investigate how they impacted the scale with a numerical response. Although per capita shredding was higher for the native amphipod at all temperatures, the higher abundance of the invader led to higher relative impact scores; hence, the replacement of the native by the invasive amphipod is predicted to drive an increase in shredding. This could be interpreted as a positive effect on the ecosystem function, leading to a faster accumulation of amphipod biomass and a greater rate of fine particulate organic matter (FPOM) provisioning for the ecosystem. However, the high density of invaders compared with natives may lead to the exhaustion of the resource in sites with relatively low leaf detritus levels.
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Affiliation(s)
- Benjamin Pile
- School of Biology, University of Leeds, Leeds LS2 9JT, West Yorkshire, UK
| | - Daniel Warren
- Animal and Plant Health Agency (APHA), Sand Hutton YO41 1LZ, York, UK
| | | | - Lee E Brown
- School of Geography and Water@Leeds, University of Leeds, Leeds LS2 9JT, West Yorkshire, UK
| | - Alison M Dunn
- School of Biology, University of Leeds, Leeds LS2 9JT, West Yorkshire, UK
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11
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Hector TE, Gehman ALM, King KC. Infection burdens and virulence under heat stress: ecological and evolutionary considerations. Philos Trans R Soc Lond B Biol Sci 2023; 378:20220018. [PMID: 36744570 PMCID: PMC9900716 DOI: 10.1098/rstb.2022.0018] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
As a result of global change, hosts and parasites (including pathogens) are experiencing shifts in their thermal environment. Despite the importance of heat stress tolerance for host population persistence, infection by parasites can impair a host's ability to cope with heat. Host-parasite eco-evolutionary dynamics will be affected if infection reduces host performance during heating. Theory predicts that within-host parasite burden (replication rate or number of infecting parasites per host), a key component of parasite fitness, should correlate positively with virulence-the harm caused to hosts during infection. Surprisingly, however, the relationship between within-host parasite burden and virulence during heating is often weak. Here, we describe the current evidence for the link between within-host parasite burden and host heat stress tolerance. We consider the biology of host-parasite systems that may explain the weak or absent link between these two important host and parasite traits during hot conditions. The processes that mediate the relationship between parasite burden and host fitness will be fundamental in ecological and evolutionary responses of host and parasites in a warming world. This article is part of the theme issue 'Infectious disease ecology and evolution in a changing world'.
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Affiliation(s)
- T. E. Hector
- Department of Biology, University of Oxford, Oxford, Oxfordshire OX1 3SZ, UK
| | - A.-L. M. Gehman
- Hakai Institute, End of Kwakshua Channel, Calvert Island, BC Canada, V0N 1M0,Institute for the Oceans and Fisheries, University of British Columbia, 2202 Main Mall, Vancouver, BC Canada, V6T 1Z4
| | - K. C. King
- Department of Biology, University of Oxford, Oxford, Oxfordshire OX1 3SZ, UK
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12
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Palmer-Young EC, Ryabov EV, Markowitz LM, Boncristiani DL, Grubbs K, Pawar A, Peterson R, Evans JD. Host-driven temperature dependence of Deformed wing virus infection in honey bee pupae. Commun Biol 2023; 6:333. [PMID: 36973325 PMCID: PMC10042853 DOI: 10.1038/s42003-023-04704-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Accepted: 03/14/2023] [Indexed: 03/29/2023] Open
Abstract
The temperature dependence of infection reflects changes in performance of parasites and hosts. High temperatures often mitigate infection by favoring heat-tolerant hosts over heat-sensitive parasites. Honey bees exhibit endothermic thermoregulation-rare among insects-that can favor resistance to parasites. However, viruses are heavily host-dependent, suggesting that viral infection could be supported-not threatened-by optimum host function. To understand how temperature-driven changes in performance of viruses and hosts shape infection, we compared the temperature dependence of isolated viral enzyme activity, three honey bee traits, and infection of honey bee pupae. Viral enzyme activity varied <2-fold over a > 30 °C interval spanning temperatures typical of ectothermic insects and honey bees. In contrast, honey bee performance peaked at high (≥ 35 °C) temperatures and was highly temperature-sensitive. Although these results suggested that increasing temperature would favor hosts over viruses, the temperature dependence of pupal infection matched that of pupal development, falling only near pupae's upper thermal limits. Our results reflect the host-dependent nature of viruses, suggesting that infection is accelerated-not curtailed-by optimum host function, contradicting predictions based on relative performance of parasites and hosts, and suggesting tradeoffs between infection resistance and host survival that limit the viability of bee 'fever'.
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Affiliation(s)
| | - Eugene V Ryabov
- USDA-ARS Bee Research Laboratory, Beltsville, MD, USA
- Department of Entomology, University of Maryland, College Park, MD, USA
| | - Lindsey M Markowitz
- USDA-ARS Bee Research Laboratory, Beltsville, MD, USA
- Department of Biology, University of Maryland, College Park, MD, USA
| | | | - Kyle Grubbs
- USDA-ARS Bee Research Laboratory, Beltsville, MD, USA
| | - Asha Pawar
- USDA-ARS Bee Research Laboratory, Beltsville, MD, USA
| | | | - Jay D Evans
- USDA-ARS Bee Research Laboratory, Beltsville, MD, USA
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13
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Munch SB, Rogers TL, Symons CC, Anderson D, Pennekamp F. Constraining nonlinear time series modeling with the metabolic theory of ecology. Proc Natl Acad Sci U S A 2023; 120:e2211758120. [PMID: 36930600 PMCID: PMC10041132 DOI: 10.1073/pnas.2211758120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2022] [Accepted: 02/08/2023] [Indexed: 03/18/2023] Open
Abstract
Forecasting the response of ecological systems to environmental change is a critical challenge for sustainable management. The metabolic theory of ecology (MTE) posits scaling of biological rates with temperature, but it has had limited application to population dynamic forecasting. Here we use the temperature dependence of the MTE to constrain empirical dynamic modeling (EDM), an equation-free nonlinear machine learning approach for forecasting. By rescaling time with temperature and modeling dynamics on a "metabolic time step," our method (MTE-EDM) improved forecast accuracy in 18 of 19 empirical ectotherm time series (by 19% on average), with the largest gains in more seasonal environments. MTE-EDM assumes that temperature affects only the rate, rather than the form, of population dynamics, and that interacting species have approximately similar temperature dependence. A review of laboratory studies suggests these assumptions are reasonable, at least approximately, though not for all ecological systems. Our approach highlights how to combine modern data-driven forecasting techniques with ecological theory and mechanistic understanding to predict the response of complex ecosystems to temperature variability and trends.
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Affiliation(s)
- Stephan B. Munch
- Southwest Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, Santa Cruz, CA95060
- Department of Applied Mathematics, University of California, Santa Cruz, CA95060
| | - Tanya L. Rogers
- Southwest Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, Santa Cruz, CA95060
| | - Celia C. Symons
- Department of Ecology and Evolutionary Biology, University of California, Irvine, CA92697
| | - David Anderson
- Department of Zoology, University of British Columbia, Vancouver, BCV6T 1Z4, Canada
| | - Frank Pennekamp
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, Zurich8057, Switzerland
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14
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Angst P, Ebert D, Fields PD. Population genetic analysis of the microsporidium Ordospora colligata reveals the role of natural selection and phylogeography on its extremely compact and reduced genome. G3 (BETHESDA, MD.) 2023; 13:jkad017. [PMID: 36655395 PMCID: PMC9997559 DOI: 10.1093/g3journal/jkad017] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2022] [Revised: 01/02/2023] [Accepted: 01/11/2023] [Indexed: 01/20/2023]
Abstract
The determinants of variation in a species' genome-wide nucleotide diversity include historical, environmental, and stochastic aspects. This diversity can inform us about the species' past and present evolutionary dynamics. In parasites, the mode of transmission and the interactions with the host might supersede the effects of these aspects in shaping parasite genomic diversity. We used genomic samples from 10 populations of the microsporidian parasite Ordospora colligata to investigate present genomic diversity and how it was shaped by evolutionary processes, specifically, the role of phylogeography, co-phylogeography (with the host), natural selection, and transmission mode. Although very closely related microsporidia cause diseases in humans, O. colligata is specific to the freshwater crustacean Daphnia magna and has one of the smallest known eukaryotic genomes. We found an overlapping phylogeography between O. colligata and its host highlighting the long-term, intimate relationship between them. The observed geographic distribution reflects previous findings that O. colligata exhibits adaptations to colder habitats, which differentiates it from other microsporidian gut parasites of D. magna predominantly found in warmer areas. The co-phylogeography allowed us to calibrate the O. colligata phylogeny and thus estimate its mutation rate. We identified several genetic regions under potential selection. Our whole-genome study provides insights into the evolution of one of the most reduced eukaryotic genomes and shows how different processes shape genomic diversity of an obligate parasite.
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Affiliation(s)
- Pascal Angst
- Department of Environmental Sciences, Zoology, University of Basel, Basel 4051, Switzerland
| | - Dieter Ebert
- Department of Environmental Sciences, Zoology, University of Basel, Basel 4051, Switzerland
| | - Peter D Fields
- Department of Environmental Sciences, Zoology, University of Basel, Basel 4051, Switzerland
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15
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Manlik O, Mundra S, Schmid‐Hempel R, Schmid‐Hempel P. Impact of climate change on parasite infection of an important pollinator depends on host genotypes. GLOBAL CHANGE BIOLOGY 2023; 29:69-80. [PMID: 36176231 PMCID: PMC10092497 DOI: 10.1111/gcb.16460] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2022] [Revised: 09/07/2022] [Accepted: 09/26/2022] [Indexed: 05/20/2023]
Abstract
Climate change is predicted to affect host-parasite interactions, and for some hosts, parasite infection is expected to increase with rising temperatures. Global population declines of important pollinators already have been attributed to climate change and parasitism. However, the role of climate in driving parasite infection and the genetic basis for pollinator hosts to respond often remain obscure. Based on decade-long field data, we investigated the association between climate and Nosema bombi (Microsporidia) infection of buffed-tailed bumblebees (Bombus terrestris), and whether host genotypes play a role. For this, we genotyped 876 wild bumblebee queens and screened for N. bombi infection of those queens between 2000 and 2010. We recorded seven climate parameters during those 11 years and tested for correlations between climate and infection prevalence. Here we show that climatic factors drive N. bombi infection and that the impact of climate depends on mitochondrial DNA cytochrome oxidase I (COI) haplotypes of the host. Infection prevalence was correlated with climatic variables during the time when queens emerge from hibernation. Remarkably, COI haplotypes best predict this association between climatic factors and infection. In particular, two host haplotypes ("A" and "B") displayed phenotypic plasticity in response to climatic variation: Temperature was positively correlated with infection of host haplotype B, but not haplotype A. The likelihood of infection of haplotype A was associated with moisture, conferring greater resistance to parasite infection during wetter years. In contrast, infection of haplotype B was unrelated to moisture. To the best of our knowledge, this is the first study that identifies specific host genotypes that confer differential parasite resistance under variable climatic conditions. Our results underscore the importance of mitochondrial haplotypes to ward off parasites in a changing climate. More broadly, this also suggests that COI may play a pertinent role in climate change adaptations of insect pollinators.
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Affiliation(s)
- Oliver Manlik
- Biology Department, College of ScienceUnited Arab Emirates UniversityAl AinUnited Arab Emirates
- Evolution and Ecology Research Centre, School of Biological Earth and Environmental ScienceUniversity of New South WalesSydneyNew South WalesAustralia
| | - Sunil Mundra
- Biology Department, College of ScienceUnited Arab Emirates UniversityAl AinUnited Arab Emirates
- Khalifa Center for Genetic Engineering and BiotechnologyUnited Arab Emirates UniversityAl AinUnited Arab Emirates
| | - Regula Schmid‐Hempel
- Khalifa Center for Genetic Engineering and BiotechnologyUnited Arab Emirates UniversityAl AinUnited Arab Emirates
| | - Paul Schmid‐Hempel
- ETH Zurich, Institute of Integrative Biology (IBZ), ETH‐Zentrum CHNZurichSwitzerland
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16
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Ameline C, Voegtli F, Andras J, Dexter E, Engelstädter J, Ebert D. Genetic slippage after sex maintains diversity for parasite resistance in a natural host population. SCIENCE ADVANCES 2022; 8:eabn0051. [PMID: 36399570 PMCID: PMC9674289 DOI: 10.1126/sciadv.abn0051] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Accepted: 10/04/2022] [Indexed: 06/16/2023]
Abstract
Although parasite-mediated selection is a major driver of host evolution, its influence on genetic variation for parasite resistance is not yet well understood. We monitored resistance in a large population of the planktonic crustacean Daphnia magna over 8 years, as it underwent yearly epidemics of the bacterial pathogen Pasteuria ramosa. We observed cyclic dynamics of resistance: Resistance increased throughout the epidemics, but susceptibility was restored each spring when hosts hatched from sexual resting stages. Host resting stages collected across the year showed that largely resistant host populations can produce susceptible sexual offspring. A genetic model of resistance developed for this host-parasite system, based on multiple loci and strong epistasis, is in partial agreement with our findings. Our results reveal that, despite strong selection for resistance in a natural host population, genetic slippage after sexual reproduction can be a strong factor for the maintenance of genetic diversity of host resistance.
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Affiliation(s)
- Camille Ameline
- Department of Environmental Sciences, Zoology, University of Basel, Vesalgasse 1, 4051 Basel, Switzerland
| | - Felix Voegtli
- Department of Environmental Sciences, Zoology, University of Basel, Vesalgasse 1, 4051 Basel, Switzerland
| | - Jason Andras
- Department of Environmental Sciences, Zoology, University of Basel, Vesalgasse 1, 4051 Basel, Switzerland
| | - Eric Dexter
- Department of Environmental Sciences, Zoology, University of Basel, Vesalgasse 1, 4051 Basel, Switzerland
| | - Jan Engelstädter
- School of Biological Sciences, The University of Queensland, Brisbane, Australia
| | - Dieter Ebert
- Department of Environmental Sciences, Zoology, University of Basel, Vesalgasse 1, 4051 Basel, Switzerland
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17
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Chown SL. Macrophysiology for decision‐making. J Zool (1987) 2022. [DOI: 10.1111/jzo.13029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- S. L. Chown
- Securing Antarctica's Environmental Future, School of Biological Sciences Monash University Melbourne Victoria Australia
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18
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Kirk D, O’Connor MI, Mordecai EA. Scaling effects of temperature on parasitism from individuals to populations. J Anim Ecol 2022; 91:2087-2102. [PMID: 35900837 PMCID: PMC9532350 DOI: 10.1111/1365-2656.13786] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Accepted: 07/15/2022] [Indexed: 11/27/2022]
Abstract
Parasitism is expected to change in a warmer future, but whether warming leads to substantial increases in parasitism remains unclear. Understanding how warming effects on parasitism in individual hosts (e.g. parasite load) translate to effects on population-level parasitism (e.g. prevalence, R0 ) remains a major knowledge gap. We conducted a literature review and identified 24 host-parasite systems that had information on the temperature dependence of parasitism at both individual host and host population levels: 13 vector-borne systems and 11 environmentally transmitted systems. We found a strong positive correlation between the thermal optima of individual- and population-level parasitism, although several of the environmentally transmitted systems exhibited thermal optima >5°C apart between individual and population levels. Parasitism thermal optima were close to vector performance thermal optima in vector-borne systems but not hosts in environmentally transmitted systems, suggesting these thermal mismatches may be more common in certain types of host-parasite systems. We also adapted and simulated simple models for both types of transmission modes and found the same pattern across the two modes: thermal optima were more strongly correlated across scales when there were more traits linking individual- to population-level processes. Generally, our results suggest that information on the temperature dependence, and specifically the thermal optimum, at either the individual or population level should provide a useful-although not quantitatively exact-baseline for predicting temperature dependence at the other level, especially in vector-borne parasite systems. Environmentally transmitted parasitism may operate by a different set of rules, in which temperature dependence is decoupled in some systems, requiring the need for trait-based studies of temperature dependence at individual and population levels.
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Affiliation(s)
- Devin Kirk
- Department of Biology, Stanford University, Stanford, USA
- Department of Zoology, University of British Columbia, Vancouver, Canada
| | - Mary I. O’Connor
- Department of Zoology, University of British Columbia, Vancouver, Canada
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19
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Spaan JM, Leavitt N, Shen J, Bundy T, Burrows L, Ingram C, Maehara TR, Ndungu I, Mutuku M, Owino G, Odiere M, Steinauer ML. Genotypic-specific heat shock response of vector susceptibility to Schistosoma mansoni. Ecosphere 2022; 13:e4207. [PMID: 36590709 PMCID: PMC9797131 DOI: 10.1002/ecs2.4207] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Accepted: 04/27/2022] [Indexed: 01/05/2023] Open
Abstract
Living organisms are vulnerable to thermal stress which causes a diversity of physiological outcomes. Previous work has shown that the snail vectors (Biomphalaria glabrata) of an important human pathogen, Schistosoma mansoni, revert from resistant to susceptible after short exposure to a heat stress as low as 31oC; however, due to lack of replicability among labs and genetic lines of snails, it has been hypothesized that this effect is genotype dependent. We examined the effects of heat shock on resistance of two species of snail vectors including B. glabrata and B. sudanica. We used 3 different inbred laboratory snail lines in addition to the F1 generation of field collected snails from Lake Victoria, Kenya, an area with high levels of schistosomiasis transmission. Our results showed marginal effects of heat shock on prevalence of infection in B. glabrata, and that this response was genotype specific. We found no evidence of a heat shock effect on prevalence of infection in B. sudanica or on intensity of infection (number of infectious stages shed) in either snail species. Such environmentally influenced defense responses stress the importance of considering this unique interaction between snail and parasite genotypes in determining infection dynamics under climate changes.
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Affiliation(s)
- Johannie M. Spaan
- Department of Basic Medical Sciences, Western University of Health Sciences, Lebanon, Oregon 97355
| | - Nathaniel Leavitt
- Department of Basic Medical Sciences, Western University of Health Sciences, Lebanon, Oregon 97355
| | - Jessica Shen
- Department of Basic Medical Sciences, Western University of Health Sciences, Lebanon, Oregon 97355
| | - Taylor Bundy
- Department of Medicine, Oregon Health and Science University, Portland, Oregon 97239
| | - Lillian Burrows
- Department of Basic Medical Sciences, Western University of Health Sciences, Lebanon, Oregon 97355
| | - Christopher Ingram
- Department of Basic Medical Sciences, Western University of Health Sciences, Lebanon, Oregon 97355
| | - Thomas R. Maehara
- M.D. School of Medicine, Western Michigan University Home Stryker, Kalamazoo, Michigan 49001
| | - Ibrahim Ndungu
- Centre for Biotechnology Research and Development, Kenya Medical Research Institute, Nairobi, Kenya
| | - Martin Mutuku
- Centre for Biotechnology Research and Development, Kenya Medical Research Institute, Nairobi, Kenya
| | - George Owino
- Neglected Tropical Diseases Unit, Center for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - Maurice Odiere
- Neglected Tropical Diseases Unit, Center for Global Health Research, Kenya Medical Research Institute, Kisumu, Kenya
| | - Michelle L. Steinauer
- Department of Basic Medical Sciences, Western University of Health Sciences, Lebanon, Oregon 97355
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20
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Peacock SJ, Kutz SJ, Hoar BM, Molnár PK. Behaviour is more important than thermal performance for an Arctic host-parasite system under climate change. ROYAL SOCIETY OPEN SCIENCE 2022; 9:220060. [PMID: 36016913 PMCID: PMC9399711 DOI: 10.1098/rsos.220060] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2022] [Accepted: 08/02/2022] [Indexed: 05/10/2023]
Abstract
Climate change is affecting Arctic ecosystems, including parasites. Predicting outcomes for host-parasite systems is challenging due to the complexity of multi-species interactions and the numerous, interacting pathways by which climate change can alter dynamics. Increasing temperatures may lead to faster development of free-living parasite stages but also higher mortality. Interactions between behavioural plasticity of hosts and parasites will also influence transmission processes. We combined laboratory experiments and population modelling to understand the impacts of changing temperatures on barren-ground caribou (Rangifer tarandus) and their common helminth (Ostertagia gruehneri). We experimentally determined the thermal performance curves for mortality and development of free-living parasite stages and applied them in a spatial host-parasite model that also included behaviour of the parasite (propensity for arrested development in the host) and host (long-distance migration). Sensitivity analyses showed that thermal responses had less of an impact on simulated parasite burdens than expected, and the effect differed depending on parasite behaviour. The propensity for arrested development and host migration led to distinct spatio-temporal patterns in infection. These results emphasize the importance of considering behaviour-and behavioural plasticity-when projecting climate-change impacts on host-parasite systems.
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Affiliation(s)
- Stephanie J. Peacock
- Department of Ecosystem and Public Health, University of Calgary, 3280 Hospital Drive NW, Calgary, AB Canada, T2N 4Z6
- Department of Biological Sciences, University of Toronto Scarborough, 1265 Military Trail, Toronto, ON Canada, M1C 1A4
| | - Susan J. Kutz
- Department of Ecosystem and Public Health, University of Calgary, 3280 Hospital Drive NW, Calgary, AB Canada, T2N 4Z6
| | - Bryanne M. Hoar
- Department of Ecosystem and Public Health, University of Calgary, 3280 Hospital Drive NW, Calgary, AB Canada, T2N 4Z6
| | - Péter K. Molnár
- Department of Biological Sciences, University of Toronto Scarborough, 1265 Military Trail, Toronto, ON Canada, M1C 1A4
- Department of Ecology and Evolutionary Biology, University of Toronto, 25 Willcocks Street, Toronto, ON Canada, M5S 3B2
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21
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Robinson HE, Alexander JD, Bartholomew JL, Hallett SL, Hetrick NJ, Perry RW, Som NA. Using a mechanistic framework to model the density of an aquatic parasite Ceratonova shasta. PeerJ 2022; 10:e13183. [PMID: 35441056 PMCID: PMC9013479 DOI: 10.7717/peerj.13183] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Accepted: 03/07/2022] [Indexed: 01/12/2023] Open
Abstract
Ceratonova shasta is a myxozoan parasite endemic to the Pacific Northwest of North America that is linked to low survival rates of juvenile salmonids in some watersheds such as the Klamath River basin. The density of C. shasta actinospores in the water column is typically highest in the spring (March-June), and directly influences infection rates for outmigrating juvenile salmonids. Current management approaches require quantities of C. shasta density to assess disease risk and estimate survival of juvenile salmonids. Therefore, we developed a model to simulate the density of waterborne C. shasta actinospores using a mechanistic framework based on abiotic drivers and informed by empirical data. The model quantified factors that describe the key features of parasite abundance during the period of juvenile salmon outmigration, including the week of initial detection (onset), seasonal pattern of spore density, and peak density of C. shasta. Spore onset was simulated by a bio-physical degree-day model using the timing of adult salmon spawning and accumulation of thermal units for parasite development. Normalized spore density was simulated by a quadratic regression model based on a parabolic thermal response with river water temperature. Peak spore density was simulated based on retained explanatory variables in a generalized linear model that included the prevalence of infection in hatchery-origin Chinook juveniles the previous year and the occurrence of flushing flows (≥171 m3/s). The final model performed well, closely matched the initial detections (onset) of spores, and explained inter-annual variations for most water years. Our C. shasta model has direct applications as a management tool to assess the impact of proposed flow regimes on the parasite, and it can be used for projecting the effects of alternative water management scenarios on disease-induced mortality of juvenile salmonids such as with an altered water temperature regime or with dam removal.
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Affiliation(s)
- H. Eve Robinson
- Arcata Fish and Wildlife Office, U.S. Fish and Wildlife Service, Arcata, CA, United States of America,California State Polytechnic University, Humboldt, Arcata, CA, United States of America
| | - Julie D. Alexander
- Department of Microbiology, Oregon State University, Corvallis, OR, United States of America
| | - Jerri L. Bartholomew
- Department of Microbiology, Oregon State University, Corvallis, OR, United States of America
| | - Sascha L. Hallett
- Department of Microbiology, Oregon State University, Corvallis, OR, United States of America
| | - Nicholas J. Hetrick
- Arcata Fish and Wildlife Office, U.S. Fish and Wildlife Service, Arcata, CA, United States of America
| | - Russell W. Perry
- U.S. Geological Survey, Western Fisheries Research Center, Cook, WA, United States of America
| | - Nicholas A. Som
- Arcata Fish and Wildlife Office, U.S. Fish and Wildlife Service, Arcata, CA, United States of America,California State Polytechnic University, Humboldt, Arcata, CA, United States of America
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22
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Schampera C, Agha R, Manzi F, Wolinska J. Parasites do not adapt to elevated temperature, as evidenced from experimental evolution of a phytoplankton-fungus system. Biol Lett 2022; 18:20210560. [PMID: 35168375 PMCID: PMC8847893 DOI: 10.1098/rsbl.2021.0560] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Global warming is predicted to impact the prevalence and severity of infectious diseases. However, empirical data supporting this statement usually stem from experiments in which parasite fitness and disease outcome are measured directly after temperature increase. This might exclude the possibility of parasite adaptation. To incorporate the adaptive response of parasites into predictions of disease severity in a warmer world, we undertook an experimental evolution assay in which a fungal parasite of phytoplankton was maintained at elevated or control temperatures for six months, corresponding to 100–200 parasite generations. Host cultures were maintained at the respective temperatures and provided as substrate, but were not under parasite pressure. A reciprocal infection experiment conducted after six-month serial passages revealed no evidence of parasite adaptation. In fact, parasite fitness at elevated temperatures was inferior in parasite populations reared at elevated temperatures compared with those maintained under control temperature. However, this effect was reversed after parasites were returned to control temperatures for a few (approx. 10) generations. The absence of parasite adaptation to elevated temperatures suggests that, in phytoplankton–fungus systems, disease outcome under global warming will be largely determined by both host and parasite thermal ecology.
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Affiliation(s)
- Charlotte Schampera
- Leibniz Institute of Freshwater Ecology and Inland Fisheries (IGB), Berlin, Germany
| | - Ramsy Agha
- Leibniz Institute of Freshwater Ecology and Inland Fisheries (IGB), Berlin, Germany
| | - Florent Manzi
- Leibniz Institute of Freshwater Ecology and Inland Fisheries (IGB), Berlin, Germany.,Department of Biology, Chemistry, Pharmacy, Institute of Biology, Freie Universität (FU) Berlin, Berlin, Germany
| | - Justyna Wolinska
- Leibniz Institute of Freshwater Ecology and Inland Fisheries (IGB), Berlin, Germany.,Department of Biology, Chemistry, Pharmacy, Institute of Biology, Freie Universität (FU) Berlin, Berlin, Germany
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23
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Kunze C, Luijckx P, Jackson AL, Donohue I. Alternate patterns of temperature variation bring about very different disease outcomes at different mean temperatures. eLife 2022; 11:72861. [PMID: 35164901 PMCID: PMC8846586 DOI: 10.7554/elife.72861] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Accepted: 01/05/2022] [Indexed: 02/01/2023] Open
Abstract
The dynamics of host-parasite interactions are highly temperature-dependent and may be modified by increasing frequency and intensity of climate-driven heat events. Here, we show that altered patterns of temperature variance lead to an almost order-of-magnitude shift in thermal performance of host and pathogen life-history traits over and above the effects of mean temperature and, moreover, that different temperature regimes affect these traits differently. We found that diurnal fluctuations of ±3°C lowered infection rates and reduced spore burden compared to constant temperatures in our focal host Daphnia magna exposed to the microsporidium parasite Ordospora colligata. In contrast, a 3-day heatwave (+6°C) did not affect infection rates, but increased spore burden (relative to constant temperatures with the same mean) at 16°C, while reducing burden at higher temperatures. We conclude that changing patterns of climate variation, superimposed on shifts in mean temperatures due to global warming, may have profound and unanticipated effects on disease dynamics. Global warming is increasing average temperatures and causing extreme temperature fluctuations and heatwaves. These changes may affect when, where, and how often infectious disease outbreaks occur. This could have profound impacts on agriculture, human health, and wildlife. Studying how extreme temperatures or temperature fluctuations alter infections in laboratory animals may help scientists to better understand the impact of climate change on disease. A small aquatic invertebrate, such as a water flea, is one good candidate for such studies. These tiny creatures can be grown in small glass jars in temperature-controlled aquariums. Kunze, Luijckx et al. show that temperature fluctuations and heat waves have complex effects on parasitic infections in water fleas. In the experiments, water fleas housed with a parasite that infects them were exposed to constant temperatures, fluctuating temperatures, or three-day heatwaves, while being kept at a broad range of mean water temperatures. Then, Kunze, Luijckx et al. measured how these conditions affected the water fleas’ longevity, reproduction, and parasite infections. This revealed that temperature variations had a unique effect on the life span, and reproduction and infection rates of the water fleas, depending on the average water temperature the animals were kept at. Heatwaves drastically increased the number of parasites in the water fleas at an average water temperature of 16 °C but had no effect at all or decreased the number of parasites at 19 °C and 22 °C, respectively. Similarly, at high average water temperatures (>24 °C), temperature fluctuations reduced the number of water fleas infected with parasites and the number of parasites in each infected flea. Moreover, the maximum temperature at which parasites were able to cause infections was 5 °C lower under fluctuating temperatures than under constant temperatures. Kunze and Luijckx et al. show that consistent high temperatures, temperature changes, extreme weather events, and mean water temperature affect disease outcomes in water fleas. More studies are needed to assess how temperature variations change the course of diseases in other organisms and to understand the underlying mechanisms. Learning more about disease-temperature interactions will help scientists predict climate change-driven disease outbreaks.
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Affiliation(s)
- Charlotte Kunze
- Institute for Chemistry and Biology of the Marine Environment [ICBM], Carl von Ossietzky University of Oldenburg, Oldenburg, Germany.,Department of Zoology, School of Natural Sciences, Trinity College Dublin, Dublin, Ireland
| | - Pepijn Luijckx
- Department of Zoology, School of Natural Sciences, Trinity College Dublin, Dublin, Ireland
| | - Andrew L Jackson
- Department of Zoology, School of Natural Sciences, Trinity College Dublin, Dublin, Ireland
| | - Ian Donohue
- Department of Zoology, School of Natural Sciences, Trinity College Dublin, Dublin, Ireland
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24
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Sckrabulis JP, Altman KA, Raffel TR. Using metabolic theory to describe temperature and thermal acclimation effects on parasitic infection. Am Nat 2022; 199:789-803. [DOI: 10.1086/719409] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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25
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Willis AR, Reinke AW. Factors That Determine Microsporidia Infection and Host Specificity. EXPERIENTIA SUPPLEMENTUM (2012) 2022; 114:91-114. [PMID: 35544000 DOI: 10.1007/978-3-030-93306-7_4] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Microsporidia are a large phylum of obligate intracellular parasites that infect an extremely diverse range of animals and protists. In this chapter, we review what is currently known about microsporidia host specificity and what factors influence microsporidia infection. Extensive sampling in nature from related hosts has provided insight into the host range of many microsporidia species. These field studies have been supported by experiments conducted in controlled laboratory environments which have helped to demonstrate host specificity. Together, these approaches have revealed that, while examples of generalist species exist, microsporidia specificity is often narrow, and species typically infect one or several closely related hosts. For microsporidia to successfully infect and complete their life cycle within a compatible host, several steps must occur, including spore germination, host cell invasion, and proliferation of the parasite within the host tissue. Many factors influence infection, including temperature, seasonality, nutrient availability, and the presence or absence of microbes, as well as the developmental stage, sex, and genetics of the host. Several studies have identified host genomic regions that influence resistance to microsporidia, and future work is likely to uncover molecular mechanisms of microsporidia host specificity in more detail.
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Affiliation(s)
- Alexandra R Willis
- Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada
| | - Aaron W Reinke
- Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada.
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26
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Reyes-Montes MDR, Duarte-Escalante E, Frías-De-León MG, Pérez-Rodríguez A, Meraz-Ríos B. Impact of Climate Change on Dermatophytosis. Fungal Biol 2022. [DOI: 10.1007/978-3-030-89664-5_4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Palmer-Young EC, Raffel TR, Evans JD. Hot and sour: parasite adaptations to honeybee body temperature and pH. Proc Biol Sci 2021; 288:20211517. [PMID: 34847766 PMCID: PMC8634619 DOI: 10.1098/rspb.2021.1517] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2021] [Accepted: 10/28/2021] [Indexed: 01/14/2023] Open
Abstract
Host temperature and gut chemistry can shape resistance to parasite infection. Heat and acidity can limit trypanosomatid infection in warm-blooded hosts and could shape infection resistance in insects as well. The colony-level endothermy and acidic guts of social bees provide unique opportunities to study how temperature and acidity shape insect-parasite associations. We compared temperature and pH tolerance between three trypanosomatid parasites from social bees and a related trypanosomatid from poikilothermic mosquitoes, which have alkaline guts. Relative to the mosquito parasites, all three bee parasites had higher heat tolerance that reflected body temperatures of hosts. Heat tolerance of the honeybee parasite Crithidia mellificae was exceptional for its genus, implicating honeybee endothermy as a plausible filter of parasite establishment. The lesser heat tolerance of the emerging Lotmaria passim suggests possible spillover from a less endothermic host. Whereas both honeybee parasites tolerated the acidic pH found in bee intestines, mosquito parasites tolerated the alkaline conditions found in mosquito midguts, suggesting that both gut pH and temperature could structure host-parasite specificity. Elucidating how host temperature and gut pH affect infection-and corresponding parasite adaptations to these factors-could help explain trypanosomatids' distribution among insects and invasion of mammals.
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Bruijning M, Fossen EIF, Jongejans E, Vanvelk H, Raeymaekers JAM, Govaert L, Brans KI, Einum S, De Meester L. Host–parasite dynamics shaped by temperature and genotype: Quantifying the role of underlying vital rates. Funct Ecol 2021. [DOI: 10.1111/1365-2435.13966] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Marjolein Bruijning
- Department of Ecology and Evolutionary Biology Princeton University Princeton NJ USA
- Department of Animal Ecology and Physiology Radboud University Nijmegen The Netherlands
| | - Erlend I. F. Fossen
- Centre for Biodiversity Dynamics Department of Biology NTNUNorwegian University of Science and Technology Trondheim Norway
- Animal Ecology Department of Ecology and Genetics Uppsala University Uppsala Sweden
| | - Eelke Jongejans
- Department of Animal Ecology and Physiology Radboud University Nijmegen The Netherlands
- Animal Ecology NIOO‐KNAW Wageningen The Netherlands
| | - Héléne Vanvelk
- Laboratory of Aquatic Ecology, Evolution and Conservation KU Leuven Leuven Belgium
| | | | - Lynn Govaert
- Laboratory of Aquatic Ecology, Evolution and Conservation KU Leuven Leuven Belgium
- Department of Evolutionary Biology and Environmental Studies University of Zurich Zürich Switzerland
- Department of Aquatic Ecology Eawag Swiss Federal Institute of Aquatic Science and Technology Dübendorf Switzerland
| | - Kristien I. Brans
- Laboratory of Aquatic Ecology, Evolution and Conservation KU Leuven Leuven Belgium
| | - Sigurd Einum
- Centre for Biodiversity Dynamics Department of Biology NTNUNorwegian University of Science and Technology Trondheim Norway
| | - Luc De Meester
- Laboratory of Aquatic Ecology, Evolution and Conservation KU Leuven Leuven Belgium
- Leibniz Institüt für Gewasserökologie und Binnenfischerei (IGB) Berlin Germany
- Institute of Biology Freie Universität Berlin Berlin Germany
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Sequential infection of Daphnia magna by a gut microsporidium followed by a haemolymph yeast decreases transmission of both parasites. Parasitology 2021; 148:1566-1577. [PMID: 35060463 PMCID: PMC8564772 DOI: 10.1017/s0031182021001384] [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] [Indexed: 01/19/2023]
Abstract
Over the course of seasonal epidemics, populations of susceptible hosts may encounter a wide variety of parasites. Parasite phenology affects the order in which these species encounter their hosts, leading to sequential infections, with potentially strong effects on within-host growth and host population dynamics. Here, the cladoceran Daphnia magna was exposed sequentially to a haemolymph-infecting yeast (Metschnikowia bicuspidata) and a gut microsporidium (Ordospora colligata), with experimental treatments reflecting two possible scenarios of parasite succession. The effects of single and co-exposure were compared on parasite infectivity, spore production and the overall virulence experienced by the host. We show that neither parasite benefited from coinfection; instead, when hosts encountered Ordospora, followed by Metschnikowia, higher levels of host mortality contributed to an overall decrease in the transmission of both parasites. These results showcase an example of sequential infections generating unilateral priority effects, in which antagonistic interactions between parasites can alleviate the intensity of infection and coincide with maladaptive levels of damage inflicted on the host.
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30
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Friesen O, Poulin R, Lagrue C. Temperature and multiple parasites combine to alter host community structure. OIKOS 2021. [DOI: 10.1111/oik.07813] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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31
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Ezenwa VO, Civitello DJ, Classen AT, Barton BT, Becker DJ, Brenn-White M, Deem SL, Kutz S, Malishev M, Penczykowski RM, Preston DL, Vannatta JT, Koltz AM. Response to Charlier et al.: Climate-Disease Feedbacks Mediated by Livestock Methane Emissions Are Plausible. Trends Ecol Evol 2021; 36:578-579. [PMID: 33966920 DOI: 10.1016/j.tree.2021.04.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Accepted: 04/13/2021] [Indexed: 11/19/2022]
Affiliation(s)
- Vanessa O Ezenwa
- Odum School of Ecology and Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, GA 30602, USA.
| | | | - Aimée T Classen
- The Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Brandon T Barton
- Department of Biological Sciences, Mississippi State University, Mississippi State, MS 39762, USA
| | - Daniel J Becker
- Department of Biology, Indiana University, Bloomington, IN 47405, USA
| | - Maris Brenn-White
- Institute for Conservation Medicine, Saint Louis Zoo, St. Louis, MO 63110, USA
| | - Sharon L Deem
- Institute for Conservation Medicine, Saint Louis Zoo, St. Louis, MO 63110, USA
| | - Susan Kutz
- Department of Ecosystem and Public Health, Faculty of Veterinary Medicine, University of Calgary, Calgary, AB T2N 4Z6, Canada
| | | | | | - Daniel L Preston
- Department of Fish, Wildlife and Conservation Biology, Colorado State University, Fort Collins, CO 80523, USA
| | - J Trevor Vannatta
- Department of Biological Sciences, Purdue University, West Lafayette, IN 47907, USA
| | - Amanda M Koltz
- Department of Biology, Washington University in St. Louis, St. Louis, MO 63130, USA
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32
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Roberts KE, Longdon B. Viral susceptibility across host species is largely independent of dietary protein to carbohydrate ratios. J Evol Biol 2021; 34:746-756. [PMID: 33586293 PMCID: PMC8436156 DOI: 10.1111/jeb.13773] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2020] [Revised: 02/02/2021] [Accepted: 02/07/2021] [Indexed: 12/23/2022]
Abstract
The likelihood of a successful host shift of a parasite to a novel host species can be influenced by environmental factors that can act on both the host and parasite. Changes in nutritional resource availability have been shown to alter pathogen susceptibility and the outcome of infection in a range of systems. Here, we examined how dietary protein to carbohydrate altered susceptibility in a large cross-infection experiment. We infected 27 species of Drosophilidae with an RNA virus on three food types of differing protein to carbohydrate ratios. We then measured how viral load and mortality across species was affected by changes in diet. We found that changes in the protein:carbohydrate in the diet did not alter the outcomes of infection, with strong positive inter-species correlations in both viral load and mortality across diets, suggesting no species-by-diet interaction. Mortality and viral load were strongly positively correlated, and this association was consistent across diets. This suggests changes in diet may give consistent outcomes across host species, and may not be universally important in determining host susceptibility to pathogens.
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Affiliation(s)
- Katherine E. Roberts
- Centre for Ecology & ConservationCollege of Life and Environmental SciencesUniversity of ExeterPenrynUK
| | - Ben Longdon
- Centre for Ecology & ConservationCollege of Life and Environmental SciencesUniversity of ExeterPenrynUK
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33
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Abstract
Climate change affects ecological processes and interactions, including parasitism. Because parasites are natural components of ecological systems, as well as agents of outbreak and disease-induced mortality, it is important to summarize current knowledge of the sensitivity of parasites to climate and identify how to better predict their responses to it. This need is particularly great in marine systems, where the responses of parasites to climate variables are less well studied than those in other biomes. As examples of climate's influence on parasitism increase, they enable generalizations of expected responses as well as insight into useful study approaches, such as thermal performance curves that compare the vital rates of hosts and parasites when exposed to several temperatures across a gradient. For parasites not killed by rising temperatures, some simple physiological rules, including the tendency of temperature to increase the metabolism of ectotherms and increase oxygen stress on hosts, suggest that parasites' intensity and pathologies might increase. In addition to temperature, climate-induced changes in dissolved oxygen, ocean acidity, salinity, and host and parasite distributions also affect parasitism and disease, but these factors are much less studied. Finally, because parasites are constituents of ecological communities, we must consider indirect and secondary effects stemming from climate-induced changes in host-parasite interactions, which may not be evident if these interactions are studied in isolation.
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Affiliation(s)
- James E Byers
- Odum School of Ecology, University of Georgia, Athens, Georgia 30602, USA;
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34
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Abstract
Climate change is expected to have complex effects on infectious diseases, causing some to increase, others to decrease, and many to shift their distributions. There have been several important advances in understanding the role of climate and climate change on wildlife and human infectious disease dynamics over the past several years. This essay examines 3 major areas of advancement, which include improvements to mechanistic disease models, investigations into the importance of climate variability to disease dynamics, and understanding the consequences of thermal mismatches between host and parasites. Applying the new information derived from these advances to climate-disease models and addressing the pressing knowledge gaps that we identify should improve the capacity to predict how climate change will affect disease risk for both wildlife and humans.
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Affiliation(s)
- Jason R. Rohr
- Department of Biological Sciences, Environmental Change Initiative, Eck Institute of Global Health, University of Notre Dame, Notre Dame, Indiana, United States of America
- * E-mail:
| | - Jeremy M. Cohen
- Department of Forest and Wildlife Ecology, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
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35
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Abstract
Information on parasites and disease in marine ecosystems lags behind terrestrial systems, increasing the challenge of predicting responses of marine host–parasite systems to climate change. However, here I examine several generalizable aspects and research priorities. First, I advocate that quantification and comparison of host and parasite thermal performance curves is a smart approach to improve predictions of temperature effects on disease. Marine invertebrate species are ectothermic and should be highly conducive to this approach given their generally short generation times. Second, in marine systems, shallow subtidal and intertidal areas will experience the biggest temperature swings and thus likely see the most changes to host–parasite dynamics. Third, for some responses like parasite intensity, as long as the lethal limit of the parasite is not crossed, on average, there may be a biological basis to expect temperature-dependent intensification of impacts on hosts. Fourth, because secondary mortality effects and indirect effects of parasites can be very important, we need to study temperature effects on host–parasite dynamics in a community context to truly know their bottom line effects. This includes examining climate-influenced effects of parasites on ecosystem engineers given their pivotal role in communities. Finally, other global change factors, especially hypoxia, salinity, and ocean acidity, covary with temperature change and need to be considered and evaluated when possible for their contributing effects on host–parasite systems. Climate change–disease interactions in nearshore marine environments are complex; however, generalities are possible and continued research, especially in the areas outlined here, will improve our understanding. Information on parasites and disease in marine ecosystems lags behind terrestrial systems, increasing the challenge of predicting responses of marine host-parasite systems to climate change. This Essay highlights five general principles to guide the study of the response of marine host-parasite interactions to climate change, including the effects of temperature, oxygen, acidity, and salinity.
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Affiliation(s)
- James E. Byers
- Odum School of Ecology, University of Georgia, Athens, Georgia, United States of America
- * E-mail:
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36
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Kirk D, Luijckx P, Jones N, Krichel L, Pencer C, Molnár P, Krkošek M. Experimental evidence of warming-induced disease emergence and its prediction by a trait-based mechanistic model. Proc Biol Sci 2020; 287:20201526. [PMID: 33049167 DOI: 10.1098/rspb.2020.1526] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Predicting the effects of seasonality and climate change on the emergence and spread of infectious disease remains difficult, in part because of poorly understood connections between warming and the mechanisms driving disease. Trait-based mechanistic models combined with thermal performance curves arising from the metabolic theory of ecology (MTE) have been highlighted as a promising approach going forward; however, this framework has not been tested under controlled experimental conditions that isolate the role of gradual temporal warming on disease dynamics and emergence. Here, we provide experimental evidence that a slowly warming host-parasite system can be pushed through a critical transition into an epidemic state. We then show that a trait-based mechanistic model with MTE functional forms can predict the critical temperature for disease emergence, subsequent disease dynamics through time and final infection prevalence in an experimentally warmed system of Daphnia and a microsporidian parasite. Our results serve as a proof of principle that trait-based mechanistic models using MTE subfunctions can predict warming-induced disease emergence in data-rich systems-a critical step towards generalizing the approach to other systems.
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Affiliation(s)
- Devin Kirk
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Canada
| | - Pepijn Luijckx
- School of Natural Sciences, Zoology Department, Trinity College Dublin, University of Dublin, Dublin, Republic of Ireland
| | - Natalie Jones
- School of Biological Sciences, University of Queensland, Brisbane, Australia
| | - Leila Krichel
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Canada
| | - Clara Pencer
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Canada
| | - Péter Molnár
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Canada.,Laboratory of Quantitative Global Change Ecology, Department of Biological Sciences, University of Toronto Scarborough, Toronto, Canada
| | - Martin Krkošek
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Canada
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37
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Williams MA, Holland CV, Donohue I. Warming can alter host behavior in a similar manner to infection with behavior-manipulating parasites. Oecologia 2020; 194:65-74. [PMID: 32876762 DOI: 10.1007/s00442-020-04745-2] [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: 01/17/2020] [Accepted: 08/26/2020] [Indexed: 11/29/2022]
Abstract
Parasites are ecologically ubiquitous and, by modifying the physiology and behavior of their host organisms, act as key regulators of the dynamics and stability of ecosystems. It is, however, as yet unclear how parasitic relationships will act to moderate or accelerate the ecological impacts of global climate change. Here, we explore experimentally how the effects of parasites on both the physiology and behavior of their hosts can be moderated by warming, utilising a well-established aquatic host-parasite model system-the ecologically important amphipod Gammarus duebeni and its acanthocephalan parasite Polymorphus minutus. We show that, while only warming affected measured components of host physiology, parasite infection and warming both supressed predator-avoidance behavior of the host independently, yet in a similar manner. Six degrees of warming altered geotactic behaviors to the same extent as infection with behavior-manipulating parasites. These results indicate a novel mechanism by which parasites impact their ecosystems that could be critical to predicting the ecological impacts of warming. Our findings highlight the need for holistic knowledge of interaction networks, incorporating multiple interaction types and behaviors, to predict the effects of both warming and parasitism on the dynamics and stability of ecosystems.
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Affiliation(s)
- Maureen A Williams
- Department of Zoology, School of Natural Sciences, Trinity College Dublin, Dublin, Dublin 2, Ireland. .,School of Aquatic and Fishery Sciences, University of Washington, Seattle, WA, USA.
| | - Celia V Holland
- Department of Zoology, School of Natural Sciences, Trinity College Dublin, Dublin, Dublin 2, Ireland
| | - Ian Donohue
- Department of Zoology, School of Natural Sciences, Trinity College Dublin, Dublin, Dublin 2, Ireland
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38
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Cator LJ, Johnson LR, Mordecai EA, Moustaid FE, Smallwood TRC, LaDeau SL, Johansson MA, Hudson PJ, Boots M, Thomas MB, Power AG, Pawar S. The Role of Vector Trait Variation in Vector-Borne Disease Dynamics. Front Ecol Evol 2020; 8:189. [PMID: 32775339 PMCID: PMC7409824 DOI: 10.3389/fevo.2020.00189] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Many important endemic and emerging diseases are transmitted by vectors that are biting arthropods. The functional traits of vectors can affect pathogen transmission rates directly and also through their effect on vector population dynamics. Increasing empirical evidence shows that vector traits vary significantly across individuals, populations, and environmental conditions, and at time scales relevant to disease transmission dynamics. Here, we review empirical evidence for variation in vector traits and how this trait variation is currently incorporated into mathematical models of vector-borne disease transmission. We argue that mechanistically incorporating trait variation into these models, by explicitly capturing its effects on vector fitness and abundance, can improve the reliability of their predictions in a changing world. We provide a conceptual framework for incorporating trait variation into vector-borne disease transmission models, and highlight key empirical and theoretical challenges. This framework provides a means to conceptualize how traits can be incorporated in vector borne disease systems, and identifies key areas in which trait variation can be explored. Determining when and to what extent it is important to incorporate trait variation into vector borne disease models remains an important, outstanding question.
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Affiliation(s)
- Lauren J. Cator
- Department of Life Sciences, Imperial College London, Ascot, United Kingdom
| | - Leah R. Johnson
- Department of Statistics, Virginia Polytechnic Institute and State University, Blacksburg, VA, United States
| | - Erin A. Mordecai
- Department of Biology, Stanford University, Stanford, CA, United States
| | - Fadoua El Moustaid
- Department of Biological Sciences, Virginia Polytechnic Institute and State University, Blacksburg, VA, United States
- BresMed America Inc, Las Vegas, NV, United States
| | | | - Shannon L. LaDeau
- The Cary Institute of Ecosystem Studies, Millbrook, NY, United States
| | | | - Peter J. Hudson
- Center for Infectious Disease Dynamics and Department of Biology, Pennsylvania State University, University Park, PA, United States
| | - Michael Boots
- Department of Integrative Biology, University of California, Berkeley, Berkeley, CA, United States
| | - Matthew B. Thomas
- Department of Entomology, Pennsylvania State University, University Park, PA, United States
| | - Alison G. Power
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, NY, United States
| | - Samraat Pawar
- Department of Life Sciences, Imperial College London, Ascot, United Kingdom
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39
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Zukowski N, Kirk D, Wadhawan K, Shea D, Start D, Krkošek M. Predators can influence the host-parasite dynamics of their prey via nonconsumptive effects. Ecol Evol 2020; 10:6714-6722. [PMID: 32724544 PMCID: PMC7381593 DOI: 10.1002/ece3.6401] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2019] [Revised: 04/04/2020] [Accepted: 04/29/2020] [Indexed: 12/18/2022] Open
Abstract
Ecological communities are partly structured by indirect interactions, where one species can indirectly affect another by altering its interactions with a third species. In the absence of direct predation, nonconsumptive effects of predators on prey have important implications for subsequent community interactions. To better understand these interactions, we used a Daphnia-parasite-predator cue system to evaluate if predation risk affects Daphnia responses to a parasite. We investigated the effects of predator cues on two aspects of host-parasite interactions (susceptibility to infection and infection intensity), and whether or not these effects differed between sexes. Our results show that changes in response to predator cues caused an increase in the prevalence and intensity of parasite infections in female predator-exposed Daphnia. Importantly, the magnitude of infection risk depended on how long Daphnia were exposed to the cues. Additionally, heavily infected Daphnia that were constantly exposed to cues produced relatively more offspring. While males were ~5× less likely to become infected compared to females, we were unable to detect effects of predator cues on male Daphnia-parasite interactions. In sum, predators, prey, and their parasites can form complex subnetworks in food webs, necessitating a nuanced understanding of how nonconsumptive effects may mediate these interactions.
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Affiliation(s)
- Nicolette Zukowski
- Department of Ecology and Evolutionary BiologyUniversity of TorontoTorontoONCanada
- School of Public Health, University of CaliforniaBerkeleyCAUSA
| | - Devin Kirk
- Department of Ecology and Evolutionary BiologyUniversity of TorontoTorontoONCanada
- Department of BiologyStanford UniversityStanfordCAUSA
| | - Kiran Wadhawan
- Department of Ecology and Evolutionary BiologyUniversity of TorontoTorontoONCanada
| | - Dylan Shea
- Department of Ecology and Evolutionary BiologyUniversity of TorontoTorontoONCanada
| | - Denon Start
- Department of Ecology and Evolutionary BiologyUniversity of TorontoTorontoONCanada
- Center for Population BiologyUniversity of CaliforniaDavisCAUSA
| | - Martin Krkošek
- Department of Ecology and Evolutionary BiologyUniversity of TorontoTorontoONCanada
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40
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Abstract
Recent declines of wild pollinators and infections in honey, bumble and other bee species have raised concerns about pathogen spillover from managed honey and bumble bees to other pollinators. Parasites of honey and bumble bees include trypanosomatids and microsporidia that often exhibit low host specificity, suggesting potential for spillover to co-occurring bees via shared floral resources. However, experimental tests of trypanosomatid and microsporidial cross-infectivity outside of managed honey and bumble bees are scarce. To characterize potential cross-infectivity of honey and bumble bee-associated parasites, we inoculated three trypanosomatids and one microsporidian into five potential hosts – including four managed species – from the apid, halictid and megachilid bee families. We found evidence of cross-infection by the trypanosomatids Crithidia bombi and C. mellificae, with evidence for replication in 3/5 and 3/4 host species, respectively. These include the first reports of experimental C. bombi infection in Megachile rotundata and Osmia lignaria, and C. mellificae infection in O. lignaria and Halictus ligatus. Although inability to control amounts inoculated in O. lignaria and H. ligatus hindered estimates of parasite replication, our findings suggest a broad host range in these trypanosomatids, and underscore the need to quantify disease-mediated threats of managed social bees to sympatric pollinators.
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41
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Claar DC, Wood CL. Pulse Heat Stress and Parasitism in a Warming World. Trends Ecol Evol 2020; 35:704-715. [PMID: 32439076 DOI: 10.1016/j.tree.2020.04.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2019] [Revised: 04/03/2020] [Accepted: 04/06/2020] [Indexed: 01/15/2023]
Abstract
Infectious disease outbreaks emerged across the globe during the recent 2015-2016 El Niño event, re-igniting research interest in how climate events influence disease dynamics. While the relationship between long-term warming and the transmission of disease-causing parasites has received substantial attention, we do not yet know how pulse heat events - common phenomena in a warming world - will alter parasite transmission. The effects of pulse warming on ecological and evolutionary processes are complex and context dependent, motivating research to understand how climate oscillations drive host health and disease. Here, we develop a framework for evaluating and predicting the effects of pulse warming on parasitic infection. Specifically, we synthesize how pulse heat stress affects hosts, parasites, and the ecological interactions between them.
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Affiliation(s)
- Danielle C Claar
- University of Washington School of Aquatic and Fishery Sciences, Seattle, WA 98105, USA; NOAA Climate and Global Change Postdoctoral Scholar, Boulder, CO 80301, USA.
| | - Chelsea L Wood
- University of Washington School of Aquatic and Fishery Sciences, Seattle, WA 98105, USA
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42
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Palmer-Young EC, Ngor L, Nevarez RB, Rothman JA, Raffel TR, McFrederick QS. Temperature dependence of parasitic infection and gut bacterial communities in bumble bees. Environ Microbiol 2019; 21:4706-4723. [PMID: 31573120 PMCID: PMC7316186 DOI: 10.1111/1462-2920.14805] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2019] [Accepted: 09/13/2019] [Indexed: 11/30/2022]
Abstract
High temperatures (e.g., fever) and gut microbiota can both influence host resistance to infection. However, effects of temperature-driven changes in gut microbiota on resistance to parasites remain unexplored. We examined the temperature dependence of infection and gut bacterial communities in bumble bees infected with the trypanosomatid parasite Crithidia bombi. Infection intensity decreased by over 80% between 21 and 37°C. Temperatures of peak infection were lower than predicted based on parasite growth in vitro, consistent with mismatches in thermal performance curves of hosts, parasites and gut symbionts. Gut bacterial community size and composition exhibited slight but significant, non-linear, and taxon-specific responses to temperature. Abundance of total gut bacteria and of Orbaceae, both negatively correlated with infection in previous studies, were positively correlated with infection here. Prevalence of the bee pathogen-containing family Enterobacteriaceae declined with temperature, suggesting that high temperature may confer protection against diverse gut pathogens. Our results indicate that resistance to infection reflects not only the temperature dependence of host and parasite performance, but also temperature-dependent activity of gut bacteria. The thermal ecology of gut parasite-symbiont interactions may be broadly relevant to infectious disease, both in ectothermic organisms that inhabit changing climates, and in endotherms that exhibit fever-based immunity.
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Affiliation(s)
- Evan C Palmer-Young
- Department of Entomology, University of California Riverside, Riverside, CA, USA
| | - Lyna Ngor
- Department of Entomology, University of California Riverside, Riverside, CA, USA
| | | | - Jason A. Rothman
- Department of Entomology, University of California Riverside, Riverside, CA, USA
| | - Thomas R Raffel
- Department of Biology, Oakland University, Rochester, MI, USA
| | - Quinn S McFrederick
- Department of Entomology, University of California Riverside, Riverside, CA, USA
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43
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Padfield D, Castledine M, Buckling A. Temperature-dependent changes to host-parasite interactions alter the thermal performance of a bacterial host. ISME JOURNAL 2019; 14:389-398. [PMID: 31628440 DOI: 10.1038/s41396-019-0526-5] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2019] [Revised: 09/18/2019] [Accepted: 09/22/2019] [Indexed: 01/26/2023]
Abstract
Thermal performance curves (TPCs) are used to predict changes in species interactions, and hence, range shifts, disease dynamics and community composition, under forecasted climate change. Species interactions might in turn affect TPCs. Here, we investigate how temperature-dependent changes in a microbial host-parasite interaction (the bacterium Pseudomonas fluorescens, and its lytic bacteriophage, SBW[Formula: see text]) changes the host TPC and the ecological and evolutionary mechanisms underlying these changes. The bacteriophage had a narrower thermal tolerance for infection, with their critical thermal maximum ~6 °C lower than those at which the bacteria still had high growth. Consequently, in the presence of phage, the host TPC changed, resulting in a lower maximum growth rate. These changes were not just driven by differences in thermal tolerance, with temperature-dependent costs of evolved resistance also playing a major role: the largest cost of resistance occurred at the temperature at which bacteria grew best in the absence of phage. Our work highlights how ecological and evolutionary mechanisms can alter the effect of a parasite on host thermal performance, even over very short timescales.
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Affiliation(s)
- Daniel Padfield
- College of Life and Environmental Sciences, Environment and Sustainability Institute, University of Exeter, Penryn, Cornwall, TR10 9EZ, UK.
| | - Meaghan Castledine
- College of Life and Environmental Sciences, Environment and Sustainability Institute, University of Exeter, Penryn, Cornwall, TR10 9EZ, UK
| | - Angus Buckling
- College of Life and Environmental Sciences, Environment and Sustainability Institute, University of Exeter, Penryn, Cornwall, TR10 9EZ, UK
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Mordecai EA, Caldwell JM, Grossman MK, Lippi CA, Johnson LR, Neira M, Rohr JR, Ryan SJ, Savage V, Shocket MS, Sippy R, Stewart Ibarra AM, Thomas MB, Villena O. Thermal biology of mosquito-borne disease. Ecol Lett 2019; 22:1690-1708. [PMID: 31286630 PMCID: PMC6744319 DOI: 10.1111/ele.13335] [Citation(s) in RCA: 245] [Impact Index Per Article: 49.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Revised: 05/22/2019] [Accepted: 06/06/2019] [Indexed: 12/11/2022]
Abstract
Mosquito-borne diseases cause a major burden of disease worldwide. The vital rates of these ectothermic vectors and parasites respond strongly and nonlinearly to temperature and therefore to climate change. Here, we review how trait-based approaches can synthesise and mechanistically predict the temperature dependence of transmission across vectors, pathogens, and environments. We present 11 pathogens transmitted by 15 different mosquito species - including globally important diseases like malaria, dengue, and Zika - synthesised from previously published studies. Transmission varied strongly and unimodally with temperature, peaking at 23-29ºC and declining to zero below 9-23ºC and above 32-38ºC. Different traits restricted transmission at low versus high temperatures, and temperature effects on transmission varied by both mosquito and parasite species. Temperate pathogens exhibit broader thermal ranges and cooler thermal minima and optima than tropical pathogens. Among tropical pathogens, malaria and Ross River virus had lower thermal optima (25-26ºC) while dengue and Zika viruses had the highest (29ºC) thermal optima. We expect warming to increase transmission below thermal optima but decrease transmission above optima. Key directions for future work include linking mechanistic models to field transmission, combining temperature effects with control measures, incorporating trait variation and temperature variation, and investigating climate adaptation and migration.
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Affiliation(s)
- Erin A. Mordecai
- Department of BiologyStanford University371 Serra MallStanfordCAUSA
| | | | - Marissa K. Grossman
- Department of Entomology and Center for Infectious Disease DynamicsPenn State UniversityUniversity ParkPA16802USA
| | - Catherine A. Lippi
- Department of Geography and Emerging Pathogens InstituteUniversity of FloridaGainesvilleFLUSA
| | - Leah R. Johnson
- Department of StatisticsVirginia Polytechnic and State University250 Drillfield DriveBlacksburgVAUSA
| | - Marco Neira
- Center for Research on Health in Latin America (CISeAL)Pontificia Universidad Católica del EcuadorQuitoEcuador
| | - Jason R. Rohr
- Department of Biological SciencesEck Institute of Global HealthEnvironmental Change InitiativeUniversity of Notre Dame, Notre DameINUSA
| | - Sadie J. Ryan
- Department of Geography and Emerging Pathogens InstituteUniversity of FloridaGainesvilleFLUSA
- School of Life SciencesUniversity of KwaZulu‐NatalDurbanSouth Africa
| | - Van Savage
- Department of Ecology and Evolutionary Biology and Department of BiomathematicsUniversity of California Los AngelesLos AngelesCA90095USA
- Santa Fe Institute1399 Hyde Park RdSanta FeNM87501USA
| | - Marta S. Shocket
- Department of BiologyStanford University371 Serra MallStanfordCAUSA
| | - Rachel Sippy
- Department of Geography and Emerging Pathogens InstituteUniversity of FloridaGainesvilleFLUSA
- Institute for Global Health and Translational SciencesSUNY Upstate Medical UniversitySyracuseNY13210USA
| | - Anna M. Stewart Ibarra
- Institute for Global Health and Translational SciencesSUNY Upstate Medical UniversitySyracuseNY13210USA
| | - Matthew B. Thomas
- Department of Entomology and Center for Infectious Disease DynamicsPenn State UniversityUniversity ParkPA16802USA
| | - Oswaldo Villena
- Department of StatisticsVirginia Polytechnic and State University250 Drillfield DriveBlacksburgVAUSA
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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.
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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
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Shocket MS, Magnante A, Duffy MA, Cáceres CE, Hall SR. Can hot temperatures limit disease transmission? A test of mechanisms in a zooplankton–fungus system. Funct Ecol 2019. [DOI: 10.1111/1365-2435.13403] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
| | | | - Meghan A. Duffy
- Department of Ecology and Evolutionary Biology University of Michigan Ann Arbor MI USA
| | - Carla E. Cáceres
- School of Integrative Biology University of Illinois at Urbana‐Champaign Urbana IL USA
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Kirk D, Luijckx P, Stanic A, Krkošek M. Predicting the Thermal and Allometric Dependencies of Disease Transmission via the Metabolic Theory of Ecology. Am Nat 2019; 193:661-676. [PMID: 31002572 DOI: 10.1086/702846] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
The metabolic theory of ecology (MTE) provides a general framework of allometric and thermal dependence that may be useful for predicting how climate change will affect disease spread. Using Daphnia magna and a microsporidian gut parasite, we conducted two experiments across a wide thermal range and fitted transmission models that utilize MTE submodels for transmission parameters. We decomposed transmission into contact rate and probability of infection and further decomposed probability of infection into a product of gut residence time (GRT) and per-parasite infection rate of gut cells. Contact rate generally increased with temperature and scaled positively with body size, whereas infection rate had a narrow hump-shaped thermal response and scaled negatively with body size. GRT increased with host size and was longest at extreme temperatures. GRT and infection rate inside the gut combined to create a 3.5 times higher probability of infection for the smallest relative to the largest individuals. Small temperature changes caused large differences in transmission. We also fit several alternative transmission models to data at individual temperatures. The more complex models-parasite antagonism or synergism and host heterogeneity-did not substantially improve the fit to the data. Our results show that transmission rate is the product of several distinct thermal and allometric functions that can be predicted continuously across temperature and host size using the MTE.
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Downs CJ, Schoenle LA, Han BA, Harrison JF, Martin LB. Scaling of Host Competence. Trends Parasitol 2019; 35:182-192. [DOI: 10.1016/j.pt.2018.12.002] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2018] [Revised: 12/13/2018] [Accepted: 12/13/2018] [Indexed: 12/31/2022]
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Bernhardt JR, Sunday JM, O'Connor MI. Metabolic Theory and the Temperature-Size Rule Explain the Temperature Dependence of Population Carrying Capacity. Am Nat 2018; 192:687-697. [PMID: 30444656 DOI: 10.1086/700114] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
The temperature dependence of highly conserved subcellular metabolic systems affects ecological patterns and processes across scales, from organisms to ecosystems. Population density at carrying capacity plays an important role in evolutionary processes, biodiversity, and ecosystem function, yet how it varies with temperature-dependent metabolism remains unclear. Though the exponential effect of temperature on intrinsic population growth rate, r, is well known, we still lack clear evidence that population density at carrying capacity, K, declines with increasing per capita metabolic rate, as predicted by the metabolic theory of ecology (MTE). We experimentally tested whether temperature effects on photosynthesis propagate directly to population carrying capacity in a model species, the mobile phytoplankton Tetraselmis tetrahele. After maintaining populations at a fixed resource supply and fixed temperatures for 43 days, we found that carrying capacity declined with increasing temperature. This decline was predicted quantitatively when models included temperature-dependent metabolic rates and temperature-associated body-size shifts. Our results demonstrate that warming reduces carrying capacity and that temperature effects on body size and metabolic rate interact to determine how temperature affects population dynamics. These findings bolster efforts to relate metabolic temperature dependence to population and ecosystem patterns via MTE.
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50
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Roberts KE, Hadfield JD, Sharma MD, Longdon B. Changes in temperature alter the potential outcomes of virus host shifts. PLoS Pathog 2018; 14:e1007185. [PMID: 30339695 PMCID: PMC6209381 DOI: 10.1371/journal.ppat.1007185] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Revised: 10/31/2018] [Accepted: 10/02/2018] [Indexed: 12/26/2022] Open
Abstract
Host shifts-where a pathogen jumps between different host species-are an important source of emerging infectious disease. With on-going climate change there is an increasing need to understand the effect changes in temperature may have on emerging infectious disease. We investigated whether species' susceptibilities change with temperature and ask if susceptibility is greatest at different temperatures in different species. We infected 45 species of Drosophilidae with an RNA virus and measured how viral load changes with temperature. We found the host phylogeny explained a large proportion of the variation in viral load at each temperature, with strong phylogenetic correlations between viral loads across temperature. The variance in viral load increased with temperature, while the mean viral load did not. This suggests that as temperature increases the most susceptible species become more susceptible, and the least susceptible less so. We found no significant relationship between a species' susceptibility across temperatures, and proxies for thermal optima (critical thermal maximum and minimum or basal metabolic rate). These results suggest that whilst the rank order of species susceptibilities may remain the same with changes in temperature, some species may become more susceptible to a novel pathogen, and others less so.
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Affiliation(s)
- Katherine E. Roberts
- Biosciences, College of Life & Environmental Sciences, University of Exeter, Penryn Campus, Penryn, Cornwall, United Kingdom
| | - Jarrod D. Hadfield
- Institute of Evolutionary Biology, School of Biological Sciences, The University of Edinburgh, Ashworth Laboratories, Edinburgh, United Kingdom
| | - Manmohan D. Sharma
- Biosciences, College of Life & Environmental Sciences, University of Exeter, Penryn Campus, Penryn, Cornwall, United Kingdom
| | - Ben Longdon
- Biosciences, College of Life & Environmental Sciences, University of Exeter, Penryn Campus, Penryn, Cornwall, United Kingdom
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