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Poulin R, Salloum PM, Bennett J. Evolution of parasites in the Anthropocene: new pressures, new adaptive directions. Biol Rev Camb Philos Soc 2024. [PMID: 38984760 DOI: 10.1111/brv.13118] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2024] [Revised: 06/27/2024] [Accepted: 07/02/2024] [Indexed: 07/11/2024]
Abstract
The Anthropocene is seeing the human footprint rapidly spreading to all of Earth's ecosystems. The fast-changing biotic and abiotic conditions experienced by all organisms are exerting new and strong selective pressures, and there is a growing list of examples of human-induced evolution in response to anthropogenic impacts. No organism is exempt from these novel selective pressures. Here, we synthesise current knowledge on human-induced evolution in eukaryotic parasites of animals, and present a multidisciplinary framework for its study and monitoring. Parasites generally have short generation times and huge fecundity, features that predispose them for rapid evolution. We begin by reviewing evidence that parasites often have substantial standing genetic variation, and examples of their rapid evolution both under conditions of livestock production and in serial passage experiments. We then present a two-step conceptual overview of the causal chain linking anthropogenic impacts to parasite evolution. First, we review the major anthropogenic factors impacting parasites, and identify the selective pressures they exert on parasites through increased mortality of either infective stages or adult parasites, or through changes in host density, quality or immunity. Second, we discuss what new phenotypic traits are likely to be favoured by the new selective pressures resulting from altered parasite mortality or host changes; we focus mostly on parasite virulence and basic life-history traits, as these most directly influence the transmission success of parasites and the pathology they induce. To illustrate the kinds of evolutionary changes in parasites anticipated in the Anthropocene, we present a few scenarios, either already documented or hypothetical but plausible, involving parasite taxa in livestock, aquaculture and natural systems. Finally, we offer several approaches for investigations and real-time monitoring of rapid, human-induced evolution in parasites, ranging from controlled experiments to the use of state-of-the-art genomic tools. The implications of fast-evolving parasites in the Anthropocene for disease emergence and the dynamics of infections in domestic animals and wildlife are concerning. Broader recognition that it is not only the conditions for parasite transmission that are changing, but the parasites themselves, is needed to meet better the challenges ahead.
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Affiliation(s)
- Robert Poulin
- Department of Zoology, University of Otago, P.O. Box 56, Dunedin, New Zealand
| | - Priscila M Salloum
- Department of Zoology, University of Otago, P.O. Box 56, Dunedin, New Zealand
| | - Jerusha Bennett
- Department of Zoology, University of Otago, P.O. Box 56, Dunedin, New Zealand
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2
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O'Neill X, White A, Boots M. The evolution of parasite virulence under targeted culling and harvesting in wildlife and livestock. Evol Appl 2023; 16:1697-1707. [PMID: 38020874 PMCID: PMC10660816 DOI: 10.1111/eva.13594] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2023] [Revised: 07/27/2023] [Accepted: 09/01/2023] [Indexed: 12/01/2023] Open
Abstract
There is a clear need to understand the effect of human intervention on the evolution of infectious disease. In particular, culling and harvesting of both wildlife and managed livestock populations are carried out in a wide range of management practices, and they have the potential to impact the evolution of a broad range of disease characteristics. Applying eco-evolutionary theory we show that once culling/harvesting becomes targeted on specific disease classes, the established result that culling selects for higher virulence is only found when sufficient infected individuals are culled. If susceptible or recovered individuals are targeted, selection for lower virulence can occur. An important implication of this result is that when culling to eradicate an infectious disease from a population, while it is optimal to target infected individuals, the consequent evolution can increase the basic reproductive ratio of the infection, R 0 , and make parasite eradication more difficult. We show that increases in evolved virulence due to the culling of infected individuals can lead to excess population decline when sustainably harvesting a population. In contrast, culling susceptible or recovered individuals can select for decreased virulence and a reduction in population decline through culling. The implications to the evolution of virulence are typically the same in wildlife populations, that are regulated by the parasite, and livestock populations, that have a constant population size where restocking balances the losses due to mortality. However, the well-known result that vertical transmission selects for lower virulence and transmission in wildlife populations is less marked in livestock populations for parasites that convey long-term immunity since restocking can enhance the density of the immune class. Our work emphasizes the importance of understanding the evolutionary consequences of intervention strategies and the different ecological feedbacks that can occur in wildlife and livestock populations.
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Affiliation(s)
- Xander O'Neill
- Department of MathematicsMaxwell Institute for Mathematical Sciences, Heriot‐Watt UniversityEdinburghUK
| | - Andy White
- Department of MathematicsMaxwell Institute for Mathematical Sciences, Heriot‐Watt UniversityEdinburghUK
| | - Mike Boots
- Department of Integrative BiologyUniversity of CaliforniaBerkeleyCaliforniaUSA
- Centre for Ecology and Conservation, BiosciencesUniversity of ExeterCornwallUK
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3
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Rutle KH, Skern‐Mauritzen R, Nilsen F, Mateos‐Rivera A, Eide AGS, Jansson E, Quintela M, Besnier F, Allyon F, Fjørtoft HB, Glover KA. Aquaculture-driven evolution of the salmon louse mtDNA genome. Evol Appl 2023; 16:1328-1344. [PMID: 37492153 PMCID: PMC10363823 DOI: 10.1111/eva.13572] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Revised: 05/17/2023] [Accepted: 06/06/2023] [Indexed: 07/27/2023] Open
Abstract
Resistance toward the antiparasitic pyrethroid, deltamethrin, is reported in the Atlantic salmon louse (Lepeophtheirus salmonis salmonis), a persistent ectoparasite of farmed and wild salmonids. The resistance mechanism is linked to mitochondrial DNA (mtDNA), where genetic markers for resistance have been identified. Here, we investigated how widespread pyrethroid use in aquaculture may have influenced mtDNA variation in lice, and the dispersion of resistant haplotypes across the North Atlantic, using historical (2000-2002 "pre-resistance") and contemporary (2014-2017 "post-resistance") samples. To study this, we sequenced ATPase 6 and cytochrome b, genotyped two genetic markers for deltamethrin resistance, and genotyped microsatellites as "neutral" controls of potential population bottlenecks. Overall, we observed a modest reduction in mtDNA diversity in the period 2000-2017, but no reduction in microsatellite variation was observed. The reduction in mtDNA variation was especially distinct in two of the contemporary samples, fixed for one and two haplotypes, respectively. By contrast, all historical samples consisted of close to one mtDNA haplotype per individual. No population genetic structure was detected among the historical samples for mtDNA nor microsatellites. By contrast, significant population genetic differentiation was observed for mtDNA among some of the contemporary samples. However, the observed population genetic structure was tightly linked with the pattern of deltamethrin resistance, and we therefore conclude that it primarily reflects the transient mosaic of pyrethroid usage in time and space. Two historically undetected mtDNA haplotypes dominated in the contemporary samples, both of which were linked to deltamethrin resistance, demonstrating primarily two origins of deltamethrin resistance in the North Atlantic. Collectively, these data demonstrate that the widespread use of pyrethroids in commercial aquaculture has substantially altered the patterns of mtDNA diversity in lice across the North Atlantic, and that long-distance dispersion of resistance is rapid due to high level of genetic connectivity that is observed in this species.
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Affiliation(s)
| | | | - Frank Nilsen
- Department of Biological SciencesUniversity of BergenBergenNorway
| | | | | | | | | | | | | | - Helene Børretzen Fjørtoft
- Department of Biological SciencesUniversity of BergenBergenNorway
- Department of Biological Sciences in AalesundNorwegian University of Science and TechnologyAalesundNorway
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4
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Qiao L, Xu J, Yang Z, Li X, Chen L, Sun H, Mu Y. Residual Risk of Avermectins in Food Products of Animal Origin and Their Research Progress on Toxicity and Determination. FOOD REVIEWS INTERNATIONAL 2022. [DOI: 10.1080/87559129.2022.2132402] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Affiliation(s)
- Lu Qiao
- Key Laboratory of Control of Quality and Safety for Aquatic Products, Ministry of Agriculture and Rural Affairs, Chinese Academy of Fishery Sciences, Beijing, China
| | - Jinhua Xu
- Key Laboratory of Control of Quality and Safety for Aquatic Products, Ministry of Agriculture and Rural Affairs, Chinese Academy of Fishery Sciences, Beijing, China
| | - Zhen Yang
- Key Laboratory of Control of Quality and Safety for Aquatic Products, Ministry of Agriculture and Rural Affairs, Chinese Academy of Fishery Sciences, Beijing, China
| | - Xingyang Li
- Key Laboratory of Control of Quality and Safety for Aquatic Products, Ministry of Agriculture and Rural Affairs, Chinese Academy of Fishery Sciences, Beijing, China
- College of Food Science and Engineering, Bohai University, Jinzhou, China
| | - Lu Chen
- Key Laboratory of Control of Quality and Safety for Aquatic Products, Ministry of Agriculture and Rural Affairs, Chinese Academy of Fishery Sciences, Beijing, China
- College of Food Science and Engineering, Bohai University, Jinzhou, China
| | - Huiwu Sun
- Key Laboratory of Control of Quality and Safety for Aquatic Products, Ministry of Agriculture and Rural Affairs, Chinese Academy of Fishery Sciences, Beijing, China
| | - Yingchun Mu
- Key Laboratory of Control of Quality and Safety for Aquatic Products, Ministry of Agriculture and Rural Affairs, Chinese Academy of Fishery Sciences, Beijing, China
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5
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Guragain P, Båtnes AS, Zobolas J, Olsen Y, Bones AM, Winge P. IIb-RAD-sequencing coupled with random forest classification indicates regional population structuring and sex-specific differentiation in salmon lice ( Lepeophtheirus salmonis). Ecol Evol 2022; 12:e8809. [PMID: 35414904 PMCID: PMC8986551 DOI: 10.1002/ece3.8809] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2022] [Revised: 03/18/2022] [Accepted: 03/22/2022] [Indexed: 11/29/2022] Open
Abstract
The aquaculture industry has been dealing with salmon lice problems forming serious threats to salmonid farming. Several treatment approaches have been used to control the parasite. Treatment effectiveness must be optimized, and the systematic genetic differences between subpopulations must be studied to monitor louse species and enhance targeted control measures. We have used IIb-RAD sequencing in tandem with a random forest classification algorithm to detect the regional genetic structure of the Norwegian salmon lice and identify important markers for sex differentiation of this species. We identified 19,428 single nucleotide polymorphisms (SNPs) from 95 individuals of salmon lice. These SNPs, however, were not able to distinguish the differential structure of lice populations. Using the random forest algorithm, we selected 91 SNPs important for geographical classification and 14 SNPs important for sex classification. The geographically important SNP data substantially improved the genetic understanding of the population structure and classified regional demographic clusters along the Norwegian coast. We also uncovered SNP markers that could help determine the sex of the salmon louse. A large portion of the SNPs identified to be under directional selection was also ranked highly important by random forest. According to our findings, there is a regional population structure of salmon lice associated with the geographical location along the Norwegian coastline.
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Affiliation(s)
- Prashanna Guragain
- Cell, Molecular Biology and Genomics GroupDepartment of BiologyNorwegian University of Science and TechnologyTrondheimNorway
- Taskforce Salmon LiceDepartment of BiologyNorwegian University of Science and TechnologyTrondheimNorway
| | - Anna Solvang Båtnes
- Taskforce Salmon LiceDepartment of BiologyNorwegian University of Science and TechnologyTrondheimNorway
| | - John Zobolas
- Cell, Molecular Biology and Genomics GroupDepartment of BiologyNorwegian University of Science and TechnologyTrondheimNorway
| | - Yngvar Olsen
- Taskforce Salmon LiceDepartment of BiologyNorwegian University of Science and TechnologyTrondheimNorway
| | - Atle M. Bones
- Cell, Molecular Biology and Genomics GroupDepartment of BiologyNorwegian University of Science and TechnologyTrondheimNorway
- Taskforce Salmon LiceDepartment of BiologyNorwegian University of Science and TechnologyTrondheimNorway
| | - Per Winge
- Cell, Molecular Biology and Genomics GroupDepartment of BiologyNorwegian University of Science and TechnologyTrondheimNorway
- Taskforce Salmon LiceDepartment of BiologyNorwegian University of Science and TechnologyTrondheimNorway
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Pulkkinen K, Ketola T, Laakso J, Mappes J, Sundberg L. Rich resource environment of fish farms facilitates phenotypic variation and virulence in an opportunistic fish pathogen. Evol Appl 2022; 15:417-428. [PMID: 35386393 PMCID: PMC8965373 DOI: 10.1111/eva.13355] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Revised: 01/27/2022] [Accepted: 02/01/2022] [Indexed: 12/05/2022] Open
Abstract
Phenotypic variation is suggested to facilitate the persistence of environmentally growing pathogens under environmental change. Here, we hypothesized that the intensive farming environment induces higher phenotypic variation in microbial pathogens than natural environment, because of high stochasticity for growth and stronger survival selection compared to the natural environment. We tested the hypothesis with an opportunistic fish pathogen Flavobacterium columnare isolated either from fish farms or from natural waters. We measured growth parameters of two morphotypes from all isolates in different resource concentrations and two temperatures relevant for the occurrence of disease epidemics at farms and tested their virulence using a zebrafish (Danio rerio) infection model. According to our hypothesis, isolates originating from the fish farms had higher phenotypic variation in growth between the morphotypes than the isolates from natural waters. The difference was more pronounced in higher resource concentrations and the higher temperature, suggesting that phenotypic variation is driven by the exploitation of increased outside-host resources at farms. Phenotypic variation of virulence was not observed based on isolate origin but only based on morphotype. However, when in contact with the larger fish, the less virulent morphotype of some of the isolates also had high virulence. As the less virulent morphotype also had higher growth rate in outside-host resources, the results suggest that both morphotypes can contribute to F. columnare epidemics at fish farms, especially with current prospects of warming temperatures. Our results suggest that higher phenotypic variation per se does not lead to higher virulence, but that environmental conditions at fish farms could select isolates with high phenotypic variation in bacterial population and hence affect evolution in F. columnare at fish farms. Our results highlight the multifaceted effects of human-induced environmental alterations in shaping epidemiology and evolution in microbial pathogens.
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Affiliation(s)
- Katja Pulkkinen
- Department of Biological and Environmental ScienceUniversity of JyväskyläJyväskyläFinland
| | - Tarmo Ketola
- Department of Biological and Environmental ScienceUniversity of JyväskyläJyväskyläFinland
| | - Jouni Laakso
- Research Programme in Organismal and Evolutionary Biology, Faculty of Biological and Environmental Sciences, University of HelsinkiHelsinkiFinland
| | - Johanna Mappes
- Department of Biological and Environmental ScienceUniversity of JyväskyläJyväskyläFinland
- Research Programme in Organismal and Evolutionary Biology, Faculty of Biological and Environmental Sciences, University of HelsinkiHelsinkiFinland
| | - Lotta‐Riina Sundberg
- Department of Biological and Environmental ScienceUniversity of JyväskyläJyväskyläFinland
- Nanoscience CenterUniversity of JyväskyläJyväskyläFinland
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Mladineo I, Hrabar J, Trumbić Ž, Manousaki T, Tsakogiannis A, Taggart JB, Tsigenopoulos CS. Community Parameters and Genome-Wide RAD-Seq Loci of Ceratothoa oestroides Imply Its Transfer between Farmed European Sea Bass and Wild Farm-Aggregating Fish. Pathogens 2021; 10:pathogens10020100. [PMID: 33494355 PMCID: PMC7912605 DOI: 10.3390/pathogens10020100] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Revised: 01/14/2021] [Accepted: 01/19/2021] [Indexed: 12/28/2022] Open
Abstract
Wild fish assemblages that aggregate within commercial marine aquaculture sites for feeding and shelter have been considered as a primary source of pathogenic parasites vectored to farmed fish maintained in net pens at an elevated density. In order to evaluate whether Ceratothoa oestroides (Isopoda, Cymothoidae), a generalist and pestilent isopod that is frequently found in Adriatic and Greek stocks of farmed European sea bass (Dicentrarchus labrax), transfers between wild and farmed fish, a RAD-Seq (restriction-site-associated DNA sequencing)-mediated genetic screening approach was employed. The double-digest RAD-Seq of 310 C. oestroides specimens collected from farmed European sea bass (138) and different wild farm-aggregating fish (172) identified 313 robust SNPs that evidenced a close genetic relatedness between the “wild” and “farmed” genotypes. ddRAD-Seq proved to be an effective method for detecting the discrete genetic structuring of C. oestroides and genotype intermixing between two populations. The parasite prevalence in the farmed sea bass was 1.02%, with a mean intensity of 2.0 and mean abundance of 0.02, while in the wild fish, the prevalence was 8.1%; the mean intensity, 1.81; and the mean abundance, 0.15. Such differences are likely a consequence of human interventions during the farmed fish’s rearing cycle that, nevertheless, did not affect the transfer of C. oestroides.
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Affiliation(s)
- Ivona Mladineo
- Institute of Oceanography and Fisheries, Laboratory of Aquaculture, 21000 Split, Croatia;
- Institute of Parasitology, Biology Centre of Czech Academy of Science, 37005 Ceske Budejovice, Czech Republic
- Correspondence: or
| | - Jerko Hrabar
- Institute of Oceanography and Fisheries, Laboratory of Aquaculture, 21000 Split, Croatia;
| | - Željka Trumbić
- University Department of Marine Studies, University of Split, 21000 Split, Croatia;
| | - Tereza Manousaki
- Hellenic Centre for Marine Research, Institute of Marine Biology, Biotechnology and Aquaculture (IMBBC), 71003 Heraklion, Greece; (T.M.); (A.T.); (C.S.T.)
| | - Alexandros Tsakogiannis
- Hellenic Centre for Marine Research, Institute of Marine Biology, Biotechnology and Aquaculture (IMBBC), 71003 Heraklion, Greece; (T.M.); (A.T.); (C.S.T.)
| | - John B. Taggart
- Institute of Aquaculture, Faculty of Natural Sciences, University of Stirling, Stirling FK9 4LA, UK;
| | - Costas S. Tsigenopoulos
- Hellenic Centre for Marine Research, Institute of Marine Biology, Biotechnology and Aquaculture (IMBBC), 71003 Heraklion, Greece; (T.M.); (A.T.); (C.S.T.)
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8
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Coates A, Phillips BL, Oppedal F, Bui S, Overton K, Dempster T. Parasites under pressure: salmon lice have the capacity to adapt to depth-based preventions in aquaculture. Int J Parasitol 2020; 50:865-872. [PMID: 32652129 DOI: 10.1016/j.ijpara.2020.05.009] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2020] [Revised: 05/04/2020] [Accepted: 05/12/2020] [Indexed: 10/23/2022]
Abstract
The evolution of pesticide resistance has driven renewed interest in non-chemical pest controls in agriculture. Spatial manipulations (physical barriers and fallowing, for example) can be an effective method of prevention, but these too might impose selection and cause rapid adaptation in pests. In salmon aquaculture, various non-chemical approaches have emerged to combat parasitic salmon lice (Lepeophtheirus salmonis) - a major pest with clear signs of evolved chemical resistance. 'Depth-based' preventions, now widely implemented, reduce infestation rates by physically segregating salmon from lice in their infective copepodid stage occurring in surface waters. Copepodids distributed deeper in the water column, however, can bypass these barriers and infest farms. If swimming depth is a heritable trait, we may see rapid evolutionary shifts in response to widespread depth-based prevention. We collected lice from Norwegian salmon farms and assayed more than 11,250 of their laboratory-reared offspring across 37 families. The vertical distributions of copepodids were measured using experimental water columns pressurised to simulate conditions at 0, 5 and 10 m depths. We demonstrated that lice respond strongly to hydrostatic pressure: an increase in pressure doubled the number of lice that migrated to the top of columns. There was also a large effect of family on this response, with the percentage of lice ascending to the top of pressurised columns ranging from 17 to 79% across families. Families with a weak swimming response to pressure are expected to occur deeper in the water column and so be more likely to infest farms employing depth-based preventions. If this between-family variation reflects genetic variation, then the parasite population may have the capacity to adapt to preventative measures. Such adaptation would have important commercial and ecological implications.
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Affiliation(s)
- Andrew Coates
- Sustainable Aquaculture Laboratory - Temperate and Tropical (SALTT), School of BioSciences, University of Melbourne, Victoria 3010, Australia; Spatial Ecology and Evolution Lab (SpEEL), School of BioSciences, University of Melbourne, Victoria 3010, Australia
| | - Ben L Phillips
- Spatial Ecology and Evolution Lab (SpEEL), School of BioSciences, University of Melbourne, Victoria 3010, Australia
| | - Frode Oppedal
- Institute of Marine Research, Matre Aquaculture Research Station, 5984 Matredal, Norway
| | - Samantha Bui
- Institute of Marine Research, Matre Aquaculture Research Station, 5984 Matredal, Norway
| | - Kathy Overton
- Sustainable Aquaculture Laboratory - Temperate and Tropical (SALTT), School of BioSciences, University of Melbourne, Victoria 3010, Australia
| | - Tim Dempster
- Sustainable Aquaculture Laboratory - Temperate and Tropical (SALTT), School of BioSciences, University of Melbourne, Victoria 3010, Australia.
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9
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Thompson CRS, Fields DM, Bjelland RM, Chan VBS, Durif CMF, Mount A, Runge JA, Shema SD, Skiftesvik AB, Browman HI. The planktonic stages of the salmon louse ( Lepeophtheirus salmonis) are tolerant of end-of-century pCO 2 concentrations. PeerJ 2019; 7:e7810. [PMID: 31632848 PMCID: PMC6796963 DOI: 10.7717/peerj.7810] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Accepted: 09/01/2019] [Indexed: 01/13/2023] Open
Abstract
The copepod Lepeophtheirus salmonis is an obligate ectoparasite of salmonids. Salmon lice are major pests in salmon aquaculture and due to its economic impact Lepeophtheirus salmonis is one of the most well studied species of marine parasite. However, there is limited understanding of how increased concentration of pCO2 associated with ocean acidification will impact host-parasite relationships. We investigated the effects of increased pCO2 on growth and metabolic rates in the planktonic stages, rearing L. salmonis from eggs to 12 days post hatch copepodids under three treatment levels: Control (416 µatm), Mid (747 µatm), and High (942 µatm). The pCO2 treatment had a significant effect on oxygen consumption rate with the High treatment animals exhibiting the greatest respiration. The treatments did not have a significant effect on the other biological endpoints measured (carbon, nitrogen, lipid volume, and fatty acid content). The results indicate that L. salmonis have mechanisms to compensate for increased concentration of pCO2and that populations will be tolerant of projected future ocean acidification scenarios. The work reported here also describes catabolism during the lecithotrophic development of L. salmonis, information that is not currently available to parameterize models of dispersal and viability of the planktonic free-living stages.
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Affiliation(s)
| | - David M Fields
- Bigelow Laboratory for Ocean Sciences, East Boothbay, ME, United States of America
| | - Reidun M Bjelland
- Austevoll Research Station, Institute of Marine Research, Storebø, Norway
| | - Vera B S Chan
- LEMAR, Institut Français de Recherche pour l'Exploitation de la Mer, UMR 6539 (UBO/CNRS/IRD/Ifremer), Plouzané, France
| | - Caroline M F Durif
- Austevoll Research Station, Institute of Marine Research, Storebø, Norway
| | - Andrew Mount
- Department of Biological Sciences, Clemson University, Clemson, SC, United States of America
| | - Jeffrey A Runge
- School of Marine Sciences, University of Maine, Orono, ME, United States of America.,Gulf of Maine Research Institute, Portland, ME, United States of America
| | - Steven D Shema
- Austevoll Research Station, Institute of Marine Research, Storebø, Norway
| | | | - Howard I Browman
- Austevoll Research Station, Institute of Marine Research, Storebø, Norway
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10
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Jacobs A, De Noia M, Praebel K, Kanstad-Hanssen Ø, Paterno M, Jackson D, McGinnity P, Sturm A, Elmer KR, Llewellyn MS. Genetic fingerprinting of salmon louse (Lepeophtheirus salmonis) populations in the North-East Atlantic using a random forest classification approach. Sci Rep 2018; 8:1203. [PMID: 29352185 PMCID: PMC5775277 DOI: 10.1038/s41598-018-19323-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2017] [Accepted: 12/17/2017] [Indexed: 12/13/2022] Open
Abstract
Caligid sea lice represent a significant threat to salmonid aquaculture worldwide. Population genetic analyses have consistently shown minimal population genetic structure in North Atlantic Lepeophtheirus salmonis, frustrating efforts to track louse populations and improve targeted control measures. The aim of this study was to test the power of reduced representation library sequencing (IIb-RAD sequencing) coupled with random forest machine learning algorithms to define markers for fine-scale discrimination of louse populations. We identified 1286 robustly supported SNPs among four L. salmonis populations from Ireland, Scotland and Northern Norway. Only weak global structure was observed based on the full SNP dataset. The application of a random forest machine-learning algorithm identified 98 discriminatory SNPs that dramatically improved population assignment, increased global genetic structure and resulted in significant genetic population differentiation. A large proportion of SNPs found to be under directional selection were also identified to be highly discriminatory. Our data suggest that it is possible to discriminate between nearby L. salmonis populations given suitable marker selection approaches, and that such differences might have an adaptive basis. We discuss these data in light of sea lice adaption to anthropogenic and environmental pressures as well as novel approaches to track and predict sea louse dispersal.
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Affiliation(s)
- A Jacobs
- Institute of Biodiversity, Animal Health & Comparative Medicine, College of Medical, Veterinary & Life Sciences, University of Glasgow, Glasgow, UK
| | - M De Noia
- Institute of Biodiversity, Animal Health & Comparative Medicine, College of Medical, Veterinary & Life Sciences, University of Glasgow, Glasgow, UK
| | - K Praebel
- Norwegian College of Fishery Science, UiT The Arctic University of Norway, N-9037, Tromsø, Norway
| | | | - M Paterno
- Department of Biology, University of Padova, Padova, Italy
| | | | - P McGinnity
- School of Biological, Earth and Environmental Sciences, University College Cork, Cork, Ireland
| | - A Sturm
- Institute of Aquaculture, University of Stirling, Stirling, UK
| | - K R Elmer
- Institute of Biodiversity, Animal Health & Comparative Medicine, College of Medical, Veterinary & Life Sciences, University of Glasgow, Glasgow, UK
| | - M S Llewellyn
- Institute of Biodiversity, Animal Health & Comparative Medicine, College of Medical, Veterinary & Life Sciences, University of Glasgow, Glasgow, UK.
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11
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Mennerat A, Ugelvik MS, Håkonsrud Jensen C, Skorping A. Invest more and die faster: The life history of a parasite on intensive farms. Evol Appl 2017; 10:890-896. [PMID: 29151880 PMCID: PMC5680424 DOI: 10.1111/eva.12488] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2017] [Accepted: 04/11/2017] [Indexed: 01/05/2023] Open
Abstract
Organisms are expected to respond to alterations in their survival by evolutionary changes in their life history traits. As agriculture and aquaculture have become increasingly intensive in the past decades, there has been growing interest in their evolutionary effects on the life histories of agri‐ and aquacultural pests, parasites, and pathogens. In this study, we used salmon lice (Lepeophtheirus salmonis) to explore how modern farming might have affected life history evolution in parasites. We infected salmon hosts with lice from either farmed or unfarmed locations, and monitored life history traits of those parasites in laboratory conditions. Our results show that compared to salmon lice from areas unaffected by salmon farming, those from farmed areas produced more eggs in their first clutch, and less eggs later on; they achieved higher infestation intensities in early adulthood, but suffered higher adult mortality. These results suggest that salmon lice on farms may have been selected for increased investment in early reproduction, at the expense of later fecundity and survival. This call for further empirical studies of the extent to which farming practices may alter the virulence of agricultural parasites.
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Affiliation(s)
- Adèle Mennerat
- Department of Biology University of Bergen Bergen Norway.,Ecologie et Dynamique des Systèmes Anthropisés (FRE 3498) CNRS/Université de Picardie Jules Verne Amiens France
| | | | | | - Arne Skorping
- Department of Biology University of Bergen Bergen Norway
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