Project

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Parasite radiations: Domino effect of host radiations?

English title Parasite radiations: Domino effect of host radiations?
Applicant Blasco Costa Isabel
Number 169211
Funding scheme Project funding (Div. I-III)
Research institution Muséum d'Histoire Naturelle
Institution of higher education Non-profit organisations (libraries, museums, foundations) and administration - NPO
Main discipline Zoology
Start/End 01.07.2017 - 30.06.2020
Approved amount 314'431.00
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All Disciplines (3)

Discipline
Zoology
Ecology
Genetics

Keywords (10)

co-phylogenetics; phylogeography; host-parasite associations; parasite speciation; diversity patterns; Single nucleotide polymorphisms; Platyhelminths; host-parasite interactions; interspecific interactions; Salmonidae

Lay Summary (French)

Lead
Les radiations d'espèces (la diversification rapide d’espèces en plusieurs espèces sœurs) ont des effets sur l'écosystème en modifiant la dynamique du réseau et des interactions trophiques. On ne sait cependant que peu de choses sur la façon dont ces radiations affectent d'autres interactions interspécifiques, comme les associations hôte-parasite. Ce projet nous permettra de chercher les déterminants de la diversité et de la structure génétique des parasites dans des hôtes qui se sont diversifiés récemment.
Lay summary

Les corégones (complexe d'espèces Coregonus lavaretus - "féra" ou "felchen"), constituent un exemple majeur de radiation animale avec de multiples espèces et des populations divergentes, à divers niveaux du continuum de spéciation, depuis la dernière glaciation. Ce modèle de radiation nous permet de rechercher des patterns parallèles de diversification dans leurs espèces parasites. Le but de ce projet est de mieux comprendre le rôle des processus évolutifs et écologiques par lesquels la diversité de l'hôte peut déclencher la diversification des parasites en favorisant leur spécificité. Nous vérifierons si la diversité des parasites suit l'hypothèse d'hétérogénéité de l'habitat. Nous quantifierons la différenciation génétique des populations de parasites dans une diversité d'espèces hôtes. Nous examinerons la contribution des traits écologiques du parasite et de l'hôte à la congruence de leurs structures phylogéographiques respectives.

Dans une perspective sociétale, cette recherche est importante pour mieux comprendre l'émergence de nouvelles maladies parasitaires et les changements de distribution des parasites. De plus, les corégones sont des salmonidés indigènes en Europe, sont très importants commercialement et considérés comme vulnérables au changement climatique par l’UICN. La surveillance de leurs infections parasitaires pourrait être utilisée comme outil d'alerte précoce à des fins de gestion et de conservation de ces poissons.

Direct link to Lay Summary Last update: 22.05.2017

Lay Summary (English)

Lead
Adaptive species radiations (i.e. the diversification of species into sister-species flocks by adaptation to different ecological environments in short evolutionary time) have ecosystem effects through altering trophic interactions and “food-web” dynamics. Yet little is known about how radiations affect other interspecific interactions, such as host-parasite associations. This project will allow us to investigate the determinants of diversity and genetic structure of parasites in hosts that have recently diversified.
Lay summary

The Swiss and Scandinavian whitefish (Coregonus lavaretus complex) is a major example of animal radiations with multiple species and divergent populations at different stages of the speciation continuum since last glaciation. This fish model radiation allows us to search for parallel patterns of diversification in parasite species composing the communities infecting this host. In this project we will use a combination of field data, population genomics approaches, and co-phylogenetic analyses, with the ultimate aim of understanding the role of evolutionary and ecological processes at different geographical scales by which host diversity may trigger parasite diversification promoting host specificity. We will assess whether parasite diversity follows the habitat heterogeneity hypothesis. We will quantify genetic differentiation of parasite populations across a diversity of host species over a large geographical scale. We will examine the contribution of parasite and host ecological traits to the congruence of host and parasite phylogeographic structures.

From a social perspective, this research is important to better understand the emergence of new parasitic diseases, the impact of biological invasions, or changes in the distribution of parasites that are related to parasite specificity. Furthermore, whitefish are native salmonids to Europe, commercially important and considered as species vulnerable to climate change by IUCN. Monitoring parasite infection levels can be used as early warning tools for management and conservation purposes.

Direct link to Lay Summary Last update: 22.05.2017

Responsible applicant and co-applicants

Employees

Publications

Publication
Histopathological characterisation of retinal lesions associated to Diplostomum species (Platyhelminthes: Trematoda) infection in polymorphic Arctic charr Salvelinus alpinus
Padrós F., Knudsen R., Blasco-Costa I. (2018), Histopathological characterisation of retinal lesions associated to Diplostomum species (Platyhelminthes: Trematoda) infection in polymorphic Arctic charr Salvelinus alpinus, in International Journal for Parasitology: Parasites and Wildlife, 7(1), 68-74.

Collaboration

Group / person Country
Types of collaboration
Philine Feulner, Eawag Switzerland (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
- Research Infrastructure
Profesor Rune Knudsen, The Arctic University of Norway Norway (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
- Research Infrastructure
Francesc Padrós Spain (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
Ole Seehausen, Eawag and University of Bern Switzerland (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
- Research Infrastructure

Scientific events

Active participation

Title Type of contribution Title of article or contribution Date Place Persons involved
British Society for Parasitology Spring Meeting 2018 Talk given at a conference Determinants of genetic structure and diversity patterns in parasite populations (invited speaker) 08.04.2018 University of Aberystwyth, Wales, U.K., Great Britain and Northern Ireland Blasco Costa Isabel;


Communication with the public

Communication Title Media Place Year
Talks/events/exhibitions Our world? The world of parasites! Western Switzerland International 2018

Associated projects

Number Title Start Funding scheme
163446 Speciation Genomics of the Swiss Alpine Whitefish Radiation 01.10.2016 Project funding (Div. I-III)

Abstract

Adaptive species radiations (i.e. the diversification of species into sister-species flocks by adaptation to different ecological environments in short evolutionary time) have ecosystem effects through altering trophic interactions and “food-web” dynamics. Yet little is known about how radiations affect other interspecific interactions, such as host-parasite associations. Analogous to how a diverse habitat can support a diverse community of free-living species and lead to species radiations, a species-rich or genetically divergent pool of hosts may provide variable but resource-rich habitats that may promote parasite species radiations. Pioneering studies suggest that host diversity promotes parasite diversification into separate genetic species as a consequence of rapid host speciation. However, several crucial questions remain unanswered. First, how general is this process? Do other parasite taxa also diversify as a consequence of rapid host speciation? Which parasite traits predispose them to diversify? What processes generating variability will underpin novel adaptations among distinct parasite population leading to speciation? These questions are key to our understanding of the speciation process in parasites and the evolution towards host specificity. Typically a single host is capable of supporting a diverse community of parasites, and thus a sister-species complex of free-living organisms may act as an arena for the origin of a burst of closely related (sister-species complexes of) parasite species. The Swiss and Scandinavian whitefish (Coregonus lavaretus complex) represent a major example of animal radiations with multiple species and divergent populations, which represent different stages of the speciation continuum. This model of a fish radiation as a host allows us to search for parallel patterns of diversification in parasite species composing the communities infecting this host. Here we will examine the genetic make-up of several parasite species with contrasting life-history strategies across whitefish sister-species with a range of genetic and ecological differentiation, in order to disentangle host and parasite ecological traits driving parasite differentiation and favouring host specificity. We will use a combination of field data, population genomic approaches [single-nucleotide polymorphisms (SNPs)] and co-phylogenetic analyses, with the ultimate aim of understanding the role of evolutionary and ecological processes at different geographical scales by which host diversity may trigger parasite diversification and promote host specificity. 1. We will assess whether parasite diversity follows the habitat heterogeneity hypothesis by correlating parasite diversity indexes with the degree of genetic and ecological differentiation between host species within and across lakes. 2. We will quantify genetic differentiation of parasite populations across a diversity of host ecotypes over a large geographical scale. 3. We will examine the contribution of parasite and host ecological traits to the congruence of host and parasite phylogeographic structures. Unravelling determinants of diversification and genetic structure in parasites can greatly benefit from a comparative approach in which co-occurring species in populations of recently speciated hosts are investigated simultaneously. The novelty herein lies in both its comparative and trans-disciplinary approaches linking ecological and molecular epidemiology concepts, with population genomics and evolution. Integration of key findings at the multiple scales of the study will allow proposing a general framework for the interplay of ecological and evolutionary processes promoting parasite diversification in an interspecies interaction context.
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