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Svanbäck, Richard
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Publications (10 of 39) Show all publications
Zha, Y., Alexander, E., Johansson, F. & Svanbäck, R. (2018). Effects of predation stress and food ration on perch gut microbiota. Microbiome, 6, Article ID 28.
Open this publication in new window or tab >>Effects of predation stress and food ration on perch gut microbiota
2018 (English)In: Microbiome, ISSN 0026-2633, E-ISSN 2049-2618, Vol. 6, article id 28Article in journal (Refereed) Published
Abstract [en]

Background: Gut microbiota provide functions of importance to influence hosts' food digestion, metabolism, and protection against pathogens. Factors that affect the composition and functions of gut microbial communities are well studied in humans and other animals; however, we have limited knowledge of how natural food web factors such as stress from predators and food resource rations could affect hosts' gut microbiota and how it interacts with host sex. In this study, we designed a two-factorial experiment exposing perch (Perca fluviatilis) to a predator (pike, Esox lucius), and different food ratios, to examine the compositional and functional changes of perch gut microbiota based on 16S rRNA amplicon sequencing. We also investigated if those changes are host sex dependent.

Results: We showed that overall gut microbiota composition among individual perch significantly responded to food ration and predator presence. We found that species richness decreased with predator presence, and we identified 23 taxa from a diverse set of phyla that were over-represented when a predator was present. For example, Fusobacteria increased both at the lowest food ration and at predation stress conditions, suggesting that Fusobacteria are favored by stressful situations for the host. In concordance, both food ration and predation stress seemed to influence the metabolic repertoire of the gut microbiota, such as biosynthesis of other secondary metabolites, metabolism of cofactors, and vitamins. In addition, the identified interaction between food ration and sex emphasizes sex-specific responses to diet quantity in gut microbiota.

Conclusions: Collectively, our findings emphasize an alternative state in gut microbiota with responses to changes in natural food webs depending on host sex. The obtained knowledge from this study provided us with an important perspective on gut microbiota in a food web context.

National Category
Microbiology Ecology
Identifiers
urn:nbn:se:uu:diva-341520 (URN)10.1186/s40168-018-0400-0 (DOI)000424692400001 ()29409543 (PubMedID)
Funder
Swedish Research Council, VR-2011-05646, VR-2012-4592Swedish Foundation for Strategic Research , ICA10-0015
Available from: 2018-02-09 Created: 2018-02-09 Last updated: 2018-03-28Bibliographically approved
Marklund, M. H. K., Svanbäck, R., Zha, Y., Scharnweber, K. & Eklöv, P. (2018). The influence of habitat accessibility on the dietary and morphological specialisation of an aquatic predator. Oikos, 127(1), 160-169
Open this publication in new window or tab >>The influence of habitat accessibility on the dietary and morphological specialisation of an aquatic predator
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2018 (English)In: Oikos, ISSN 0030-1299, E-ISSN 1600-0706, Vol. 127, no 1, p. 160-169Article in journal (Refereed) Published
Abstract [en]

Individual diet and habitat specialisation are widespread in animal taxa and often related to levels of predation and competition. Mobile consumers such as predatory fish can stabilise lake food webs by ranging over a larger area than their prey, thereby switching between habitats. Although, this switching assumes that the predator has equal preference for the available prey, individual diet specialisation and morphological adaptations to different habitats could potentially prevent individuals from switching between habitats. In this study, we assessed the niche width and individual specialisation in Eurasian perch Perca fluviatilis in response to a shift in habitat use by manipulating the ability for this top predator to couple habitats. We ran an eight weeks pond experiment, to test the effect of habitat switching on diet and morphological specialisations. We show that habitat coupling influenced individual diet specialisation and niche use in expected directions where specialisation increased with decreasing habitat switching. In contrast to expectations, the morphological variation decreased with increasing diet specialisation. Our results expand on previous work and suggest that individual specialisation and niche width can impact the ability of mobile predators to couple habitats. Furthermore, it shows the importance of individual specialisations in relation to habitat coupling.

Place, publisher, year, edition, pages
John Wiley & Sons, 2018
National Category
Ecology
Identifiers
urn:nbn:se:uu:diva-315718 (URN)10.1111/oik.04094 (DOI)000419102100015 ()
Funder
Swedish Research CouncilSwedish Research Council Formas
Available from: 2017-02-20 Created: 2017-02-20 Last updated: 2018-02-07Bibliographically approved
Boughman, J. W. & Svanbäck, R. (2017). Synergistic selection between ecological niche and mate preference primes diversification. Evolution, 71(1), 6-22
Open this publication in new window or tab >>Synergistic selection between ecological niche and mate preference primes diversification
2017 (English)In: Evolution, ISSN 0014-3820, E-ISSN 1558-5646, Vol. 71, no 1, p. 6-22Article in journal (Refereed) Published
Abstract [en]

The ecological niche and mate preferences have independently been shown to be important for the process of speciation. Here, we articulate a novel mechanism by which ecological niche use and mate preference can be linked to promote speciation. The degree to which individual niches are narrow and clustered affects the strength of divergent natural selection and population splitting. Similarly, the degree to which individual mate preferences are narrow and clustered affects the strength of divergent sexual selection and assortative mating between diverging forms. This novel perspective is inspired by the literature on ecological niches; it also explores mate preferences and how they may contribute to speciation. Unlike much comparative work, we do not search for evolutionary patterns using proxies for adaptation and sexual selection, but rather we elucidate how ideas from niche theory relate to mate preference, and how this relationship can foster speciation. Recognizing that individual and population niches are conceptually and ecologically linked to individual and population mate preference functions will significantly increase our understanding of rapid evolutionary diversification in nature. It has potential to help solve the difficult challenge of testing the role of sexual selection in the speciation process. We also identify ecological factors that are likely to affect individual niche and individual mate preference in synergistic ways and as a consequence to promote speciation. The ecological niche an individual occupies can directly affect its mate preference. Clusters of individuals with narrow, differentiated niches are likely to have narrow, differentiated mate preference functions. Our approach integrates ecological and sexual selection research to further our understanding of diversification processes. Such integration may be necessary for progress because these processes seem inextricably linked in the natural world.

Place, publisher, year, edition, pages
WILEY-BLACKWELL, 2017
Keywords
Divergent selection, diversification, ecological niche, mate preference, natural selection, niche width, preference function, preference variation, sexual selection, speciation
National Category
Ecology Evolutionary Biology Genetics
Identifiers
urn:nbn:se:uu:diva-319808 (URN)10.1111/evo.13089 (DOI)000394439600002 ()27748954 (PubMedID)
Funder
Swedish Research Council
Available from: 2017-04-10 Created: 2017-04-10 Last updated: 2017-11-29Bibliographically approved
Svanbäck, R., Zha, Y., Brönmark, C. & Johansson, F. (2017). The interaction between predation risk and food ration on behavior and morphology of Eurasian perch. Ecology and Evolution, 7(20), 8567-8577
Open this publication in new window or tab >>The interaction between predation risk and food ration on behavior and morphology of Eurasian perch
2017 (English)In: Ecology and Evolution, ISSN 2045-7758, E-ISSN 2045-7758, Vol. 7, no 20, p. 8567-8577Article in journal (Refereed) Published
Abstract [en]

The risk of both predation and food level has been shown to affect phenotypic development of organisms. However, these two factors also influence animal behavior that in turn may influence phenotypic development. Hence, it might be difficult to disentangle the behavioral effect from the predator or resource-level effects. This is because the presence of predators and high resource levels usually results in a lower activity, which in turn affects energy expenditure that is used for development and growth. It is therefore necessary to study how behavior interacts with changes in body shape with regard to resource density and predators. Here, we use the classic predator-induced morphological defense in fish to study the interaction between predator cues, resource availability, and behavioral activity with the aim to determine their relative contribution to changes in body shape. We show that all three variables, the presence of a predator, food level, and activity, both additively and interactively, affected the body shape of perch. In general, the presence of predators, lower swimming activity, and higher food levels induced a deep body shape, with predation and behavior having similar effect and food treatment the smallest effect. The shape changes seemed to be mediated by changes in growth rate as body condition showed a similar effect as shape with regard to food-level and predator treatments. Our results suggests that shape changes in animals to one environmental factor, for example, predation risk, can be context dependent, and depend on food levels or behavioral responses. Theoretical and empirical studies should further explore how this context dependence affects fitness components such as resource gain and mortality and their implications for population dynamics.

Place, publisher, year, edition, pages
John Wiley & Sons, 2017
National Category
Ecology
Identifiers
urn:nbn:se:uu:diva-332712 (URN)10.1002/ece3.3330 (DOI)000413308700034 ()29075472 (PubMedID)
Available from: 2017-10-31 Created: 2017-10-31 Last updated: 2018-01-26Bibliographically approved
Bartels, P., Hirsch, P. E., Svanbäck, R. & Eklöv, P. (2016). Dissolved Organic Carbon Reduces Habitat Coupling by Top Predators in Lake Ecosystems. Ecosystems (New York. Print), 19, 955-967
Open this publication in new window or tab >>Dissolved Organic Carbon Reduces Habitat Coupling by Top Predators in Lake Ecosystems
2016 (English)In: Ecosystems (New York. Print), ISSN 1432-9840, E-ISSN 1435-0629, Vol. 19, p. 955-967Article in journal (Refereed) Published
Abstract [en]

Increasing input of terrestrial dissolved organic carbon (DOC) has been identified as a widespread environmental phenomenon in many aquatic ecosystems. Terrestrial DOC influences basal trophic levels: it can subsidize pelagic bacterial production and impede benthic primary production via light attenuation. However, little is known about the impacts of elevated DOC concentrations on higher trophic levels, especially on top consumers. Here, we used Eurasian perch (Perca fluviatilis) to investigate the effects of increasing DOC concentrations on top predator populations. We applied stable isotope analysis and geometric morphometrics to estimate long-term resource and habitat utilization of perch. Habitat coupling, the ability to exploit littoral and pelagic resources, strongly decreased with increasing DOC concentrations due to a shift toward feeding predominantly on pelagic resources. Simultaneously, resource use and body morphology became increasingly alike for littoral and pelagic perch populations with increasing DOC, suggesting more intense competition in lakes with high DOC. Eye size of perch increased with increasing DOC concentrations, likely as a result of deteriorating visual conditions, suggesting a sensory response to environmental change. Increasing input of DOC to aquatic ecosystems is a common result of environmental change and might affect top predator populations in multiple and complex ways.

Keywords
allochthony, brownification, food web coupling, visibility, foraging, climate change
National Category
Biological Sciences
Identifiers
urn:nbn:se:uu:diva-294185 (URN)10.1007/s10021-016-9978-x (DOI)000386710000001 ()
Available from: 2016-05-18 Created: 2016-05-18 Last updated: 2017-10-17Bibliographically approved
Faulks, L., Svanbäck, R., Eklöv, P. & Östman, Ö. (2015). Genetic and morphological divergence along the littoral–pelagic axis in two common and sympatric fishes: perch, Perca fluviatilis (Percidae) and roach, Rutilus rutilus (Cyprinidae). Biological Journal of the Linnean Society, 114(4), 929-940
Open this publication in new window or tab >>Genetic and morphological divergence along the littoral–pelagic axis in two common and sympatric fishes: perch, Perca fluviatilis (Percidae) and roach, Rutilus rutilus (Cyprinidae)
2015 (English)In: Biological Journal of the Linnean Society, ISSN 0024-4066, E-ISSN 1095-8312, Vol. 114, no 4, p. 929-940Article in journal (Refereed) Published
Abstract [en]

Individuals are constantly in competition with one another and, on both ecological and evolutionary timescales, processes act to reduce this competition and promote the gain of fitness advantages via diversification. Here we have investigated the genetic (AFLP) and morphological (geometric morphometrics) aspects of the littoral–pelagic axis, a commonly observed resource polymorphism in freshwater fishes of postglacial lakes. We found a large degree of variation in the genetic and morphological divergence between littoral and pelagic perch and roach across Swedish lakes. Although there was evidence of assortative mating (elevated kinship values) in both species, we could not find any significant coupling of morphology and genetic divergence. Instead, there was evidence that the extent of resource polymorphism may be largely caused by phenotypic plasticity. These results suggest that assortative mating, which can lead to genetically determined adaptive divergence, does occur in these species, particularly perch, but not according to genetically fixed morphological traits. The behavioural mechanisms facilitating associative mating need to be investigated to explore the interaction between phenotypic plasticity and adaptive genetic divergence and their roles in diversification.

Keywords
adaptation, AFLP, diversification, phenotypic plasticity, postglacial lakes, resource polymorphism
National Category
Evolutionary Biology Ecology
Identifiers
urn:nbn:se:uu:diva-252431 (URN)10.1111/bij.12452 (DOI)000351206700016 ()
Available from: 2015-05-07 Created: 2015-05-07 Last updated: 2017-12-04Bibliographically approved
Svanbäck, R., Quevedo, M., Olsson, J. & Eklöv, P. (2015). Individuals in food webs: the relationships between trophic position, omnivory and among-individual diet variation. Oecologia, 178(1), 103-114
Open this publication in new window or tab >>Individuals in food webs: the relationships between trophic position, omnivory and among-individual diet variation
2015 (English)In: Oecologia, ISSN 0029-8549, E-ISSN 1432-1939, Vol. 178, no 1, p. 103-114Article in journal (Refereed) Published
Abstract [en]

Among-individual diet variation is common in natural populations and may occur at any trophic level within a food web. Yet, little is known about its variation among trophic levels and how such variation could affect phenotypic divergence within populations. In this study we investigate the relationships between trophic position (the population’s range and average) and among-individual diet variation. We test for diet variation among individuals and across size classes of Eurasian perch (Perca fluviatilis), a widespread predatory freshwater fish that undergoes ontogenetic niche shifts. Second, we investigate among-individual diet variation within fish and invertebrate populations in two different lake communities using stable isotopes. Third, we test potential evolutionary implications of population trophic position by assessing the relationship between the proportion of piscivorous perch (populations of higher trophic position) and the degree of phenotypic divergence between littoral and pelagic perch sub-populations. We show that among-individual diet variation is highest at intermediate trophic positions, and that this high degree of among-individual variation likely causes an increase in the range of trophic positions among individuals. We also found that phenotypic divergence was negatively related to trophic position in a population. This study thus shows that trophic position is related to and may be important for among-individual diet variation as well as to phenotypic divergence within populations.

Place, publisher, year, edition, pages
Springer Berlin/Heidelberg, 2015
Keywords
Trophic position, Evolution, Communities, Populations, Eco-evolutionary feedback
National Category
Ecology
Identifiers
urn:nbn:se:uu:diva-252435 (URN)10.1007/s00442-014-3203-4 (DOI)000354725200009 ()25651804 (PubMedID)
Available from: 2015-05-07 Created: 2015-05-07 Last updated: 2017-12-04Bibliographically approved
Faulks, L., Svanbäck, R., Ragnarsson-Stabo, H., Eklöv, P. & Östman, Ö. (2015). Intraspecific Niche Variation Drives Abundance-Occupancy Relationships in Freshwater Fish Communities. American Naturalist, 186(2), 272-283
Open this publication in new window or tab >>Intraspecific Niche Variation Drives Abundance-Occupancy Relationships in Freshwater Fish Communities
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2015 (English)In: American Naturalist, ISSN 0003-0147, E-ISSN 1537-5323, Vol. 186, no 2, p. 272-283Article in journal (Refereed) Published
Abstract [en]

A positive relationship between occupancy and average local abundance of species is found in a variety of taxa, yet the mechanisms driving this association between abundance and occupancy are still enigmatic. Here we show that freshwater fishes exhibit a positive abundance-occupancy relationship across 125 Swedish lakes. For a subset of 9 species from 11 lakes, we estimated species-specific diet breadth from stable isotopes, within-lake habitat breadth from catch data for littoral and pelagic nets, adaptive potential from genetic diversity, abiotic niche position, and dispersal capacity. Average local abundance was mainly positively associated with both within-lake habitat and diet breadth, that is, species with larger intraspecific variation in niche space had higher abundances. No measure was a good predictor of occupancy, indicating that occupancy may be more directly related to abundance or abiotic conditions than to niche breadth per se. This study suggests a link between intraspecific niche variation and a positive abundance-occupancy relationship and implies that management of freshwater fish communities, whether to conserve threatened or control invasive species, should initially be aimed at niche processes.

Keywords
amplified fragment length polymorphism (AFLP), conservation, distribution, habitat generalism, local-regional scale, stable isotopes
National Category
Evolutionary Biology Ecology Zoology
Identifiers
urn:nbn:se:uu:diva-260809 (URN)10.1086/682004 (DOI)000358447800013 ()
Funder
Carl Tryggers foundation Swedish Research Council
Available from: 2015-08-28 Created: 2015-08-25 Last updated: 2017-12-04Bibliographically approved
Nonaka, E., Svanbäck, R., Thibert-Plante, X., Englund, G. & Brännström, Å. (2015). Mechanisms by Which Phenotypic Plasticity Affects Adaptive Divergence and Ecological Speciation. American Naturalist, 186(5), E126-E143
Open this publication in new window or tab >>Mechanisms by Which Phenotypic Plasticity Affects Adaptive Divergence and Ecological Speciation
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2015 (English)In: American Naturalist, ISSN 0003-0147, E-ISSN 1537-5323, Vol. 186, no 5, p. E126-E143Article in journal (Refereed) Published
Abstract [en]

Phenotypic plasticity is the ability of one genotype to produce different phenotypes depending on environmental conditions. Several conceptual models emphasize the role of plasticity in promoting reproductive isolation and, ultimately, speciation in populations that forage on two or more resources. These models predict that plasticity plays a critical role in the early stages of speciation, prior to genetic divergence, by facilitating fast phenotypic divergence. The ability to plastically express alternative phenotypes may, however, interfere with the early phase of the formation of reproductive barriers, especially in the absence of geographic barriers. Here, we quantitatively investigate mechanisms under which plasticity can influence progress toward adaptive genetic diversification and ecological speciation. We use a stochastic, individual based model of a predator-prey system incorporating sexual reproduction and mate choice in the predator. Our results show that evolving plasticity promotes the evolution of reproductive isolation under diversifying environments when individuals are able to correctly select a more profitable habitat with respect to their phenotypes (i.e., adaptive habitat choice) and to assortatively mate with relatively similar phenotypes. On the other hand, plasticity facilitates the evolution of plastic generalists when individuals have a limited capacity for adaptive habitat choice. We conclude that plasticity can accelerate the evolution of a reproductive barrier toward adaptive diversification and ecological speciation through enhanced phenotypic differentiation between diverging phenotypes.

Keywords
assortative mating, eco-evolutionary dynamics, ecological, speciation, habitat choice, individual-based model, phenotypic plasticity
National Category
Zoology Ecology
Identifiers
urn:nbn:se:uu:diva-268410 (URN)10.1086/683231 (DOI)000363928900003 ()
Funder
Swedish Research Council
Available from: 2015-12-06 Created: 2015-12-04 Last updated: 2017-12-01Bibliographically approved
Nonaka, E., Brännström, R. & Svanbäck, R. (2014). Assortative mating can limit the evolution of phenotypic plasticity. Evolutionary Ecology, 28(6), 1057-1074
Open this publication in new window or tab >>Assortative mating can limit the evolution of phenotypic plasticity
2014 (English)In: Evolutionary Ecology, ISSN 0269-7653, E-ISSN 1573-8477, Vol. 28, no 6, p. 1057-1074Article in journal (Refereed) Published
Abstract [en]

Phenotypic plasticity, the ability to adjust phenotype to the exposed environment, is often advantageous for organisms living in heterogeneous environments. Although the degree of plasticity appears limited in nature, many studies have reported low costs of plasticity in various species. Existing studies argue for ecological, genetic, or physiological costs or selection eliminating plasticity with high costs, but have not considered costs arising from sexual selection. Here, we show that sexual selection caused by mate choice can impede the evolution of phenotypic plasticity in a trait used for mate choice. Plasticity can remain low to moderate even in the absence of physiological or genetic costs, when individuals phenotypically adapted to contrasting environments through plasticity can mate with each other and choose mates based on phenotypic similarity. Because the non-choosy sex (i.e., males) with lower degrees of plasticity are more favored in matings by the choosy sex (i.e., females) adapted to different environments, directional selection toward higher degrees of plasticity is constrained by sexual selection. This occurs at intermediate strengths of female choosiness in the range of the parameter value we examined. Our results demonstrate that mate choice is a potential source of an indirect cost to phenotypic plasticity in a sexually selected plastic trait.

National Category
Ecology Genetics
Identifiers
urn:nbn:se:uu:diva-238731 (URN)10.1007/s10682-014-9728-5 (DOI)000344075200006 ()
Available from: 2014-12-16 Created: 2014-12-16 Last updated: 2017-12-05Bibliographically approved
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