Portrait O SOtto E. Seppälä


Present position:

Professor, Head of Research Institute
Head of working group "Aquatic Evolutionary Ecology"

Research area:

Host-parasite interactions


+43 512 507-50207

photo credit: EAWAG

Employment History · Research · Staff · Projects · Teaching · Publications

Employment History

  • March 2021 - present: Head of the Research Department for Limnology, Mondsee, University of Innsbruck

  • Jul 2019-present: Professor at the Research Department for Limnology, Mondsee, University of Innsbruck

  • 2010–Jul 2019: Senior assistant (Oberassistant), Eawag / ETH Zürich, Switzerland and Adjunct Professor (Docent), University of Jyväskylä, Finland (teaching skills: excellent, evaluated by the faculty)

  • 2007-2009: Post-doctoral researcher, Eawag / ETH Zürich, Switzerland

  • 2006-2007: Post-doctoral researcher, University of Jyväskylä, Finland"
  • 2005: PhD, University of Jyväskylä, Finland (thesis awarded with the highest grade "approved with honours")

  • 2002: MSc, University of Jyväskylä, Finland



Current main research interests

  • Host-parasite interactions in variable environments
  • Interactions among coinfecting parasites
  • Natural selection on immune defence traits
  • Host manipulation by parasites


Natalia Gogoleva, PostDoc

Georgios Katsianis, PhD

Vinayaka Hegde, PhD

Katri Seppälä, technical assistant (part time)



SnailPop survey

Evolutionary adaptation to heatwaves in an aquatic grazer (FWF)

Climate change increases the frequency and intensity of summer heatwaves, which can have even stronger ecological effects than gradual warming. Whether natural populations can persist under climate change depends on their ability to evolutionarily adapt to changing conditions. This may, however, depend on interactions with other ecological factors that can alter phenotypic selection on and/or evolutionary potential in organisms. Research questions/objectives - This project aims to provide a comprehensive study of climate change-mediated evolution in an aquatic grazer Lymnaea stagnalis (Gastropoda). First, the project examines (1) if snails show evolutionary potential (i.e., heritable phenotypic variation) in their responses to heatwaves and (2) how phenotypic selection operates on those responses, to create predictions of snails' evolution under heatwaves. Second, the project tests if these predictions hold (3) under artificial selection and (4) in the field where populations are exposed to different thermal conditions. Furthermore, the project examines (5) if the above evolutionary processes depend on ecological variation in snails' resource (i.e., food) quality. Approach/methods - The above research questions are addressed in a series of experiments utilising a quantitative genetic framework. The analyses focus on key fitness-related traits of both juvenile (growth) and adult snails (growth, fecundity). Evolutionary potential in snails' responses to heatwaves is examined using planned breeding that allows partitioning of phenotypic variation into different genetic and non-genetic variance components. Phenotypic selection on responses to heatwaves is quantified by linking among-individual variation in thermal performance to estimates of snails' overall fitness. Evolutionary responses will then be tested using experimental evolution in the lab and examining phenotypic differentiation among natural populations that originate from different thermal conditions. Investigations on evolutionary potential and phenotypic selection are linked to ecological variation by testing their dependence on the quality of natural food sources that snails use (i.e., macrophytes, plant detritus). Level of originality/innovation - No earlier study has comprehensively examined evolutionary processes related to adaptation to climate change, which prevents predicting the long-term persistence of natural populations. Moreover, the dependence of climate change-mediated evolution on variation in other ecological/environmental factors is overlooked in earlier research.

Sensitivity of eDNA detection of cercaria dermatitis pathogens in Upper Austrian lakes
co-operation partner together with with the Natural History Museum Vienna (lead) and the Department of Water Management of Upper Austria (ABOL)
Cercariae are infectious larvae of trematods, which develop in snails and, after hatching, infect other intermediate hosts or the final hosts. Certain cercariae (e.g. Trichobilharzia species) can cause cercaria dermatitis, also called swimmer´s itch. The pilot study carried out in 2019 for the detection of cercaria dermatitis pathogens in Upper Austria bathing lakes by means of DNA barcoding was used to develop the basis for the genetic detection of cercariae dermatitis pathogens using the DNA barcoding approach. In the follow-up project 2020, the primers for the detection of Trichobilharzia species and thus the detection of pathogens in water samples (eDNA) are to be optimized. In addition, the temporal and spatial sensitivity of the method should be examined and DNA barcodes generated from new species.

Contact persons: Nikolaus Szucsich, Elisabeth Haring (NHM Vienna)
Collaborators: Hubert Blatterer, Hans-Peter Grasser, Wolfgang Heinisch, Florian Billinger (Department of Water Management of Upper Austria), Nikolaus Helmer, Christoph Hörweg, Helmut Sattmann, Luise Kruckenhauser, Michael Duda, Susanne Reier (NHM Vienna), Otto Seppälä, Petr Horak (Charles University in Prague), Jana Bulantová (Charles University in Prague)


Evolution of immune defence traits
Immune defence is the main physiological barrier against parasites. Its evolution, however, is difficult to predict since the form and strength of natural selection on quantitative components of immune function are generally poorly understood. We examine the form and strength of natural selection on immune defence traits of a freshwater snail (Lymnaea stagnalis), focusing on variation in selection over space and time, variation in selection imposed by different parasites, and the relative importance of immune traits in determining susceptibility. We do this both at phenotypic and gene expression level. Additionally, we investigate the evolutionary potential of immune system by examining the genetic variation in and architecture of immune traits.
Contact persons: Teo Cereghetti, Cansu Cetin, Rosina Beer, Otto Seppälä
Collaborators: Philine Feulner, Coen Adema

Responses and adaptation to environmental stress
In nature, organisms are typically exposed to various environmental stressors. These stressors can be natural or induced by human activities. In this project, we investigate the responses and adaptation of a freshwater snail (Lymnaea stagnalis) to multiple stressors imposed by global change (climate change, chemical pollution) and natural enemies (parasites, predators). Our main focus is in stress interactions, their long-term consequences for life-history and defence traits, and evolutionary adaptation of snails to stress.
Contact persons: Tiina Salo, Elia Schmitter, Otto Seppälä
Collaborators: Katja Räsänen, Christian Stamm, Francis Burdon

Interactions among co-infecting parasites
Host individuals are often simultaneously infected with multiple parasite species and genotypes. Co-infecting parasites can interact, which affects their fitness. Interactions among parasites are expected to modify host-parasite ecology and evolution, but these questions are usually not examined considering the variation in interactions between different combinations of co-infecting parasite genotypes. We examine the interactions between trematode parasites, focusing especially on the genetic specificity of these interactions.
Contact person: Otto Seppälä
Collaborators: Jukka Jokela, Curt Lively



University of Innsbruck:





  • Seppälä O., Schlegel T. (2023). Substrate specificity of phenoloxidase-like activity in an ecoimmunological model species Lymnaea stagnalis, Journal of Molluscan Studies 89(1): eyad005, https://doi.org/10.1093/mollus/eyad005

  • Langeloh L., Jokela J., Seppälä K., Seppälä O. (2023). Ecological determinants of variation in phenotypic selection on quantitative immune defence traits. Oikos, 2023: e09506. https://doi.org/10.1111/oik.09506


  • Seppälä O., Yohannes E., Salo T. (2022). Condition-dependent immune function in a freshwater snail revealed by stable isotopes. Freshwater Biology 67: 1287–1297. https://doi.org/10.1111/fwb.13917


  • Seppälä O., Çetin C., Cereghetti T., Feulner P.G.D., Adema C.M. (2021). Examining adaptive evolution of immune activity: opportunities provided by gastropods in the age of "omics". Philosophical Transactions B 376(1825): 20200158. https://doi.org/10.1098/rstb.2020.0158

  • Seppälä O., Walser J.C., Cereghetti T., Seppälä K., Saalo T., Adema C.M. (2021). Transcriptome profiling of Lymnaea stagnalis (Gastropoda) for ecoimmunological research. BMC Genomics 22: 144, https://doi.org/10.1186/s12864-021-07428-1


  • Seppälä O., Lively C.M., Jokela J. (2020). Coinfecting parasites can modify fluctuating selection dynamics in host-parasite coevolution. Ecology and Evolution,10:9600–9612 doi: 10.1002/ece3.6373

  • Blasco-Costa I., Seppälä K., Feijen F., Zajac N., Klappert K., Jokela J. (2020). A new species of Atriophallophorus Deblock & Rosé, 1964 (Trematoda: Microphallidae) described from in vitro-grown adults and metacercariae from Potamopyrgus antipodarum (Gray, 1843)(Mollusca: Tateidae), Journal of Helminthology 94:1-15, https://doi.org/10.1017/S0022149X19000993


  • Leicht K., Seppälä, O. (2019). Direct and transgenerational effects of an experimental heatwave on early life stages in a freshwater snail. Freshwater Biology 64:2131-2140, doi: 10.1111/fwb.13401

  • Salo T., Kropf T., Burdon F.J., Seppälä O. (2019). Diurnal variation around an optimum and near-critically high temperature does not alter the performance of an ecothermic aquatic grazer, Ecology and Evolution 9:11695-11706, doi: 10.1002/ece3.5666

  • Leicht K., Jokela J., Seppälä O. (2019). Inbreeding does not alter the response to an experimental heat wave in a freshwater snail. PLoS ONE 14(8): e0220669, https://doi.org/10.1371/journal.pone.022066


  • Salo T., Räsänen K., Stamm C., Burdon F.J., Seppälä O. (2018). Simultaneous exposure to a pulsed and a prolonged anthropogenic stressor can alter consumer multifunctionality. Oikos 127: 1437-1448.

  • Langeloh L., Seppälä O. (2018). Relative importance of chemical attractiveness to parasites for susceptibility to trematode infection. Ecology and Evolution 8: 8921-8929.


  • Salo T., Stamm C., Burdon F.J., Räsänen K., Seppälä O. (2017). Resilience to heat waves in the aquatic snail Lymnaea stagnalis: additive and interactive effects with micropollutants. Freshwater Biology 62: 1831-1846.

    Leicht K., Seppälä K., Seppälä O. (2017). Potential for adaptation to climate change: family-level variation in fitness-related traits and their responses to heat waves in a snail population. BMC Evolutionary Biology 17, 140.

    Langeloh L., Behrmann-Godel J., Seppälä O. (2017). Natural selection on immune defense: a field experiment. Evolution 71: 227-237.



  • Seppälä O., Louhi K.-R., Karvonen A., Rellstab C., Jokela J. (2015). Relative reproductive success of co-infecting parasite genotypes under intensified within-host competition. Infection, Genetics and Evolution 36: 450–455, https://doi.org/10.1016/j.meegid.2015.08.015.

  • Seppälä O., Leicht K. (2015). Quality attracts parasites: host condition-dependent chemo-orientation of trematode larvae. Functional Ecology 29: 791–795, https://www.jstor.org/stable/48576994.

  • Seppälä O. (2015). Natural selection on quantitative immune defence traits: a comparison between theory and data. Journal of Evolutionary Biology 28: 1–9, https://doi.org/10.1111/jeb.12528.


  • Leicht K., Seppälä O. (2014). Infection success of Echinoparyphium aconiatum (Trematoda) in its snail host under high temperature: role of host resistance. Parasites & Vectors 7: 192, DOI: 10.1186/1756-3305-7-192.


  • Leicht K., Jokela J., Seppälä O. (2013). An experimental heat wave changes immune defence and life history traits in a freshwater snail. Ecology and Evolution 3: 4861–4871, https://doi.org/10.1002/ece3.874.

  • Seppälä O., Karvonen A., Kuosa M., Haataja M., Jokela J. (2013). Are sick individuals weak competitors? Competitive ability of snails parasitized by a gigantism-inducing trematode. PLoS ONE 8: e79366, https://doi.org/10.1371/journal.pone.0079366.

  • Seppälä O., Leicht K. (2013). Activation of the immune defence of the freshwater snail Lymnaea stagnalis by different immune elicitors. Journal of Experimental Biology 216: 2902–2907, https://doi.org/10.1242/jeb.084947.


  • Seppälä O., Karvonen A., Rellstab C., Louhi K.-R., Jokela J. (2012). Reciprocal interaction matrix reveals complex genetic and dose-dependent specificity among coinfecting parasites. American Naturalist 180: 306–315, https://doi.org/10.1086/666985.

  • King K. C., Seppälä O., Neiman M. (2012). Is more better? Polyploidy and parasite resistance. Biology Letters 8: 598–600, https://doi.org/10.1098/rsbl.2011.1152.

  • Seppälä O., Karvonen A.,Valtonen E. T. (2012). Behavioural mechanisms underlying ‘specific’ host manipulation by a trophically transmitted parasite. Evolutionary Ecology Research 14: 73–81.


  • Seppälä O., Karvonen A., Haataja M., Kuosa M., Jokela J. (2011). Food makes you a target: disentangling genetic, physiological, and behavioral effects determining susceptibility to infection. Evolution 65: 1367–1375, https://doi.org/10.1111/j.1558-5646.2010.01205.x.

  • Seppälä O., Karvonen A., Valtonen E. T. (2011). Eye fluke-induced cataracts in natural fish populations: is there potential for host manipulation? Parasitology 138: 209–214, DOI: 10.1017/S0031182010001228.

  • Seppälä O., Jokela J. (2011). Immune defence under extreme ambient temperature. Biology Letters 7: 119–122, https://doi.org/10.1098/rsbl.2010.0459.



  • Karvonen A., Seppälä O.,Valtonen E. T. (2009). Host immunization shapes interspecific associations in trematode parasites. Journal of Animal Ecology 78: 945–952, https://www.jstor.org/stable/40405829.

  • Benesh D. P., Seppälä O., Valtonen E. T. (2009). Acanthocephalan size and sex affect the modification of intermediate host coloration. Parasitology 136: 847–854, DOI: 10.1017/S0031182009006180.

  • Seppälä O., Karvonen A., Valtonen E. T., Jokela J. (2009). Interactions among co-infecting parasite species: a mechanism maintaining genetic variation in parasites? Proceedings of the Royal Society B 276: 691–697, DOI: 10.1098/rspb.2008.1229.

  • Benesh D. P., Hasu T., Seppälä O., Valtonen E. T. (2009). Seasonal changes in host phenotype manipulation by an acanthocephalan: time to be transmitted? Parasitology 136: 219–230, DOI: 10.1017/S0031182008005271.


  • Seppälä O., Jokela J. (2008). Host manipulation as a parasite transmission strategy when manipulation is exploited by non-host predators. Biology Letters 4: 663–666, https://doi.org/10.1098/rsbl.2008.0335.

  • Seppälä O., Valtonen E. T., Benesh D. P. (2008). Host manipulation by parasites in the world of dead-end predators: adaptation to enhance transmission? Proceedings of the Royal Society B 275: 1611–1615, https://doi.org/10.1098/rspb.2008.0152

  • Karvonen A., Seppälä O. (2008). Effect of eye fluke infection on the growth of whitefish (Coregonus lavaretus) – an experimental approach. Aquaculture 279: 6–10, https://doi.org/10.1016/j.aquaculture.2008.04.013.

  • Karvonen A., Seppälä O. (2008). Eye fluke infection and lens size reduction in fish: a quantitative analysis. Diseases of Aquatic Organisms 80: 21–26, DOI: 10.3354/dao01918
  • Seppälä O., Liljeroos K., Karvonen A., Jokela J. (2008). Host condition as a constraint for parasite reproduction. Oikos 117: 749–753, https://doi.org/10.1111/j.0030-1299.2008.16396.x
  • Benesh D. P., Valtonen E. T., Seppälä O. (2008). Multidimensionality and intra-individual variation in host manipulation by an acanthocephalan. Parasitology 135, 617–626,  DOI: 10.1017/S0031182008004216.

  •  Seppälä O., Karvonen A., Valtonen E. T. (2008). Shoaling behaviour of fish under parasitism and predation risk. Animal Behaviour 75, 145–150, https://doi.org/10.1016/j.anbehav.2007.04.022.


  • Santos M. J., Karvonen A., Pedro J. C., Faltýnková A., Seppälä O., Valtonen E. T. (2007). Qualitative and quantitative behavioral traits in a community of furcocercarial trematodes – tools for species separation? Journal of Parasitology 93: 1319–1323, DOI: 10.1645/GE-1225.1.

  • Vainikka A., Rantala M. J., Seppälä O., Suhonen J. (2007). Do male mealworm beetles, Tenebrio molitor, sustain the honesty of pheromone signals under immune challenge? Acta Ethologica 10: 63–72, https://doi.org/10.1007/s10211-007-0031-0.

  • Seppälä O., Karvonen A., Valtonen E. T. (2007). Phenotypic variation in infectivity of Diplostomum spathaceum cercariae within a population. Journal of Parasitology 93: 1244–1246, https://www.jstor.org/stable/40058856.


  • Karvonen A., Savolainen M., Seppälä O., Valtonen E. T. (2006). Dynamics of Diplostomum spathaceum infection in snail hosts at a fish farm. Parasitology Research 99: 341–345, DOI: 10.1007/s00436-006-0137-8.

  • Karvonen A., Terho P., Seppälä O., Jokela J., Valtonen E. T. (2006). Ecological divergence of closely related Diplostomum (Trematoda) parasites. Parasitology 133: 229–235, DOI: 10.1017/S0031182006000242.

  • Vainikka A., Seppälä O., Löytynoja K., Rantala M. J. (2006). Fitness consequences of female preference for male pheromones in Tenebrio molitor. Evolutionary Ecology Research 8: 943–957.

  • Seppälä O., Karvonen A., Valtonen E. T. (2006). Host manipulation by parasites and risk of non-host predation: is manipulation costly in an eye fluke–fish interaction? Evolutionary Ecology Research 8: 871–879, doi: 10.1098/rsbl.2008.0335.

  • Seppälä O., Karvonen A., Valtonen E. T. (2006). Susceptibility of eye fluke-infected fish to predation by bird hosts. Parasitology 132: 575–579, DOI: 10.1017/S0031182005009431.

  • Karvonen A., Cheng G.-H., Seppälä O., Valtonen E. T. (2006). Intestinal distribution and fecundity of two species of Diplostomum parasites in definitive hosts. Parasitology 132: 357–362, DOI: 10.1017/S0031182005009091.


  • Seppälä O., Karvonen A., Valtonen E. T. (2005). Impaired crypsis of fish infected with a trophically transmitted parasite. Animal Behaviour 70: 895–900, https://doi.org/10.1016/j.anbehav.2005.01.021.

  • Seppälä O., Karvonen A., Valtonen E. T. (2005). Manipulation of fish host by eye flukes in relation to cataract formation and parasite infectivity. Animal Behaviour 70: 889–894, https://doi.org/10.1016/j.anbehav.2005.01.020.

  • Karvonen A., Paukku S., Seppälä O., Valtonen E. T. (2005). Resistance against eye flukes: naive versus previously infected fish. Parasitology Research 95: 55–59, DOI: 10.1007/s00436-004-1246-x.


  • Karvonen A., Seppälä O., Valtonen E. T. (2004). Eye fluke-induced cataract formation in fish: quantitative analysis using an ophthalmological microscope. Parasitology 129: 473–478, DOI: 10.1017/s0031182004006006.

  • Karvonen A., Seppälä O., Valtonen E. T. (2004). Parasite resistance and avoidance behaviour in preventing eye fluke infections in fish. Parasitology 129: 159–164, DOI: 10.1017/s0031182004005505.

  • Seppälä O., Karvonen A., Valtonen E. T. (2004). Parasite-induced change in host behaviour and susceptibility to predation in an eye fluke–fish interaction. Animal Behaviour 68: 257–263, https://doi.org/10.1016/j.anbehav.2003.10.021.

  • Karvonen A., Hudson P. J., Seppälä O., Valtonen E. T. (2004). Transmission dynamics of a trematode parasite: exposure, acquired resistance and parasite aggregation. Parasitology Research 92: 183–188, DOI: 10.1007/s00436-003-1035-y.


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