Research

My current work focuses on the eco-evolutionary dynamics of opportunist pathogen bacteria. I also research the consequences of environmental variability at various levels of biological organisation. 

I use theoretical modelling, microcosm experiments, and virulence assays with insects and fish as tools. 

My research career started early 90’s when I joined the Jyväskylä Soil Ecology Group led by Veikko Huhta, Heikki Setälä and Jari Haimi. I did my PhD on decomposer food webs, nutrient cycling and plant growth. After completing my thesis I changed subject to population biology and worked with Veijo Kaitala and Esa Ranta. The aim was to develop stochastic population and community theory and test the models with microbial communities living in aquatic microcosms.

I currently work in the University of Helsinki as a professor. I am also a senior researcher in the CoE in Biological Interactions (Universities of Helsinki and Jyväskylä). 

Group

• Anni-Maria Örmälä
• Jani Anttila
• Ilona Merikanto
• Lauri Mikonranta
• Mikael Lindén

Co-operation

• Veijo Kaitala
• Lasse Ruokolainen
• Johanna Mappes
• Tarmo Ketola
• Lotta-Riina Sundberg
• Kati Saarinen
• Teppo Hiltunen
• Matti Jalasvuori
• Ville Friman
• Carita Lindstedt
• Raine Kortet
• Mike Fowler
• Ji Zhang

Alumni

• Ji Zhang
• Minna Pekkonen
• Ville Friman
• Teppo Hiltunen

Publications

[google.scholar profile]

2014

• Zhang, J., Laakso, J., Mappes, J., Laanto, E., Ketola, T. , Bamford, JKH., Kunttu, H., Sundberg, L-R. 2014. Association of colony morphotype on virulence, growth and resistance against protozoan predation in the fish pathogen Flavobacterium columnare. FEMS microbiology. DOI: 10.1111/1574-6941.12356

• Isomaa, M., Kaitala, V., Laakso, J. 2014. Precautionary management of Baltic Sea cod (Gadus morhua callaris) under different environmental noise and harvesting strategies. Boreal Environment Research 19: 39–50.

• Isomaa, M., Kaitala, V. Laakso, J. 2014 Initial age structure affects the recovery of a heavily over-harvested population.  Ecological Modelling. 286: 45–52.

2013

• Ketola, T., Mikonranta, L., Zhang, J., Saarinen, K., Örmälä, A-M., Mappes, J., Laakso, J. 2013. Evolved generalism at fluctuating temperatures comes with a cost of lowered virulence. Evolution, 67: 2936–2944. DOI: 10.1111/evo.12148

• Anttila, J. Ruokolainen, L., Laakso, J. Kaitala, V. 2013. Loss of species diversity generates disease outbreaks. PLoS ONE. 8(8): e71621

• Hiltunen, T. Laakso, J. 2013. Relative importance of competition and predation in resource pulse environment - an experimental test with a microbial community. BMC Ecology 13:29.

• Isomaa, M., Kaitala, J. Laakso, J. 2013. Baltic cod (Gadus morhua callaris) recovery potential under different environment and fishery scenarios. Ecological Modelling 266:118-125.

• Pekkonen, M., Ketola, T., Laakso, J. 2013. Resource availability and competition shape the evolution of survival and growth ability in a bacterial community. PLoS ONE 8(9): e76471. 

2012

• Fowler, M., Laakso, J., Kaitala, V., Ruokolainen, L., Ranta, E. 2012. Species dynamics alter diversity-biomass stability relationships. Ecology Letters, 15:1387-1392. doi: 10.1111/j.1461-0248.2012.01862.x

• Pekkonen, M., Laakso, J. 2012. Temporal changes in species interactions in simple aquatic bacterial communities. BMC Ecology 12:18. doi:10.1186/1472-6785-12-18

• Kortet, R., Niemelä, P., Vainikka, A., Laakso, J. 2012. Do females prefer males with similar personalities? An analysis of boldness, mate choice and bacterial resistance in the field cricket Gryllus integer. Evolutionary Parasitology and Immunology, 1: 1-6. 

• Zhang, J., Friman, V., Laakso, J., Mappes, J. 2012. Interactive effects between diet quality, and host and pathogen genotypes define the severity of infection. Ecology and Evolution 2: 2347–2356. doi: 10.1002/ece3.356 

• Hiltunen, T., Friman, V., Kaitala, V, Mappes J., Laakso, J. 2012. Predation and resource fluctuations drive eco-evolutionary dynamics of a bacterial community. Acta Oecologia, 38: 77-83. doi: 1146-609X 

• Mikonranta, L., Friman, V., Laakso, J. 2012. Anti-predatory adaptation and genetic drift attenuate bacterial virulence in environmental reservoirs. PLoS ONE, 7(8): e43801. doi:10.1371/journal.pone.0043801. 

• Merikanto, I., Laakso, J., Kaitala, V., 2012. Outside-host growth of pathogens attenuates epidemiological outbreaks. PLoS ONE,  7(11): 7(11): e50158. doi:10.1371/journal.pone.0050158

•  Laanto, E., Bamford, J.K.H., Laakso, J. Sundberg, L.-R. 2012. Phage-driven loss of virulence in a fish pathogenic bacterium. PLoS ONE, 7(12): e53157. doi:10.1371/journal.pone.0053157

2011

• Friman, V-P., Laakso, J. 2011 Pulsed resource dynamics constrain the evolution of predator–prey interactions. American Naturalist, 177(3) 334-345.

• Friman, V., Hiltunen, T., Jalasvuori, M., Lindstedt, C., Laanto, E., Örmälä, A-M., Laakso, J., Mappes, J., Bamford, J. 2011 High temperature and parasitic bacteriophages select indirectly bacterial virulence in outside-host-environment. PLoS One, 6(3) e17651. doi:10.1371/journal.pone.0017651 

• Pekkonen, M., Korhonen J., Laakso, J.  2011. Increased survival during famine improves fitness of bacteria in pulsed resource environment. Evolutionary Ecology Research, 13: 1-18.

• Friman, V.-P., Laakso, J. Koivu-Orava, M., Hiltunen, T. 2011. Pulsed-resource dynamics increase the asymmetry of antagonistic coevolution between a predatory protist and a prey bacterium. Journal of Evolutionary Biology, doi: 10.1111/j.1420-9101.2011.02379.x

− 2010

• Friman, V-P., Hiltunen, T., Lindstedt, C., Laakso, J., Mappes, J. 2009. Predation on multiple trophic levels shapes the evolution of pathogen virulence. PLoS ONE, 4(8): e6761.

• Friman, V.-P., Hiltunen, T., Laakso, J., Kaitala, V. 2008. Prey resource availability drives evolution of predator-prey relationship. Proceedings of the Royal Society B, 275: 1625-1633.

• Ranta, E., Kaitala, V., Fowler, M.S., Laakso, J., Ruokolainen, L. O’Hara, R. 2008. The structure and strength of environmental variation modulate covariance patterns. A reply to Houlahan et al. 2008. Oikos, 117: 1914.

• Ranta, E., Kaitala, V., Fowler, M.S., Laakso, J., Ruokolainen, L., O’Hara, R. 2008. Detecting compensatory dynamics in competitive communities under environmental forcing. Oikos, 117: 1907-1911.

• Hiltunen, T., Laakso, J.,  Kaitala, V., Suomalainen, L.-R., Pekkonen, M. 2008. Temporal variability in resource availability affects diversity of aquatic bacterial communities. Acta Oecologica, 33: 291-299. 

• Laakso, J. Kaitala, V., Ranta, E. 2006. Population dynamic consequences of adaptive growth rate in fluctuating environment. Ecological Modelling, 194:132-140. 

• Hiltunen, T., Laakso, J., Kaitala, V. 2006. Interactions between environmental variability and immigration rate control patterns of species diversity. Ecological Modelling, 194: 125-131.

• Ketola, T., Laakso, J., Kaitala, V., Airaksinen, S. 2004. Evolution of Hsp90 expression in Tetrahymena thermophila (Protozoa, Ciliata) populations exposed to thermally variable environment. Evolution, 58: 741-748.

• Laakso, J., Kaitala, V., Ranta, E. 2004. Nonlinear biological responses to disturbance affect population extinction risk. Oikos 104: 142-148.

• Laakso, J., Löytynoja, K., Kaitala, V. 2003. Environmental noise and population dynamics of the ciliated protozoa Tetrahymena thermophila in aquatic microcosms. Oikos, 102: 663-671.

• Gårdmark A., Enberg, K., Ripa, J., Laakso, J., Kaitala, V. 2003. The ecology of recovery. Ann. Zool. Fenn. 40: 131-144.

• Laakso, J., Kaitala, V., Ranta, E. 2003. Nonlinear biological responses to disturbance: consequences on population dynamics. Ecological Modelling, 162: 247-258. 

• Sulkava, P., Huhta, V., Laakso, J., Gylén, E-R. 2001. Influence of soil fauna and habitat patchiness on plant (Betula pendula) growth and carbon dynamics in a microcosm experiment. Oecologia 129: 133-138.

• Laakso, J., Kaitala, V., Ranta, E. 2001. How does environmental variation translate into biological processes? Oikos 92: 119-122.

• Ylikarjula, J., Alaja, S., Laakso, J., Tesar, D. 2000. Effects of patch number and dispersal patterns on population dynamics and synchrony. Journal of Theoretical Biology 207: 377-387.

• Ranta, E., Lundberg, P., Kaitala, V., Laakso, J. 2000. Visibility of the environmental noise modulating population dynamics. Proceedings of the Royal Society B 267:1851-1856.

• Laakso, J., Setälä, H., Palojärvi, A. 2000. Influence of decomposer food web structure and nitrogen availability on plant growth. Plant and Soil 225:153-165.

• Laakso, J., Setälä, H. 2000. Impacts of wood ants (Formica aquilonia Yarr.) on the invertebrate food web of boreal forest floor. Annales Zoologici Fennici 37: 93-100.

• Katajisto J., Huhta V., Laakso J., 1999. Plant effects on the soil community: a microcosm experiment. Eur. J. Soil Biol. 35: 17-21.

• Laakso, J., Setälä, H. 1999. Population and ecosystem-level effects of predation on nematodes. Oecologia 120: 279-286.

• Laakso, J., Setälä H. 1999. Sensitivity of primary production to changes in the architecture of belowground food webs. Oikos 87: 57-64.

• Laakso, J. 1999. Short-term effects of wood ants (Formica aquilonia Yarr.) on soil animal community structure. Soil Biology and Biochemistry 31: 337-343.

• Laakso, J. 1998. Sensitivity of ecosystem functioning to changes in the structure of soil food webs. Thesis. University of Jyväskylä, 28 p. 

• Laakso, J., Setälä, H. 1998. Composition and trophic structure of detrital food web in ant (Formica aquilonia) nest mounds and in the surrounding soil. Oikos 81: 266-278.

• Setälä, H., Laakso, J., Mikola, J., Huhta, V. 1998. Functional diversity of decomposer organisms in relation to primary production. Applied Soil Ecology 9: 25-31. 

• Laakso, J., Setälä, H. 1997. Nest mounds of wood ants (Formica aquilonia): hot spots for litter dwelling earthworms. Oecologia 111: 565-569.

• Huhta, V., Sulkava, P., Laakso, J. 1996. Impact of soil faunal structure on decomposition and N-mineralisation in relation to temperature and moisture in forest soil. - Pedobiologia 40: 505-513.

• Laakso J., Salminen J., Setälä H., 1995. Effects of abiotic conditions and microarthropod predation on the structure and function of soil animal communities, Acta Zool. Fenn. 196: 162-167.