Alexander Kotrschal

Alexander Kotrschal


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Works at Department of Zoology
Telephone 08-16 40 27
Visiting address Svante Arrheniusväg 18 B
Room D 544b
Postal address Zoologiska institutionen: Etologi 106 91 Stockholm


Alexander Kotrschal

group leader


I am a Biologist with a strong interest in both Animal Behaviour and Evolution. My topics range from phenotypic plasticity of behaviour and physiology to the evolution of brain size and cognitive ability. I predominantly work with fish - be it cichlids from Lake Tanganyika, Salmon from Canada and Sweden, or Guppies from Trinidad - but also work with Chinese frogs, wild house mice and nightingales.
As a previous Erwin Schrödinger fellow (Austrian Science Fund) I was involved in a large-scale experiment in which we experimentally investigate brain size evolution of vertebrates. After determining the costs and benefits of a large brain using artificial brain size selection in Guppies at Uppsala University, Sweden, I moved to the Konrad Lorenz Institute of the Veterinary School in Vienna to investigate how animals with large and small brains perform in a naturalistic setting and whether they differ in immunity. At Stockholm University (since autumn 2014) we continue to pursue a number of questions with those large- and small-brained fish. The last years I was a forskare in a Wallenberg project investigating the basis of sociality, which includes another artificial selection approach with guppies. This work is ongoing. In 2018 I received a Vetenskapsrådet fellowship (VR - Etableringsbidrag) and Carl Tryggers Stiftelse grant. Together with three amazing postdocs

Regina Vega TrejoDavid Mitchell, and Catarina Vila Pouca

we now investigate the role of predation in cognitive and brain evolution. If you are interested in joining this project please get in touch.

I am an Associate Editor for Evolutionary Ecology and got the Niko Tinbergen Award in 2016.


You can find copies of my papers on my Research Gate site:
Kotrschal ResearchGate

I am also on google.scholar:
Kotrschal GoogleScholar

Here are my publications:
(last update Nov 2019)




55. Mitchell D., Vega-Trejo R., Kotrschal A. (2019) Experimental translocations to low predation lead to non-parallel increases in relative brain size

Biology Letters accepted


54. Corral‐López A., Romensky M, Kotrschal A., Buechel S.D., Kolm N. (2019) Brain size affects the responsiveness in mating behavior to variation in predation pressure and sex ratio

Journal of Evolutionary Biology online early


53. Herczeg G., Urszán, T.J., Orf A., Nagy G., Kotrschal A., Kolm N. (2019) Yes, correct context is indeed the key: an answer to Haave_Audet et al. 2019

Journal of Evolutionary Biology online early


52. Tsuboi M., van der Bijl W., Kopperud B.T., Erritzøe J., Voje K.L., Kotrschal A., Yopak K.A., Collin S.P., Iwaniuk A., Kolm N. (2019) Reply to: Comparisons of static brain-body allometries across vertebrates must distinguish between indeterminate and determinate growth

Nature Ecology and Evolution 3(10): 1405-1406


51. Marhounová L.*, Kotrschal A.*, Kverková K., Kolm N.**, Némec P.** (2019) Artificial selection on brain size leads to matching changes in overall number of neurons

Evolution 73(9): 2003-2012

*shared first, ** shared last


50. Kotrschal A., Corral-Lopez A., Kolm N. (2019) Large brains, short life: selection on brain size impacts intrinsic lifespan

Biology Letters 15(5): 20190137


49. Fong S., Buechel S.D., Boussard A., Kotrschal A., Kolm N. (2019) Plastic changes in brain morphology in relation to learning environmental enrichment in the guppy (Poecilia reticulata)

Journal of Experimental Biology 222(10), jeb200402


48. Huang C.H., Zhong M.J., Liao W.B., Kotrschal A. (2019) Investigating the role of body size, ecology, and behavior in anuran eye size evolution.

Evolutionary Ecology 1: 1-14


47. Herczeg G., Urszán, T.J., Orf A., Nagy G., Kotrschal A., Kolm N. (2019) Brain size predicts behavioural plasticity in guppies (Poecilia reticulata): an experiment.

Journal of Evolutionary Biology 32(3): 218-226


46. Kotrschal A. Einsatz von Selektionslinien in der Verhaltensbiologischen Forschung. In: Methoden der Verhaltensbiologie. Naguib M. (Ed.) Springer (in press), scheduled release: Autumn 2019




45. Bloch N.I., Corral-Lopez A., Buechel S., Kotrschal A., Mank J.E. (2018) Early neurogenomic response associated with variation in guppy female mate preference.

Nature Ecology & Evolution 2(11): 1772-1780


44. Tsuboi M., van der Bijl W., Kopperud B.T., Erritzøe J., Voje K.L., Kotrschal A., Yopak K.A., Collin S.P., Iwaniuk A., Kolm N. (2018) Breakdown of brain-body allometry and the encephalization of birds and mammals.

Nature Ecology & Evolution 2(9): 1492



43. Corral-Lopez A., Kotrschal A., Kolm N. (2018) Selection for relative brain size affects context-dependent male preferences, but not discrimination, of female body size in guppies.

Journal of Experimental Biology jeb 175240



42. Szorkovszky A.*, Kotrschal A.*, Herbert Read J.E., Buechel S.D., Romenskyy M., Rosen E., van der Bijl W., Pelckmans K., Kolm N., Sumpter D.J.T. (2018) Assortatative interactions revealed by sorting of animal groups.

*shared first

Animal Behaviour 142: 165-179



41. Yu X., Zhong M.J., Li D.Y., Liao W.B., Kotrschal A. (2018) Large-brained frogs mature later and live longer.

Evolution 72(5) 1174-1183


40. Sumpter D., Szorkovsky A., Kotrschal A., Kolm N., Herbert-Read J. (2018) Using activity and sociability to characterize collective motion.

Philosophical Transactions of the Royal Society B: Biological Sciences 373(1746)

39. Kotrschal A., Kotrschal K. (2017) The Fish brain. In: The welfare of fish. Kristiansen T., Fernö A., Pavlidis M., van de Vies H. (Eds.) Springer.
Book chapter, scheduled release: Autumn 2018


38. Buechel S.D., Boussard A., Kotrschal A., van der Bijl W., Kolm N. (2018) Brain size affects performance in a reversal-learning test.

Proceedings of the Royal Society B: Biological Sciences 285(1871)


37. Kotrschal A., Szorkovszky A., Romenskyy M., Perna A., Buechel S.D., Zeng H., Pelckmans K., Sumpter D., Kolm N. (2018) Brain size does not impact shoaling dynamics in unfamiliar groups of guppies (Poecilia reticulata).

Behavioural Processes 147: 13-20.




36. Liao W.B., Yi L., Mao J.Z., Yan H., Feng L., Kotrschal A. (2017) Seasonality and brain size are negatively associated in frogs: Evidence for the expensive brain framework.
Scientific Reports, 7:16629

35. Corral-Lopez A., Garate-Olaizola M., Buechel S.D., Kolm N.*, Kotrschal A.* (2017) On the role of body size, brain size and eye size in visual acuity.
*shared last
Behavioral Ecology and Sociobiology 71:179

34. Kotrschal A., Zeng H.L., Bijl W., Oehman-Mägi C., Pelckmans K., Kolm N. (2017) Evolution of brain region volumes during artificial selection for relative brain size.
Evolution 71(12): 2942-2951


33. Herbert Read J.E., Rosen E., Szorkovsky A., Ioannou C.C., Rogell B., Perna A., Ramnarine I.W., Kotrschal A., Kolm N., Krause J., Sumpter D. (2017) How predation shapes the social interaction rules in fish.
Proceedings of the Royal Society B: Biological Sciences, 284: 20171126

32. Szorkovszky A., Kotrschal A., Herbert Read J.E., Dumpter D.J.T., Kolm N., Pelckmans K. (2017) An efficient method for sorting and quantifying individual social traits based on group-level behaviour.
Methods in Ecology and Evolution, 8(12): 1735-1744

31. Kotrschal A., Deacon, A., Magurran A., Kolm N. (2017) Predation pressure shapes brain anatomy in the wild.
Evolutionary Ecology, 31(5): 619-633

30. Hayward, A., Tsuboi, M., Owuso C. Kotrschal A., Kolm N. Evolutionary associations between host traits and parasite load: insights from Lake Tanganyika cichlids.
Journal of Evolutionary Biology, 30(6): 1056-1067

29. Corral-Lopez A., Bloch N.I., Kotrschal A., van der Bijl W., Büchel S.D., Mank J.E., Kolm N. Female brain size affects the assessment of male attractiveness during mate choice.
Science Advances, 3 (3): e1601990 pdf
New Scientist


28. Buechel, S.D., Booksmythe, I., Kotrschal A., Jennions, M.D., Kolm, D. Artificial selection on male genitalia length alters female brain size.
Proceedings of the Royal Society - Biological Sciences, 283(1843): 1796
daily mail ;-) 

27. Liao, W.B., Lou, S.L., Zeng, Y. & Kotrschal, A. 2016. Large brains, small guts: The expensive tissue hypothesis supported in anurans.
American Naturalist, 188(6):693-700

26. Zeng, Y., Lou, S.L., Liao, W.B., Jehle, R., Kotrschal A. 2016 Sexual selection impacts brain anatomy in frogs and toads.
Ecology and Evolution, 6(19):7070-7079 online

25. Tsuboi, M., Kotrschal, A., Hayward, A., Buechel, S. D., Zidar, J., Løvlie, H. & Kolm, N. 2016. Evolution of brain-body allometry in Lake Tanganyika cichlids.
Evolution, 70: 1559-1568 online

24. Kotrschal A, Kolm N, Penn DJ 2016 Selection for brain size impairs innate, but not adaptive immune responses.
Proceedings of the Royal Society - Biological Sciences, 283(1826): 20152857. pdf


23. Kotrschal A, Corral-Lopez A, Szidat S, Kolm N. 2015 The effect of brain size evolution on feeding propensity, digestive efficiency and juvenile growth
Evolution, 69(11): 3013-3020.

22. van der Bijl W, Thyselius M, Kotrschal A, Kolm N. 2015 Brain size affects the behavioural response to predators in female guppies (Poecilia reticulata).
Proceedings of the Royal Society - Biological Sciences, (1812), 20151132 pdf

21. Chen Y*, Harrison P*, Kotrschal A*, Kolm N**, Mank JE** & Panula P**. 2015 Expression change in Angiopoietin-1 underlies change in relative brain size in fish. 282 (1810), 20150872
Proceedings of the Royal Society - Biological Sciences, pdf
* shared first
** shared last

20. Kotrschal A, Büchel S, Zala S, Corral-Lopez A, Penn D & Kolm N. 2015 Brain size affects female but not male survival under predation threat.
Ecology Letters, 18 (7), 646-652.
New Scientist

19. Fischer, S., Bessert, M., Kotrschal, A., Taborsky, B. 2015. Rearing group size determines social competence and brain structure in a cooperatively breeding cichlid.
American Naturalist, 186 (1), 123-140.

18. Kotrschal, A., Corral‐Lopez, A., Zajitschek, S., Immler, S., Maklakov, A. A. & Kolm, N. 2015. Positive genetic correlation between brain size and sexual traits in male guppies artificially selected for brain size.
Journal of Evolutionary Biology, 28 (4), 841-850.

17. Tsuboi, M., Husby, A., Kotrschal, A., Hayward, A., Buechel, S. D., Zidar, J., Løvlie, H. & Kolm, N. 2015. Comparative support for the expensive tissue hypothesis: Big brains are correlated with smaller gut and greater parental investment in Lake Tanganyika cichlids.
Evolution, 69, 190-200.

16. Corral Lopez A, Eckerström Liedholm S, van der Bijl W, Kotrschal A & Kolm N. 2015. No association between brain size and male sexual behavior in the guppy.
Current Zoology, 61 (2), 265-273.


15. Kotrschal, A., Lievens, E. J., Dahlbom, J., Bundsen, A., Semenova, S., Sundvik, M., Maklakov, A. A., Winberg, S., Panula, P. & Kolm, N. 2014. Artificial selection on relative brain size reveals a positive genetic correlation between brain size and proactive personality in the guppy.
Evolution, 68: 1139-1149.

14. Kotrschal, A., Trombley, S., Rogell, B., Brannström, I., Foconi, E., Schmitz, M. & Kolm, N. 2014. The mating brain: early maturing sneaker males maintain investment into the brain also under fast body growth in Atlantic salmon (Salmo salar).
Evolutionary Ecology, 28, 1043-1055.

13. Kotrschal, A., Szidat, S. & Taborsky, B. 2014. Developmental plasticity of growth and digestive efficiency in dependence of early‐life food availability.
Functional Ecology, 28, 878-885.

12. Kotrschal, A., Corral-Lopez, A., Amcoff, M. & Kolm, N. 2014. A larger brain confers a benefit in a spatial mate search learning task in male guppies.
Behavioral Ecology, aru227.


11. Kotrschal, A., Rogell, B., Bundsen, A., Svensson, B., Zajitschek, S., Brännström, I., Immler, S., Maklakov, A. A. & Kolm, N. 2013. The benefit of evolving a larger brain: big-brained guppies perform better in a cognitive task.
Animal Behaviour, 86, e4-e6.

10. Kotrschal, A., Rogell, B., Bundsen, A., Svensson, B., Zajitschek, S., Brännström, I., Immler, S., Maklakov, A. A. & Kolm, N. 2013. Artificial selection on relative brain size in the guppy reveals costs and benefits of evolving a larger brain.
Current Biology, 23, 168-171.
Time Magazine


9. Kotrschal, A., Sundström, L. F., Brelin, D., Devlin, R. & Kolm, N. 2012. Inside the heads of David and Goliath: environmental effects on brain morphology among wild and growth‐enhanced coho salmon Oncorhynchus kisutch.
Journal of Fish Biology, 81, 987-1002.

8. Kotrschal, A., Rogell, B., Maklakov, A. A. & Kolm, N. 2012. Sex-specific plasticity in brain morphology depends on social environment of the guppy, Poecilia reticulata.
Behavioral Ecology and Sociobiology, 66, 1485-1492.

7. Kotrschal, A., Räsänen, K., Kristjánsson, B. K., Senn, M. & Kolm, N. 2012. Extreme sexual brain size dimorphism in sticklebacks: a consequence of the cognitive challenges of sex and parenting?
Plos One, 7, e30055.
New Scientist

6. Kotrschal, A., Heckel, G., Bonfils, D. & Taborsky, B. 2012. Life-stage specific environments in a cichlid fish: implications for inducible maternal effects.
Evolutionary Ecology, 26, 123-137.

2011 and before.

5. Kotrschal, A., Fischer, B. & Taborsky, B. 2011. A noninvasive method to determine fat content in small fish based on swim bladder size estimation.
Journal of Experimental Zoology Part A: Ecological Genetics and Physiology, 315, 408-415.

4. Kotrschal, A. & Taborsky, B. 2010. Resource Defence or Exploded Lek?–A Question of Perspective.
Ethology, 116, 1189-1198.

3. Kotrschal, A. & Taborsky, B. 2010. Environmental change enhances cognitive abilities in fish.
Plos Biology, 8, e1000351.

2. Ilmonen, P., Kotrschal, A. & Penn, D. J. 2008. Telomere attrition due to infection.
Plos One, 3, e2143.

1. Kotrschal, A., Ilmonen, P. & Penn, D. J. 2007. Stress impacts telomere dynamics.
Biology Letters, 3, 128-130.


Last updated: December 13, 2019

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