Dr Isabel Santos Magalhaes

Research interests

I am interested in studying mechanisms that generate and maintain biodiversity, particularly in the presence of gene flow. My main interests are on how natural selection and sexual selection and environmental heterogeneity can lead to population divergence and even reproductive isolation. Understanding the efficacy of these mechanisms when there is migration of individuals (gene flow) between populations has become one of the central issues of evolutionary biology. I try to do this by using a combination of genetic data with ecological, morphological and behavioural data.
So far I have been looking at these issues using African cichlid fish, a model system for the study of species divergence without geographical isolation, due to their rapid radiation. They are a family of fish made of generally very young lineages, with an immense phenotypic diversity and with an enormous capability of adaptation. During my PhD I looked at  the selective forces that maintain diversity in young haplochromine cichlid species from Lake Victoria that still exchange genes and how the disappearance of their habitat and degradation of water quality are affecting the balance between gene flow and selection. After my PhD I have looked at the behaviour of sand-dwelling cichlids from Lake Malawi to try to gain more insight into how divergence in an extended phenotype (sand bowers) contributes to their diversity. It has been suggested that the sand bowers built by males are used by females to access their potential mates (direct sexual selection) and also in male-male competition for territories and females (indirect sexual selection).
During my current position I am using the same type of methods I used during my PhD to analyse data that compare geographic variation in traits potentially involved in complex plant-insect interaction on the dioecious plant Silene latifolia and its pollinator-seed predator Hadena bicruris.


1.    Magalhaes I.S., Mwaiko S., Seehausen O (2010). Sympatric colour polymorphisms associated with non-random gene flow in cichlid fish of Lake Victoria. Molecular Ecology 19: 3285-3300.
2.    Magalhaes I.S., Seehausen O (2010). Inheritance of male colour in an incipient species pair of Lake Victoria cichlid fish. Journal of Evolutionary Biology, 23: 914-924.
3.    Magalhaes, I.S., Mwaiko S., Mrosso .H.D.J., Schneider M.V., Seehausen O. (2009) Disruptive selection and adaptive phenotypic plasticity during incipient speciation in Lake Victoria cichlid fish. Journal of Evolutionary Biology 22:  260-274.
4.    Seehausen O., Terai Y., Magalhaes I.S., Carleton K.L., Mrosso H.D.J., Miyagi R., van der Sluijs I., Schneider M.V., Tachida H., Imai H., Okada N. (2008) Speciation through sensory drive in cichlid fish. Nature 455: 620-627.
5.    Magalhaes I. S., Lurling M., Roijackers R., Spaak, P. (2004) Vertical distribution of Daphnia in Lake Berendonck (The Netherlands) during progressive hypolimnion oxygen depletion. Proceedings of the XXIX congress of the International Association of Theoretical and Applied Limnology (SIL).

Book Chapter
6.    Seehausen O., Magalhaes I.S. (2010). Geographical mode and evolutionary mechanism of ecological speciation in cichlid fish. From field observations to mechanisms. A program in Evolutionary Biology. Princeton University Press, Princeton. 

Institute of Botany
Rue Emile-Argand 11
CH-2000 Neuchâtel
E-mail: isabel.santos@unine.ch