|Department of Evolutionary Biology
Morgenbreede 45, 33615 Bielefeld
Phone: 0521-106 2820
One of our recent stats papers [Nakagawa & Schielzeth 2013. Meth. Ecol. Evol. 4: 133-142] has been recommended by the Faculty of 1000. In the paper we review and discussed approaches to quantify the amount of variance explained in linear mixed effects models. We suggest a general approach to quantify the proportion of variance explained by the fixed effects ('marginal R2') and by the model as a whole ('conditional R2'). The methods have already partly been implemented in the R package MuMIn by Kamil Bartoń and another implementation is available on the 'sample(ECOLOGY)' blog by Jon Lefcheck.
I am an evolutionary biologist and passionate naturalist with a particular interest in microevolution. Microevolution is focused on evolutionary change that takes place within populations and that ultimately lead to divergence between populations. I make use of quantitative genetic techniques for studying the genetic architecture of sexually selected traits and of molecular markers for localizing additive genetic variation in the genome ('QTL mapping'). Two particularly intriguing topics are the evolution of sexual ornamentation and of behavioral strategies for successful reproductions. Another special focus lies on the sources of variation in mating preferences, an important component of sexual selection. Other interests include life history evolution, inbreeding depression, condition-dependent trait expression, biostatistics and animal migration. [read more]
I am currently establishing the club-legged grasshopper (Gomphocerus sibiricus) as a model system for evolutionary research. The species is remarkable for its sexually dimorphic ornament: males possess swollen front legs (‘Popeye arms’) that are presented to the females during display. The system is amenable to laboratory and field work, which offers great opportunities for testing results from the lab in the natural environment. Another key advantage is that the species allows studies within populations as well as between populations/subspecies. The main aim of my work is to understand the coevolution and conflict between the sexes using quantitative genetic and genomic tools. By doing so, I am addressing fundamental evolutionary questions such as the evolution of sexual signals and the evolutionary dynamics of indirect genetic effects. [read more]
Anasuya Chakrabarty and Pablo Valverde have recently started their PhD projects on the behavioural and evolutionary ecology of sexual selection in club-legged grasshoppers. And even more recently, Amy Backhouse has complemented the team as a technical assistant. Please don't hesitate to contact me if you are interested in working on topics of sexual selection using quantitative genetic approaches. [read more]
Most recent [read more]
Miranda, A.C., Schielzeth, H., Sonntag, T. & Partecke, J. (in press). Urbanisation and its effects on personality traits: a result of microevolution or phenotypic plasticity? Global Change Biol.
Ramm, S.A., Jonker, R.M., Reinhold, K., Székely, T., Trillmich, F., Schmoll, T., Schielzeth, H. & Freckleton, R.P. (2013). Comment on Bateman in nature: predation on offspring reduces the potential for sexual selection. Science 340: 549.
Schielzeth, H. & Nakagawa, S. (2013). Nested by design:model fitting and interpretation in a mixed model era. Meth. Ecol. Evol. 4: 14–24.
Nakagawa, S. & Schielzeth, H. (2013). A general and simple method for obtaining R2 from generalized linear mixed-effects models. Meth. Ecol. Evol. 4: 133–142. [Implementation in R by Kamil Bartoń] [R code on Blog 'sample(ECOLOGY)']
Husby, A., Schielzeth, H., Forstmeier, W., Gustafsson, L. & Qvarnström, A. (2013). Sex chromosome linked genetic variance and the evolution of sexual dimorphism of quantitative traits. Evolution 67: 609–619.