Male birds are often brightly coloured and their plumage colour patterns tend to be specific to a species, often varying considerably even among closely related species. Recently we have shown that traits such as plumage colour or song can evolve as species recognition signals that help individuals to identify appropriate potential mates. Our theory shows that preferences can evolve for individuals whose plumage coloration or song distinguishes them from members of closely related species that live nearby. Using population genetic modelling we have shown that species recognition traits, arising through mutation, spread rapidly to fixation. Our model shows that this is likely to occur wherever there exist local ecological adaptations in traits such as food preferences, beak morphology or body dimensions; the trait becomes a marker for the ecological adaptation, giving individuals a reason to prefer those with the trait over those lacking it. This novel insight leads to several predictions the testing of which, together with the development of needed further theory, form the basis of the proposed study. Although applications of the theory are here described for birds, the theory is more general and additional tests to those proposed below could be included, for example on cichlid fish in the African rift valley lakes.
The Ph.D. may include:
1. Analysis of the bird literature to estimate dispersal distances, from natal to breeding locations, in relation to species’ ranges. This analysis is needed because theoretically speciation depends on movement between niches being low (theory suggests <4% birds moving from one niche to the other each generation).
2. Analysis of existing data sets of species plumage colours and location or construction of a phylogenetic tree for selected taxa to carry out phylogenetic analyses to test the predictions that:
i. Some colour traits that distinguish species evolved within the range of the ancestral species. This is worth investigating because the new theory suggests that speciation can occur within species that contain local ecological adaptions.
ii. Colour traits evolved at the time of speciation. This is predicted because given local ecological adaptions, it is the evolution of the novel colour traits that drives speciation.
3. Elaboration of our existing model to investigate the population genetic consequences of various types of sexual imprinting not so far analysed. New theory is needed to analyse the effects of which parent is imprinted on (father or mother or both), and to account for cases in which it is only the males that are brightly coloured, the coloration of the females providing camouflage.
4. Development of a population genetic model to investigate the evolution of so-called ‘magic traits’. These are traits which are i) advantageous in the habitat in which they occur and ii) are sufficiently visible that they can themselves be used as basis of mate choice, thus obviating the need for novel plumage colours.
The project will thus develop new methodology to address problems of fundamental importance in evolutionary theory: methods of speciation and the evolution of mechanisms of mate choice.
Your main supervisor will be Richard Sibly http://www.reading.ac.uk/biologicalsciences/about/staff/r-m-sibly.aspx
. You will be mainly based in Biological Sciences at the University of Reading, where you will work alongside others making similar models.
Student profile: We encourage applications from all biological and/or mathematical disciplines. We will provide training in ecology, population genetics and computer programming as needed.
To apply please email [email protected]
first and please give evidence of interest in the aims of QMEE http://www.imperial.ac.uk/qmee-cdt/
, research experience/potential and degree class obtained or expected in BSc/MSc.
Supervisors: Richard Sibly and Mark Pagel at University of Reading; Tim Barraclough and Joe Tobias at Imperial