Thowsend C.R, and Harper J.L. 2006. Ecology: from individuals to ecosystems. Blackwell Scientific Publishers Bell, G. 2008. Selection: the Mechanism of Evolution, second edition. Oxford University Press. Case, T.D. 1999. An Illustrated Guide to Theoretical Ecology. Oxford University Press. Falconer, D. F. 1989. Introduction to quantitative genetics. Longman Scientific and Technical, Essex, UK. Hartl, D. L., and A. G. Clark. 1997. Principles of population genetics. Sinauer Associates, Sunderland. Lynch, M., and B. Walsh. 1998. Genetic analysis of quantitative traits. Sinauer Associates, Sunderland - Massachussets, USA. Thomas, F. Guégan, J. F. and Renaud, F. 2009. Ecology and Evolution of Parasitism Hosts to Ecosystems. Oxford University Press. :