In conclusion, proteins of the femoral gland secretions of the common wall lizard show a sufficient level of variability to make them hypothetically suitable to be used as chemical signals of individual identity. Surely, this potentiality still remains a hypothesis that needs an explicit demonstration, since the occurrence of individual variability alone does not necessarily imply that proteins are effectively used as chemical signals, nor that they actually transfer information about individual identity: the variability is a necessary but not sufficient condition (Beecher 1989). Ad hoc behavioral tests with manipulated scents combined with in-depth biochemical analysis which allows protein identification are therefore necessary in order to infer their actual role in femoral gland secretions. In addition, only by widening the geographic sampling and by combining proteomic and genetic **data** it will be possible to quantify and disentangle the environmental and phylogenetic effects on protein composition.
