Valeria Souza is a professor in the Faculty of Sciences at the National Autonomous University of Mexico (UNAM) and an investigator in the Laboratory of Molecular and Experimental Evolution, Department of Evolutionary Ecology in UNAM’s Institute of Ecology. Address for Souza: Laboratorio de Evolución Molecular y Experimental, Depto. de Ecología Evolutiva, Instituto de Ecología, UNAM, Apto. Postal 70-275, C.U., C.P. 04510, México D.F., México. Internet: souza@servidor.unam.mx