“…Over the last three decades, the simple form of this periodic wave family has provided an invaluable reference point for the study of periodic travelling waves in more general reaction-diffusion systems. This work has focussed in particular on the existence and stability of periodic travelling waves (Ermentrout, 1981;Maginu, 1979Maginu, , 1981Kapitula, 1994), other cases with exact solutions (Cope, 1979;Romero et al, 2000) and the generation of periodic travelling waves by environmental heterogeneities (Auchmuty & Nicolis, 1976;Hagan, 1981;Kopell, 1981;Kay & Sherratt, 2000;Sherratt, 2003) and behind invasive wavefronts (Sherratt, 1994(Sherratt, , 1996Ermentrout et al, 1997;Petrovskii et al, 1998;Petrovskii & Malchow, 2000, 2001Webb & Sherratt, 2004;Garvie, 2007).…”