ACKNOWLEDGMENTS
This special issue is a result of a minisymposium organized by Jane M. Heffernan (JMH) for an annual meeting of the Society for Mathematical Biology held in Toronto in July 2008. JMH would like to thank all of the authors for their contributions and the referees for their useful comments. She would also like to thank Mathematical Population Studies editor-in-chief, Noël Bonneuil, for making this special issue a success. JMH is supported by NSERC, MITACS, and an Early Researcher Award. She is a NSERC UFA holder at York University.