This special issue of Acta Biotheoretica is a selection of papers presented at the 4th international conference of the Francophone Society of Theoretical Biology (SFBT) which was held from 03-05 June, 2013 in Dakar (Senegal). This outstanding international scientific meeting was organized by the Francophone Society of Theoretical Biology, the International Joint Unit on Mathematics and Computer Modeling of Complex Systems (UMMISCO), the Research Institute for Development (IRD) and Dakar Cheikh Anta Diop University (UCAD). The conference was, also, sponsored by the African Institute of Mathematical Science of Senegal (AIMS-Senegal) and the Developing Countries committee (COPED) of the Sciences Academy of the Institute of France.

The main theme of the conference focused on the Dynamics of populations, epidemiology and renewable resources. A hundred papers were presented over 3 days, in four thematic sessions: a general session, a session on systems modeling of fisheries, a session on modeling of epidemiological systems and a special session on mathematics and computer sciences.

After a rigorous selection by internationally well-knowen referees and following a reviewing by the editorial committee, ten articles were selected for this special issue. The topics covered by these manuscripts focus essentially on fisheries and epidemiology.

In addition to these two specific themes, in-depth general studies were addressed on stability, complexity and robustness in population dynamics and on the reduction of nonautonomus population dynamics models with two time scales.

Finally, the guest editorial committee very warmly thanks the SFBT board of directors, the scientific committee, the organizers and all the partners and participants in this 4th SFBT international conference.

Also, the guest editorial committee wishes to thank the editor in chief of Acta Biotheoretica and the entire Springer staff for their support in the process of reviewing and editing this issue.