Dr. Andrea Perna (Ecole Polytechnique de l'Université de Nantes), Prof. David Sumpter (Mathematics Department, Uppsala Universty) and Dr. Guy Theraulaz (CRCA, CNRS) will be the editors of a special issue on Collective Decision in Biological Swarms for the Swarm Intelligence Journal. This special issue calls for papers focusing on different aspects and issues of collective decision in animal groups, exploring the problem in different animal models and focusing on different aspects of decision: what is the pooling function? by what mechanisms can informed individuals lead the group? what compromise is found in the trade-off for speed and accuracy? In summary, how do individuals within a group integrate information in order to reach consensus? and when does the group better split than reach a consensus?