1 Department of General Systems Studies, The University of Tokyo, 3-8-1 Komaba, Megro, 153-8902 Tokyo, Japan. Electronic address: toshi.n.suzuki@gmail.com.
2 Institute of Biology, University of Neuchatel, Rue Emile Argand 11, CH-2000 Neuchatel, Switzerland. Electronic address: klaus.zuberbuehler@unine.ch.