[1] ETH, Dept Environm Sci, CH-8092 Zurich, Switzerland
[2] Natl Univ Singapore, Dept Biol Sci, Singapore 117543, Singapore
[3] Univ Calif San Diego, Div Biol Sci, Ecol Behav & Evolut Sect, La Jolla, CA 92093 USA
[4] Yale Univ, Dept Ecol & Evolutionary Biol, New Haven, CT 06520 USA