Affiliation: | Netherlands Institute of Ecology, PO Box 40, 6666 ZG Heteren, The Netherlands;; NERC Centre for Population Biology, Imperial College at Silwood Park, Ascot, Berks. SL5 7PY, UK;; Institute of Evolutionary and Ecological Sciences, Leiden University, PO Box 9516, 2300 RA, Leiden, The Netherlands;and *;†Department of Biology, Imperial College at Silwood Park, Ascot SL5 7PY, UK |