1. Division of Biodiversity, Institute of Nature and Environmental Technology, Kanazawa University, Kanazawa 920–1192, Japan
2. Sukarami Assessment Institute for Agricultural Technology, PO Box 34, Padang, West Sumatra 25001, Indonesia
3. Department of Biology, Faculty of Science, Andalas University, Limau Manis, Padang, West Sumatra 25163, Indonesia
4. NERC Centre for Population Biology and Department of Biological Sciences, Imperial College London, Silwood Park Campus, Ascot SL5 7PY, UK