1. Department of Biology, University of York, Wentworth Way, York YO10 5DD, UK.
2. Butterfly Conservation, Manor Yard, East Lulworth, Wareham, Dorset BH20 5QP, UK.
3. AgroEcology Department, Rothamsted Research, Harpenden, Hertfordshire AL5 2JQ, UK.
4. Environment and Sustainability Institute, University of Exeter, Penryn, Cornwall TR10 9EZ, UK.
5. NERC (Natural Environment Research Council) Centre for Ecology and Hydrology, Benson Lane, Crowmarsh Gifford, Oxfordshire OX10 8BB, UK.