Submitted to PNAS Classification: Biological Sciences - Ecology Fever impacts on host life history traits, but is this a cost? Sam L. Elliot1, Charlotte M. Horton1, Simon Blanford1,2 and Matthew B. Thomas1,3 Author affiliation: 1 NERC Centre for Population Biology, Imperial College London, Silwood Park Campus, Ascot, Berks, SL5 7PY, UK 2 Institute of Cell, Animal and Population Biology, Ashworth Laboratories, West Mains Road, University of Edinburgh, Edinburgh, EH9 3JT, UK 3 Department of Agricultural Sciences, Imperial College London, Wye Campus, Wye, Ashford, Kent, TN25 5AH, UK Corresponding author: Sam Elliot, NERC Centre for Population Biology, Imperial College London, Silwood Park Campus, Ascot, Berks, SL5 7PY, UK. Tel: +44 (0)20 7594 2529. Fax: +44 (0)1344 873173. E-mail:
[email protected] Manuscript information: 11 text pages (16 total), 1 figure Word and character counts: 273 words in Abstract 25, 675 characters in paper (incl. spaces) ABSTRACT Fever is one mechanism by which animals may defend themselves against pathogens but, as with other defenses, may have consequences for the host. In ectotherms such as the desert locust (Schistocerca gregaria), fever temperatures are attained through modified behavioural thermoregulation. We have previously demonstrated that the fitness benefits of behavioural fever in S. gregaria can be substantial: a fever temperature just 2-4°C higher than the normal can make the difference between zero and near-normal reproduction when infected with a fungal pathogen. Here we examined whether there are costs associated with these elevated temperatures by holding adult, gregarious S. gregaria at elevated temperatures for one or five hours per day and for ten or twenty days.