1. School of Biological Sciences, University of East Anglia, Norwich NR4 7TJ, UK
2. Comparative Spermatology Laboratory, Department of Medical Bioscience, University of the Western Cape, Private Bag X17, Bellville 7535, South Africa
3. Environmental and Nano Sciences Group, Department of Chemistry, University of the Western Cape, Private Bag X17, Bellville 7535, South Africa
4. Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute (Swiss TPH), 4123 Allschwil, Switzerland