Reaction norms of parasite transmission across the different host lines. Parasite transmission (± SE) measured as the total number of successful transmissions. (a) Parasite strains averaged by origin: Laboratory (black dots), Fribourg (white dots) and Orsay (grey dots). (b) The three parasite strains of laboratory origin: Emco (black dots), Emwa (white dots) and Noco (grey dots). (c) The two parasite strains from Orsay: Ors 3 (black dots) and Ors 5 (white dots). Raw data are presented in the Figures though analyses were performed on square-root transformed data.