Infection loads at the time of mortality were greater in frogs exposed to the hybrid than to Bd-GPL (F[22,3] = 92.349; r2 = 0.926; p < 0.0001) but the magnitude of this effect was greater for B. ephippium than for I. parva (t = −2.89; p = 0.0084). This evidence concerns the gene IL31RA and infection.