Susceptibility of fire-bellied toad (B. bombina and B. variegata) tadpoles to predation

B. bombina and B. variegata are ecologically distinct taxa that nevertheless hybridise in nature wherever their distribution ranges adjoin. These data were collected to test the hypothesis that B. variegata tadpoles are more susceptible to predation than those of B. bombina. The former develop in ephemeral aquatic sites that can be predator-free, whereas the latter are found in predator-rich semi-permanent ponds. Tadpoles of both taxa were raised under under uniform laboratory conditions and their relative predation risk was assessed over a four-week period using dragonfly larvae as predators. The tadpoles were reared in the presence of chemical predation cues so that they could develop a predator-induced phenotype. The data confirm our hypothesis. These results suggest that B. variegata traits associated with higher predation risk produce barriers to gene flow across the hybrid zone.