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.