Tadpoles at the edge of the population are no more vulnerable than those at the centre.
The African clawed frog is a notorious invader but it also takes some parasites with it to new regions.
What was particularly interesting about the responses of the tadpoles was that they were similar even through they had very different evolutionary histories with the three species we chose.
Invasive frogs can have a major impact on the environment. Some move continents by human trade or travel. But determining how to control them can lead to policies that limit their spread and effects.