New research suggests that frogs which from groups which have been exposed to a deadly virus, Ranavirus, breed at younger ages.
Scientists at the University of Exeter have been studying European common frogs in the UK compared frog populations exposed to ranavirus and those free from the disease. They found that while the youngest breeding frogs in disease-free populations are four years old, in virus-exposed groups they breed as young as two.
What is ranavirus?
Ranavirus is believed to be spreading in the UK. The major cause of Ranavirus is the movement of animals and soils due to human activity.
Globally, amphibians are the most threatened group of vertebrates. Emerging infectious diseases such as Ranavirus play a large role in the threatened status.
The importance of studying how animals avoid viruses
Dr Lewis Campbell, who conducted the research during his PhD at the University of Exeter’s Penryn Campus in Cornwall, said:”We live in times of increasing environmental change, so understanding how wildlife diseases change the ability of their hosts to cope with such uncertainty is increasingly critical.”
Why do frogs breed young?
Campbell explained: “Our research shows that the ages of the frogs that return to breed varies between populations which are known to have ranavirus and those which don’t. We found significantly fewer old frogs and significantly more young frogs at populations which have ranavirus.”
Future research on disease-challenged populations
Dr Xavier Harrison, of the Zoological Society of London, said: “We often think of the negative consequences of wildlife disease as being the death of infected individuals in the short term. But this study shows that even when a population seems to have survived a disease outbreak and appears otherwise healthy, there are still lingering consequences of that disease months or years afterwards. If we really want to understand the full impact of wildlife diseases in nature we need to monitor disease-challenged populations over much longer timescales.”