A secret war between cane toads and parasitic lungworms is raging across Australia
When the first cane toads were brought from South America to Queensland in 1935, many of the parasites that troubled them were left behind.
- When the first cane toads were brought from South America to Queensland in 1935, many of the parasites that troubled them were left behind.
- But deep inside the lungs of at least one of those pioneer toads lurked small nematode lungworms.
An eternal arms race
- Parasites and their hosts are locked into an eternal arms race.
- But at the same time, any new trick that enables a host to detect, avoid or repel the parasites is favoured as well.
- So it’s a case of parasites evolving to infect, and hosts evolving to defeat that new tactic.
The march of the toads
- But when hosts invade new territory, it can play havoc with the evolutionary matching between local hosts and parasites.
- The Queensland toads are homebodies and spend their lives in a small area, often reusing the same shelter night after night.
- For a lungworm larva, having lots of toads in a small area, reusing and sharing shelter sites, makes it simple to find a new host.
Lungworms from the invasion front
- To understand how this co-evolution is playing out between cane toads and their lungworms, we did some experiments pairing hosts and parasites from different locations in Australia.
- What would happen when toad and lungworm strains that had been separated by 90 years of invasion were reintroduced to each other?
- Read more:
In the evolutionary arms race between cane toads and lungworms, skin secretions play a surprising role
Lee A Rollins receives funding from the Australian Research Council. Rick Shine receives funding from the Australian Research Council. Greg Brown does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.