For every living species in the world today, there is at least one parasite that infects it. Some scientists estimate that half of all species on Earth are parasites.
This week’s critter is a trematode (also known as a fluke) that has chosen to parastitise not one, but three separate animals. Curtuteria australis starts life as an egg inside the gut of a tōrea, oystercatcher, hatches inside a whelk and matures inside the muscly foot of a cockle.
Worm just out of its cyst Photo: Haseeb Randhawa & Robert Poulin
