Similar to other flat worms, such as the liver flukes those parasites use the snail as an intermediate host on their way into the terminal host, a bird in this case.

The bird distributes the parasite's eggs by it's excrements. The amber snail then infects itself by eating the eggs. The miracidia hatch inside the snail and infect it's main digestive gland.

In the snail's digestive gland the miracidia change into cercaries and produce sporocystes, long tubes that can contain several hundred cercaries.

One or several of these tubes stretch until into the snail's tentacles and begin to pulsate in there. The obvious colour and the sporocystes' movement attracts birds that hack for the snail's tentacles. The bird rips off the snail's tentacles which cannot be withdrawn because of the sporocystes tubes inside.

Inside the bird's digestive tract the cercaries change into the parasite's adult stage, which then reproduces sexually and lays eggs. Thos are distributed by the bird to infect further snails, which closes the generation cycle.