The world of parasites and hosts is a strange place.
However, few host interactions are as strange (and fascinating!) as the less than ideal relationship between birds, snails and a parasitic flatworm called Leucochloridium paradox.
Contrary to the gif shown (more on that later), L. paradoxum spends the majority of its life in the body of a bird (host), which isn’t all too fussed about their new inhabitant. Once within the bird, the flatworm reproduces and releases its eggs through the bird’s digestive tract.
At this stage you're probably asking how does the bird get acquainted with L. paradoxum to begin with, and what's with the snail? Good questions.
To answer them, we need to talk about the intermediate host, which in this case, is indeed the humble snail.🐌
In case you weren’t aware, snails eat bird faeces- which, sometimes, can contain the eggs of L. paradoxum. Once ingested by the snail, the parasite travels to the digestive system where it develops into a sporocyst, rapidly reproduces and forms long tubes of broodsacs (sacs containing larvae).
As the broodsacs grow, they spread out into the snail's eyestalks and pulse green/yellow/brown. As you can clearly see in the attached gif, these can then be easily mistaken for caterpillars, which are a meal of choice for- you guessed it- birds!
Jean O'Dwyer
GIF: NURIE MOHAMED/SOURCE: GILLES SAN MARTIN/WIKIMEDIA https://en.wikipedia.org/wiki/File:Leucochloridium.ogv
