My own flatworm story began 25 years ago. One evening I spotted shiny pink, ribbon-like creatures by torchlight, sliding around outside our back door. You can read the original story on my blog.
My discovery of the strange stretchy creature, now described as Australoplana sanguinea, coincided with other reports of Australian and New Zealand flatworm finds, and led me to send live specimens to a PhD student in Belfast. These multiple-eyed planarians were thought to have entered the UK in the pots of imported plants (the first record was in 1980 on the Isles of Scilly). We had moved to our house in late 1993, so the flatworms almost certainly arrived before we did.
Since 1995 I have become used to finding Australoplana sanguinea every now and again. They dissolve earthworms in a disgusting way, and earthworms are hugely important for our soil. They break down organic matter, releasing nutrients that can be used by plants through the actions of bacteria and fungi on the digested particles they excrete. They also mix soil layers and create countless little spaces as they burrow, so that soil becomes looser, softer and crumblier – accessible to air, water and roots. Thankfully, our earthworm population has recovered well.