I love leading mushroom hikes, not to pick and eat them, but to admire their beauty and their outsized role in our ecosystems. All too often, though, a slug has got there before me and ruined an otherwise perfect mushroom by eating patches of its cap, like this Tacky Green Russula:
Most of us find slugs mildly repulsive. Maine has sixteen species, including the gray garden slug
and the Winding Mantleslug:
The yellow one, about an inch long, that we see most often on fungi in Maine is (I think) an Arion slug of some kind:
It was a slow day for both the slug and me, so I decided to try and get a closeup look at how it actually eats.
It has a sort of tongue called a radula, with lots of very tiny teeth, and it protrudes this enough to scrape away at the surface of the mushroom.
If you look carefully in some of these photos you can just see what I think are the teeth, 0.2mm long.:
The white patch is where it has eaten the surface away.
It is looking at me sluggishly through the eye spot at the tip of its right upper tentacle:
Their vision is poor; they can see light and dark, but no details. The lower tentacles are to do with smell and touch.
Eyes on the Wild 