Fomes excavatus with peculiar markings

A Fomes excavatus (Tinder Conch) growing from a paper birch (Betula papyrifera) with some unusual scratch-like markings on the surface. They do not look like the kinds of marks a rodent would leave if it were eating a conch.

comments (5)

Christine Young

Lion

Interesting! I wonder what made them? Maybe an insect, like a beetle. Or a snail? Posted 6 years ago
1. Gary B
  
  Lion
  
  Doesn't look like a snail or slug feeding trail. Aren't those sort of spiraling? Some insect but what kind? I've never seen anything like this before. Of course, it was winter when I took the photo so there was no chance of finding the culprit. Posted 6 years ago
2. 1. Christine Young
    
    Lion
    
    It doesn't look particularly snail/slug-ish except that the lines are straight. Crayfish sometimes scrape algae off fungi and rocks. I've never seen the marks they make though. Any streams nearby? Flies, like crane flies and gall midges feed on fungus; but, I think they normally tunnel from underneath the cap. That's why I thought maybe a beetle because so many of them feed on fungi, such as rove beetles, darkling beetles, weevils, sap beetles, fungus beetles. Beetles in the family Ciidae are tiny, but feed on bracket fungi. But, there's no frass visible, and beetles tend to leave piles of frass. Some moths feed on fungi too...Hmm. Posted 6 years ago
  2. 1. Gary B
      
      Lion
      
      That crayfish would the equivalent of an aqualung to get to this tree and then a ladder :). Nearest stream is more than 500 feet away. It might be some sort of beetle but a surface feeder. I don't know what the feeding patterns of moth larvae would be on a fungus of that type. The moths I've read about that do eat fungi apparently go for the softer varieties. Posted 6 years ago
    2. 1. Christine Young
        
        Lion
        
        Haha, so we can rule out crayfish. My bet would be on beetle, I think. Posted 6 years ago