Category Archives: Invertebrates

Slugs!

By Bruce Rottink, Volunteer Nature Guide and Retired Research Forester

All photos by Bruce Rottink.

 

Slugs are a common sight at Tryon Creek State Natural Area (TCSNA).  Just by chance, I’ve personally seen slugs at TCSNA every month except January and February.  In November 2014, Tryon Creek Nature Guide Sharon Hawley wrote a Naturalist Note on slugs. You can read it here. This current note does not repeat the wonderful information that Sharon provided.

 

Banana slugs (Ariolimax columbianus) are a common species found at TCSNA.  They are one of the slug species that are native to the Pacific Northwest.  They were given their scientific name in 1851.  These are not the slugs that typically cause problems in most people’s gardens.

 

Banana slugs are pretty low down in the food chain, and according to documentation on the web, are sometimes eaten by raccoons, garter snakes, ducks and even salamanders.

 

What is Slug Food?         

Slugs eat a variety of things, including both living and dead vegetation.  You can see slugs crawling on many types of plants.  The picture below shows a slug on a stinging nettle (Urtica dioica) plant at TCSNA.  I was a little surprised to see it there.

picture 1

Banana slug crawling on stinging nettle!

 

Below is a picture of a slug banquet I discovered occurring on the West Horse Loop Trail (and remembering the word “horse” is important here.)

picture 2

Banana slugs feasting on horse poop at TCSNA.

 

Frequently I lead student nature hikes at the park, and oftentimes I’ve heard of kids attending an outdoor camp where they are encouraged to lick slugs.  Just thinking of this picture ensures that I personally will never lick a slug.  But enough of that!

 

The picture below shows a slug which climbed about 3 feet up the side of a tree near the Old Main Trail in order to get a taste of this mushroom.  According to reports in the literature, mushrooms are one of their favorite foods.

picture 3

Banana slug sampling a mushroom on the side of a tree.

 

The slug (of unknown species) in the photo below, is deeply exploring a trillium (Trillium ovatum) blossom.  It appears that this slug may have chewed off substantial chunks of the trillium’s petals.  Now it appears to be going out whole-hog for the core of the flower.

picture 4

Slug feeding on a trillium blossom.

 

The banana slugs at TCSNA have lots of things to eat and explore.

 

Staying Safe

Slugs are slow moving creatures, and I can’t imagine what predator they could successfully run away from.  So slugs have chosen to employ camouflage.  While the vast majority of the banana slugs at TCSNA have black spots, scientists who have studied the species have reported that a few, like the one below, do not.

picture 5

What appears to be a banana slug without spots.

 

Camouflage, with or without spots, means that you have to look like something else, or at least blend in to the environment.  Below are several pictures of things I’ve seen on TCSNA trails that I’ve momentarily confused with a slug.

picture 6

Curled dead alder leaf, with some kinds of white streaks on the back.

 

 

picture 7

Woody plant root sticking out above the trail, polished by hikers stepping on it.

 

 

picture 8

Curled, dead fern frond.

 

I can’t even begin to imagine how many banana slugs live at TCSNA.  However, we must admit they are very successful, and make a contribution to the Park by helping turn plant material, both dead and alive, into soil.

 

 

 

 

 

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