Dusky slug

The Dusky Slug (Arion subfuscus) is a European slug that is now established in Michigan. I found it on the edge of the National Guard Reservation near Grayling, Michigan. I’m not sure how it found its way this relatively remote area.

Dusky slug

The Dusky Slug recently was split into two species. The other species is Arion fuscus.   They are distinguished by molecular data and internal characters. I did not want to dissect a slug so I must be content with identifying my slug as part of the A. subfucus complex.

Dusky Slug is one of the round back slugs in the family Ariondea. They differ from the keel back slugs in the family Limacidae by their rounded backs, smaller size, and lack of an internal shell. Unlike the keel back slugs they can roll up if threatened. The respiratory opening of a rounded back is toward the middle or the front of the mantle shield and on the keel back slugs it is at the rear of the shield. (See Leopard Slug post.)

Dusky Slugs eat a wide variety of foods but mostly they consume fungi and decaying plant material. They also eat insect larva, algae, and plants. The one I photographed was feeding on Common Milkweed (Asclepias syriaca).

Dusky slug

I am often surprised the things I see in the natural world. I was not aware of non-native slugs and now I have seen two species. Get out into nature and look. You never know what you will find.

Copyright 2014 by Donald Drife

Webpage Michigan Nature Guy
Follow MichiganNatureGuy on Facebook