Slug Name Dropping

Slugs are always interesting to watch and once you’ve mastered the large obvious ones like the Banana Slug and the Chocolate Arion it’s time to develop one’s observation skill a little and try to figure out the smaller native and non-native slugs that can be found in British Columbia.

Two good (but sufficiently challenging) slugs for the beginner are the Reticulate Taildropper (Prophysaon andersonii) and the Yellow-bordered Taildropper (Prophysaon foliolatum). Both of these at first glance look very similar. Fortunately there are some obvious field marks that can be used to separate the two species.

Reticulate Taildropper (Prophysaon andersonii)
Note the unmarked gray foot fringe of the Reticulate Taildropper (Prophysaon andersonii).

The slug pictured above is a Reticulate Taildropper that I photographed while out searching for mushrooms at Merville Woods. Close observation and some deductive reasoning led me to this identification:

  1. Colour of the Mucus – Both have a yellow coloured body mucus but the Reticulate Taildropper’s is a brighter, lemon-yellow colour. This slug had quite bright yellow mucus.
  2. Foot colour – Turn the slug over (yes, you have to touch it) and check the colour of the foot – the Reticulate Taildropper has a white sole, the Yellow-bordered Taildropper has a cream coloured sole with a dark line that marks the site of tail self-amputation. This slug was more white than cream and lacked the line.
  3. Fringe markings – Look at the fringe of the foot – the Reticulate Taildropper has an pale fringe without dark vertical bars, the Yellow-bordered Taildropper has distinct markings on its fringe. Compare with the picture of the Yellow-bordered Taildropper in my post Taildroppers.
  4. Size – The Reticulate Taildropper is smaller (60 mm) compared to the larger Yellow-bordered Taildropper (100 mm+)
  5. Mantle Colour/Markings – As you would expect, the border of the mantle of the Yellow-bordered Taildropper is a noticeable yellow. The Reticulate Taildropper is less so.

So there you have it.

On your next walk in the woods keep an eye out for these cool slugs and and then do a little taildropping name dropping! Your friends might be simply impressed that you picked up the slug!

If you’re interested in reading more about other spineless creatures check out Circus of the Spineless, this month hosted at Wild About Ants!

Circus of the Spineless