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iLabs: Visitor Question — Are These The Same Snails Eating My Garden?!

July 23, 2012

We have been incredibly busy these last several days collecting photographs, questions, and answers to questions for our visitors. At the risk of sounding like a cable TV series, it has been “Snail Week” in our lab!!!  In that time we have been capturing the progress of the aquatic snail eggs in our lab as they progress toward their ultimate hatching. Many of you have been in the lab taking part in the developments and activities related to this, as well as asking a lot of questions. We first thank you. Your interest has helped to make this a fun project for all.

Now that we’ve had our wonderful “birth news” yesterday, we want to get back to our list of snail questions.

Saturday we had a gentleman ask if these were the same kind of snails eating his garden. We are happy to tell him, “No.”  His question, however, dovetailed with one asked by a number of people, “What kind of snails do you have?”

Let’s answer the last question first, then we’ll talk about the ones eating that man’s garden.

We seem to have snails from two or three families of gastropods:

Here’s a shot of two of our snail types:

Ramshorn and common pond snail in our aquarium

A Ramshorn snail (left) and a Common Pond Snail (right)

These three families used to be part of a “suborder” referred to as the Basommatophora.   These are air-breathing snails, with eyes at the base of their tentacles (unlike land snails whose eyes are at the ends of the tentacles). The above three families were the most abundant in this group and populate creeks, ponds, ditches and shallow lakes worldwide. Their shells are thin, translucent and sometimes colorless, and they lack an operculum. Wikipedia gives a good description of this structure:

The operculum is attached to the upper surface of the foot and in its most complete state, it serves as a sort of “trapdoor” to close the aperture of the shell when the soft parts of the animal are retracted.

They are known as Pulmonate gastropods, a group that does also contain terrestrial snails, and in fact the aquatic varieties started out as terrestrial snails.  As such, they have no gills, but instead have retained from their terrestrial origin a mantle cavity that functions as a pseudo-lung, providing that conditions remain moist. They can climb out of water for short periods of time to avoid predators or obtain atmospheric oxygen. The other type of aquatic snails are the Caenogastropods,. We have none of these.  Though there are a few freshwater varieties, the Caenogastropods are mostly marine varieties. They have both gills and operculums.

A good site with a listing of many varieties of freshwater aquarium snails, including information on the above three families can be found on fishforums.net.  There is another site with some good information on these snails as well, called Planet Inverts.

The largest number of our snails are the Common Pond Snails and the Ramshorn snails. As to genus/species names, characteristic genus examples of each are:

  • Planorbidae or Ramshorn: Helisoma sp.
  • Lymnaeidae or Common Pond Snails: Lymnaea sp.
  • Physidae or Bladder,Tadpole or Pouch Snails: Physa sp.

Now, as to the snail eating up our visitor’s garden, don’t feel alone. I collected some beautiful fungi a week ago in Schenck Forest with Dr. Larry Grand, one prize being an orange Chanterelle mushroom that I placed in our forest floor/wood rot terrarium.

Chanterelle mushroom  - orange

Here is one of the prizes from my hike in Schenck Forest with Dr. Larry Grand, an orange Chanterelle mushroom that I’ve placed in our forest floor terrarium.

I discovered that I was not alone in my admiration of this mushroom. Here is the latest shot of that mushroom, as a friendly neighborhood land snail has decided it is a tasty treat:

Chanterelle mushroom and a land snail

The latest “admirer” of our Chanterelle mushroom.

For anyone who wants to try their hand at identifying the snail eating their garden, or any land snails in general, here’s an online resource we found that has a lot of good information:

Land Snails of the Great Smoky Mountains (Eastern Region) (PDF)

Non-toxic ways to protect your garden from snails and slugs can be found here.

Stay with us. More answers to more questions coming up shortly!

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One Comment leave one →
  1. July 23, 2012 12:41 pm

    Reblogged this on NC Museum of Natural Sciences Blogs.

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