Hi,

I'm new to the list and am more of a native plant enthusiast but also interested in
all sorts of critters that can be found in the woods. I had begun asking around by
email about a local snail species and it's gotten complicated so I thought I'd post
the discussion here to see if anyone has additional insights or comments or could
benefit from it.

PS ...you folks might enjoy my insect pictures: http://www.edgehill.net/insects
--
Paul Furman
http://www.edgehill.net
san francisco native plants



"Jeanne M. Wilson" <[log in to unmask]>wrote:

> Hello,
>
> ...some little "critters" I noticed in my garden starting several years ago.
> [see the pictures: http://members.telocity.com/~jlmw1815/snails ]
> These appear to be tiny snails (shells about 3/8 to 5/8 " across, and only
> about 1/8 to 1/4 " thick).  The tightly coiled flat shell is carried almost
> horizontally across the snail's bluish-grey body.  I have never, ever seen
> these snails eating plants, or even ON my plants.
>
> To me, they look somewhat like the carnivorous snails (but smaller)
> described in some literature as having a taste for eating the big, fat
> snails imported from Europe.
>
> Because they are so pretty, and because I suspect (hope) they may be helping
> to fight all the miscellaneous slugs and other pests, I am careful not to
> kill them, and I avoid as much as possible using ANY poisons in my small
> garden.
>
> I wondered if any of the experts on this list are familiar with these little
> snails, and can tell me whether my suspicions are right about their feeding
> habits.
>
> By the way, I have always been astounded by the way big, yellow-brown banana
> slugs, like the one Paul pictures on his website, seem to survive just fine
> in my hot Central Valley (Davis) garden -- under my redwood deck.  Makes me
> strongly suspect that I've been watering too much and planting the wrong
> things all these years, and confirms that I have quite a ways to go in
> converting certain parts of my yard to natives.
>
> Jeanne



Dan Yoshimoto wrote:

> Paul,
>         I checked the web site and your snail looks like Haplotrema
> vancouverensis, Len, 1839.  We have them in our forests and cleared
> landsites here.  My friend has them also in his forests.  They are
> predators (carnivourous) and don't eat plants, but do eat our other native
> snails.
>         A friend who works at the Humboldt Co. Agriculture Department
> (Eureka) has thought of testing them to control the common garden snail,
> Helix aspersa.
> BUT,
> There is another snail, very similar looking that Phil might be able to
> tell you about.  He was here about a year ago, collecting some of our local
> snails and said that there were slight, almost undistinguishable.
>         Well, I hope that that helps a bit.
> Dan




Phil Liff-Grieff wrote:

> Paul,
>
> I took a look at your pictures (very nice, by the way) and, based on the photos
> and the size given for these critters, it is likely that you've got Oxychilus
> draparnaldi, a glass snail that is found throughout Europe and many parts of the
> US.  This species was probably introduced into the US in the mid 1800's and is
> found in urban/suburban areas that are well planted and moist.
>
> I have found conflicting information about their feeding habits.  Pilsbry (1946)
> states, "It is said to be carniverous by preference".  On the other hand, Hannah
> states in a publication on introduced species from 1966 that glass snails "do a
> certain amount of damage to plants but this apparently is minor compared to the
> depredations of larger snails and slugs."  So, I leave it to you to decide.
>
> I am troubled by the color of the shells in your photos- they appear more
> green/yellow than one would expect from O. draparnaldi.  On the other hand, the
> dark blue-grey animal is fairly characteristic of this species.
>
> Hope this helps,
>
> Phil Liff-Grieff