Saturday, 27 September 2008

Some Introduced Snails and Slugs

.....Terrestrial Molluscs

I came a across a Great Yellow Slug, Lehmannia flava, in the veggie garden today (not an unusual occurrence) and I though I'd post it here along with some other introduced molluscs which inhabit my backyard. I think it was Bill Mollison who said something to the effect of, "You don't have a slug excess, you've got a duck deficit!" Well as it happens we do have a large population of chickens and ducks in the yard and by and large they do a good job of keeping the numbers down. However there are always the ones that escape detection. Here are a few of them.


(Click to Enlarge Photos)
Cochlicella barbara - Small Pointed Snail


Oxychilus alliarius - Garlic Snail



Helix aspersa - Common Garden Snail


Lehmannia flava - Great Yellow Slug


Lehmannia nyctelia - Striped Field Slug



11 comments:

  1. Beaut pictures Mosura, of course you didn't need a very fast shutter speed. ;-)

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  2. If I weren't almost entirely vegan, how would a garlic snail taste?

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  3. Cochlicella ventrosa's had a rebadge - it is now known as Cochlicella barbara (Linnaeus, 1758)

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  4. Thanks Duncan - Yep - a lot easier than birds.

    Thanks Tony - Don't know if I want to taste one but they do in fact smell of garlic - hence the name.

    Thanks Kevin - for the correction. I've edited the text accordingly. Also found it has a common name according to DPIW

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  5. I think I like the look of the Garlic Snail best, it seems the most innocuous. I bet it's turns out to be the most damaging of the lot!

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  6. thanks Jenny - Don't know how much of a problem they are ecologically but in the garden I have to look pretty hard to find them. The shells are only 5-6mm in diameter. They are found naturally in Britain so you may have them near you.

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  7. Oxychilus spp are carnivores that are welcome in gardens where they are likely to munch a range of small garden pests. Despite that they are quite invasive in disturbed bushland, O. cellarius especially, and I reckon they must have some kind of impact on some native inverts. The only native thing I've ever actually seen one eating was an amphipod.

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  8. Thanks Kevin - Aside from direct predation I wonder if they have any impact by way of displacing native species. Try as I may, I have not managed to find any native snail species in the bush behind my place. Maybe I'm looking in the wrong places.

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  9. There are certainly many urban and rural fringe bush areas where there are many introduced snails and not a lot of natives. Very difficult to say (or test) whether the exotics themselves are doing the displacing. Really tiny bush remnants (say, below a hectare) will sometimes have no natives left whatsoever, but any substantial remnant usually has something hanging on somewhere. However, many of the hardiest species are tiny.

    Most native snails are most often found under rocks, under logs or in leaf litter (especially around the base of trees).

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  10. Thanks Kevin - I live on 1 acre, about half of which is bush but it is contiguous with a very large area of bushland. I shall keep looking. I'm sure something must be living up there.

    Oh... and while reading some 'Tasmanian Naturalist' magazines I suddenly realised where I know your name from.

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  11. Nice shots Mosura! I'd like to get started looking at gastropods here.

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