Back in July, Christopher Taylor over at Catalogue of Organisms had a post about snails in which he casually mentioned that the giant African snail Achatina fulica was a predator of invertebrates. "What?" I exclaimed upon reading that, "This ludicrous error must be corrected!" and quickly left a comment on Christopher's post to indicate that Achatina fulica was a dreaded plant pest with the implication that it was unlikely to be a predator of invertebrates.
Imagine my surprise and embarrassment when the March issue of the American Malacological Bulletin arrived early in August (because I had become a member only a few months earlier) to present, among other interesting articles, a short note titled "Giant African snail, Achatina fulica, as a snail predator"1.
The paper reports that individuals of A. fulica have been observed consuming the slug Veronicella cubensis in Hawaii. On one occasion the authors offered a live slug to 3 juvenile A. fulica with the following results:
All three A. fulica climbed on top of the slug and proceeded to consume the integument of the slug. It took over five minutes for the snails to kill the slug. During the first three minutes, the slug crawled and pulled the snails with it as it moved. In the last two minutes, the slug seemed distressed and tried to curl up. After the slug stopped moving, the snails continued to consume the slug for a few minutes.According to the authors, carnivorous behavior by A. fulica has not been reported before.
Achatina fulica is an introduced species in Hawaii and many other places. It is considered a serious plant pest in areas where it is not native (more info from the USDA). Now we know that introduced populations of A. fulica may threaten not only agricultural and native plants but possibly also native gastropod species.
I have one criticism for the subject paper. Since A. fulica was observed eating slugs not snails, the title of the paper should have been "Giant African snail, Achatina fulica, as a slug predator".
1Meyer, W.M., Hayes, K.A. & Meyer, A.L. (2008). Giant African snail, Achatina fulica, as a snail predator. American Malacological Bulletin 24:117-119.