Ants and Landsnails

It is a well-known fact that empty shells of landsnails can often be
encountered in and around ant-nests. In the Middle East especially the
so-called Harvest ants belonging to the genus Messor are involved in
collecting snails. They store the snails temporarily in their nests and they
are used as an additional source of protein. Afterwards the empty shells are
removed from the nest an can be collected easily from the other waste
products laying in a circle around the nests. In this way I could collect in
my village Kibbutz Netzer Sereni, Israel, the following species in fairly
large numbers: Granopupa granum, Euchondrus aff. ovularis, Euchondrus
sulcidens, Ceciliodes acicula, Paralaoma caputspinulae (=Punctum lederi),
Xeropicta vestalis joppensis, Xerocrassa davidiana, Microxeromagna
armillata, Monacha syriaca, Caracollina lenticula and Theba pisana. Of
Xeropicta, Monacha and Theba only juvenile shells were encountered. Only the
a fairly large species: Helix engaddensis, and one with a heavy shell
Sphincterochila aharonii, are missing from the list of the species living in
that particular biotope: a sandstone hill (Mienis, 1974). So the rubble
around the nests of harvest ants can be exploited by giving us a quick idea
of what is living in a particular area.

Urbanski (1965) pointed to a relationship in the form of snails and seeds
found in and around ant nest. Among the material mentioned above there are
indeed species with a form of a seed (Granopupa, Euchondrus, Paralaoma and
maybe Caracollina), but others certainly not.

Ant species exist in the tropics, for example Pheidologeton diversus, which
are known to attack even living specimens of Achatina fulica and carry them
over considerable distances (up to 20 m) to their nest (Van der Meer-Mohr,
1931).

All these snails seem to serve as food for the ants and the empty shells are
always removed from the nests.

At least one case is known to me in which a snail species is actually living
in ant nests, however, at the moment I fail to remember the reference.

References:
Mienis, H.K., 1974. [Ants as collectors of snailshells.] C.B. Ned. Malac.
Ver., 158: 257-258. (in Dutch)
Urbanski, J., 1965. Ernteameisen als Sammler von Schneckengehaeusen. Mitt.
D.M.G., 6: 72.
Van der Meer-Mohr, J.C., 1931. Ueber Ameisen als Schneckenfeinde. Misc.
Zool. Sumatrana, 52: 1-3.


Best regards,

Henk K. Mienis
National Mollusc Collection
Dept. Evolution, Systematics & Ecology
Hebrew University of Jerusalem
IL-91904 Jerusalem, Israel

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P.S. Helmut note that Fritz Seidl from Braunau has also published a paper on
this subject, but I do not have it in front of me at the moment.

----- Original Message -----
From: uri bar-zeev <[log in to unmask]>
To: <[log in to unmask]>
Sent: Monday, July 09, 2001 9:26 AM
Subject: ants and landshells


> Dear Land-Sheller's
>
> While I was looking after land shells, I "discovered" that there are
> Plenty of empty shells in the grit of seeds around Ants nest.
> Most of them are of the kind of Euchondrus septemdentatus, which looks
very
> much like a wheat grain by itself.
> Now my question is - why?
> Were they collected by the ants as 'seeds' and than disappointedly
removed?
> Or were they collected as nutrition for the ants?
> Or maybe dug out by the ants while digging their nest?
> Are you familiar with these phenomena?
> Please shed some light ;-)
> Regards - uri