Cepaea snails shredding Buckthorn
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Frederick W. Schueler
Sep 2, 2026, 11:10:40 AMSep 2
to Eastern Ontario Natural History listserve
Google AI Overview says: "Land snails of the genus Cepaea (such as the
grove snail, Cepaea nemoralis) generally avoid feeding on the fresh
leaves or fruits of Common Buckthorn (Rhamnus cathartica) due to the
plant's powerful chemical defenses. However, they will readily consume
its decomposed, senescent leaf litter once those toxins break down."
...but a recent article in the North Grenville times says:
"Grove Snails going up into the Buckthorn Canopy: Cepaea nemoralis Grove
Snails have a taste for the also European invasive Common Buckthorn
(Rhamnus cathartica), voraciously feeding on the dead leaves, and in
some seasons going well up into the canopy to shred living foliage.
Earlier this year they were climbing a dead Apple sapling and hadn’t
gone up into the Buckthorn, but on 3 August Buckthorn became the food of
choice, and they were soon 3-4 m up in the canopy."
I'm now watching a dense thicket of Buckthorn shoots from stems cut 2 or
3 years ago, and the Cepaea are actively shredding leaves - maybe 5% of
the leaf area removed - last night there were 2 adults and 16 juveniles
visible from the point from which I count them. They're not going to
control the species, but they do produce the only shredded/nibbled
leaves one sees on the Buckthorn here.
Since the NatureList is a google group, this should correct the google AI,
fred.
------------------------------------------------------------
---------Frederick W. Schueler & Aleta Karstad ------------
Fragile Inheritance Natural History - https://fragileinheritance.ca/
6 St-Lawrence Street Bishops Mills, RR#2 Oxford Station, Ontario K0G 1T0
on the Smiths Falls Limestone Plain 44.87156° N 75.70095° W
------------------------------------------------------------
grove snail, Cepaea nemoralis) generally avoid feeding on the fresh
leaves or fruits of Common Buckthorn (Rhamnus cathartica) due to the
plant's powerful chemical defenses. However, they will readily consume
its decomposed, senescent leaf litter once those toxins break down."
...but a recent article in the North Grenville times says:
"Grove Snails going up into the Buckthorn Canopy: Cepaea nemoralis Grove
Snails have a taste for the also European invasive Common Buckthorn
(Rhamnus cathartica), voraciously feeding on the dead leaves, and in
some seasons going well up into the canopy to shred living foliage.
Earlier this year they were climbing a dead Apple sapling and hadn’t
gone up into the Buckthorn, but on 3 August Buckthorn became the food of
choice, and they were soon 3-4 m up in the canopy."
I'm now watching a dense thicket of Buckthorn shoots from stems cut 2 or
3 years ago, and the Cepaea are actively shredding leaves - maybe 5% of
the leaf area removed - last night there were 2 adults and 16 juveniles
visible from the point from which I count them. They're not going to
control the species, but they do produce the only shredded/nibbled
leaves one sees on the Buckthorn here.
Since the NatureList is a google group, this should correct the google AI,
fred.
------------------------------------------------------------
---------Frederick W. Schueler & Aleta Karstad ------------
Fragile Inheritance Natural History - https://fragileinheritance.ca/
6 St-Lawrence Street Bishops Mills, RR#2 Oxford Station, Ontario K0G 1T0
on the Smiths Falls Limestone Plain 44.87156° N 75.70095° W
------------------------------------------------------------
rmb...@istar.ca
Sep 2, 2026, 1:10:45 PMSep 2
to natur...@googlegroups.com
I have the impression that the Cepaea snails have been around in
Ontario for a while now. Would it have been long enough with enough
generations that they would have evolved to be more inclined to eat
the buckthorn?
Rose-Marie
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Frederick W. Schueler
Sep 2, 2026, 7:30:46 PMSep 2
to Eastern Ontario Natural History listserve
On 9/2/2026 1:10 PM, rmb...@istar.ca wrote:
>
> I have the impression that the Cepaea snails have been around in Ontario
> for a while now. Would it have been long enough with enough generations
> that they would have evolved to be more inclined to eat the buckthorn?
* well, the problem is they're both European, so if ours are so
>
> I have the impression that the Cepaea snails have been around in Ontario
> for a while now. Would it have been long enough with enough generations
> that they would have evolved to be more inclined to eat the buckthorn?
enthusiastic about the Buckthorn, why isn't this better known? The ones
where we've seen them eating the Buckthorn have only been on that side
of the road for about 15 years, but there might have been something that
selected for rhamnivory in that time.
fred.
================================================
I Macaulay
Sep 2, 2026, 8:30:00 PMSep 2
to natur...@googlegroups.com
Seems that for years folks did not eat tomatoes, then someone had a go.
Perhaps they were starving last year and discovered buck thorn in desperation.
Barking up the wrong tree so to speak.
Senility has been a smooth transition for me.
Note New Hours
Ian Macaulay Carp, Ontario
Open at 11:AM Close at 5:00 PM
45.2397 N long: 76.0991 W Elv 137 M UTMDon't Forget to Save the Stamps
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e.g. g
Sep 3, 2026, 11:25:28 AMSep 3
to natur...@googlegroups.com
(Hmmm... is there an income opportunity somewhere in this? like goat husbandry as a business to control brush. as a snaeglherd, with a proven lineage of snails against buckthorn! ...and what IS the collective name for snails? on the land in action: a slowth? a shredding of snails? is a breeding farm a baroquery?)
E.G.
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I Macaulay
Sep 3, 2026, 12:08:57 PMSep 3
to 'e.g. g' via NatureList
Twood be freight, as in iscargo.
Senility has been a smooth transition for me.
Note New Hours
Ian Macaulay Carp, Ontario
Open at 11:AM Close at 5:00 PM
45.2397 N long: 76.0991 W Elv 137 M UTMDon't Forget to Save the Stamps
To view this discussion visit https://groups.google.com/d/msgid/naturelist/1709725326.1194256.1788449112496%40mail.yahoo.com.
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