Cepaea nemoralis

Cepaea nemoralis

Cepaea nemoralis

Cepaea nemoralis

A cool call today that followed up on an identification I did a few years ago.  A co-worker’s husband and fellow herper, Dave Broughel, had found a land snail on the wall of his building (NYS Thruway) in Albany, and was wondering about an I.D.  I had seen the snail several years before in Long Island, it and because of the black lip at the edge of the shell opening (the operculum), I had guessed the European* introduced brown-lipped or grove snail, Cepaea nemoralis.  Another land snail in this genus, C. hortensis, also from Europe, and also reported from N.Y. historically, lacks this black lip.  C. hortensis however is more common in greenhouses.  This was C. nemoralis.  The succesful immigration of a snail like C. nemoralis, and its amazing success  is a fascinating story in and of itself.  Not really “invasive” in terms of numbers- or economic damage, it seems to build up and survive in small clusters- hot zones of sort.  Where, 1 or 2 after 3/4/5 years- build up to 100′s  AND THIS IS WHAT WE HAD HERE.  I went down tonight after Dave had told me that dozens of the snail were now on the walls of the building, on trees, and on thistle plants.  Stimulated by the continued wet/warm conditions that we have had this year- they were out in force.  He shot me a cell phone photo. Yup, there they were again!  And, yup- this was now a substantial population.  Like a little kid, I just couldn’t wait for the day to end!   I knew that right after work I’d make my drive down to Albany to photograph the molluscan maurauders for a story at NaturalistGuy.  C. nemoralis is a strikingly colorful animal.  In the class Mollusca, I have long wanted to follow such a ground zero of the snail world.  A location where I could better understand how they might spread, and what type of damage if any they might do.  I’m also very intrigued by the varying morphological forms (polymorphisms) within the clusters- and why these forms might be beneficial for the species- if at all.  From solid yellow, to handsomely striped across the shell- there were many color forms here.**  And I finally shot natural images (in-situ) of the snail sitting out the dry day on honey-locust trees.  A tree, which apparently was attractive to this snail, and which could be one of its primary hosts in this “hot zone.”  Land snails in urban areas of Upstate N.Y. are a rare site period.  Yes there are some varieties that can be found consistently under logs and debris if you look hard, but really, C. nemoralis is filling a niche not occupied by another large native land snails.  This is a good thing.  Our most common large land snail is the white-lipped snail, but that snail seems to hug relatively undistirubed lands, and from my experience enjoys more calcaresous (high pH) condtitions.

Like many snails C. nemoralis is a hemaphrodite, male and female reproductive organs in the same animal.  But they still have to mate, one exchanging sperm with the other.  To add to that, the female can store sperm for some time, and in fact her young might be the young of several different fathers.  After a period of time- mid-summer I presume in N.Y., up to 50 eggs are depostied and miniature versions of the adults hatch.  The specimens that I saw tonight appeared to be a mix of aprox. 1 to 2 year olds, as well as sexually mature adults.  The literature states that the brown-lipped snail can live up to 8 years.   FYI, this is Phylum Mollusca, Class Gastropoda.  So enjoy the images here!  And please, do not rush through them, they should be viewed at a snails pace.  More to come! NG.

*Per the literature: “Portugal and central Spain to SW Hungary and Bosnia, in Italy to Lucania, in the north to S Sweden, in the E to NW Poland, Latvia, Kaliningrad, Estonia (Hiiumaa island).”

**Wikipedia direct quote:  “These polymorphisms have been highly studied as part research in heredity and evolution. They are thought to act as camouflage to avoid predation from, for example, the Song Thrush, but also have implications for the body heat of the animal: darker shells heat up more quickly, with consequences for rates of metabolism and loss of moisture (crucial in snail locomotion). In particular, grove snails with dark brown appear to preferentially be found in dark woodlands, whilst snails with light yellow shells and thin banding are more commonly found in grassland.”

NG note: I’m guessing there might be more to the polymorphism story with this snail, since in the U.S., one might expect the polymorphisms to be driven in one direction or the other- if presumbily (and I don’t know yet ), if one color really DOES have a survival advantage over another.  At this time I have no evidence that they are predated on by birds in Albany.  I did not see many empty shells around to indicate that snails from this population were being fed upon by other creatures.  But I’d like to work that answer (question?).