Let's not gloss over the glossy pillars: Cochliocopa lubrica (Cochliocopidae)

Dicrocoelium dendriticum stages
and intermediate hosts
Acrylic on canvas by Jeba Jesudoss

Cochliocopa lubrica is also known as Cionella lubrica or the glossy pillar. It is a rather beautiful land snail species that is the intermediate host of the ruminant parasite – Dicrocoelium dendriticum and of the nematodes Protostrongylus rufescens, Meullerius capillaris, Elaphostrongylus cervi, Varestrongylus capreoli, Varestrongylus pneumonicus and Skrjabingylus nasicola. 

C. lubrica is a holarctic species found throughout North America, Europe, Africa, parts of Asia and New Zealand. In the United States, it is found on both sides of the continental divide. Being a land snail, it is found in forests and grassy areas, often close to human dwellings.

The snail is about 5 – 7 mm long and 2-3 mm wide. It has a brown ( ranging from off-white to almost amber), smooth, glossy, translucent shell which is bluntly rounded at the apex. There are 5-7 whorls. The opening/aperture is ovate and wide, and lacks denticles.  The soft parts of the body is dark blue-black.

Cochliocopa lubrica
Muséum national histoire naturelle /
CC BY
(https://creativecommons.org/licenses/by/4.0)
via Wikimedia

Experimental studies have shown that C. lubrica can tolerate high temperatures of 37 – 40 C and survive through a drought for 50 -70 days. However, snails infected with Dicrocoelium were less resistant than uninfected snails. 

While many other snail genera can be first intermediate hosts of D. dendriticium in parts of the world, C. lubrica is epizootically important in North America. For example, in a 1952 study on a heavily infected sheep farm in New York,  Mapes C.R. found that only C. lubrica out of 16 mollusc species studied harbored the sporocysts or cercariae of D. dendriticum. He also found that the distribution of the snail was similar to known areas where dicrocoeliasis occurred. 

Interestingly, C. lubrica is small enough to be preyed upon by other predator snails (a phenomenon called malacophagy). In experimental conditions, Nesovitrea hammonis (a snail found in Europe) was shown to be capable of preying upon C. lubrica, but not well enough to be a biological control agent. 

References:

Grewal, P. S., et al. "Parasitism of molluscs by nematodes: types of associations and evolutionary trends." Journal of Nematology 35.2 (2003): 146.

Badie, A., and Daniel Rondelaud. "Influence Du Parasitisme Sur La Résistance De Cionella Lubrica Müller A La Température Et A La Dessication." (1982).

Mapes, Cortland R. "Cionella lubrica (Muller), a new intermediate host of Dicrocoelium dendriticum (Rudolphi, 1819) Looss, 1899 (Treinatoda: Dicrocoeliidae)." Journal of Parasitology 38.1 (1952).

https://www.carnegiemnh.org/science/mollusks/va_cochlicopa_lubrica.html

http://fieldguide.mt.gov/speciesDetail.aspx?elcode=IMGAS11010