Copse Snail, Arianta arbustorum

The Copse Snail (Arianta arbustorum) is a medium-sized species of land snail, a terrestrial pulmonate gastropod mollusk belonging to the family Helicidae.

There are several subspecies that are recognized: A. a. alpicola, A. a. arbustorum, A. a. canigonensis, A. a. picea, A. a. pseudorudis, A. a. repellini, A. a. styriaca, and A. a. vareliensis.

This species is native to Europe and can be found in the Netherlands, Austria, Slovakia, the Czech Republic, Poland, Switzerland, Norway, Iceland, the British Isles, Kaliningrad, Finland, Latvia, Estonia, Bulgaria, and western Ukraine.

It is introduced to North America, but is only known from Canada, where established populations are known from New Brunswick, Ontario, and Newfoundland.

This species has not yet become established in the USA, but it is considered to represent a potentially serious threat as a pest, an invasive species which could negatively affect agriculture, natural ecosystems, commerce or human health. Therefore, it has been proposed that this species be given top national quarantine significance in the USA.

The shell is normally brown with a number of pale yellowish rows of spots and normally with a brown band above the periphery, sometimes yellowish, reddish, or with a greenish hue, weakly striated with fine spiral lines on the upper side. The shell has 5 to 5.5 convex whorls with deep suture. The last whorl is fairly descending close to the aperture. The umbilicus is totally covered by the reflected columellar margin.

The shell measures 18 to 15 millimeters wide and 12 to 22 millimeters high. The dimensions are locally variable.

The shape of the shell is globular in most present-day populations, but initially is believed to have been depressed in the Pleistocene, before lowlands were invaded and the shells became globular, reinvading mountain regions except some secluded spots among glaciers.

This animal is usually black.

It inhabits forests and open habitats of any kind. It needs humidity and it lives also in disturbed areas. It might locally tolerate non-calcareous substrate, in north Scotland also on sandhills.

It feeds on green herbs, feces, and dead animals.

It snails hatched more than 50 meters apart from each other, they are considered isolated since they would not move more than 25 meters. They normally move about 7 to 12 meters in a year, mostly along water currents. This species makes and uses love darts during mating. Reproduction is normally after copulation, but self-fertilization is also a possibility. The size of the egg is 3.2 millimeters. Maturity is achieved after two to four years. The maximum age is up to fourteen years.

Image Caption: Arianta arbustorum Small garden snail, on a wood fence.Credit: Håkan Svensson/Wikipedia (CC BY-SA 3.0)