Distribution
This species is native to the Mediterranean region (including Egypt) and western Europe, from northwest Africa and Iberia east to Asia Minor, and north to the British Isles.
It comprises a set of north African endemic forms and subspecies that were described at the beginning of the 20th century, on the basis of shell characteristics. The most common one, Cornu aspersum aspersum (synonym Helix aspersa aspersa), has become very abundant in all human-disturbed habitats in regions with a Mediterranean, temperate and even subtropical climate.
Cornu aspersum is a typically anthropochorous species; in other words this species has been spread to various geographical areas deliberately and /or accidentally by humans. It is nowadays widespread throughout the world, and occurs in in many zones that have climates differing from the original Mediterranean climate in which it first occurred. Its presence is reported on the American continents, as well as in Australia and in Asia. Because of this fact, the most likely explanation for resemblances between populations located on either side of the Mediterranean would be passive transport due to human activities. Transfers involving this species may have started in the Neolithic revolution (around 8500 BP). In the present time these introductions continue to occur, and in some cases give rise to catastrophic destruction of habitat.
It is very widely introduced and naturalised elsewhere in the world and its non-native distribution include other parts of Europe: Bohemia in the Czech Republic since 2008; southern Africa, Australia, New Zealand, North America and southern South America. It was introduced to California as a food animal in the 1850s and is now a notorious agricultural pest there, especially in citrus groves. Many areas have quarantines established for preventing the importation of the snail in plant matter.
Read more about this topic: Helix Aspersa
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