Helix pomatia

Geographic Range

Helix pomatia is indigenous to Central and Southeast Europe, but has been moved by humans all over Europe, Asia, and the Americas. ("Helix Pomatia", 2007)

Habitat

Helix pomatia prefers low-lying chalk and limestone areas but can be found up to 1830 meters in altitude. They can also be seen in vineyards, gardens, thickets and parks. They require a habitat that is humid with fairly constant, mild temperatures; and they cannot tolerate heavy rains or direct sunlight. ("Helix Pomatia", 2007; "The Living World of Molluscs", 2007; Fretter and Peake, 1975; "U.S Department of Agriculture", 1996)

  • Range elevation
    1830 (high) m
    6003.94 (high) ft

Physical Description

Helix pomatia has a brown shell with three to five light brown bands, four to five whorls, and are round or conical. A mature shell can range from 3.8-5.0 centimeters in height and diameter and is approximately one-third of their weight. ("All You Need to Know About Snails", 2007; "Helix Pomatia", 2007; "The Living World of Molluscs", 2007; Fretter and Peake, 1975; Rogers, 1908; "U.S Department of Agriculture", 1996)

  • Range length
    3.8 to 5.0 cm
    1.50 to 1.97 in

Development

The embryos of Helix pomatia undergo development that is typical of veliger larvae. In the case that an embryo becomes dehydrated, it is usually able to survive. The snails emerge from their shells three to four weeks after they are deposited in a hole dug by their parent, depending on both the temperature and humidity. Each newly-hatched snail typically weighs twenty-seven milligrams and has both male and female reproductive organs. The snails live in the hole dug by the parent for a little over a week, feeding on the empty eggshells.

Shells grow incrementally until they reach maturity. Growth of the shell is inhibited by adverse weather conditions such as extreme heat or dryness, but eight hours of sunlight is optimal. Shells cannot reach full development unless they are able to access a rich calcium carbonate food-source ("All You Need to Know About Snails", 2007; "Helix Pomatia", 2007; Fretter and Peake, 1975; "U.S Department of Agriculture", 1996)

Reproduction

Helix pomatia has a mate-selection process in which they court each other for several hours. The mates they ultimately select are usually not from different locations.

The mating process occurs in five steps: (1) With their heads up, snails circle each other and feel one another with their tentacles. (2)After becoming stimulated, one of the snails injects a calcareous “love-dart” into the sole of the other snail. Once it becomes exhausted, the other snail does the same thing. (3)After resting, they align in such a way that their genital openings overlap. This act further stimulates the snails. (4)The two snails twist their bodies around one another so that the penis and vagina are connected. One snail receives a spermatophore in a process that takes four to seven minutes. (5)In the final stage, the penis is removed. However, the two snails can remain attached with their feet together for several hours.

Snails can undergo the aforementioned mating ritual up to two times a year. However, if they live in a densely populated area, mating activity is reduced because the increased slime secretion suppresses reproduction. ("All You Need to Know About Snails", 2007; "Helix Pomatia", 2007; Fretter and Peake, 1975; "U.S Department of Agriculture", 1996)

Mating in Helix pomatia usually takes place among mature snails in the late spring and early summer, but can occur as last as October. After fertilization occurs, the snails can deposit anywhere from eight to thirty eggs. Sexual maturity is reached in two to four years. ("Helix Pomatia", 2007; Fretter and Peake, 1975; "U.S Department of Agriculture", 1996)

  • Breeding interval
    Two to six times per year
  • Breeding season
    From late spring into early fall
  • Range number of offspring
    8 to 30
  • Range gestation period
    3 to 4 weeks
  • Range age at sexual or reproductive maturity (female)
    2 to 4 years
  • Range age at sexual or reproductive maturity (male)
    2 to 4 years

Helix pomatia typically selects a light, moist, deep soil in order to ensure that its eggs fully develop. After laying their eggs in a hole, which can take 15-20 minutes per egg, they cover them with a mixture of slime and soil. No other direct parental care is provided. ("U.S Department of Agriculture", 1996)

  • Parental Investment
  • no parental involvement
  • pre-hatching/birth
    • protecting
      • male
      • female

Lifespan/Longevity

Helix pomatia lives in the wild have a typical lifespan of five years, while those that are held in captivity can live longer than ten years. Egg deposition affects lifespan because it causes significant weight loss. Snails that inhabit densely populated areas also suffer from higher mortality rates. Nematodes, trematodes, fungi, and other parasite are capable of infecting dense snail populations, causing high mortality. ("Helix Pomatia", 2007; "U.S Department of Agriculture", 1996)

  • Range lifespan
    Status: wild
    10+ (high) years

Behavior

When Helix pomatia forage, a slime trail is left behind. While navigating their surroundings, they use their slime secretions to move on the rough or slick surfaces. In order to reduce the loss of water while moving on dry surfaces, they utilize a technique called “jumping,” which entails using only specific parts of their foot sole. The snails are able to follow the trail back home, and to return to the food source the proceeding day. They are nocturnal because of the cooler temperatures at night. The snails hibernate in the winter because they are not able to survive the cold temperatures of the winter months. Prior to hibernation, they dig a hole and lay shell-mouth up. They completely retract into their shells and secrete a mucus covering, called an epiphragm, to seal the shell’s opening. ("Helix Pomatia", 2007; Fretter and Peake, 1975; "U.S Department of Agriculture", 1996)

Home Range

No specific data was found on this topic.

Communication and Perception

No specific data was found on this topic.

Food Habits

Most feeding occurs between sunset and midnight. While feeding, the snails use their radula to brush the food. They require a calcium rich food source for shell growth and maintenance, and also feed on a variety of fruits, vegetables, flowers and leaves. (Fretter and Peake, 1975; "U.S Department of Agriculture", 1996)

  • Plant Foods
  • leaves
  • fruit
  • flowers
  • sap or other plant fluids

Predation

Young Helix pomatia are preyed upon by birds, insects, toads and mice. Snail eggs can also be predated by newly-hatched snails. Secreted slime, although not poisonous or unpalatable, often deters predation. ("Helix Pomatia", 2007; "U.S Department of Agriculture", 1996)

  • Known Predators
    • Humans, frogs, parasitic nematodes, ground beetles, hedgehogs, slow worms, centipedes

Ecosystem Roles

The grazing of Helix pomatia potentially has important effects on the plant community

Economic Importance for Humans: Positive

Helix pomatia is cultivated and eaten as food. (Rogers, 1908; "U.S Department of Agriculture", 1996)

  • Positive Impacts
  • food

Economic Importance for Humans: Negative

Helix pomatia can cause significant crop damage ("U.S Department of Agriculture", 1996)

  • Negative Impacts
  • crop pest

Conservation Status

Helix pomatia or its habitat receives some level of protection throughout much of Europe, even where introduced such as the United Kingdom. ("Helix Pomatia", 2007; "Second Report by the United Kingdom under Article 17 on the implementation of the Directive from from January 2001 to December 2006", 2007)

Contributors

Jacqueline Lach (author), Rutgers University, Michelle Schwartz (author), Rutgers University, David Howe (editor, instructor), Rutgers University .

Glossary

Nearctic

living in the Nearctic biogeographic province, the northern part of the New World. This includes Greenland, the Canadian Arctic islands, and all of the North American as far south as the highlands of central Mexico.

World Map

Neotropical

living in the southern part of the New World. In other words, Central and South America.

World Map

Palearctic

living in the northern part of the Old World. In otherwords, Europe and Asia and northern Africa.

World Map

agricultural

living in landscapes dominated by human agriculture.

arboreal

Referring to an animal that lives in trees; tree-climbing.

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

crepuscular

active at dawn and dusk

ectothermic

animals which must use heat acquired from the environment and behavioral adaptations to regulate body temperature

fertilization

union of egg and spermatozoan

folivore

an animal that mainly eats leaves.

food

A substance that provides both nutrients and energy to a living thing.

frugivore

an animal that mainly eats fruit

herbivore

An animal that eats mainly plants or parts of plants.

hibernation

the state that some animals enter during winter in which normal physiological processes are significantly reduced, thus lowering the animal's energy requirements. The act or condition of passing winter in a torpid or resting state, typically involving the abandonment of homoiothermy in mammals.

internal fertilization

fertilization takes place within the female's body

introduced

referring to animal species that have been transported to and established populations in regions outside of their natural range, usually through human action.

metamorphosis

A large change in the shape or structure of an animal that happens as the animal grows. In insects, "incomplete metamorphosis" is when young animals are similar to adults and change gradually into the adult form, and "complete metamorphosis" is when there is a profound change between larval and adult forms. Butterflies have complete metamorphosis, grasshoppers have incomplete metamorphosis.

motile

having the capacity to move from one place to another.

native range

the area in which the animal is naturally found, the region in which it is endemic.

nocturnal

active during the night

oviparous

reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.

polygynandrous

the kind of polygamy in which a female pairs with several males, each of which also pairs with several different females.

seasonal breeding

breeding is confined to a particular season

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

suburban

living in residential areas on the outskirts of large cities or towns.

temperate

that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).

terrestrial

Living on the ground.

tropical savanna and grassland

A terrestrial biome. Savannas are grasslands with scattered individual trees that do not form a closed canopy. Extensive savannas are found in parts of subtropical and tropical Africa and South America, and in Australia.

savanna

A grassland with scattered trees or scattered clumps of trees, a type of community intermediate between grassland and forest. See also Tropical savanna and grassland biome.

temperate grassland

A terrestrial biome found in temperate latitudes (>23.5? N or S latitude). Vegetation is made up mostly of grasses, the height and species diversity of which depend largely on the amount of moisture available. Fire and grazing are important in the long-term maintenance of grasslands.

References

2007. "All You Need to Know About Snails" (On-line). Accessed November 01, 2007 at http://www.escargot.fr/uk/tout.htm.

2007. "Helix Pomatia" (On-line). The Trail of the Snail. Accessed October 17, 2007 at http://www.arnobrosi.com/pomatia.html.

Joint Nature Conservation Committee. Second Report by the United Kingdom under Article 17 on the implementation of the Directive from from January 2001 to December 2006. S1026 - Helix pomatia - Roman snail. Peterborough: Joint Nature Conservation Committee. 2007. Accessed October 21, 2008 at www.jncc.gov.uk/article17.

2007. "The Living World of Molluscs" (On-line). Amazing Facts About Snails. Accessed November 01, 2007 at http://weichtiere.at/english/gastropoda/index.html.

U.S Department of Agriculture. 1996. "U.S Department of Agriculture" (On-line). Raising Snails. Accessed October 17, 2007 at http://www.nal.usda.gov/afsic/AFSIC_pubs/srb96-05.htm.

Fretter, V., J. Peake. 1975. Pulmonates, Volume I. London: Academic Press.

Rogers, J. 1908. The Shell Book. Boston, MA: Charles T. Branford CO.