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Gastrocopta armifera

What do they look like?

Armed snaggletooth snails have shells that are whitish in color. They average 3.0 to 5.0 mm in length and 2.0 to 2.6 mm in diameter, with 6 to 7 shell spirals. The shell shape is oval, and it gets larger toward the bottom. There are teeth-like projections called lamellae on the opening of the shell. The soft body is almost as long as the shell, and the color is usually mottled, with many blotches. Armed snaggletooth snails have two pairs of tentacles, with eyes at the tips of the tentacles. (Baker, 1939; Burch and Jung, 1988; Burch and Pearce, 1990; Hubricht, 1972; Pilsbry, 1948)

  • Range length
    3.0 to 5.0 mm
    0.12 to 0.20 in

Where do they live?

Armed snaggletooth snails, Gastrocopta armifera, are native to North America. In the United States, they are found from Arkansas and Florida in the south, to Vermont, Michigan, northeastern Wisconsin, and Nebraska in the north. They may also be found in southern Quebec and Ontario in Canada, mainly near Lake Erie and Lake Ontario. In Michigan, snails have mainly been collected from the southern half of the lower peninsula. ("Gastrocopta armifera", 2013a; Burch and Jung, 1988; Hubricht, 1985)

What kind of habitat do they need?

Armed snaggletooth snails are commonly found living in rotten logs and leaf litter in forests, as well as beneath limestone outcroppings. In the Great Lakes region, this species was found to be in many different habitats. Armed snaggletooth snails can also survive in dry conditions, and are therefore occasionally found in prairies. They can also survive temperatures from about 44°C to -20°C. (Baker, 1939; Basch, et al., 1961; Burch and Pearce, 1990; Nekola, 2003; Riddle and Miller, 1988; Riddle, 1990)

How do they grow?

These snails lay their eggs in moist areas and produce a gelatinous substance to make the eggs stick together. The time it takes for eggs to hatch depends on moisture and temperature. Eggs of this species are relatively large, averaging 1.0 to 1.2 mm in diameter. These snails are considered adults when the lip on the opening of the shell forms. (Burch and Pearce, 1990; Gugler, 1963; Tompa, 1984)

How do they reproduce?

Armed snaggletooth snails are hermaphrodites, meaning that each snail has both male and female reproductive parts. Mates may be found by following mucus trails that the snails leave behind. There is usual a courtship ritual, and then the snails mate. Each snail will insert sperm into the other snail. (Burch and Pearce, 1990; Gugler, 1963; Tompa, 1984)

In addition to two snails mating, armed snaggletooth snails can also reproduce by self-fertilization. Since each snail has both male and female reproductive parts, they can sometimes use their own sperm to fertilize their own eggs. These snails breed in the warmer months of the year, and may breed more when its raining. They become old enough to mate when the lip of the shell opening forms. Each snail can produce 3 to 6 eggs at a time. They often lay their eggs at night, and they lay them inside the shell, before pushing them out with their body. (Burch and Pearce, 1990; Gugler, 1963; Tompa, 1984)

  • How often does reproduction occur?
    Armed snaggletooth snails likely breed once a year.
  • Breeding season
    Armed snaggletooth snails breed during the warmer months of the year.
  • Range number of offspring
    3 to 6

Armed snaggletooth snails provide nutrients in their eggs for the offspring to grow and develop, and produce a sticky substance to cover the eggs. After they lay the eggs, the parents leave and provide no more parental care. (Burch and Jung, 1988)

  • Parental Investment
  • pre-fertilization
    • provisioning

How long do they live?

Armed snaggletooth snails probably live about one year. (Burch and Jung, 1988; Burch and Pearce, 1990)

How do they behave?

These snails are active at night, and are also more active when there is higher humidity and cooler temperatures. To survive the winter, snails can decrease the amount of water in their body, and also form a covering over the opening of the shell. This covering prevents water loss. The snails can also form this same covering during dry periods. Snails traditionally crawl over the ground and other surfaces, leaving a slime trail, but sometimes they can move in a way called "loping". To lope, the snail forms an arch with its body, with its middle part off the ground. They do this to avoid rough surfaces or to not lose water. (Burch and Pearce, 1990; Pearce, 1989; Riddle and Miller, 1988; Riddle, 1990)

  • Range territory size
    10 (high) m^2

Home Range

Armed snaggletooth snails live in about 10 square meters of space. (Burch and Pearce, 1990; Nekola, 2012)

How do they communicate with each other?

To communicate with each other, these snails leave mucus trails. When a snail comes across another snail's mucus trail, it can tell if it was left by a snail of the same species or a different species. Their eyes can detect light and their tentacles can detect chemicals. They can also use their sense of smell to find food. (Atkinson, 2013; Nordsieck, 2011; Pearce, 1997)

What do they eat?

Armed snaggletooth snails feed on fungi and decomposing plants. They use a toothed organ called a radula to scrape or grind food. (Baker, 1939; Burch and Pearce, 1990)

What eats them and how do they avoid being eaten?

Armed snaggletooth snails are preyed on by beetle larvae and other insects, birds, rodents, and small mammals, particularly voles and shrews. Armed snaggletooth snails have scales on the opening of their shells, which help to protect their soft bodies. ("Illinois Snails and Slugs", 2009; Burch and Pearce, 1990)

What roles do they have in the ecosystem?

These snails disperse plant seeds and fungal spores, by moving them to new locations where they can grow. They also break down decomposing matter in the forest, by eating it and digesting it. Many related snails can be infected by parasitic worms called nematodes, but it is not known if this species has any parasites. (Burch and Pearce, 1990)

Do they cause problems?

Armed snaggletooth snails do not cause any problems for humans.

How do they interact with us?

Armed snaggletooth snails do not have any positive effects on humans.

Are they endangered?

Armed snaggletooth snails are not an endangered species. However, their population is threatened in North Carolina, and they have also disappeared from Louisiana. Scientists should study these locations and determine what is causing these population decreases, to make sure that populations in other states do not become endangered. ("Gastrocopta armifera", 2013a; "Gastrocopta armifera", 2013b; IUCN, 2013)

Contributors

Renee Mulcrone (author), Special Projects, Jeremy Wright (editor), University of Michigan-Ann Arbor.

References

2013. "Gastrocopta armifera" (On-line). International Union for Conservation of Nature and Natural Resources. Accessed August 20, 2013 at http://www.iucnredlist.org/search.

2013. "Gastrocopta armifera" (On-line). NatureServe. Accessed August 20, 2013 at http://www.natureserve.org/explorer/servlet/NatureServe?searchSciOrCommonName=gastrocopta+armifera&x=0&y=0.

2003. "Gastroptera armifera" (On-line). Encyclopedia of Life. Accessed April 16, 2013 at http://eol.org/pages/453144/overview.

Illinois Department of Natural Resources. Illinois Snails and Slugs. 1. Springfield, IL: Illinois Department of Natural Resources. 2009. Accessed December 16, 2013 at http://www.dnr.state.il.us/publications/pdf/00000656.pdf.

Atkinson, J. 2013. "Michigan State University Snail Laboratory" (On-line). Accessed May 15, 2013 at https://www.msu.edu/~atkinso9/.

Baker, F. 1939. Fieldbook of Illinois land snails, Illinois Natural History Survey Manual 2. Urbana, Illinois: Illinois Natural History Survey.

Basch, P., P. Bainer, J. Wilhm. 1961. Some ecological characteristics of the molluscan fauna of a typical grassland situation in east central Kansas. American Midland Naturalist, 66/1: 178-199. Accessed August 20, 2013 at http://www.jstor.org/stable/2422876.

Burch, J., Y. Jung. 1988. Land snails of the University of Michigan biological station area. Walkerana, 3/9: 1-177.

Burch, J., T. Pearce. 1990. Terrestrial gastropoda. Pp. 201-310 in D Dindal, ed. Soil Biology Guide. New York: John Wiley and Sons.

Gugler, C. 1963. The eggs and egg-laying habits of some midwestern land snails. Transactions of the Kansas Academy of Science (1903-), 66/2: 195-201. Accessed December 15, 2013 at http://www.jstor.org/stable/3626560.

Hotopp, K. 2005. "Pennsylvania land snails: Gastrocopta armifera (Say, 1821)" (On-line). Carnegie Natural History Museum, Mollusks. Accessed June 05, 2013 at http://www.carnegiemnh.org/science/default.aspx?id=16826.

Hubricht, L. 1972. Gastrocopta armifera (Say). The Nautilus, 85: 73-77. Accessed December 15, 2013 at http://archive.org/stream/nautilus85amer/nautilus85amer_djvu.txt.

Hubricht, L. 1985. The distributions of the native land mollusks of the Eastern United States. Fieldiana, Zoology New Series, 24: 1-191. Accessed August 20, 2013 at http://www.archive.org/stream/distributionsofn24hubr/distributionsofn24hubr_djvu.txt.

IUCN, 2013. "The IUCN Red List of Threatened Species. Version 2013.2" (On-line). Accessed December 27, 2013 at www.iucnredlist.org.

Nekola, J. 2003. Large-scale terrestrial gastropod community composition patterns in the Great Lakes region of North America. Diversity and Distributions, 9: 55-71. Accessed August 20, 2013 at http://biology.unm.edu/jhbrown/Documents/511Readings/NekolaR4.pdf.

Nekola, J. 2012. The impact of a utility corridor on terrestrial gastropod biodiversity. Biodiversity and Conservation, 21: 781-785. Accessed August 20, 2013 at http://sev.lternet.edu/~jnekola/nekola%20pdf/biocon-preprint.pdf.

Nordsieck, R. 2011. "The eyes of snails" (On-line). The living world of mollusks. Accessed May 10, 2013 at http://www.molluscs.at/gastropoda/index.html?/gastropoda/morphology/eyes.html.

Pearce, T. 1997. Interference and resource competition in two land snails: adults inhibit conspecific juvenile growth in field and laboratory. Journal of Molluscan Studies, 63: 389-399. Accessed August 20, 2013 at http://mollus.oxfordjournals.org/content/63/3/389.full.pdf.

Pearce, T. 1989. Loping locomotion in terrestrial gastropods. Walkerana, 3/10: 229-237. Accessed August 20, 2013 at http://www.carnegiemnh.org/uploadedFiles/CMNH_Site/Mollusks/Downloads/Pearce1989.pdf.

Pilsbry, H. 1948. Land mollusca of North America (North of Mexico). Monographs of the Academy of Natural Sciences of Philadelphias, 3: 1-1113. Accessed August 20, 2013 at http://books.google.com/books/about/Land_Mollusca_of_North_America.html?id=EyHywT05a0QC.

Riddle, W. 1990. High temperature tolerance in three species of land snails. Journal of Thermal Biology, 15/2: 119-124.

Riddle, W., V. Miller. 1988. Cold-hardiness in several species of land snails. Journal of Themal Biology, 13/4: 163-167. Accessed August 20, 2013 at http://www.sciencedirect.com/science/article/pii/0306456588900289.

Tompa, A. 1984. Land snails (Stylommatophora). Pp. 47-139 in A Tompa, N Verdonk, J van den Biggelaar, eds. The Mollusca, Vol. 7, reproduction. London: Academic Press, Inc.

 
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Mulcrone, R. 2014. "Gastrocopta armifera" (On-line), Animal Diversity Web. Accessed December 18, 2018 at http://www.biokids.umich.edu/accounts/Gastrocopta_armifera/

BioKIDS is sponsored in part by the Interagency Education Research Initiative. It is a partnership of the University of Michigan School of Education, University of Michigan Museum of Zoology, and the Detroit Public Schools. This material is based upon work supported by the National Science Foundation under Grant DRL-0628151.
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