Animal Diversity Web

Geographic Range

Littorina irrorata is found in salt marshes that extend from Long Island, New York, south along the coast to central Florida. L. irrorata is also found of west of Florida extending along the Gulf Coast to Texas. (Emerson and Jacobson, 1976; Rehder, 1981)

• Biogeographic Regions
• nearctic
• atlantic ocean

Habitat

Littorina irrorata is found in brackish water marshes and can be found on marsh grass living at or above the water level. It is usually associated with marsh plants in the genus Spiratina. (Rehder, 1981)

• Habitat Regions
• saltwater or marine

• Aquatic Biomes
• coastal
• brackish water

• Wetlands
• marsh

• Other Habitat Features
• estuarine
• intertidal or littoral

Physical Description

The shell size of Littorina irrorata ranges from 19 mm to about 32 mm high. The shell is thick and broad. The aperture is oval in shape. The shell is shaped like an elongated cone, being longer than wide. Usually a grayish white color, it has tiny, short streaks of reddish brown on the spiral ridges. The shell is also opaque and dull. The columella and callus is usually a pale reddish brown color and the outer lip of the shell is stout, sharp and usually has tiny regular grooves on the inside edge. The inside of the sharp outer lip is marked with red-brown streaks. The whorls on the shell are almost flat and it has about 8 to 10 whorls, which gradually increase. The shell may have a greenish tinge from fine algal growth. (Andrews, 1981; Rehder, 1981)

• Other Physical Features
• ectothermic
• heterothermic
• bilateral symmetry

• Range length

  19 to 32 mm

  0.75 to 1.26 in

Development

Nothing was documented about the species but about the genus. In a closely related species, Littorina littorea, the embryo hatches as a veliger larva. The planktonic distributive larval stage has been eclipsed. Littorina neritoides and L. littorea eggs are set free singly into the plankton hatching as veligers. In L. littoralis, the eggs are laid in gelatinous layers attached to the substratum, hatching at the crawling stage. In L. saxatlis, the young merge at the crawling stage as viviparous forms and the young remain protected within the maternal body. In L. angulifera, a veliger larva is expelled. (Purchon, 1968)

Reproduction

Information is not known.

Most of what is known about reproduction is for the genus Littorina. In some species of Littorina, the males are not only smaller than the females but their shell has a more elongated spire and narrow aperture. In this genus fertilization occurs internally. The delivery of the spermatozoa into the mantle city of the female would be rendered more efficient if the ciliated pathway were extended on to a projection from the body of the male. It is natural, therefore, that a penis bearing a lateral ciliated seminal groove should develop on the right side of the male. In many mesogastropods and in the hermaphrodites in which exchange of sperm cannot be reciprocal since male and female aperture are widely separate, the partners orientate themselves in the same direction and the male may the female, settle on the right side of the body, and even be carried about by her, as in Littorina spp. Some Littorina spp. (e.g. L. littorea, L. neritoides) have pelagic capsules extruded from an ovipositor situated near the genital aperture in a position comparable to that of the penis. Here the capsule receives its final form and its outer layers harden the contact with seawater. The ventral wall of the pallial oviduct usually fails to develop glands and so provides an easy pathway for the sperm. The female L. irrorata is known to produce floating egg capsules. (Rehder, 1981; Wilbur and Vonge, 1964)

• Key Reproductive Features
• sexual
• fertilization
  • internal
• oviparous

Females lay eggs and no parental investment is involved thereafter.

• Parental Investment
• pre-fertilization
  • provisioning

Behavior

When the tide is out, L. irrorata withdraws into its shell which may remain dry and exposed to the sun for hours. This snail is usually found on marsh grass where it leaves a mucus trail.

Littorina irrorata climbs marsh grasses as water temperatures rise. This probably serves two functions: obtaining more oxygen (since warmer waters have less oxygen) and avoiding predators. (Andrews, 1981; Henry, et al., 1993)

• Key Behaviors
• motile

Communication and Perception

The eye structure of Littorina irrorata have been described. Eyes are lateral to the cephalic tentacle. The animal is able to detect light and motion.

Experiments found the snails preferred vertical bars over horizontal bars, suggesting they can see and sense plant stems, where they are usually found in nature. Another study found L. irrorata positively reponds to plant odors found in its environment. (Duval, et al., 1994; Hamilton, 1982; Hamilton, et al., 1983)

• Communication Channels
• chemical

• Perception Channels
• visual
• tactile
• chemical

Food Habits

Littorina irrorata is an herbivore that feeds mainly on algae. It grazes over the surface of marsh grass, usually Spiratina species. Members of the genus Littorina are known to move in response to chemical emanation from food at a distance. (Andrews, 1981; National Oceanic and Atmospheric Administration and Environmental Protection Agency, 2004; Purchon, 1968; Wilbur and Vonge, 1964)

• Primary Diet
• herbivore
  • algivore
• detritivore

• Plant Foods
• algae

• Other Foods
• detritus
• microbes

Predation

Littorina irrorata is preyed on by fish, crabs (particularly blue crabs), birds, sea urchins, and small mammals. In Connecticut, research found diamondback terrapins also fed on this species. (National Oceanic and Atmospheric Administration and Environmental Protection Agency, 2004; Snyder, 2001; Whitelaw, 2000)

• Known Predators

  • fish (Actinopterygii)
  • crabs (Decapoda)
  • blue crabs (Calinectes sapidus)
  • sea urchins (Echinoidea)
  • small mammals (Mammalia)
  • diamondback terrapin (Malaclemys terrapin)

Ecosystem Roles

When predators are removed, periwinkles feed heavily and negatively impact Spartina, a marsh plant. (National Oceanic and Atmospheric Administration and Environmental Protection Agency, 2004)

• Ecosystem Impact
• biodegradation

Economic Importance for Humans: Positive

Periwinkles are sensitive to toxic agents and are used for toxicology studies. (National Oceanic and Atmospheric Administration and Environmental Protection Agency, 2004)

• Positive Impacts
• research and education

Conservation Status

• IUCN Red List

  No special status

• US Federal List

  No special status

• CITES

  No special status

Contributors

Renee Sherman Mulcrone (editor).

Abel Munoz (author), Troy Ladine (editor), East Texas Baptist University.

References

Andrews, J. 1981. A field guide: Texas shells. Austin: University of Texas Press.

Duval, M., A. Calzetta, D. Rittschof. 1994. Behavioral responses of Littorina irrorata (SAY) to water-borne odors. Journal of Chemical Ecology, 20: 3321-3334.

Emerson, W., M. Jacobson. 1976. American The Museum of Natural History: guide to shells: land, freshwater and marine, from Nova Scotia to Florida. New York: Alfred A. Knopf.

Graça, M., S. Newell, R. Kneib. 2000. Grazing rates of organic matter and living fungal biomass of decaying Spartina alterniflora by three species of salt-marsh invertebrates. Marine Biology, 136: 281-289.

Hamilton, P. 1982. Behavioral responses to visual stimuli by the snail, Littorina irrorata. Animal Behaviour, 30: 752-760.

Hamilton, P. 1976. Predation on Littorina irrorata by Callinectes sapidus (Crustacea: Portunidae). Bulletin of Marine Science, 26: 403-409.

Hamilton, P., S. Ardizzoni, J. Penn. 1983. Eye structure and optics in the intertidal snail Littorina irrorata. Journal of Comparative Physiology: A. Sensory neural and behavioral physiology, 152: 435-446.

Henry, R., A. Williams, C. McBride. 1993. Responses of the marsh periwinkle, Littoraria (littorina) irrorata to temperature, salinity and desiccation, and the potential physiological relationship to climbing behavior. Marine Behavior and Physiology, 24: 45-54.

Hyman, L. 1967. The invertebrates. New York: McGraw-Hill Book Company.

National Oceanic and Atmospheric Administration, , Environmental Protection Agency. 2004. "Periwinkle (Littorina irrorata)" (On-line). N. C. Plant and Animal Species Fact Sheets. Accessed January 03, 2005 at http://www.estuaries.gov/pdf/Periwinkle.pdf.

Pechnik, J. 2000. Biology of the invertebrates. Boston: McGraw-Hill Book Company.

Purchon, R. 1968. The biology of the Mollusca. London: Pergamon Press.

Rehder, H. 1981. The Audubon Society field guide to North America seashells. New York: Alfred A. Knopf.

Snyder, R. 2001. "Salt Marsh Molluscs" (On-line). Flora and Fauna of Northwest Florida. Accessed December 22, 2004 at http://www.uwf.edu/rsnyder/ffnwf/salmars/saltmollusc.html.

Whitelaw, D. 2000. "Prey availability for the diamondback terrapin population of Milford Marsh, Connecticut" (On-line). Research Conducted at the University of New Haven, Connecticut, 1999. Accessed January 03, 2005 at http://journal.conncoll.edu/~dmwhi/milfordpaper.html.

Wilbur, K., C. Vonge. 1964. Physiology of Mollusca. New York: Academic Press.