Coffee Bean Snail

A cluster of coffee bean snails, Melampus coffeus, showing variation in shell color and pattern. Photo courtesy of Candy Feller, Smithsonian Environmental Research Center.

A solitary M. coffeus on a branch of the red mangrove, Rhizophora mangle. Photo L. Holly Sweat, Smithsonian Marine Station at Fort Pierce.

M. coffeus on mangrove leaf litter. Photo courtesy of Kathy Hill, Smithsonian Marine Station at Fort Pierce.

Species Name:
Melampus coffeus Linnaeus 1758

Common Name:
Coffee Bean Snail
Coffee Melampus

Species Description:
The coffee bean snail, Melampus coffeus, is a small intertidal snail. The shell is ovate, tapering toward the base. Most snails are brown with three horizontal light bands (Kaplan 1988), but the background color in some individuals may range from shades of gray or tan to yellowish brown. The aperture is narrow and long, with a sharp outer lip and an inner margin bearing two teeth (Kaplan 1988). The pale brown inner lip is turned slightly backwards, and the spire is conical. Unlike many other snails, M. coffeus lacks an operculum (Ruppert & Barnes 1994).

Potentially Misidentified Species:
The coffee bean snail may be mistaken for the eastern melampus, M. bidentatus, which is very similar in appearance. The shell of the eastern melampus is also brown with light bands, and reaches a length of about 1.8 cm (Andrews 1994). In addition, incised spiral lines are present on the upper shoulder of the shell. The eastern melampus is more prevalent in salt marshes (Mook 1973); whereas, M. coffeus is found mostly among mangrove roots and branches (Proffitt & Devlin 2005).

II. HABITAT AND DISTRIBUTION

Regional Occurrence:
The coffee bean snail inhabits intertidal zones along both coasts of Florida and throughout the Caribbean. Most populations are found around roots and branches of mangroves (Proffitt & Devlin 2005).

IRL Distribution:
The coffee bean snail is found throughout the IRL, usually associated with: the red mangrove, Rhizophora mangle; the white mangrove, Laguncularia racemosa; and the black mangrove, Avicennia germinans.

III. LIFE HISTORY AND POPULATION BIOLOGY

Age, Size, Lifespan:
Little information is available concerning the maximum age and size of M. coffeus. Most adult snails are approximately 1-2 cm (Kaplan 1988). Studies on populations in Tampa Bay documented size ranges between 0.5 and 1.9 cm in length (Proffitt & Devlin 2005). Maia & Tanaka (2007) found the largest snails in one Brazilian estuary on stands of the red mangrove, R. mangle.

Abundance:
Abundance estimates for M. coffeus in the IRL are scarce. However, previous studies have documented densities between 1 and 143 individuals per square meter in various mangrove ecosystems throughout Florida (Proffitt & Devlin 2005, Raulerson 2004).

Reproduction, Embryology & Larval Development:
The coffee bean snail is a simultaneous hermaphrodite, and individuals copulate to produce gelatinous egg masses which are laid under leaves and on decaying wood (Russell-Hunter et al. 1972). Both M. coffeus and M. bidentatus can lay several batches, totaling over 33,000 eggs per year (Apley 1968). Melampus is one of the few pulmonate snails that reproduce via planktonic larvae called veligers (Ruppert & Barnes 1994). Once the eggs hatch, the veligers spend approximately 4-6 weeks in the plankton before returning to the mangroves on a high tide and metamorphosing into juvenile snails (Apley 1968, Holle & Dineen 1957).

IV. PHYSICAL TOLERANCES

Temperature:
Little information exists regarding the temperature tolerances for M. coffeus. However, the tropical and subtropical range of the species suggests that it thrives best in warmer waters.

Salinity:
Little information exists regarding the temperature tolerances for M. coffeus. However, the tropical and subtropical range of the species suggests that it thrives best in warmer waters.

Respiration & Migration:
The coffee bean snail is one of over 16,000 described species of pulmonate gastropods found in temperate to tropical latitudes worldwide (Ruppert & Barnes 1994). These snails are characterized by the presence of a lung, which had been converted from the mantle cavity. A small opening, called a pneumostome, is present on the right side where the mantle cavity remains unfused. Gills are absent, and the mantle cavity has become highly vascularized. Most gas exchange occurs through diffusion in the pneumostome. The coffee bean snail migrates vertically as the tide rises (eg. Proffitt & Devlin 2005) to avoid predation and approaching water, though it descends into the water to release larvae (Ruppert & Barnes 1994).

V. COMMUNITY ECOLOGY

Trophic Mode:
The coffee bean snail is a detritivore/herbivore, foraging on new and decaying mangrove leaf litter (Proffitt & Devlin 2005, Raulerson 2004). Studies suggest that the rapid consumption of brown or yellowing leaves over green vegetation is due to the increased effort required by M. coffeus to break through the waxy cuticle of healthy leaves (Proffitt et al. 1993). Therefore, most litter assimilated by the snails is unhealthy or decaying. In some studies, almost half of the seasonal litter fall in mangrove forests was consumed by M. coffeus (Proffitt & Devlin 2005), with faster rates of herbivory on A. germinans and L. racemosa than R. mangle (McKee & Faulkner 2000). See “Ecological Importance” below to learn more about the significance of mangrove litter consumption by the coffee bean snail.

Predators:
Vertical migration during incoming tides reduces predation risk for M. coffeus. However, the snail is still preyed upon by birds such as the white ibis, Eudocimus albus (Proffitt & Devlin 2005), and terrestrial mammals. When M. coffeus are in the surrounding waters, they may be consumed by several fish species, including: the killifish, Fundulus heteroclitus (Proffitt & Devlin 2005); porcupinefish, Diodon hystrix; and the bluestriped grunt, Haemulon sciurus (Randall 1967).

Associated Species:
No known obligate associations exist for M. coffeus. However, coffee bean snails are associated with several organisms common to mangroves habitats. For extensive lists of other species found throughout mangrove ecosystems, please refer to the Mangrove Habitats page.

VI. SPECIAL STATUS

Special Status:
None

Ecological Importance:
The coffee bean snail is an important consumer of leaf litter and detritus in mangrove ecosystems, and is the only known direct consumer in southwest Florida (Proffitt et al. 1993, McIvor & Smith 1995, McKee & Faulkner 2000). These snails also consume dead or dying leaves from the tree, with removal rates exceeding 200 g m^-2 annually (McKee & Faulkner 1995), depending on the mangrove species. In addition, an average population can produce about 3 x 10⁶ larvae annually (Proffitt & Devlin 2005), providing an energy pathway within mangrove communities from detritus and leaf litter to higher order consumers.

VII. REFERENCES & FURTHER READING

Andrews, J. 1994. A field guide to shells of the Florida coast. Gulf Publishing Co. Houston, Texas. USA. 182 pp.

Apley, ML. 1968. Field and experimental studies on pattern and control of reproduction in Melampus bidentatus (Say). PhD Dissertation. Syracuse Univ. Syracuse, NY. USA.

Holle, PA & CF Dineen. 1957. Life history of the salt marsh snail, Melampus bidentatus Say. Nautilus. 70: 90-95.

Kaplan, EH. 1988. A field guide to southeastern and Caribbean seashores: Cape Hatteras to the Gulf coast, Florida, and the Caribbean. Houghton Mifflin Co. Boston, MA. USA. 425 pp.

Maia, RC & MO Tanaka. 2007. Avaliação de eféitos de species de mangue na distribuição de Melampus coffeus (Gastropoda, Ellobiidae) no Ceará, nordeste do Brasil. Iberingia. Sér. Zool. Porto Alagre. 97: 379-382.

McIvor, CC & TJ Smith III. 1995. Differences in the crab fauna of mangrove areas at a southwest Florida and a northeast Australia location: implications for leaf litter processing. Estuaries. 18: 291-597.

McKee, KL & P Faulkner. 2000. Restoration of biogeochemical function in mangrove forests. Restor. Ecol. 8: 247-259.

Mook, MS. 1973. Intertidal zonation of Melampus bidentatus Say and Melampus coffeus L. (Gastropoda: Pulmonata). MS thesis. University of South Florida. Tampa, FL. USA.

Mook, D. 1986. Absorption efficiencies of the intertidal mangrove dwelling mollusk Melampus coffeus Linne and the rocky intertidal mollusk Acanthopleura granulata Gemlin. PSZN I: Mar. Ecol. 7: 105-113.

Proffitt, CE & DJ Devlin. 2005. Grazing by the intertidal gastropod Melampus coffeus greatly increases mangrove leaf litter degradation rates. Mar. Ecol. Prog. Ser. 296: 209-218.

Proffitt, CE, Johns, KM, Cochrane, CB, Devlin, DJ, et al. 1993. Filed and laboratory experiments on the consumption of mangrove leaf litter by the macrodetritivore Melampus coffeus L. (Gastropoda: Pulmonata). FL Sci. 56: 211-222.

Randall, JE. 1967. Food habits of reef fishes of the West Indies. Stud. Trop. Oceanogr. 5: 665-847.

Raulerson, GE. 2004. Leaf litter processing by macrodetritivores in natural and restored neotropical mangrove forests. Master’s Thesis. Louisiana State Univ. Baton Rouge, LA. USA. 141 pp.

Ruppert, EE & RD Barnes. 1994. Invertebrate zoology, 6th edition. Saunders College Publishing. Orlando, FL. USA. 1056 pp.

Russell-Hunter, WD, Apley, ML & RD Hunter. 1972. Early life-history of Melampus and the significance of semilunar synchrony. Biol. Bull. 143: 623-656.

Report by: LH Sweat, Smithsonian Marine Station at Fort Pierce
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Page last updated: 17 August 2009