> Habitat & Distribution
Helisoma trivolvis ranges throughout North America, from arctic Canada to Florida, and has been introduced sporadically around the world. This is the “ramshorn” snail commonly seen in the aquarium, and has doubtless been spread artificially by hobbyists and water gardeners. It is not well adapted to lotic waters, in east Tennessee and U. S. Atlantic drainages (below) being found primarily in lakes, ponds, swamps, and the calmest areas of coastal rivers. It thrives in rich, eutrophic environments, and does not occur in especially acidic waters. FWGNA incidence rank I-5.
> Ecology & Life History
Helisoma trivolvis populations often demonstrate a weedy or pioneering habit in the wild (Eversole 1978). Laboratory populations can mature with as little as three months in culture, laying perhaps 20 - 40 eggs per week thereafter, depending on culture conditions (van der Schalie & Berry 1973). Outcrossing is preferred but self-fertilization is possible (Paraense & Correa 1988).
Jokinen’s (1987) analysis of the distribution of H. trivolvis
in Connecticut and New York led her to classify it as a “C-D tramp,”
potentially present in nearly every community. Dillon’s (2000:
360-363) reanalysis of these data suggested that H. trivolvis populations in Connecticut may be R-adapted, common in rich but unpredictable environments, demonstrating high reproductive effort relative to body size.
The bulbous, planispiral shell of H. trivolvis typically enfolds a large pocket of air, rendering it positively buoyant, and thus it is commonly found among floating vegetation. Helisoma trivolvis seems to have a stronger trophic apparatus than most freshwater snails; able to ingest macrophyte tissue and thriving on lettuce, as well as grazing rather nonspecifically on the periphyton (Smith 1989 a & b, Lombardo & Cooke 2002). Its predators include leeches (Klemm 1975, Dillon 2000:303-304) and crayfish (Alexander & Covich 1991b). It has played the white rat in several studies of community ecology (Boerger 1975, Brown 1982).
Helisoma trivolvis has served as a model organism for neurobiological studies (Bulloch & Ridgway 1989, Cole et al. 2002, Geddis & Rehder 2003), and its hemoglobin has attracted the attention of physiologists (Herskovits & Hamilton 1994). It hosts a variety of trematode parasites (Sapp & Loker 2000, Fried & LaTerra 2002), including the worm that has recently become a pest in commercial catfish ponds (Venable, Gaude & Klerks 2000).
> Taxonomy & Systematics
Phenotypic plasticity in shell morphology can be significant in this species. The 29Nov04 essay below reviews a striking case of gigantism in H. trivolvis, and the essay of 18Feb05 details a population in Mt. Pleasant, SC, where individuals inhabiting the pond vegetation behind an earth dam bear slender shells (0.165 ratio height:diameter) while individuals inhabiting rip-rap rock surfaces below the dam bear stout shells (0.245 height:diameter).
Such phenotypic plasticity has led to a proliferation of synonyms, including: ammon, binnyi, corpulentum, intertextum, pilsbryi, subcrenatum, tenue, and truncatum. Baker (1945) placed trivolvis in the subgenus Pierosoma, which Burch (following Taylor 1966) subsumed under Baker's subgenus Planorbella and promoted to genus rank. But we agree with Hubendick (1955) that the relatively minor attribute of shell coiling apparently the basis for this move does not warrant reacognition of Planorbella at the generic level. See my essay of 11Apr08 from the link below for more.
> Supplementary Resources [PDF]
- Helisoma distribution in Atlantic drainages (2013)
- Helisoma distribution in eastern Tennessee River drainages (2011)
- Virginia species account with county distribution (2011)
- Helisoma trivolvis in a New
River pool, courtesy of Alan Cressler.
- Pretty photo of living H. trivolvis courtesy of Chris Lukhaup.
- See my 29Nov04 post to the FWGNA blog on Gigantic Pulmonates for several additional photos of H. trivolvis.
- My FWGNA post of 18Feb05 on Shell Morphology, Current, and Substrate also featured a Helisoma trivolvis population.
- See my post to the FWGNA blog of 11Apr08 for a review of the Classification of the Planorbidae.
- Or view the (Hubendick 1955) classification of North American planorbids in a tabular format [here].
- See my post of 26Sept14 for good, comparative figures illustrating "The egg masses of freshwater pulmonate snails."
Baker, F. C. (1945)
The Molluscan Family Planorbidae. Urbana: University of Illinois Press.
Baker, H. B. (1946) Index to F. C. Baker's "The Molluscan Family Planorbidae." Nautilus, 59, 127-41.
Boerger, H. (1975) A comparison of the life cycles, reproductive ecologies, and size-weight relationships of Helisoma anceps, H. campanulatum, and H. trivolvis (Gastropoda, Planorbidae). Can. J. Zool. 53: 1812-1824. 1975.
Brown, K.M. (1982) Resource overlap and competition in pond snails: An experimental analysis. Ecology: 63: 412-422.
Burch, J. B. (1989) North American Freshwater Snails. Malacological Publications, Hamburg, MI. 365 pp.
Bulloch, A.G.M. & Ridgway, R.L. (1989) Neuronal plasticity in the adult invertebrate nervous system. J. Neurobiol. 20: 295-311.
Cole, A.G., Mashkournia, A., Parries, S.C. & Goldberg, J.I. (2002) Regulation of early embryonic behavior by nitric oxide in the pond snail Helisoma trivolvis. J. Exp. Biol. 205: 3143-3152.
Dillon, R. T., Jr. (2000) The Ecology of Freshwater Molluscs. Cambridge University Press, Cambridge, England. 509 pp.
Eversole, A. (1978) Life cycles, growth and population bioenergetics of the snail, Helisoma trivolvis (Say). J. Moll. Stud., 44: 209-222.
Fried, B. & LaTerra, R. (2002) In vitro and in vivo encystment of the cercariae of Echinostoma caproni. J. Parasitol. 88: 1124-1129.
Geddis, M.S. & Rehder, V. (2003) Initial stages of neural regeneration in Helisoma trivolvis are dependent upon PLA sub(2) activity. J. Neurobiol. 54: 555-565.
Herskovits, T.T. & Hamilton, M.G. (1994) The molecular weight and subunit organization of Helisoma trivolvis (Say) hemoglobin: Light-scattering and scanning transmission electron microscopic studies. Comp. Biochem. Physiol. 107B: 433-441.
Hubendick, B. (1955) Phylogeny in the Planorbidae. Trans. Zool. Soc. London 28: 453-542.
Jokinen, E. (1987) Structure of freshwater snail communities: Species-area relationships and incidence categories. Amer. Malac. Bull. 5: 9 - 19.
Lombardo, P & Cooke, G. D. (2002) Consumption and preference of selected food types by two freshwater gastropod species. Arch. Hydrobiol. 155: 667-685.
Mancia, M.R. & Fried, B. ( 1995) Chemoattraction and dietary preferences of Helisoma trivolvis (Gastropoda: Planorbidae) for leaf lettuce and Tetramin. Veliger 38: 73-75.
Morris, J.R. & Boag, D.A. (1982) On the dispersion, population structure, and life history of a basommatophoran snail, Helisoma trivolvis, in central Alberta. Can. J. Zool. 60: 2931-2940.
Paraense, W.L. & Correa, L.R. (1988) Self-fertilization in the freshwater snails Helisoma duryi and Helisoma trivolvis. Mem. Inst. Oswaldo Cruz. 83: 405-409.
Rowan, W. (1966) Autumn migration of Helisoma trivolis in Montana. Nautilus 79: 108-109.
Sapp, K.K. & Loker, E.S. (2000) Mechanisms underlying digenean-snail specificity: Role of miracidial attachment and host plasma factors. J. Parasitol. 86: 1012-1019.
Smith, D. (1989a) Tests of feeding selectivity in Helisoma trivolvis (Gastropoda: Pulmonata). Trans. Am. Micros. Soc. 108: 394-402.
Smith, D. (1989b) Radula-tooth biometry in Helisoma trivolis (Gastropoda, Pulmonata): interpopulation variation and the question of adaptive significance. Can. J. Zool. 67: 1960-1965.
Stahl, T. & Lodge, D.M. (1990) Effect of experimentally induced shell damage on mortality, reproduction and growth in Helisoma trivolvis (Say, 1816). Nautilus 104: 92-95.
Taylor, D. W. (1966) Summary of North American Blancan nonmarine mollusks. Malacologia 4: 1 - 172.
van der Schalie, H., & E. Berry (1973) The effects of temperature on growth and reproduction of aquatic snails. Sterkiana, 50: 1-92.
Venable, D.L., Gaude, A.P. III, & Klerks, P.L. (2000) Control of the trematode Bolbophorus confusus in Channel Catfish Ictalurus punctatus ponds using salinity manipulation and polyculture with Black Carp Mylopharyngodon piceus. J. World Aquacult. Soc. 31: 158-166.