Aquatic Ecology

, Volume 38, Issue 1, pp 83–91 | Cite as

Competitive interactions between two successful molluscan invaders of freshwaters: an experimental study

  • Neisha J. Cope
  • Michael J. Winterbourn


The New Zealand mud snail Potamopyrgus antipodarum (Hydrobiidae) and the pulmonate Physella acuta (Physidae) have invaded freshwaters in many parts of the world and become established. They co-exist in many streams, lakes and ponds in New Zealand, often at high densities. In the present study the effects of intraspecific- and interspecific interactions between the two species on growth and reproductive output were examined in laboratory mesocosms. In 30-day experiments, growth of Potamopyrgus antipodarum was lower in high density treatments than controls providing evidence for competition at higher densities of both snail species. No competitive effect was obtained for Physella acuta when controls were compared with high-density treatments, but growth was reduced at high densities of conspecifics. Numbers of juveniles released by Potamopyrgus antipodarum in 40 day trials declined at high snail densities and were lowest at high densities of conspecifics. Egg production by Physella acuta was also reduced at high snail densities. However, when the two species were kept together at equal densities (total snail density twice that of controls), egg production by Physella acuta was significantly higher than in all other treatments, suggesting facilitation by the congenor. Lastly, in a 10-day experiment, Physella acuta grew faster in water conditioned by Potamopyrgus antipodarum than in Physa-conditioned water, whereas Potamopyrgus antipodarum showed no growth response to Physella-conditioned water. Overall, our results indicate that growth and reproductive output of both snail species are influenced more by the density of conspecifics than the presence and density of the other species. The successful co-existence of the two species in New Zealand freshwaters therefore may be a reflection, at least in part, of few competitive interactions between them.

Gastropoda Competitive interactions Growth Reproduction Physella acuta Potamopyrgus antipodarum 


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  1. Baur B. and Baur A. 1990. Experimental evidence for intra-and interspecific competition in two species of rock-dwelling snails. J. Anim. Ecol. 59: 301–315.Google Scholar
  2. Berrie A.D. 1968. Prolonged inhibition of growth in a natural population of the freshwater snail Biomphalaria sudanica tanganyicensis (Smith)in Uganda. Ann. Trop. Med. Parasit 62: 45–51.PubMedGoogle Scholar
  3. Biggs B.J.F. and Malthus T.J. 1982. Macroinvertebrates associated with various aquatic maacrophytes in the backwaters and lakes of the upper Clutha Valley, New Zealand. N.Z. J. Mar. Freshwat. Res. 16: 81–88.Google Scholar
  4. Bowler P.A. 1991. The rapid spread of the freshwater hydrobiid snail Potamopyrgus antipodarum (Gray)in the Middle Snake River, southern Idaho. Proc. Desert Fishes Council 21: 173–182.Google Scholar
  5. Brown K.M. 1982. Resource overlap and competition in pond snails: an experimental analysis. Ecology 63: 412–422.Google Scholar
  6. Cameron R.A. and Carter M.A. 1979. Intra-and interspecific effects of population density on growth and activity in some helicid land snails (Gastropoda: Pulmonata). J. Anim. Ecol. 48: 237–246.Google Scholar
  7. Cherrill A.J. and James A. 1987. Evidence for competition between mudsnails (Hydrobiidae): a field experiment. Hydrobiologia 150: 25–31.Google Scholar
  8. Collier K.J. and Winterbourn M.J. 1986. Processing of willow leaves in two suburban streams in Christchurch, New Zealand. N.Z. J. Mar. Freshwat. Res. 20: 575–582.Google Scholar
  9. Collier K.J., Wilcock R.J. and Meredith A.S. 1998. Influence of substrate type and physico-chemical conditions on macroinvertebrate faunas and biotic indices of some lowland Waikato, New Zealand, streams. N.Z. J. Mar. Freshwat. Res. 32: 1–19.Google Scholar
  10. Cope N.J. 1999. Life histories and ecological interactions of Potamopyrgus antipodarum and Physa acuta in relation to temperature. MSc thesis, University of Canterbury, Christchurch, New Zealand.Google Scholar
  11. Crowl T.A. and Covich A.P. 1990. Predator-induced life history shifts in a freshwater snail. Science 247: 949–951.Google Scholar
  12. Cross W.F. and Benke A.C. 2002. Intra-and interspecific competition among coexisting lotic snails. Oikos 96: 251–264.Google Scholar
  13. Crumpton W.J. 1978. The biology of six South Island ponds. J. Roy. Soc. N.Z. 8: 179–206.Google Scholar
  14. Dan N. and Bailey S.E.R. 1982. Growth, mortality and feeding rates of the snail Helix aspersa at different population densities in the laboratory, and the depression of activity of helicid snails by other individuals or their mucus. J. Moll. Stud. 48: 257–265.Google Scholar
  15. Death R.G. 1991. Environmental stability: its effect on stream benthic communities. PhD thesis, University of Canterbury, Christchurch, New Zealand.Google Scholar
  16. Dillon R.T. 2000. The Ecology of Freshwater Molluscs. Cambridge University Press, Cambridge, UK.Google Scholar
  17. Dillon R.T., Wethington A.R., Rhett J.M. and Smith T.P. 2002. Populations of the European freshwater pulmonate Physa acuta are not reproductively isolated from American Physa heterostropha or Physa integra. Invert. Biol. 121: 226–234.Google Scholar
  18. Edgar G.J., Barrett N.S. and Last P.R. 1999. The distribution of macroinvertebrates and fishes in Tasmanian estuaries. J. Biogeog. 26: 1169–1189.Google Scholar
  19. Fretter V. and Graham A. 1962. British Prosobranch Molluscs: Their Functional Anatomy and Ecology. Ray Society, London, UK.Google Scholar
  20. Gangloff M.M. 1998. The New Zealand mud snail in western North America. Aquatic Species Nuisance Digest 2: 25–30.Google Scholar
  21. Gorbushin A.M. 1996. The enigma of mud snail shell growth: asymmetrical competition or character displacement? Oikos 77: 85–92.Google Scholar
  22. Harding J.S. 1994. Lotic ecoregions of New Zealand. PhD thesis, University of Canterbury, Christchurch, New Zealand.Google Scholar
  23. Hill W.R. 1992. Food limitation and interspecific competition in snail-dominated streams. Can. J. Fish Aquat. Sci. 49: 1257–1267.Google Scholar
  24. Kinzelbach R. 1995. Neozoans in European waters-exemplifying the worldwide process of invasion and species mixing. Experientia 51: 526–538.Google Scholar
  25. Kohler S.L. 1992. Competition and the structure of a benthic stream community. Ecol. Monogr. 62: 165–188.Google Scholar
  26. Levy M.G., Tunis M. and Isserhoff H. 1973. Population control in snails by natural inhibitors. Nature 241: 65–66.PubMedGoogle Scholar
  27. Michaelis F.B. 1977. Biological features of Pupu Springs. N.Z. J. Mar. Freshwat. Res. 11: 357–373.Google Scholar
  28. Mouthon J. 1999. Longitudinal organisation of the mollusc species in a theoretical French river. Hydrobiologia 390: 117–128.Google Scholar
  29. Ponder W.F. 1988. Potamopyrgus antipodarum, a molluscan coloniser of Europe and Australia. J. Moll. Stud. 4: 271–286.Google Scholar
  30. Roth G. 1987. Contribution to the distribution and biology of Potamopyrgus jenkinsi E. A. Smith, 1889, in the Rhine River catchment areas (Prosobranchia: Hydrobiidae). Arch. Hydrobiol. Suppl. 79 (1): 49–68.Google Scholar
  31. Schreiber E.S.G., Glaister A., Quinn G.P. and Lake P.S. 1998. Life history and population dynamics of the exotic snail Potamopyrgus antipodarum (Prosobranchia: Hydrobiidae)in Lake Purrumbete, Victoria, Australia. Mar. Freshwat. Res. 49: 73–78.Google Scholar
  32. Shea K. and Chesson P. 2002. Community ecology theory as a framework for biological invasions. Trends Ecol. Evol. 17: 170–176.Google Scholar
  33. Strayer D.L. 1999. Effects of alien species on freshwater molluscs in North America. J. N. Am. Benthol. Soc. 18: 74–98.Google Scholar
  34. Talbot J.M. and Ward J.C. 1987. Macroinvertebrates associated with aquatic macrophytes in Lake Alexandrina, New Zealand. N.Z. J. Mar. Freshwat. Res. 21: 199–213.Google Scholar
  35. Thomas J.D. 1982. Chemical ecology of the snail hosts of schistosomiasis: snail-snail and snail-plant interactions. Malacologia 22: 81–91.Google Scholar
  36. Thomas J.D. and Aram R.H. 1974. The chemical ecology of Biomphalaria glabrata (Say), the effects of media homotypically conditioned by adult snails on the growth of juveniles. J. Exp. Zool. 190: 329–339.PubMedGoogle Scholar
  37. Underwood A.J. 1997. Experiments in Ecology: Their Logical Design and Interpretation Using Analysis of Variance. Cambridge University Press, Cambridge, UK.Google Scholar
  38. Vitousek P.M., D'Antonio C.M., Loope L.L., Rejmanek M. and Westbrooks R. 1997. Introduced species: a significant component of human-caused global change. N.Z. J. Ecol. 21: 1–16.Google Scholar
  39. Winterbourn M.J. 1970. Population studies on the New Zealand freshwater gastropod Potamopyrgus antipodarum (Gray). Proc. Malacol. Soc. Lond. 39: 139–149.Google Scholar
  40. Winterbourn M.J. 1973. A guide to the freshwater Mollusca of New Zealand. Tuatara 20: 141–159.Google Scholar
  41. Wyoming Game and Fish Commission 1998. Department Regulations, Chapter 10: Regulation for importation, possession, con-finement, transportation, sale and disposition of live wildlife. Scholar
  42. Zaranko D.T., Farara D.G. and Thompson F.G. 1997. Another exotic mollusc in the Laurentian Great Lakes: the New Zealand native Potamopyrgus antipodarum (Gray, 1843)(Gastropoda, Hydrobiidae). Can. J. Fish. Aquat. Sci. 54: 809–814.Google Scholar

Copyright information

© Kluwer Academic Publishers 2004

Authors and Affiliations

  • Neisha J. Cope
    • 1
  • Michael J. Winterbourn
    • 1
  1. 1.School of Biological SciencesUniversity of CanterburyChristchurchNew Zealand

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