Hydrobiologia

, Volume 361, Issue 1–3, pp 135–143

A comparative study of the population biology of the American immigrant triclad Dugesia tigrina (Girard) in two British lakes

  • H. Gee
  • J. R. Pickavance
  • J. O. Young
Article

Abstract

The population biology of the American immigrant triclad Dugesia tigrina was investigated in two British eutrophic lakes: Colemere, England, harbours an asexually reproducing population and Llyn Coron, North Wales, a population that reproduces both sexually and asexually. Monthly samples of triclads were taken from the undersides of stones in both lakes, and from ceramic tiles and plastic trays in Colemere and Llyn Coron, respectively, over two years. In both populations, body size-structure decreased slightly over winter, with an absence of very large and very small animals. Individual growth occurred in spring, and over summer the proportion of large and small individuals declined and increased, respectively. During September to November, size-structure was fairly stable. Increases in the size structure of the populations were associated with higher temperatures and an increased food supply; stability in size structure during the autumnal post-reproductive period, when temperatures were favourable for growth, to the occurrence of intraspecific competition for food; and decreases in size structure to lower temperatures during the winter. In both populations the density of triclads increased in summer to a peak in autumn, thereafter declining to a nadir in spring. The numerical peak in autumn was due to recruitment from reproduction, and the subsequent decline to deaths following the occurrence of intraspecific competition for food in late autumn, some invertebrate predation and winter mortality. Asexual reproduction (fission) started in June and finished during August in both populations. Laboratory experiments indicated that the occurrence and rate of fission is influenced by temperature and the amount of available food. The critical temperature for the initiation and cessation of fission lay between 14 and 16 °C in laboratory studies, and in the field fissioning started as temperatures approached 15 °C. In Llyn Coron, cocoon deposition commenced in June, peaked in July with only a very few produced in August. Triclads collected from the field outside these months could not be induced to lay cocoons in the laboratory. Laboratory experiments showed that cocoons were deposited at temperatures of 17.5, 20, and 25 °C, but not at 12.5 °C. Thus, in the field, cocoon production started when temperatures approached 15 °C in June, but had ceased whilst temperatures were still in excess of 15 °C in late August. Termination of cocoon dsposition is associated with the disappearance of large triclads in excess of 20 mm2, below which animals are not sexually mature; disappearance of large animals was due to fissioning, death after sexual reproduction, and probably shrinkage due to severe intraspecific competition for food. Laboratory experiments indicated that the Colemere population had, potentially, greater fission production than the Llyn Coron population. Despite this, the numerical size of the Colemere and Llyn Coron populations increased seven-fold and eleven-fold, respectively, over the reproductive period. Whether or not this difference in reproductive potential between the populations will continue is speculative; the introduction of D. tigrina to Llyn Coron is relatively recent and the population may still be expanding to reach the carrying capacity of the habitat. Its high reproductive output must have helped its successful invasion of the lake.

Triclad Dugesia tigrina population biology lakes 

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References

  1. Armstrong, J., 1964. The population dynamics ot the planarian Dugesia tigrina. Ecology 45: 361–365.Google Scholar
  2. Beveridge, M., 1982. Taxonomy, environment and reproduction in freshwater triclads (Turbellaria: Tricladida). Int. J. Invert. Reprod. 5: 107–113.Google Scholar
  3. Boddington, M. J. & D. F. Mettrick, 1971. Seasonal changes in the chemical composition and food reserves of the freshwater triclad Dugesia tigrina (Platyhelminthes: Turbellaria). J. Fish. Res. Bd Canada 28: 7–14.Google Scholar
  4. Callahan, J. L. & C. D. Morris, 1988. Production and maintenance of large numbers of Dugesia tigrina (Turbellaria: Tricladida) for the control of mosquitoes in the field. J. am. Mosquito Contr. Ass. 5: 10–14.Google Scholar
  5. Calow, P., 1977. The joint effect of temperature and starvation on the metabolism of triclads. Oikos 29: 87–92.Google Scholar
  6. Calow, P., M. Beveridge & R. Sibly, 1979. Heads and tails: adaptational aspects of asexual reproduction in freshwater triclads. Am. Zool. 19: 715–727.Google Scholar
  7. Cash, K. J., M. H. McKee & F. J. Wrona, 1993. Short-and long-term consequences of grouping and group foraging in the free-living flatworm Dugesia tigrina. J. anim. Ecol. 62: 529–535.Google Scholar
  8. Cash, K. J., F. J. Wrona & G. J. Scrimgeour, 1995. The effects of group size on per capita ingestion in flatworms. Freshwat. Biol. 34: 477–483.Google Scholar
  9. Chandler, C. M., 1966. Environmental factors affecting the local distributuion and abundance of four species of stream-dwelling triclads. Invest. Indiana Lakes & Streams: 1–56.Google Scholar
  10. Chandler, C. M. & J. T. Darlington, 1986. Further field studies on freshwater planarians of Tennessee (Turbellaria: Tricladida): Western Tennessee. J. Freshwat. Ecol. 3: 493–501.Google Scholar
  11. Chandler, C. M. & J. T. Darlington, 1991. A survey of the epigean planarians (Turbellaria: Tricladida: Paludicola) of Alabama. J. Freshwat. Ecol. 6: 155–160.Google Scholar
  12. Dahm, A.G., 1955. Dugesia tigrina (Girard) an American immigrant into European waters. Verh. int Ver. Limnol. 12: 554–561.Google Scholar
  13. Davies, R. W., 1969. Predation as a factor in the ecology of triclads in a small weedy pond. J. anim. Ecol. 38: 577–584.Google Scholar
  14. Davies, R.W. & T. B. Reynoldson, 1971. The incidence and intensity of predation on lake-dwelling triclads in the field. J. anim. Ecol. 40: 191–214.Google Scholar
  15. Davison, J., 1973. Population growth in Planaria Dugesia tigrina (Girard). Regulation by the absolute number in the population. J. Gen. Physiol. 61: 767–785.PubMedGoogle Scholar
  16. Den Hartog, C., 1959. Dugesia tigrina an immigrant triclad in the Netherlands. Biol. Jrb. Dodonaea 27: 68–72.Google Scholar
  17. Duigan, C. A., T. E. H. Allott, H. Bennion, J. Lancaster, D. T. Monteith, S. T. Patrick, J. Ratcliffe & J.M. Seda, 1996. The Anglesey Lakes, Wales, UK - A conservation resource. Aq. Cons.: Mar. Freshwat. Ecosystems 6: 31–55.Google Scholar
  18. Folsom, T. C. & H. F. Clifford, 1978. The population biology of Dugesia tigrina (Platyhelminthes: Turbellaria) in a thermally enriched Alberta, Canada Lake. Ecology 59: 966–975.Google Scholar
  19. Gee, H., 1990. The biology of the immigrant triclad Dugesia tigrina (Girard): a comparative study with native species. Unpubl. Ph.D. Thesis, University of Liverpool.Google Scholar
  20. Gee, H. & J. O. Young, 11993. The food niches of the invasive Dugesia tigrina (Girard) and indigenous Polycelis tenuis and P.nigra (Muller) (Turbellaria; Tricladida) in a Welsh lake. Hydrobiologia 254: 99–106.Google Scholar
  21. Gourbault, N., 1969. Expansion de Dugesia tigrina (Girard) planaire Americaine introduite en Europe. Ann. Limnol. 5: 3–7.Google Scholar
  22. Hyman, L. H., 1951. North American Triclad Turbellaria XII. Synopsis of the known species of freshwater planaria of North America. Trans. am. Microsc. Soc. 70: 154–167.Google Scholar
  23. Jenkins, M. M. & S. E. Miller, 1962. A study of the planaria (Dugesia) of an Oklahoma stream. Proc. Okl. Acad. Sci. 42: 133–142.Google Scholar
  24. Kenk, R., 1937. Sexual and asexual reproduction in Euplanaria tigrina (Girard). Biol. Bull. Woods Hole 73: 280–294.Google Scholar
  25. Kenk, R., 1941. Induction of sexuality in the asexual form of Dugesia tigrina (Girard). J. exp. Zool. 87: 55–69.Google Scholar
  26. Kenk, R., 1944. The freshwater triclads of Michigan. Misc. Publ. Mus. Zool. Univ. Michigan 60: 1–44.Google Scholar
  27. Mettrick, D. F., M. J. Boddington & S. R. Gelder, 1970. Distribution of freshwater triclads (Platyhellminthes: Turbellaria) in Central-Southern Ontario. Proc. 13th. Conf. Great Lakes Res. 1970: 71–81. Int. Ass. Great Lakes Res.Google Scholar
  28. Martin, A. J., R. M. H. Sleaby & J. O. Young, 1994. Food limitation in lake-dwelling leeches: field experiments. J. anim. Ecol. 63: 93–100.Google Scholar
  29. Milne, A., 1957. Theories of natural control of insect populations. Cold Spr. Harb. Symp. Quant. Biol. 22: 253–271.Google Scholar
  30. Pickavance, J. R., 1968. The ecology of Dugesia tigrina (Girard) - an American immigrant planarian. Unpubl. Ph. D. Thesis, Univ. Liverpool.Google Scholar
  31. Pickavance, J. R., 1971a. The diet of the immigrant planarian Dugesis tigrina (Girard). I. Feeding in the laboratory. J. anim. Ecol. 40: 623–635.Google Scholar
  32. Pickavance, J. R., 1971b. The diet of the immigrant planarian Dugesia tigrina (Girard). II. Food in the wild and comparison with some British species. J. anim. Ecol. 40: 637–650.Google Scholar
  33. Reynolds, C. S., 1979. The limnology of the eutrophic meres of the Shropshire-Cheshire plain. Field Studies 5: 93–173.Google Scholar
  34. Reynoldson, T. B., 1956. The occurrence in Britain of the American triclad Dugesia tigrina (Girard) and the status of D.gonocephala (Duges). Ann. Mag. Nat. Hist. 572: 102–105.Google Scholar
  35. Reynoldson, T. B., 1960. A quantitative study of the population biology of Polycelis tenuis (Ijima) (Turbellaria, Tricladida). Oikos 11: 125–141.Google Scholar
  36. Reynoldson, T. B., 1961. Environment and reproduction in freshwater triclads, Nature 189: 329–330.Google Scholar
  37. Reynoldson, T. B., 1966. The distribution and abundance of lake-dwelling triclads - towards a hypothesis. Adv. Ecol. Res. 3: 1–71.Google Scholar
  38. Reynoldson, T. B., 1977. The population dynamics of Dugesia polychroa (Schmidt) (Turbellaria Tricladida) in a recently constructed Anglesey pond. J. anim. Ecol. 46: 63–77.Google Scholar
  39. Reynoldson, T. B., 1983. The population biology of Turbellaria with special reference to the freshwater triclads of the British Isles. Adv. Ecol. Res. 13: 235–326.Google Scholar
  40. Reynoldson, T. B., 1985. Takeover of an Anglesey lake by an American species of triclad - the potential threat to the native triclad fauna. Bull. Brit. Ecol. Soc. 16: 80–86.Google Scholar
  41. Reynoldson. T. B. & J. O. Young, 1965. Food supply as a factor regulating population size in freshwater tricalds. Mitt. int. Ver. Limnol 13: 3–20.Google Scholar
  42. Ribas, M., M. Riutort & J. Baguna, 1989. Morphological and biochemical variation in populations of Dugesia (G.) tigrina (Turbellaria, Tricladida, Paludicola) from the western Mediterranean: biogeographical and taxonomical implications. J. Zool. Lond. 218: 609–626.Google Scholar
  43. Root, R. B., 1960. An estimate of the intrinsic rate of natural increase in the planarian, Dugesia tigrina. Ecology 41: 369–372.Google Scholar
  44. Russier-Delolme, R., 1372. Coefficients thermiques et ecologie de quelques planaires d'eau douce. Ann. Limnol. 8: 119–140.Google Scholar
  45. Seaby R M. H., A. J. Martin & J. O. Young, 1996. Food partitioning by lake-dwelling triclads and glossiphoniid leeches: field and laboratory experiments. Oecologia 106: 544–550.Google Scholar
  46. Stokely, P. S., T. S. Brown, F. Kuchan & T. J. Slaga, 1965. The distribution of freshwater triclad planarians in Jefferson County, Ohio. Ohio J. Sci. 65: 305–318.Google Scholar
  47. Thorp, J. H. & A. P. Covich (eds), 1991. Ecology and classification of North American freshwater invertebrates. Academic Press, San Diego.Google Scholar
  48. Van Der Velde, G., 1975, The immigrant triclad flatworm Dugesia tigrina (Girard) (Platyhelminthesi, Turbellaria). Range-extension and ecological position in the Netherlands. Hydrobiol. Bull. (Amsterdam) 9: 121–130.Google Scholar
  49. Vowinckel, C. & J. R. Marsden, 1971a. Reproduction of Dugesia tigrina under short-day and long-day conditions at different temperatures. I. Sexually derived individuals. J. Embryol. exp. Morph. 26: 587–598.PubMedGoogle Scholar
  50. Vowinckel, C & J. R. Marsden, 1971b. Reproduction of Dugesia tigrina under short-day and long-day conditions at different temperatures. II. Asexually derived individuals. J. Embryol. exp. Morph. 26: 599–609.PubMedGoogle Scholar
  51. Wright, J. F., 1987. Colonization of rivers and canals in Great Britain by Dugesia tigrina (Girard) (Platyhelminthes: Tricladida). Freshwat. Biol. 17: 69–78.Google Scholar
  52. Young, J. O. & T. B. Reynoldson, 1966. A quantitative study of the population biology of Dendrocoelum lacteum (Muller) (Turbellaria, Tricladida). Oikos 15: 237–264.Google Scholar

Copyright information

© Kluwer Academic Publishers 1997

Authors and Affiliations

  • H. Gee
    • 1
  • J. R. Pickavance
    • 2
  • J. O. Young
    • 1
  1. 1.School of Biological SciencesUniversity of LiverpoolLiverpoolEngland
  2. 2.Department of BiologyMemorial University of NewfoundlandSt John'sCanada

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