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The dynamics of outbreaks: Further simulation experiments with the western tent caterpillar

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Researches on Population Ecology

Summary

A stochastic model of western tent-caterpillar populations on southern Vancouver Island was used to assess conditions leading to outbreaks. Three qualitatively different populations-declining, minimal, and recovering-were exposed to six-year climatic sequences incorporating various combinations of good, bad, and mediocre spring weather. Starting populations were either distributed randomly or concentrated in and around small-, medium-, or large refuges.

The results showed that virtually any type of population could temporarily increase in numbers during two highly favorable springs. Only a very few vigorous populations, however, could sustain the momentum required to surge to outbreak proportions. No low-quality population could do so. And even vigorous populations could not achieve outbreak status unless they were initially concentrated in a sufficiently large refuge that was close enough to potentially suitable habitats to permit rapid immigration into such places as soon as their local climates improved.

The concept of “climatic release” of insect populations is discussed in the light of these findings. The results demonstrate that climatic release is inextricably linked with a population's qualitative profile and spatial distribution.

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References

  • Allee, W.C., A.E. Emerson, O. Park, T. Park andK.P. Schmidt. (1949)Principles of Animal Ecology, W. B. Saunders, Philadelphia.

    Google Scholar 

  • Berryman, A.A. (1978) Towards a theory of insect epidemiology.Res. Popul. Ecol.19: 181–196.

    Google Scholar 

  • Boer, P. J. Den. (1968) Spreading of risk and stabilization of animal numbers.Acta. biotheor.18: 165–194.

    Article  Google Scholar 

  • Clark, L.R. (1964) The population dynamics ofCardiaspina albitextura (Psyllidae).Aust. J. Zool.12: 362–380.

    Article  Google Scholar 

  • Graham, S.A. (1939) Forest insect populations.Ecol. Monog.9: 301–310.

    Article  Google Scholar 

  • Greenbank, D.O. (1956) The role of climate and dispersal in the initiation of outbreaks of the spruce budworm in New Brunswick. I. The role of climate.Can. J. Zool.34: 453–476.

    Article  Google Scholar 

  • Holling, C.S. (1973) Resilience and stability of ecological systems.Ann. Rev. Ecol. Syst.4: 1–23.

    Article  Google Scholar 

  • Itô, Y. (1961) Factors that affect the fluctuations of animal numbers, with special reference to insect outbreaks.Bull. Nat. Inst. Agr. Ser. C.13: 57–89.

    Google Scholar 

  • Ludwig, D., D.D. Jones andC.S. Holling. (1978) Qualitative analysis of insect outbreak systems. The spruce budworm and forest.J. Anim. Ecol.47: 315–332.

    Article  Google Scholar 

  • May, R.M. (1977) Thresholds and breakpoints in ecosystems with a multiplicity of stable states.Nature (London)269: 471–477.

    Article  Google Scholar 

  • May, R.M., G.R. Conway, M.P. Hassell andT.R.E. Southwood. (1974) Time delays, density-dependence and single-species oscillations.J. Anim. Ecol.43: 747–770.

    Article  Google Scholar 

  • Maynard-Smith, J. (1974)Models in ecology. Cambridge University Press, Cambridge.

    Google Scholar 

  • Neilson, M.M. andR.F. Morris. (1964) The regulation of European spruce sawfly numbers in the Maritime Provinces of Canada from 1937 to 1963.Can. Ent.96: 773–784.

    Google Scholar 

  • Readshaw, J.L. (1965) A theory of phasmatid outbreak release.Aust. J. Zool.13: 475–490.

    Article  Google Scholar 

  • Ricker, W.E. (1954) Stock and recruitment.J. Fish. Res. Bd. Can.11: 559–623.

    Google Scholar 

  • Rogers, C.E., R.D. Eikenborg andK.J. Starks. (1972) A review of greenbug outbreaks and climatological deviations in Oklahoma.Env. Ent.1: 664–668.

    Google Scholar 

  • Southwood, T.R.E. (1975) The dynamics of insect populations, inInsects, Science andSociety (ed. D. Pimentel). Academic Press, New York, 151–200.

    Google Scholar 

  • Southwood, T.R.E. andH.N. Comins. (1976) A synoptic population model.J. Anim. Ecol.45: 949–965.

    Article  Google Scholar 

  • Takahashi, F. (1964) Reproduction curve with two equilibrium points: a consideration of the fluctuation of insect population.Res. Popul. Ecol.6: 28–36.

    Google Scholar 

  • Thompson, W.A., P.J. Cameron, W.G. Wellington andI.B. Vertinsky. (1976) Degrees of heterogeneity and the survival of an insect population.Res. Popul. Ecol.18: 1–13.

    Google Scholar 

  • Thompson, W.A., W.G. Wellington, I.B. Vertinsky andE.M. Matsumura. (1977) Harvesting strategies, control styles and information levels: a study of planned disturbances to a population.Res. Popul. Ecol.18: 160–176.

    Google Scholar 

  • Uvarov, B.P. (1931) Insects and climate.Trans. Ent. Soc. London.79: 1–247.

    Google Scholar 

  • Voûte, A.D. (1946) Regulation of the density of the insect populations in virgin-forests and cultivated woods.Arch. Néer. Zool.7: 435–470.

    Article  Google Scholar 

  • Wellington, W.G. (1954a) Weather and climate in forest entomology.Meteorol. Monog.2: 11–18.

    Google Scholar 

  • Wellington, W.G. (1954b) Atmospheric circulation processes and insect ecology.Can. Ent.86: 114–127.

    Google Scholar 

  • Wellington, W.G. (1962) Population quality and the maintenance of nuclear polyhedrosis between outbreaks ofMalacosoma pluviale (Dyar).J. Ins. Pathol.4: 285–305.

    Google Scholar 

  • Wellington, W.G. (1964) Qualitative changes in populations in unstable environments.Can. Ent.96: 436–451.

    Google Scholar 

  • Wellington, W.G. (1965a) The use of cloud patterns to outline areas with different climates during population studies.Can. Ent.97: 617–631.

    Article  Google Scholar 

  • Wellington, W.G. (1965b) Some maternal influences on progeny quality in the western tent caterpillar,Malacosoma pluviale (Dyar).Can. Ent.97: 1–14.

    Google Scholar 

  • Wellington, W.G. (1977) Returning the insect to insect ecology: some consequences for pest management.Environ. Entomol.6: 1–8.

    Google Scholar 

  • Wellington, W.G., J.J. Fettes, K.B. Turner andR.M. Belyea (1950) Physical and biological indicators of the development of outbreaks of the spruce budworm,Choristoneura fumiferana (Clem.) (Lepidoptera: Tortricidae),Can. J. Res. (D),28: 308–331.

    Google Scholar 

  • Wellington, W.G., P.J. Cameron, W.A. Thompson, I.B. Vertinsky andA.S. Landsberg (1975) A stochastic model for assessing the effects of external and internal heterogeneity on an insect population.Res. Popul. Ecol.17: 1–28.

    Article  Google Scholar 

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Thompson, W.A., Vertinsky, I.B. & Wellington, W.G. The dynamics of outbreaks: Further simulation experiments with the western tent caterpillar. Res Popul Ecol 20, 188–200 (1979). https://doi.org/10.1007/BF02512624

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