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Community Stability and the Strategy of Biological Control1

Published online by Cambridge University Press:  31 May 2012

K. E. F. Watt
K. E. F. Watt
Affiliation:
Department of Zoology, University of California, Davis
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Abstract

Community organization is defined as the mean number of trophic links connecting species of different trophic levels in a community. For the special purposes of this paper, competition is assumed to occur whenever two species are known to eat the same food species. Community stability is defined as the reciprocal of the mean, for all species, of the standard error of logarithms of annual collection sizes. It is thus a measure of stability over time of the species populations in a community. Several authors writing about the relationship between community organization and community stability have insisted that the stability of a complex ecological system increases with the number of avenues by which energy can flow through it. This theory does not seem consistent with the observation that some insect pest species of notorious instability are attacked by a great number of entomophagous species. In this paper we seek additional evidence bearing on the relationship between community organization and stability, using computer analysis of data collected by the Canadian Forest Insect Survey on forest Macrolepidoptera and their food plants. After considering our results, and those of other workers, we postulate the following hypothesis. Stability at any herbivore or carnivore trophic level increases with the number of competitor species at that level, decreases with the number of competitor species that feed upon it, and decreases with the proportion of the environment containing useful food. If this hypothesis is valid, too much competition in the entomophagous trophic level will not allow the species in that level to be instable enough to control an unstable pest. Therefore, the best type of biological control agent is one that has no direct competitor species. Also, the most unstable biological control agents, and hence those capable of controlling an unstable pest, will be polyphagous.

Type
Articles
Information
The Canadian Entomologist , Volume 97 , Issue 8 , August 1965 , pp. 887 - 895
Copyright
Copyright © Entomological Society of Canada 1965

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References

Burnett, T. 1960. Control of insect pests. Fed. Proc. 19: 557–561.Google ScholarPubMed
DeBach, P., and Sundby, R. A.. 1963. Competitive displacement between ecological homologues. Hilgardia 34: 105–166.CrossRefGoogle Scholar
Edwards, R. L. 1964. Some ecological factors affecting the grasshopper populations of Western Canada. Canad. Ent. 96: 307–320.CrossRefGoogle Scholar
Elton, C. S. 1958. The ecology of invasions by animals and plants. Methuen and Co. Ltd., London.CrossRefGoogle Scholar
Holling, C. S. 1963. An experimental component analysis of population processes. Mem. ent. Soc. Can. 32: 22–32.CrossRefGoogle Scholar
Holling, C. S. 1964. The analysis of complex population processes. Canad. Ent. 96: 335–347.CrossRefGoogle Scholar
Holling, C. S., Brown, D. M. and Watt, K. E. F.. 1965. Simulation of attack by invertebrate predators. MS.Google Scholar
Liu, C. L. 1958. Monophagy versus polyphagy in the choice of entomophagous insects in biological control. Trans. int. Conf. Insect Pathol. Biol. Control, 1st, Prague, 1958: 521–531.Google Scholar
MacArthur, R. 1955. Fluctuations of animal populations and a measure of community stability. Ecology 36: 533–536.CrossRefGoogle Scholar
Margalef, D. R. 1957. Information theory in ecology. (In Spanish.) Mem. R. Acad. Barcelona 23: 373–449.Google Scholar
(Republished in English in General Systems 3: 36–71, 1958.)Google Scholar
McGugan, B. M. 1958. Forest Lepidoptera of Canada. Vol. I. Publ. 1034, Canada Dept. Agric., Ottawa.Google Scholar
Mesnil, L. P. 1958. Considerations of the use of polyvalent parasites or predators in biological control. Trans. int. Conf. Insect Pathol. Biol. Control, 1st, Prague, 1958: 427–440.Google Scholar
Miller, C. A. 1959. The interaction of the spruce budworm, Choristoneura fumiferana (Clem.), and the parasite Apanteles fumiferanae (Vier.). Canad. Ent. 91: 457–477.CrossRefGoogle Scholar
Miller, C. A. 1960. The interaction of the spruce budworm, Choristoneura fumiferana (Clem.), and the parasite Glypta fumiferanae (Vier.). Canad. Ent. 92: 839–850.CrossRefGoogle Scholar
Morris, R. F. (Editor). 1963. The dynamics of epidemic spruce budworm populations. Mem. ent. Soc. Can. 31: 332 pp.Google Scholar
Prentice, R. M. 1962. Forest Lepidoptera of Canada. Vol. 2. Bull. 128, Canada Dept. Forestry, Ottawa.Google Scholar
Prentice, R. M. 1963. Forest Lepidoptera of Canada. Vol. 3. Publ. 1013, Canada Dept. Forestry, Ottawa.Google Scholar
Solomon, M. E. 1953. Insect population balance and chemical control of pests. Chem. & Ind. (Rev.) 1953: 1143–1147.Google Scholar
Spencer, G. J. 1958. The natural control complex affecting grasshoppers in the dry belt of British Columbia. Proc. 10th int. Congr. Ent., Montreal 5: 497–502.Google Scholar
Turnbull, A. L., and Chant, D. A.. 1961. The practice and theory of biological control of insects in Canada. Canad. J. Zool. 39: 697–753.CrossRefGoogle Scholar
Varley, G. C. 1959. The biological control of agricultural pests. J. R. Soc. Arts 107: 475–490.Google Scholar
Watt, K. E. F. 1964. Comments on fluctuations of animal populations and measures of community stability. Canad. Ent. 96: 1434–1442.CrossRefGoogle Scholar
Zwölfer, H. 1963. The structure of the parasite complexes of some lepidoptera. Z. angew. Ent. 51: 346–357.CrossRefGoogle Scholar