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EXPERIMENTAL MANIPULATION OF THE PHENOLOGY OF EGG HATCH IN CYCLIC POPULATIONS OF TENT CATERPILLARS

Published online by Cambridge University Press:  31 May 2012

Judith H. Myers
Judith H. Myers
Affiliation:
The Ecology Group, Departments of Zoology and Plant Science, University of British Columbia, Vancouver, British Columbia, Canada V6T 124
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Abstract

Eggs of western tent caterpillars hatch just as leaves of their food plants are developing. To determine the impact of asynchrony between leaf development and egg hatch during a year of peak density and the initiation of decline, egg masses were introduced to four study areas after the time of normal egg hatching. Survival of caterpillars was not significantly influenced by delays of 3–6 weeks in hatching. Populations composed primarily of introduced insects and control populations declined following the summer of the experiment. Although hatching of deployed eggs was delayed, caterpillar development during warmer temperatures later in the spring was sufficiently rapid that caterpillars from all groups reached the fifth instar by mid-June, and parasitization of caterpillars from control and experimental areas was similar. Tent caterpillar survival was apparently resilient to substantial delays in egg hatch which suggests that cyclic population declines are not likely to be associated with minor variation in the synchrony of leaf development and egg hatch.

Résumé

Les oeufs de la Livrée de l’Ouest éclosent au moment où les feuilles de leurs plantes nourricières apparaissent. Pour déterminer l’impact d’un asynchronisme entre le développement des feuilles et l’éclosion des œufs au cours d’une année où la densité est à son zénith, et donc à l’approche du déclin, des masses d’oeufs ont été introduites en quatre points après le moment normal de l’éclosion. La survie des chenilles n’était pas significativement influencée par des retards de 3–6 semaines dans l’éclosion. Les populations composées surtout d’insectes introduits et les populations témoins se sont mises à décliner à la suite de l’été de l’expérience. Bien que l’éclosion des oeufs introduits ait été retardée, le développement des chenilles a été suffisamment rapide au cours des températures plus chaudes plus tard au printemps pour que les chenilles de tous les groupes atteignent le cinquième stade à la mi-juin, assurant un parasitisme aussi important dans les régions expérimentales que dans les régions témoins. La survie des chenilles ne semble pas avoir été affectée par les retards importants dans l’éclosion des oeufs, ce qui indique que les chutes de densité des populations cycliques ne sont probablement pas associées à des variations mineures du synchronisme entre le développement des feuilles et l’éclosion des oeufs.

[Traduit par la rédaction]

Type
Articles
Information
The Canadian Entomologist , Volume 124 , Issue 4 , August 1992 , pp. 737 - 742
Copyright
Copyright © Entomological Society of Canada 1992

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References

Blais, J.R., Prentice, R., Sippell, W.L., and Wallace, D.R.. 1955. Effects of weather on the forest tent caterpillar, Malacosoma disstria Hbn. in central Canada in the spring of 1953. Canadian Entomologist 87: 1–8.CrossRefGoogle Scholar
Campbell, I.M. 1989. Does climate affect host-plant quality? Annual variation in the quality of balsam fir as food for spruce budworm. Oecologia (Berlin) 81: 335–340.CrossRefGoogle ScholarPubMed
Daniel, C.J. 1990. Climate and outbreaks of the forest tent caterpillar in Ontario. Ph.D. thesis, Department of Zoology, University of British Columbia, Vancouver, B.C., Canada. 147 pp.Google Scholar
Feeny, P. 1970. Seasonal changes in-oak leaf tannins and nutrients as a cause of spring feeding by winter moth caterpillars. Ecology 51: 565–581.CrossRefGoogle Scholar
Gould, J.R., Elkinton, J.S., and Wallner, W.E.. 1990. Density-dependent suppression of experimentally created gypsy moth, Lymantria dispar (Lepidoptera: Lymantriidae), populations by natural enemies. Journal of Animal Ecology 59: 213–233.CrossRefGoogle Scholar
Liebhold, A.M., and Elkinton, J.S.. 1989. Elevated parasitism in artificially augmented populations of Lymantria dispar (Lepidoptera: Lymantriidae). Environmental Entomology 18: 986–995.CrossRefGoogle Scholar
Martinat, P.J. 1987. The role of climatic variation and weather in forest insect outbreaks. pp. 241–268 in Barbosa, P., and Schultz, J. (Eds.), Insect Outbreaks. Academic Press, New York, NY. 578 pp.Google Scholar
Myers, J.H. 1981. Interactions between western tent caterpillars and wild rose: A test of some general plant herbivore hypotheses. Journal of Animal Ecology 50: 11–25.CrossRefGoogle Scholar
Myers, J.H. 1988 a. Can a general hypothesis explain population cycles of forest Lepidoptera? Advances in Ecological Research 18: 179–242.CrossRefGoogle Scholar
Myers, J.H. 1988 b. The induced defense hypothesis: Does it apply to the population dynamics of insects? pp. 345–366in Spencer, K.C. (Ed.), Chemical Mediation of Coevolution. Academic Press, New York, NY. 609 pp.CrossRefGoogle Scholar
Myers, J.H. 1990. Population cycles of western tent caterpillars: Experimental introductions and synchrony of fluctuations. Ecology 71: 986–995.CrossRefGoogle Scholar
Myers, J.H., and Williams, K.S.. 1987. Lack of short or long term inducible defenses in the red alder-western tent caterpillar system. Oikos 48: 74–79.CrossRefGoogle Scholar
Wellington, W.G. 1952. Air-mass climatology in Ontario north of Lake Huron and Lake Superior before outbreaks of the spruce budworm, Choristoneura fumiferana (Clem.) and the forest tent caterpillar, Malacosoma disstria Hbn. Canadian Journal of Zoology 35: 293–323.CrossRefGoogle Scholar