Canadian Forest Service Publications

Modeling diapause development: phase multiplicity and simultaneity. 1994. Régnière, J. Pages 10-26 in J.A. Logan, T.M. Odell, and D.R. Gray, editors. Proceedings, diapause and gypsy moth management: status, applications and research workshop, October 2-3, 1991, Blacksburg, Virginia. USDA Forest Service, Radnor, Pennsylvania, General technical report NE 193.

Year: 1994

Available from: Laurentian Forestry Centre

Catalog ID: 16914

Language: English

Series: USDA General Technical Report

CFS Availability: PDF (request by e-mail)

Abstract

A simulation model of diapause development is described, based on the hypothesis that diapause is constituted of three distinct processes, or phases. Only the last two phases are explicitly considered. The model incorporates development rate variability in Phases II and III, photoperiod sensitivity during Phase II, and phase simultaneity. Simulation experiments show that partial phase simultaneity is equivalent to having sequential phases with a shorter Phase III. It is also shown that a high degree of phase simultaneity reduces the ability of the diapause process to prevent development completion under adverse conditions and to synchronize development. A model with two sequential phases generated realistic development completion patterns under natural weather conditions using parameters suited for spruce budworm, although accurate estimates of Phase-II parameters were not available. Sensitivity to photoperiod in the latter part of Phase II further reduced the sensitivity of the model to development-rate parameters. Nevertheless, it is concluded that accurate prediction of development completion, particularly in environments where winter temperatures regularly exceed postdiapause development thresholds, requires precise estimates of development rates during the last two phases of diapause. Such estimates may be obtained best from measurements of metabolic rate during diapause.

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