TOWARD A MODEL OF GYPSY-MOTH EGG PHENOLOGY - USING RESPIRATION RATES OF INDIVIDUAL EGGS TO DETERMINE TEMPERATURE TIME REQUIREMENTS OF PREDIAPAUSE DEVELOPMENT

In this study, respiration rates of individual gypsy moth eggs were monitored using an infrared gas analyzer as a means of determining transition between ontogenetic states under different temperature conditions. Temperature had a significant effect on respiration rate regardless of the age or ontogenetic condition of the egg. Duration of the prediapause state was temperature-dependent, and the rate of development versus temperature relationship was described by a nonlinear function. Variability of the population in duration of the prediapause state was described by a cumulative Weibull function. Data from previous studies that suggested a diapause process with changing thermal responsiveness are reinterpreted within the context of a three-phase, sequential, phenological process.