Title page for ETD etd-02012006-141735


Type of Document Dissertation
Author Gray, David Richard
URN etd-02012006-141735
Title Gypsy moth egg development : a model of phenological events
Degree PhD
Department Entomology
Advisory Committee
Advisor Name Title
Logan, Jesse A. Committee Member
McManus, M. L. Committee Member
Mullins, Donald E. Committee Member
Ravlin, Forrest W. Committee Member
Stone, Nicholas D. Committee Member
Keywords
  • Gypsy moth eggs
  • Phenology
Date of Defense 1994-01-05
Availability restricted
Abstract
A phenological model of gypsy moth egg development is proposed that distinguishes

three phases of egg development, prediapause, diapause and postdiapause. A technique

of measuring respiration rates of individual eggs was developed and respiration rate was

used as a physiological variable to distinguish the phases. The pattern of respiration rate

provided strong evidence in support of three distinct developmental phases. Respiration

rate developed embryos declined sharply as prediapause was entered and rose sharply

when diapause was completed. When the effect of age on respiration rate was removed,

temperature had a uniform effect on respiration rate throughout the egg stage. A 10°C

decrease in temperature caused an approximate 0.4 fold decrease in respiration rate,

indicating that eggs in diapause are as equally responsive to temperature as egg in a

nondiapause phase.

Developmental rate in prediapause was strongly temperature-dependent, and the

relationship was described by a non-linear function. Prediapause duration was

approximately 13 days at 31°C. The depletion of stored triglycerides was strongly linked

to the completion of prediapause

Developmental rate in postdiapause was found to be temperature- and age dependent.

Developmental response to temperature was relatively weak and linear at the

onset of postdiapause. As postdiapause advanced, the response became stronger and

non-linear. The temperature- and age-dependent developmental response was fully

described by the temperature-dependent developmental response at the onset of

postdiapause, and by a temperature-dependent rate change parameter.

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