Thesis

Life cycle synchronisation to environmental periodicities : the influence of stage specific development

Downloadable Content

Download PDF
Creator
Rights statement
Awarding institution
  • University of Strathclyde
Date of award
  • 1994
Thesis identifier
  • T8248
Qualification Level
Qualification Name
Department, School or Faculty
Abstract
  • In the natural environment many organisms demonstrate the ability to synchronise their life cycle to periodic environmental variations. Previous studies have shown that life histories consisting of a contiguous series of stages all with density independent development rates exhibiting the same dependence on time cannot synchronise to a periodic environmental variation. The same studies established that both dormancy and quiescence at specific points in the life cycle could produce strong synchronising effects. In this thesis I examine a very general strategic model of a two-stage life-cycle, each stage having a density independent development rate with a characteristic periodic time-dependence. I develop a concise circle map representation between the emergences of successive generations. The two stage circle map which relates these emergences is composed from two simple rotations and an interphase map which represents the relationship between the physiological times for the two life-history stages. I explore synchronisation behaviour of the life cycle model in terms of the qualitative dynamics that correspond to the iterative dynamic behaviour of the associated two stage circle map. I derive a series of analytic results relating the behaviour of systems whose interphase maps are interrelated and give analytic conditions for a broad class of two-stage circle maps to have a fixed point (that is for the systems they describe to reach the critical life-history stage at the same point in each environmental cycle). Finally I report the results of numerical investigations of the relationship between the biological characteristics of the development functions and the fine-scale details of the locking behaviour of the systems they define. I illustrate the practical implications of these findings by examining results obtained when the model is parameterised with data for two diverse organisms, namely a beetle Catops nigricans and a micro-organism phytoplankton.
Advisor / supervisor
  • Gurney, Bill
Resource Type
DOI
Funder

Relations

Items

Thumbnail Title Date Uploaded Visibility Actions
file details PDF of thesis T8248 2025-11-25 Public Download