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UBC Theses and Dissertations

An experimental component analysis of sexual reproduction : I. The egg production and egg fertilization processes, with some consideration of the mating process, for Drosophila melanogaster Meigen Gossard, Thomas W.


Experimental components analysis (Holling 1966) is used to develop a computer model of the four processes of sexual reproduction: mating, egg production, egg fertilization, and oviposition site selection. A general function of interacting populations is developed, and its application to mating and oviposition site selection is discussed. Data from the literature on mating are used to estimate parameter values for this function. A model of egg production and egg fertilization is developed from an experimental study of the vg strain of Drosophila melanogaster. Egg production is a complex process consisting of four components affecting individual ovarioles: ovariole activation, ovariole production, vitellegenesis, and ovariole deactivation. Threshold effects are found to exist for all four components. Egg fertilization is a simple process involving number of sperm stored and a constant probability of successful fertilization. However, results indicate that both egg fertilization and egg production become more complex beyond the range of treatments used here. Assumptions, not supported by data, are made for the processes of oviposition site selection, aging, mortality, and development. These assumptions are combined with the models of mating, egg production, and egg fertilization into a single tentative model for sexual reproduction. Simulations using this model suggest possible effects of ecological importance: a sigmoid relationship between reproductive rate and density; and a chance in tactics with increasing mortality due to predation.

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