Abstract:
Two major objectives were accomplished.
1. A summary of the work done during 1970-71 on a single species intra-specific competition model was written. 2. A multispecies predator-prey model, incorporating the competition mechanism of the single-species model, was developed almost to completion. The single species model is a computer program that describes the dynamics of a population of insects when food shortages form the only restraint upon population growth. This model deals with energy flow from food through the population's age classes, and simulated
reproduction, development, and starvation, as influenced by these flows. Population fluctuations, average densities, and other properties generated by this model correspond closely with results observed in some of the experimental situations and show the need for revision of some model mechanisms in others. The multispecies model currently simulated the Douglas-fir beetle's relation with two predators, the hairy woodpecker and a
clerid beetle. This model incorporates the intraspecific competition mechanism mentioned above, a closely analogous interspecific competition mechanism, and the predation mechanisms. Its terminology and data
requirements permit any food chain of any number of predaceous species
to be investigated. Its design permits an investigator to study various hypotheses regarding the extent to which species omitted from the modeled food chain influence the population changes of the species included in the simulation. The predator/prey model is now complete, but contains mechanical
difficulties that have prevented its successful operation thus far. Robert
Rydell, in conjunction with Scott Overton, Mary Ann Strand, and I, will attempt to remove these difficulties in the fall of 1971.
