A study of population growth of Sitophilus oryzae L. and Sitophilus granarius L. in single and mixed culture in wheat and rice : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Plant Science at Massey University

Biological interactions between organisms which contend for the same resource, have been of interest to ecologists since the days of Darwin. Although this sort of association is evident for many animal-versus-animal and plant-versus-plant situations, one group which has received particular attention is the Class Insecta. Some insect species which attack stored grain and food products are especially convenient experimental animals for the investigation of some aspects of competition. Characteristics which enable insects inhabiting stored grain and grain products to become significant pests, include a short developmental period, resistance to dessication at all stages, a high reproductive rate and extended life span. Of the many insects that have adapted themselves to a diet of dried vegetable material, a few are primary pests of grain in that they are able to bore into the sound kernels. Some major crops such as coconut, coffee and cotton, may be damaged by as many as 500-700 different species of insects but in general, the number of major insect pests of any crop is between 5 and 20. [From Introduction