Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1987. Much has been written about Tribolium spp. (Coleoptera: Tenebrionidae) both as an important pest of stored products and as an experimental animal in biological sciences. Yet there is still no consensus on some important aspects of the ecology of Tribolium in stored products ecosystems. Two of these are dealt with in this thesis. One deals with the ability of Tribolium to feed and breed in undamaged kernels of grains at storage moisture contents. In other words, is T. castaneum a primary or secondary pest of stored grains? The other problem considered in this thesis is whether or not Tribolium performs better or worse in coarser or finer flours from ground kernels. Scientific knowledge in these two aspects of the ecology of Tribolium is important in devising an integrated approach to pest management problems. These two stated problems were studied using corn and wheat as two important cereals of agricultural economies of many countries. The results in this thesis have shown that contrary to the generally held view T. castaneum is able to attack sound, undamaged kernels both in the adult and immature stages. This makes Tribolium both a primary pest and a secondary pest of stored grains. In the absence of damaged kernels Tribolium attacks sound kernels, and in the presence of both damaged and undamaged kernels, Tribolium prefers to infest damaged kernels. The results have also shown that in the range of 0.5 mm and 2 mm grain particle sizes, T. castaneum grows better in coarser flours than in finer flours of corn and wheat in terms of growth and development. U of I Only Restricted to the U of I community idenfinitely during batch ingest of legacy ETDs