Comparative performance of Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae) across populations, resource types and structural forms of those resources

The significance of Tribolium castaneum (Herbst) as a pest of stored grains will likely be influenced by the relative availability of different resources regionally and the beetles' ability to utilize each of them. Therefore the performance across the life cycle of laboratory and field populations of T castaneum on commonly available structural forms of wheat and sorghum, as conventional resources, was quantified and compared to that on cotton seed. The latter is not usually associated with T. castaneum, but large beetle infestations have been recorded commonly in cotton gins in Australia. The highest number of individuals of each stage (from a given number of eggs) developed on wheat and sorghum flour and kibbled seeds. Cotton seed did not support the development of laboratory population beetles and all neonate larvae died before pupation. In contrast, some of the field population larvae did develop on cotton flour, but their number was significantly lower in comparison to development on wheat and sorghum. Field population beetles produced significantly more eggs than did laboratory population beetles, on both the whole seed and flour. Field population females had a consistently higher fecundity (similar to 78% more eggs) than the laboratory population females, at least over the first three weeks of adult life. These results suggest that field populations of T. castaneum should be used in experiments if we are to develop a more realistic understanding of the field ecology of this species. The relative rate at which these insects infest available resources in the field also warrants further investigation. (C) 2011 Elsevier Ltd. All rights reserved.