Depth distribution of adults and immatures of two Tribolium Castaneum strains in pure and mixed cultures

Abstract

Summary The distribution of adults and immatures of two Tribolium castaneum strains in plexiglas towers was studied both in single‐strain and in mixed cultures. The adults of the + + strain tended to be, on the average, deeper in the flour than the bb adults, in pure and in mixed cultures. Adult distribution was independent of sex. The correlation between adult and egg distribution was usually negative, due to either adult movement in the flour, or to reduced fecundity and increased cannibalism of eggs where adults were numerous, or both. Larvae, and especially pupae, of bb were more abundant in the upper sections, and + + in the lower sections, of towers, both in pure and in mixed cultures and, in particular, at the higher density. In general, the distribution of the strains in the mixed cultures was very similar to the pure cultures, showing a very small effect of the interaction between the two strains, in comparison with GHENT’S results with two species. It seems that the two strains are very much alike in their ability to exploit their environment and therefore their success is the same (when pupal cannibalism is reduced) whether the biological component of the environment is composed of one or two strains.