The effect of larval age range on survival of twoTribolium castaneum strains in mixed cultures, through pupal cannibalism

Summary The effect of larval age range on survival of twoTribolium castaneum strains in mixed cultures was studied in an experimental situation in which other selective forces were reduced to a minimum. Increasing the difference in larval age setween the strains by one day resulted in a reduction of survival of the faster-developing mutant strain, because more of its earlier pupae were cannibalized by the larvae. General aspects of the effects of pupal cannibalism by larvae on the outcome of intra-specific competition (sensu lato) inTribolium are discussed.