Competitive ability as a function of sensitivity to the environment I. Competition between Tribolium castaneum and Tribolium confusum in a deteriorating environment

Summary Tribolium castaneum lines selected for high and for low sensitivity to the environment were observed in pure strain culture and in mixed 1∶1 cultures with Tribolium confusm. Since the medium was not refreshed during the experiment, the environment was continuously deteriorating and ultimately both species became extinct. Both time until extinction and total dry weight were used as a measure of competitive ability. All Tribolium castaneum lines showed higher competitive ability than Tribolium confusum. As interference was noted in all the mixed cultures, competition here demonstrates both exploitation and interference. Comparisons between the T. castaneum lines indicates higher competitive ability for lines with shorter developmental time.